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National Library Bibliotheque nationale
of Canada du Canada
W
"■" ' w"n^m mitf)iiii^tf0immmm mmw i miin ~
LESSONS
\'\\
IN
ELEMENTARY CHEMISTRY:
INORGANIC AND ORGANIC.
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BY
HENRA R ROSCOE, B.A. F.R.s. I
'"«»*0J8 o
majssTRit.
HON.
1
■'*«
MAC .
■ ^AKf:. AND CO.
fllwS.M J Jl. 1^ ' III "
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I- E S S O N .'
IN
ELEMENTARY CHEMISTRyT
«
imJiGAmc AND ORGAmc.
BY
HENRY E. ROSCOE, B.A. F.R.S.
WEN8 cUlboE, MANCBESTKIt.
^MorEscoii Of CHEMiarnr i^ owe.,, n6.
NEW EDITION.
COPP, CLARK, AND CO.
MACMILLAN AND CO.
* 1872.
M//
ri^^his
reserved,]
l g1 « WWn i M i»i i nii i i 1 . 1 ii . „
GiTD33
'
PREFACE.
IN the folWing pages I have endeavoured to a„a„ge
rne most important facts pn.l r^.• - i "<inge
Chemistry i„ a plain Z ^LZ' °''"^'"'
suited to the present '"""'"'^ ''°™'
struction. "^ -^--ements of elementary i„
the introduction of phS^ ^ r^"'' '^■*°« '^''-h
system is worse than use f I h " T. "' "'°°'
Exercises and Questionrt L^^i: f ^^^ "f
-t .earn to .or. out aLate./joTl I LS
-sirttr Lt? trv" '-'- - - '
-t^ shouid :ten^rIr:::tio:Tt
relations between the wcieht.: of „,„ .> ■
measured under varvrnf; ' """^ *''■■ ^"'""^^
and pressure ^ ' -"-"stances of temperature
cen'tLdlt '''''" °' "^'^''^ '''"* —- -d the
-.grade thermometric scale are used throughout the
VI
PREFACE. " '
^ases than is g,ven on d ,r o
Appendix, page 472 m. k Paragraph in the
^ P ge 472, may be consulted.
■^ iiave much pleasure in t^^nt-
'— , for the aid White r "''""'' ''^- ''='^'°^- '
'■" ^vising the proofs • and r . ''""" ^'' ""P^^'^''^
--andatLonColtr'^r-"""-
the chromolithographic fron,- """' ""^ °" •
-d Mr. Co„4 '"'"^^ ''^ ^'- J- D- Cooper
Manchester, %-^ ,a^ „ t.
Y' J'^'*- 1869. H. E. R,
Jn the present Edifm« t u
--3a„aMo.cC:;::;;';''^^--p''-„
°n Isomerism, &c I . f "'"^""°" "^ '"e Elements,
:---o.rie3":r;:ri;nr^--
amongst others that of Hvd '^ ^"«^'
°; '''e Primar, Phospha J^r:": 'j ""''''-' *«
0^ 'Oe artifieia, pro.uct,on of L / " t?' '^"'^ ''■^'
-angement of .,, ,„„, ^^ ^'^^ 'y ^^^^e. The
unchanged. ' '"'"'^ver, remained
H. E. R.
TABLE OF CONTENTS.
LESSON
I. Introduction . , *^°^
II. NON-METALLIC ElJEMENT^ '
III. Physical Properties of Gases, Ther- "
IV ^^''^^^^s, Diffusion of Gases, etc 2.
IV. Chemical Compounds of Oxygen 7^1 ^
Hydrogen-Composition and Pro-
perties OF Water
V. Nitrogen and the Atmospher; .* .' * ^
VI. Compounds of Nitrogen with Oxygen. ^^
Acid'''^^'' Atomic Theory-Nitric
VII. Nitrous ' Oxide-Nitric' OxiBE-ku\ ^^
MONIA ... «■ -n^M
Vni. Carbon— Carbon Dioxide f^
Chlorine-Hydrochloric Acid-Bleach- ^
ING Powder
XI. Bromine-Iodine-Flu^rine '. '. ' ' '°l
XII. Sulphur-Sulphur Dioxide . . "l
XIII. Sulphur Trioxide-Sulphuric Acid ' 'J
XV ^^''"'"^^^^^'""""-^"-'con-Boro; III
XV. Phosphorus and its Compounds . ^
XVI. Arsenic-AtomsandMolecules-QuanI ^*
XVri tJZ'"''^'"'^ "" ™^ Elements . . ,5,
XVII. The Metallic Elements-Introduction ^
—Specific and Atomic Heat— Con-
YVTTT ■ -n ^"TUTioN OP Salts . . „,
XX m"' ^'^"'"^'•^^ 0^ Crvstallographv" ■ 0^^
XIX. METALS^or THE ALKALIES AND tLir "
- - ^yf
viii
LBSSON
XX.
CONTENTS.
XXI.
XXIV.
XXV.
XXVI.
XXVII.
XXIX.
XXX.
XXXI.
XXXII.
XXXIII.
XXXIV.
XXXV.
XXXVI.
XXXVII.
xxxviii.
XXX rx.
XL.
XLI.
Metals of thp a.
MZUM-Ma,,,^^^-^'"H - ZINC - a„.
Tungsten **oi-i«UiiNu»._
Organic ChemistrvIt' • • • • • .
The rr C°«-o""os ^"'""°^'"°^- OK
o-°-mc AMMON™!" ^'^^'-^ • • . :
^ROUP OF Fattv Aciw ■■••••
The Gkoup.op Ai>^ ' * * • • .
TURPENTINES-vloFTf "^ ^°«'OfNW '
AtBUMiNous si::::;^,*^3^ ^;"*^°'"^ •
Tables AND EXERCISF3 ' • • • •
Index Weights op Gases
* • . - • • .
217
228
264
280
289
299
310
321
335
344
373
400
405
425
433
444
472
473
INTRODUCTION.
LESSON I.
produce a t^i^f Xt^ce^U ZraC^^^^^^^^^
original ones in DroDertifQ . /^^ ,„? <iitogetner from the
brought under sucTffiions" rtVZ f ''"'^'^^ '^
bodies differing from the nri<rin!i !! • ""^ '"'° o"' ™ore
if powdered sulpto^anrfin! copper S?^s''h"''=;, '^^"^'
together, the colour of the sulpK will L rl' "}""!'•
copper will disappear, and to the "naideTevt th/' -^ "'^
presents a. uniform greenish tin Lv thThl^^ V""k'^
microscope, however the nartjXJV^ "^'P °^ the
lying by Ui4 s°dl of ae pffiefnf 1 'iT"" '"^>' ''^ ''^«"
wasfi away the liehter s,1[nh.,t "^.-^^'P^ur ; and we can
heavier col^per Sd. 'X^^l Tc^Zfrl/lT^ ^
occurred: the snlnhnr o«^ ^J^ cneMtcnl action has
^/^.rf. f we next een?lt hSi^"" '"^''^ °"Iy "^^^/^^-'V^//,
see that it Toon wf^" to TL^Zl °^ *^ •"!«"^« *«
•mass we notice that both th/ir* ^"<1 j^l «amining the
disappeared as such th J ^1^ ^^^ ''" - ^ulphurW
even by the most nnUnfi ^^ ''^""°' ''« distinguished
place we havrfortSTa blaTsub';?^' ^""^ *" '" '^^'
perties entirely different frn™»t, '^""^^ possessing pro-
copper or by [he suTnhur ilere^ Possessed either gy'the
occurred j the coDoe? «n;i ^^ ^-ckemtcal cimnge has
combined chtmk^ftJ ,Tt^^ ^'^^^^'''' ^"^ ^'^ to have
these two sub^Mces IL he ^ fO'^Pp">^'i out of which
tities used In like manneV^^K'""'^ '" "'"^"'y «"* quan-
air a chemica" chL^ "flr^'l^'if <^^"A'« •?"™s m th«
°- - a '"s v/ii ; iina, although the
}
' ^^^^^^TAHy ciIEAflSTJiy. [LESSON
we burn a candle for a f», , !? ^ °'"'^'' means. Thus if
-ith air, and atrt'rSs pou^iro' " t '^'^^" bottle fi fed
shall notice that the liquM whirr^ dear lime-water, we
?'r, becomes at once mn)^ .h^^- '^^'"?'"^ «^lear in ,^ure
mvisjble gaseous body produced h^ l^^ P''^^*"'^^ of a,t
candle, which possesses brnn»..- ^^J''^ burning of the
P"re air. Althougran S^lL^' f'^^^^f fr°m those of
«'hen a candle burns, it ^s'^^'asv n'' >f^ '"?"^^ °=<«rs
? ,fvni • ''''°"' ''y a simple
I experiment not only that
'^l '^ "°t the case, but
that, on the contrar^r, an
iccurrf^ l.*?ight^'has
occurred ; this mcrease is
occasioned by the consti-
tuent parts of the tallow or
cal y w,th an mvisible gas
(called oxygen) present in
•he air. For this purpose
Fir?M'itT4'"^(^'
lo inches long, is closed
at each end with a cork •
through the upper cork a
bent glass tube passes
one several holes are bored and^m^'o'^''°rS? *« 'o^e^
taper is fastened. A benUube fB F?.' ?>%'^t ^i"^'^ * ""^"
of caustic soda, is attach^ I, ' ' ?• ')' '■"^d with pieces
;•. the figure, and thfapp^rafclPf r'"*^ T"' ^^^"
the end of one arm of a oaTr „f tl. ^™"ged is hung at
poised by weights placS in th.?' ^°<^ ^\«tly counter- -
The end of the tube (c) is Sow a,?,."^"^' u''^ "therarm.
P-e of vulcanised cio^tcU„TtSS':r„'"o^- fat
Fig. t.
1.]
INTRODUCTION,
"H:
3
as the water flow^ out of openinftL:^Ln ''" """ °"^ '
m to supply its Dlace thro,.^K 1 ^^^s tap, air must pass
removed, the taper IhfhtedandX.^ri;'^''"'"'' '* "^«n
replaced ; after'^the candle has burn, T"^}^^" <l"'<:kly
minutes, the vulcanised tub.Wi./- •'"'^^ ""^ f<""-
glass tube allowed tThangfreei ll'u ?r'"^'^' """"^ "^«
weight of the apparatus if Sr ,V, \^" '^^^ "^^' *e
candle was burnt, the pieces of ^f ■" ,'• ^^^^'^^^'-^ "'e
absorbed the subsknces Carbonic ac d ?nH ""^^ ^^^''"S
duced by the combination nf ,^„ ■ ^"° '"''"e'') Pro-
chf^ic^r acT/;\tTart:rsad"t'''^, ''""-^ -- °f
/<>« of matter never takes n.^/^l"" '' P™''^^ "^^^ «
^/'-«^A»/^,andthannchemL?tK'.'^" T""' " '«*-
on in the burning of the i^nHi v"^' ="=•> "^ '^at going
an annihilation oVma«eroccirs^'-n"^t °\t'^'^ ?"^ "«^
great principle in chemic^ srT^n J u' "^"^ "^ *'« fi^^*
demonstrated by findinTthat thi w -^ J'^' >t™ gradually
acting chemically upo! one ann^l'^*"',"^ ""= ''"''stances
same after as before ?he rh?n,f ^"'^ ^'"'^>'^ "■«•»«'" the
For determinin™ accuraS^h?''"^t'T^ °'='="^'-'^d.
an instrument called the ?i^^,w w^*" "/substances,
Fig. 2 represents one form rfSemir^fT? " ^"^P'oyed-
sists of a perforated bras^ ^am U if k^''"'^*- '' '^°"-
centre, at which is fixed a tWa^Jn \ '^''''""S about its
(c): this rests upon a horizon?.!^ . ''"'f'=-^'*«« °^ =g«e
the upright brass DiUarT-? !p«e Plane attached to
l.ghtbrafspan?(BBClwIhXth"'*°i^''^ '"="" t^^
by an agate plaie upon an "Sfu ■?^]*'"Ssuspended
end of the be^ at D D This moH»"'f^"^^«^ ^""^^ °" the
to render the amount of flictlo^ « °^ T* *•"* ^"PP"" ■«
thus to insure delicacy in the In^/"^' *' P°=''"''e, and
prevent the agate Sees from '^^.'"""ent In order to
wear on the aeate ^^TJT. ?^!"S ^P^'J' by constant
" •" "■"'b"'' ""'^'^ anu the ends (r>u)
pn, and weights addS on. tv J"! ""^ '= ?'»=<=<» « onl
instrument is in eSri^m .'^?"e.'° "*« other unHl the
'ong pointer (c) X^^^' a'^'e-J^^'^o^f"^ "■'^ "^ ''«
^ I - ft ^^ dii equal Qistance on each
when loaded with .lo^mme,C ^,?f "^ "> "igramme
the onesmilHonth part?f Se ru£?an'^et;i°;h:d" '"'"'^'"^
toa^'oteiht^Si! ^rh'^:^ ->tftss cases,
of the weigh.W as weT/^ l^. r"'** "^''""■'' *« accuracy
a^ai,st<Ju|,"f;„o7st;j;^/^' '° P'°'<^' *e instrument
tj
INTRODUCTION.
„«• ^y i . ""^ chemist is to examine the properties
of iJI substances with regard to their actions upon one
another in producing bodies essentially differing from thi
originals. In order thoroughly to carry out hfs purnote
he ,s obliged to resort to ^;r;>m>«^«/; that is he has to
place the substances which he is examining 'under cir-
cumstances, perhaps not found in nature, which he can
contro and vary. Hence chemistry is ca led an TxiJri
mental science. In thus investigating all the maSs'
«vithin his reach, whether solid, liquid, or gaseous whether
contained m the earth, sea, or air, ketLrTloiTging to
the animal or to the vegetable creation, the chemist fild^
himsdf obliged to divide substances into two greaTclasses
(I Compound SuBSTANCES-those which he is able to
split up mto two or more essentially different materials
and (2) Elements or .Simple SuBSTANCES-those which
essentSfvd'iffi'rrn/? '•"1"^' ?"•'' T °^ «'^'='' """htg
oSed °"^'°''' ^"''Stances has beeS
Compound bodies are made up of two or more elemen.
tary substances chemically combined with etch ortie?"
thus sulphur and copper are elementary bodies out of
each of these nothing different from sulphur or copper c^
be obtained ; whereas, when the two bodies are hea^S
together, a compound is formed from which b^rti of the
l^S^"^ ^«""entary constituents can at any time be pre!
pared. Water is a compound body,— it can be <in1it .^
monTau''^'"?'"^'^^'^^' ''y<»™g=" and oxygl„T'"om^
mon salt, again, is a compound of a sas fchlorini^ w,>h
a metal (sodium) ; and limestone, 4^" " nd T^
may serve as examples of compound SeswhX
phosphorus, charcoal, iron, mercury, and gold mJv be
mentioned as belonging to the class of simpll sub"ances
The fo lowing experiment well illustrates the decompoS
of a compound into two simple substances A srn^n
quam. y of the red powder called mercm^ oxide is inTro
duced mto a test tube, and heated in a gTs flame whw
hot the oxide gradually decomposes, I greHepoSt of
Uf
metallic mercurv .• ' "'^Ml^rjiV. [Lesson
cooler parts of 'L,""^" S'<">ules collecu
«vithcoWe«\!v ^'''"' «'''-'« the tnbP h "P°" "'°
"'rated by the reklnHi?"'' ^''"'^ P^e-e^ce canT H '^"^''
plunged in^totheTu^ben^ °'" ^ e'°>-'"g rWn of ?""."
of the r^H r^^ J . ^"continuintrfi.Su ^ ^^ ^oocl
qua;nteTCu"'C;^« of the nontSarZ/te^af' ''^
non-metals. These s !?„ -f"^'"' «"d with on?v fift ^''"
siiJ^"t;Vs^ci^^^^^^^^
is made ud of fh '^ °", °f matter which L^ hi ""^"" "
compo^r aldlhe^T"'^' "^ ' '•e^emtn^Pf jff?'
upon the pr^Zesf ;^f n'^" » mist maE^"^/ ^^
to the eSon anrt"'h:''''t"°"' ^nd h"Sitl°?"!?'=i
are innumerahu • .^."efit of mankinrf . ►l • ^^ '^nded
industry havt " *'"'^'i altogether n-.' ^^ mstances
cation of chemL u^^ P'-oduction of whtn ^^ ^" ^^icle
Th^ ''^ j^^^^T^^stry has not proved nf "^^ ^^'"e appli- ,
' tne elementary
» upon the
:omes fiHed
be demon-
P of wood
, the whole
to the two
her weigh
they were
Jience, are
s and the
h as goid,
elements
such as
elements,
metals is
■ are ac-
y fifteen
tute the
cience is
xamined
together
-e state.
imental
^d their
which .
- appli.
he arts
-e and
f^uence
tended
tances
hes of
ion of
irticle
appli- <.'
e.
ntary
INTRODUCTION,
la'rgfcaS ^s ^Jo^^Ji^''^^ ^^^ -"^^« P-'nted in
sm^H cS: TsTlSum are Zl"^''""'' ' ^'°^^ '^
occurring metils. Mrr!c«' n^ ^^^ '"^''^ commonly
the rarer S^^ ""^ '"'''" '^P^' ^^ ^'^^"^^"^^» ^^^
Names.
Aluminium
Antimony
ARSENIC
Bartttm .
Beryllium ,
Bismuth
Symbols.
AlT
SbT
AsT
Ba6
Be.
Bi.
BrM.
Cd. .
"o BROMINE,
*^ Cadmium .
Caesium (^g
Calcium ... * r-^
/ CARBON • • ^au
/6-
Cenum Ce
CHLORINE
Chromium ,
Cobalt
ciM.
Cr. ,
'idymium . . . . D .
t-rbium . . p-
^ FLUORINE ; ; ; F *i •
^^^^^ • - aut:
r IODINE, ; ; ' • {""iA-
Iridinm • • • • ,^ /VV
Ir . .
7 HYDROGEN \
' Indium . .
lODIN
Iridium
Iron
Lanthanum ,
Lead .
Lithium* . '
Magnesium .
• V Fe D . .
' • • ^^u • •
• • PbO . .
• • Li . . .
for an explanation of these numbers
Combining H^eights.
27 A
122
75
137
93
4i BORON .''''• uT • • • • • 210
'^o BROMf/Vp' ' ' ' ..\k n
JI2
'33
40
12
92
3S'S
52*2
Copper ! ! ! ' ' Cu'D 587
Didvmiiim • . v-u uf g^.^
.... 95
• • . . 1 12-6
19
197
r
113
127
198
56
92
207
7
24
see page 16.
Mangankse •
Merctjp.y . *
j^folybdenum' *
NnxEL
9 NITROGEN ;
/i OXYGEN I ' '
^ Palladium * '
Platinum .
Potassium . ' '
Rhodim . ; * •
Rubidium. ' * *
Ruthenium .*
/ Z SELENIUM
MnO. .
Mo .
Nb .
2% :
I
PtTE,
Rh .
Rb .
Ru. .
Silver ' • • ^e D
/ 3 'S;/z/roN
Sodium
Strontium
/f SULPHUR
Tantalum
■I nalhum ..
Thorium \ ' ' ' 1\ •
Tin. , . ■
Titanium .
Tungsten .
^^raniuni
Vanadium
Vttrium .
^-'iconium
Snrf
Ti . T
W . .
V . .
Comb,
200
96
587
94 ^
io66
3i
197-5 ■
391
104-4
85-4
Na/1. . • •
Sr . . • •
S . • *
Ta. , : •
Te. . • •
104-4
79*5
/08
28
23
87-5
32
182
129
204
231-5
118
50
184
120
5i'3
6i-6
65-2
89-6
"SEsLii-^v ^?&s', -s
q-antities, and in such k
'ra^Tiients, that their
■"^sfeiH
'.]
INTRODUCTION.
properties have not yet been satisfactorily examined
1 mis, for instance, oxygen occurs throughout the air, sea
and sohd earth, in such quantities as to^make up near^^^^
half the weight of our planet. Whereas the compounds of
yttrium, erbium, indium, &c. have only as yet been me
with !n most minute (juantities.
The elements are distributed ver>' irregularly throughout
our planet : only four occur in the air, some tKh^ve
been found in the sea ; whilst all the known el4ems
occur variously dispersed in the solid mass of theS
The following table, giving the composition by weigMof
the primary rocks, shows that the bulk of the earth% solfd
body IS made up of only eight elements, the remainder
being found in much smaller quaiitities : J.; ^^'"^^"^er
Composition of the Earth^s Solid Crust in loo parts by
weight.
Oxygen . . 44-0 to 487 | Calcium . . . 6-6 to 09
Silicon
Aluminium
Iron . .
22-8 „ 36-2 Magnesium
99 „
9*9 ,,
61
2*4
Sodium
Potassium
27 „ o-i
2*4 „ 2' J
n „ 3-1
Doubtless other elements exist undiscovered in the
^at where^^^^^^ ,V" ^^^ ''^'^''^'T ^9^ known, for >J"e find
accurate mVr^nlnf P'""^-"'' ^^^^'^^^^^ new and more
accurate methods of examining the composition of matter
have been employed, the existence of new elements has
lour years, no ess than four new elements have been
discovered by the help of the new method of spectrum
nnw.i,i ^''^^'I ""^y* ^y t^e application of more
powerful means than we at present possess, at ^me
future time be split up into simpler cons 'tuems Ts a
question which we cannot answer with certainty &^^^
Dotash an^^Slf P°'' K^f? "*" T"" ^'^^^y^ ^""^ the alkaliri
potash and soda were believed to be elements until the
r.fiv ^^' ^hen Sir H n L Lesson
chemistry hav^hrl^ '^"""d^ions of a s'^olf *• . ^'"-in
«° ascertm-rthr""^*'^^'-' been laid; and^^l ^"'^ ^'^"'-if
f> III
II.]
OXYGEN AND HYDROGEN
II
LESSON II.
NON-METALLIC ELEMENTS.
In the present work we shall consider the properties of
orde?^— "^^ ^^^^^ compounds in the following
Oxygen.
Hydrogen.
Nitrogen.
Carbon.
Chlorine.
Bromine.
Iodine.
Fluorine.
Sulphur.
Selenium.
Tellurium.
Silicon.
Boron.
Phosphorus.
Arsenic.
OXYGEN.
Symbol 0. Combining weight i(>. Density i6.
Oxygen is a colourless invisible gas, possessin? neither
astenorsmell. It exists in the free state ?n he Ssphere
of which ,t constitutes about one-fifth by bulk, wW?st in
combination with the other elements, it forms n^r y half
the weight of the solid earth, and eight-ninths by weight
of wa er. Oxygen was discovered in the year 17^4 by
Priestley, and independently in .775 by Scheele. Lav rsier
first clearly pointed out in 1778 the part played by oxygen
and explained the chemical changes that go on when
bodies burn m the air. The birth of the modern sc^n^e
of chemistry may be dated fr , the discovery o"oxyffen
,':^r"„K?J„!!.".]llP-P-^'l ■•«'™ the air, blltitrs^^e
—i -...,.^.....„v« iiuiii iuany compounds which contain it
r <i
^k- 3
Wes"ouUrom tr^''- ^"'f 'he gas on h •
O'- botSes fi?J'''.\"'^ °f the tSe InH -'"^ ^ '^ed, bub-
II.] PREIARA TION OF OXYGEN. 13
temperature, and thus the evolution of the gas is facili-
tated, but the manganese di-oxide undergoes no change
whatever. °
All the elements, with the single exception of fxuorine
combme with oxygen to form oxides. In this act of com-
bination, which IS termed oxidation, heat is always, and
light IS frequently, given off. When bodies unite with
oxygen, evolving Hght and heat, they are said to burn or
undergo combustion. All bodies which burn in the air
burn with increased briUiancy in oxygen gas ; and many
substances, such as iron, which do not readily bum in the
air, may be made to do so in oxygen. A redhot chip of
wood, or a taper with glowing wick, is suddenly rekindled
and bursts into flame when plunged into a jar of this gas.
Sulphur, which m the air burns with a pale lambent
flame, emits in oxygen a bright violet light ; and a small
piece of phosphorus, when inflamed and placed in oxyeen
burns with a dazzling light. If the jars in which these
experiments have been performed be afterwards examined
It is found that the substances produced by combustion
m oxygen possess acid characters ; they have the power
of turning red certain vegetable blue colouring matters
such as litmus : owing to this fact Lavoisier gave to
oxygen the name it bears (from o*^tJff acid, y^wt^ I pro-
duce). A bundle of fine iron wire can be easily burnt in
oxygen by tippingthe end with burning sulphur, and then
plunging the iron thus tipped into ajar of the gas • the
oxide of iron, formed by the combustion, drops down in
the molten state.
Many other substances may be employed for the pre-
paration of oxygen ; thus, if large quantities of the gas
are needed, manganese di-oxide (a substance of frequent
occurrence in nature) may be heated to redness in an iron
bottle ; 100 parts by weight of the oxide yield wx bv
weight of oxygen. AnotJier interesting decomposition by
wnich oxygen is set free is that effected by sunlight upon
the carbonic acid gas contained in the air ; this is accom-
plished by means of the green colouring matter of plants.
'4 ELEAfEATTARV CHEMISTRY rr ^
Sunlight has the Dow,.r ; -^-fAr. fI.ESsoN
is set fre^ anH • ^'l-"' '°'- 'ts growth whl' '.^^ <^^'''°"
support of th. ^ afterwards used bv !^if '^P'^^n
■nspUo^' (filLrth?'. °' respfratio^'^ Cthe'°';"'?
from the^l'/'' tI"^ ""at carbonicS L/-'"''^"'^ '^'"
ture of the Todv<:f ^P' ^^^ ^"^'"al dLs and V^' ^^^« this
Carbonic acL^ v ^' ^^ ^^^^ of the neiL^hhn. ^^ ^^"^Pera-
death whenfA''/^i^^^"' ^^d some o^h^°"""^ "^J^^^s.
^<. r ii
II.]
k
PROPERTIES OF OXYGEN,
15
:hemical analysis of that substance is said to have been
made ; and if the proportions by weight in which each of
the constituents is present be determined, a quantitative
analysis of the substance has been made. When the
composition is ascertained by bringing the constituent
parts together, we are said to determine the composition by
synthesis. If we analyse potassium chlorate we find that,
from whatever source this salt may be derived, it always
possesses the same unalterable composition. This is true
of every definite chemical compound; indeed, were it not
so, chemistry as a science could not exist. Potassium
chlorate is made up of three elementary bodies, chlorine,
potassium, and oxygen, combined together in the following
proportions by weight : —
Chlorine .
Potas :um
Oxygen .
3 5 '5 parts by weight.
391
48-0
»
Potassium Chlorate . 122*6
n
»
When this salt is heated, the whole of the oxygen comes
off as gas : I22'6 parts yield 48 parts of oxygen, while 74-6
parts of a white solid compeund of chlorine and potas-
sium, called potassium chloride, remain behind. Hence
the weight of oxygen which can be obtaihed from any
given weight of potassium chlorate, and vice versa, can
be calculated.
In order to express the composition of substances more
conwaj^ntly than can be done by writing the names of
the elementary constituents at full length, chemists use a
kind Of short-hand, or symbolic language, some of the
princij^es of which must now be shortly explained. In-
stead of writing the whole name, the first letter or the first
two fetters flf the name alone are employed to designate
me element ; soinetimes using the Latin or Greek name.
Tljus CI stan^ fw Chlorine, O for oxygen, and K (from
Kali, another n«mc for Potash) for Potassium.
■'m
0'
ff.>
, These letters, however ■ "^'^^''^^y- [Lesson
parts by wLh? . K aI ''^'°"'"^- bw kiwavs . ' **?" "«
^■um, but always ,q^, ^' "°' ''e"''"/ apy welhf f g 35 "S
parts by »ve.Vht of^n P""^' "-hile O Ln?i! ' ?'^ ^°'as-
way express by svm^^^^"- "''nee U fs?'^/' f^'^Vs '6
potassium
Chlorine .
Oxygen
39'/
35*5
^^■o = 3 X i6
or
Ci.
o..
4«J o = 3 X i6
cated bv th^ t-^.^ . ^^ ^ne prooorH-^^ t ^^ "cments
('6) is to be tXnH, ^' "^^ <=omb'n,nf^?.,i.P'^=«d below
'^eights fin fh^ " ""^^« "mes. The ,„S, r^J" o*^ oxygen
is cflledX5L".^«. '" ^> of the eleZ „°f'hecombi„!!g
gradually bernmJ^ P ^^^^ as our stort ^r i. '"®*'* com-
The ttnr^l'/^r- . '"^^'"^^ ^^^^^^
compared with that of th/ ^ ^^'^^n volume of .
JI.J
OZONE
17
p.s the unit, is found to be 1-1056. One litre of oxygen
Igas at o C, and under the pressure of 760 millimetres of
Jmercury, weighs 1-4298 grams.
OZONE.
Pure oxygen undergoes a remarkable modification
\7tl^. 'Tt£ ""^ fi""^"" discharges is passed through
the gas: it thus attains more active properties; it pos-
sesses a peculiar smell, and is able to set ffee iodine from
potassium iodide, as well as to efifect oxidations which
common oxygen is unable to bring about. This allotropic
modification of oxygen has been termed Ozone, If a series
of electnc discharges be passed through pure oxygen the
gas becomes diminished in volume by about o^Sfth!
: and IS partly transformed into ozone : i^ has not yet been
found possible thus to convert the whole of the oxygen
mtoozone. If any substance be present, such as potassTm
iodide, capable of absorbing the ozone ks it is formed! the
whole of the oxygen can be transformed into thS active
modification. The peculiar sniell which isXr^ed when
an electrical machine is worked is caused by the presence
fjT^'T^ '^t P^P"^' ^^PP^d i^ a solution of potassium
iodide and starch paste, be held opposite a point on thS
conductor of the machine, the paper becomes^ Wue,ownff
to the liberation of iodine and the formation of a bluf
compound of iodine and starch. Ozone caX obtained
m several other ways ; it is formed when a stkk of
air°'?t'rsTrnA ""7^^ ^° ^f,"^ ^^ ^ bottle fined wih moist
air , It is produced m small quantities in the electrolvtic
i^Z^TT °^ Tf ^?^" P- 37) ^ and it is foi^eTjTy the
action of strong sulphuric acid upon a salt caUed nota^
smm permanganate. ^ ^^ P^^^^
Ozone is oxygen in a condensed state. The amount of
condensation which common oxygen undergoesr^s ,^1 as
the quantity of ozone formed, bekig known the den^ftv of
ozone can be ascertained, it is forn^h; tozo^i^
times as heavy as oxygen; that is, 3 volumes of Lv^en
condense to form 2 volumes of ozone ^^ •
Ozone exists in fh ^^J^TRY. [Lesson
HYDROGEN.
n certain volcanic gases an^/'^ ''^ '"^^" P^opord^^^
- ex.. a.so..ed in ce^^^ 'ee^s "X^^d^,
«g-4.
but it is found in m.irh i,.
aS^^" '^ ^°u™ '^^'e" («ip wa,^r"?n'H'''' •^?'"''«ed with
and It IS by the dernmr^«.,\S water, and y^vvim I Drof^Iln^^
similar hyLg;a S^'^!?" 1T?'^^' °^ °f ^ome o^f^e^;
pared. HydrSgen appears tA I ' 'u* ^^^ '^ al«rays pre-
Paracelsus in the sixteenth cenn"^ ^^n first obtained by
first ex.,ctly studied by Cavendish^' ''"' ''^P'^pertieswere
"^e w.,ht or.ater ^l^^^t^i^:^^^-^^:^^
h
II.] PREPARATION OF HYDROGEN, 19
readily be obtained from it by the action of certain metals,
which decompose the water, combining with the oxygen
to form a metalHc oxide, and liberating the hydrogen as a
gas. The metals of the alkahes, potassium and sodium,
decompose water at the ordinary temperature of the air ;
some other metals, as iron, are only able to do so at a red
heat ; whilst others, for instance silver and gold, are unable
to decompose water at all. When a small piece of potas-
sium is thrown into water, an instantaneous decomposition
of the water ensues, potassium hydroxide (caustic potash)
is formed, and the hydrogen of the water is liberated,
so much heat being at the same time evolved that the
hydrogen takes fire and burns. If the potassium, or, still
better, sodium, be wrapped in a piece of wire gauze, as
shown in Fig, 4, and thus held in the water of the pneu-
matic trough, under the mouth of a cylinder, the hydrogen
gas thus liberated may be collected, and its properties
examined. Water consists of 2 parts by weight of hydro-
gen and i6 parts by weight of oxygen, and its chemical
symbol is therefore HgO. When potassium or sodium act
upon water, half the hydrogen is liberated, the metal taking
its place ; this reaction can be represented by a chemical
equation^ as follows : —
j{jo + K = ^jo+H»
or water and potassium yield potassium hydroxide and
hydrogen. This equation shows us that for every i part by
weight of hydrogen which is liberated (H), 39-1 parts by
weight of potassium (K) enter into combination. The
hydroxide which is formed dissolves in the water, but its
presence can easily be detected either by the peculiar
cau«;tic taste which the solution possesses (whence its
name, caustic potash), or by its power of turning to a
blue colour a solution of litmus which has been reddened
by an acid.
with.
The sign + used in chemical equations signifies "and" or "logetl
sef
C 2
'ran turnings, must be heated in Z?""''^''"'' ''"'^d with
steam from a small flasfc or wi " ^ '"mace (Fig. 5). and
;i^^' "TO'^gh the' tut rhydro'2r^5,^ °^^ ""t r^^
oxide of iron left in the tube Th ' in=^ " ^'^^" °«"' »"d
I he most convenient pro-
zmc, which decompose water at a rtd ^' '""'' ^= '^n <>"
hese metals are able to evofve hvd. '^' V"^"^'}'' *at
the ordinary temperature of rt. T v^'^" from water at
present. For the purnose nf ,h ^l ''^. ^ ^""'e acid be
flask or bottle is proWded wf,h "' °btaming hydrogen, a
sented in Fig. 6, some zinr h/^ ■ ""^ *"'* '"^e as rep/e-
a mixture of Le pan 0/ sulte^' are introduced, ^l^d .
sulphur, oxygen, and hydrogen 1^1 "1^* compound of
poured in through the fiVh^^fi^ ^"^ ^'8''' Pa«s of water
a rapid effervescence comm/""^'' ^'^'^ a few minutes
coyected over waTer'ir ™o*S e?or' c wfn^ '"°'-^^'^ s""^'
of oxygen Care must, ho vev er h?l . ^'^ ^^ '" "'^ ^ase
;s expelled from the flask before^'h^V^i"^" "'^' all the air
'-n.s IS easily ascertained tfb" .he'SeTv',!n'=°"^"^'^ =
^ case by filling a test
I.'.] PREPARATION OF HYDROGEN, ai
tube wit.\ the gas, and trying whether the gas burns quietly
when a lighted candle is brought to the mouth of the tube
held downwards.
If we concentrate by boiling the liquid remaining in
the flL'-'k after the evolution of the hydrogen, we find that
white crystals separate out when the liquid cools : these
consist of zinc sulphate. A given weight of zinc (with
Fig. 6.
sulphuric acid and water) can always be made to produce
a certain weight of hydrogen, and a certain weight of zinc
sulphate will always be formed. It is found by experi-
ment that 2 parts by weight of hydrogen can be obtained
by dissolving 65 "2 parts of zinc with the formation of 161*2
parts of zinc sulphate. This can be represented by the
equation —
H2S04 + Zn = ZnS04-|-H2,
which not only indicates that sulphuric acid and zinc
yield zmc sulphate and hydrogen, but also informs us as
to the weights of the respective substances taking part in
the reaction ; thus : —
Hg signifies 2 X i parts by weight of hydiogen
^ " ^^^2 " " sulphur
^4 >; 4X16=64,, „ oxygen
»"'phu/ic a'cid^^so ,h'+^'+«4-98 Parts h •
"'eigM of sulphuric ^^!^''^"°n 'ells us thL n^s*^'^*" »'
r^'ght of zinc wJw v'i ''J^ied to Zn or «c? ^^"^ "^X
^'nc sulphate 'rt» ^"^O' o-" '6i-2 o-frf.^ ^ P^"^ by
. Hyd'ogen b "n,"' °'.' P*"^ by wejP"'^ by weight of
" with a verysfoLV' ''^ ='"> when Tl^h, °1 ''>'^'-ogen.
"ame ; and i^ /h^ '^ luminous, altho.^h '* '"'""gbt to
'be oxygen orthe'ainr^'- ""^ '•ydroge1.\o',^t'""'y '"«
^^^"gen r.Jl--- bHght.^^^^^^
^^^ ' ^ 'fir. 7 ; the gJass
^aSslllT ^^'"^'"^d owing to the conH
mouth HvH?' bowever, be relit bv,LT'' '' ^'"'n-
"''"^" "^^ "« p°-ed tm^^rv;,::,^
rmi
^^' f Lesson
ts by weight of
Jat 98 parts by
^5*2 parts by
s by weight 0/
0/ hydrogen.
IS brought to
extremeiy hot
-ombines with
production of
air may easily
^ the flame of
7 ; the gJass
IN.] METRIC SYSTEM OF WEIGHTS, &*c. 23
another in the air ; but as it is lighter than air it must be
poured upwards. The specific gravity of hydrogen, wht^n
air is taken as the unit, is found to be 0*0693 \ but for
several reasons we shall find it more convenient to take
hydrogen itself as our unit, and compare the weight of the
same volumes of other gases with hydrogen instead of air.
One litre of hydrogen gas at 0° C. and 760 mm. pressure
weighs 008936 grams. Free hydrogen, like oxygen, has
never been obtained in the liquid or solid state.
[The pupil must carefully work out the examples and
exercises given for each Lesson at the end of the book, and
thus test the accuracy of his knowledge.]
^sation of
^ number
mination,
>gen does
^i^eofan
cylinder
lydrogen
IS extin-
? at i\iQ
essel to
LESSON IIL
PHYSICAT. PROPERTIES OF GASES, ETC.
It becomes now of importance to ascertain r' merely
the weights of oxygen and hydrogen capable of being
evolved by using given weights of potassium chlorate or
zinc, but likewise the volume of each gas thus obtained.
Before we can enter into these calculations there are
several important preliminaiy subjects, v/ith the principles
of which we niust make ourselves acquainted.
The first of these is the metric o\ French decimal system
of \yeights and measures ; the second is the mode of mea-
suring temperature, and the con- iction and use of ther-
mometers, together with the laws regulating'thc expansion
of gases by heat ; whilst the third relates to the measure-
ment of atmospheric pressure by means of the barometer,
and the laws regulating the changes which variations of
pressure produce in the volumes of gases.
Metric System of Weights and Measures,
There are several distinct advantages to be gained by
the adoption of this system, the chief of which is that the
system is throughout a decimal one, and hence all calcu-
Mi
r
24
sandths ; these parts arf," '^"'i"'' hundredths and th.
centimetres and ^Jy/- ^ 'ermed respectivpiv 1/ ■ "°""
tens, hnnirtisZfl^'*""- The muItiSftt'''^''''^'
measure,! and those n/' "'^.""^asuresofarerr.n^' '^"
»<5 decimetres
'00 centimetres * "
^.000 millimetres * * "
« metre.
X square metre.
ii?v'S%atf„'„'?ff'' «. "■«'«u«d by S^.f.'^"' *• ""'»« from ,h»
« '0.000.000 P^* o*" *'•« tnie di,#«„_
25
zr-oi
•53
(O
III.] METRIC SYSTEM OF WEIGHTS, &^c.
The measure on the margin is i decimetre
in length ; it contains lo centimetres and loo
millimetres. For the sake of simplicity the
word litre is used to signify i cubic decimetre
(rather less than an English quart).
Thfe French philosophers who arranged this
metric system wished to have a simple relation
between the measure of volume and that of
weight, and they determined to take as their
unit of weight the weight of i cubic centi-
metre of pure water of the temperature of 4°
Centigrade weighed at Paris. This weight is
termed a gramme, or in English gram. It is
divided like the metre into tenths, hundredths,
and thousandths, called respectively deci-j
centi-, and milli-gram; whilst to the tens!
hundreds, and thousands of grams the names
deca-, hecto-, and kilo-gram are given. A table
showing the relation between the weights and
measures of the metric system and those com-
monly in use in this country is given in the
Appendix.
Measurement of Temperature.—
Thermometers.
Measurements of changes of temperature
are always effected by ascertaining the ex-
pansion or contraction which bodies undergo
by alteration of temperature. For this purpose
liquids are generally used, as solids expand
too little and gases too much to be convenient
indicators. Mercury and alcohol are the liquids
commonly employed, especially the former,
because its rate of expansion is nearly uni-
form, and because the range of temperature
Sl^^i^''^ '^^I". the equator. The value of the metric system does not at all
rrlilP^i".^':«'^*!°" between the earth's circumference an^the metre'
-hich copie^Sve b^SScSf fbr'u^e"'""' "'''"^"^ P'"""''^ '" ^*^ ^^
= — «>
= — «9
"««
I
r^^
.'-'"•ch can be ,„c,,ur.H > "'^'^^^''^^^^- fLESSON
tne blown pe a^u^ '"^rcury, by meltme the p-Hcc k r ^
ffradii'iMn.. • , ^'lermometpr time ^.1 ^ ?^^ before
'• % Pnin.^Ti„„ th^ f ^- J bis graduation is efforf;.?
tt?H e henVor H ''I '■■"^■-' rf"nn ' this hs';r'"-y "'-"
fhall.adopt, it being the one 2""f '"^.^ ^^''''^ (whU ,1 "
scale IS placed at the free.^l ''■^'''" ">« Zero oAhe
point is ioo° r n: • ."^eezing pomt, so thaf th» k '.• ^
III.]
THERMOMETERS,
37
and those below the freezing point are ch.iractcrised by a
minus sign, thus, -—1" C, —2° C, &c. Fahrenheit divided
the same space into 180 equal parts, each of which is
called a degree Fahrenheit ; he did not, however, com-
mence his scale at the freezing point, as he erroneously
thought that he had obtained the greatest possible degree
of cold by making a mixture of snow and salt ; the tem-
perature of this mixture he found to be 32 of his degrees
below the freezing point of water ; he, therefore, called
the freezing point 32°. In Fahrenheit's scale, minus
numbers are employed to denote degrees of temperature
below the Zero of his scale ; this scale is the one in com-
mon use in England, but is the most Inconvenient one
which we could adopt. Rdaumur's scale (used in Russia
and Sweden) resembles the Centi- /r r /?
grade scale, except that the space
between the freezing and boiling
points is divided into 80 equal
parts ; so that water boils at 8o*
Rdaumur. The connexion be-
tween these three scales is seen
at a glance by reference to Fig. 8.
The relation between the de-
grees P\ahrenheit, Centigrade, and
Rdaumur is expressed by the
numbers 9, 5, 4. In converting
from degrees Fahrenheit to Cen-
tigrade or Rdaumur, we must re-
member first to subtract 32 and
then reduce ; whilst when pass-
ing from degrees Centigrade and
Rdaumur to Fahrenheit we must
add 32 after the multiplication
and division are completed.
If very exact measurements are required, several precau-
tions must be taken in the graduation and use of thermo-
meters : thus, for instance, the tube must be calibrated—
that is, the irregularities in the bore must be determined
jnn
0-
6
Fig. 8.
2S
ELEMENTARY
CHEMISTRY. TLessov
expansion of different kinds of eL«.'hr"^*°."'^""«q"aI
■n^exact experiments to ^^if:^^^^^^^^^^:^^
Q , ,, . ^■■'P^nsion of Gases by Heat
■r^^::^<^^^^tf^^^^t -"r" '- ^- equal
ferently, whilst all gases Ixpand aX^''° ^' expand dif-
The expansion of solids and lia1,^t' °' """^ "^arly so.
"-hich, in elementary chemUtrv wf ,," ^ f."''Je« «-ith
whilst a knowledee of fh^ i, ^' % ^^^^ '"ttle to do
of gases is of mZ imm'ediiSlmnf ^""^ "^^ expansion'
found by exact and laborious eZrim;??.J' ^^' •>««"
expand 3^5 part of their volume at'^o"?'?' ""^^ ^." 8^=^^
m temperature of i° Centigrade ; every increase
c?w"e IS '"""'"^^ °^ ^■■■- °^ hydrogen at o«
becoipe 274
'» 275
»> 276
or 273 -f- t
»>
')
?>
c.
>»
>»
I vIlumtTat'ir<!i°^ Z7Z°f:Z'°..-*'< -^ °--366; ;
heated to i» C. This fractTonTcil^J^fh' ""'"'Sf^ *"'"
J'^i?'^ '.°°° cubic centimetres o?hvdrLer''"''^°'"'"e
o C. will occupy when the temDeraC^^- "?ca|ured at
we must remember that the aSE .5:, WesVac;
- -nmentalists are Jmow:!^"' ° '" ^°° obtained by thesc^wo ^llownTcr
Hydrogen . ^i^lT^^' ^f^^u,.
Carbonic Add ' J * J -^^oxj 0-36556
-i^
III.] EXPANSION OF GASES BY HEAT. 29
in the ratio of the numbers 273 to 273 -|- 20. Hence we
multiply 1,000 by 293, and divide by 273. If we require to
know what the volume 1,000 cbc. measured at 20° C. will
occupy when the temperature sinks to 0°, we have to re-
member that the diminution in volume follows the same
law, and that, therefore, 293 vols, at 20° will become 273
vols, at 0°. If we have 1,000 cbc. of gas at 20°, and desire
to know the volume which it will occupy at 50°, we have
in like manner to remember, that 273 + 20, or 293 vols,
at 20°, become 273 -h 50, or 323 vols, at 50*^ ; and then
we can easily find the alteration in volume which the
1,000 cbc. of gas will undergo when heated from 20" to 50°.
Relation of Volume of Gases to Pressure.
When a gas is subjected to an increase of pressure, the
volume of the gas becomes less ; and when the pressure
is withdrawn, the gas immediately expands again, and
occupies exactly the same volume which it did before
the pressure was increased. Solid and liquid bodies can-
not be compressed in the same way. Gases are hence
known as compressible fluids, and liquids as incompressible
fluids : liquids, however, really are compressible, but only
to a very slight extent : like gases, they recover their
original volume on removal of the pressure. The law
representing the relation between the volumes of a gas
and the pressures to which the gas is subjected is a very
simple one : it is termed Boyle's or Mariott^s Law,
from the names of the discoverers : it states that the
volufne occupied by any gas is inversely proportional to
the pressure to which it is subjected. Thus, for instance,
the volume i under pressure i becomes the volume 2 under
the pressure \, the volume 3 under the pressure J, the
volume \ under the pressure 2, and the volume \ under
the pressure 3, and so on.* For a description of the
* This law, like many other physical laws, is only an approximation to the
truth as ascertained by exact experiment No gases obey the law exactly
when high pressures are usfid, and many deviate perceptibly ; still, as these
deviations are but very slight, we may assume, for the purposes of our c&lcu-
Jntion"?, the absolute truth of the Hw of Rovle.
I
^M'crimctal proof of thi. , ^^•^•^^■^ ^- fLES«>N
''■■y mercury and the'n""" ''^■''''=- Th^s Tubel fin"^' ""?
uiLTcurv sinks iV, Vu '"^ ni<-'tal. It ie .i,,.., "' '" a
y smks ,„ the tube to a point abouri/f''''" "'««''e
fl • ?h« surface of the m«^ / ° u""- f™"!
" 's sustained n th s n '", ^^ ^"^'^ ■
pressure of the air v^?""",". ''>' "'e
sure increases h» .'•''? "'" P^s-
sustained column i ''^'S'>' "f the
"»«rcury i„ the tube faf, '".' , °^ *«
generated at the e^tthi ^}^ S«cs
'"bject to this preset!. ^'"^^'"' ^'^
yolumes increase or Hi ^'- ?"'^ "'^''''
!%' to the above law '""' '"^^^d-
"icumbent pressure h'» ^' ""= ^"P^^"
greater. In esfjm^,- """J"-'^ '^ss or
of hydrogen wWcT^',"| h'^ \f"'"^
from a given we ght of zin^ *'°'i'"*'^
P'luric acid, it is cl^n. h "^ """^ sul-
to know not oilv Ih f''^* *^ "-equire
vvhich the gas k ^^f, "=">P"ature at
the atmospheric L,""'^'"'''. •"" a'so
able to comn, , " '^ "eaiured ^nd "'^ ""?" "''"^h
vS'eTof'r '''S"Ssr:^"ag?eiro'r~
weiVhf -^f Suppose now that wf^ h"^ "^^ ^'^liUtnetres of
ii
/"
HI.)
DIFFUSION OF GASES.
31
of 10 litres, the temperature of the room being 15° C.
and the barometer standing at 752 mm. We know
(i) that 122-6 parts by weight of potassium chlorate yield
4(S of oxygen ; (2) that a litre of oxygen at 0° C. and
760 mm. weighs 1*4298 grams. We must now ask, What
will 10 litres of oxygen weigh if measured at 15° C. and
under the pressure of 752 mm. ? Now, 10 litres at o"
and .760mm. will become ^Q X 76o X (273 + 15) ^ ^^.^^^^
752 X 273
at 1$'^ and 752mm. ; therefore, if 10 litres at 0° and 760mm.
weigh I4'298grams, lolitres at 15° and 752mm. will weigh
,14*298X10
— -— gr- — ■» 1 3*4" grams. Next we require to know how
many grams of chlorate will furnish this weight of
oxygen; as every 122*6 parts of chlorate yield 48 parts
t 1 11 1 1 22*6 X 1-Vd.l I
of oxygen, we shall need - ^ « 34*254 grams of
48
chlorate. In the same way we can calculate, for instance,
the weight of zinc and sulphuric acid needed to inflate a
balloon of the capacity of 150 cubic metres with hydrogen
when the thermometer stands at 11° C. and the barometer
at 763 mm. [The student will do well to work out numerous
examples of this kind, in order to familiarize himself with
these methods of calculation (see Exercises at the end of
the book).]
Diffusion of Gases.
^ Another physical property of gases is that of diffusion.
Gas«s which, when mixed together, do not combine
chemically, have the power of becoming intimately mixed
together, even when differing in specific gravity, and when
the heavier gas is placed at the bottom, and both remain
at rest. This important property is called the diffusive
power of gases. The rate at which gases diffuse varies
greatly. Thus, a bottle filled with hydrogen lost 94*5 per
cent, of this gas when left exposed to the air in the same
time as that in which a bottle of carbonic acid lost onlv
m II
II ^^^^f^^TAJiV CHEMISTRY rr .
4.7 per cent, of this ^as in f i, [Lesson
sichTsC '"-"^h'hi "^"eTort'of ^^'^°- 'J''^-
"o^^^,\y?^^k^iZ^V^, "//fusion, as
\ ^ydrogen . .
j ^itrogen . .
Cajbon Dioxide
density
air= I.
0-06926
0*9713
'•1056
I '5290
-^^de
eiisity.
3779
i'or5
0-9510
08087
Velocity of
amusion.
air;
3-830
I -014
0-949
o-8i2o
IV.)
SYNTHESIS OF WATER,
33
LESSON IV.
OXIDES OF HYDROGEN.
wghf^f ''•^"' '''■'"'''''■ Symbol H,0.. Combining
Fiji. la
, wh7sS tlTtj ^otreforhlS^' "^ Mr,Cavc-ndisl,
volume of oxygen to fom water \nlfT """*' ^''^ °"«
t Cavendish male a mixtu eTthese.asel^^^?''"^" "^'^•
I tion by volume in a iar and tti»^ in ^ j , '" "''^ propor-
j a sfong dry vessel -erb^nSate^^^^^^^^^
34 ELEMENTARY CHEMrSTRY. [Lesson
spark could be oassed fhrr^M^K llf ^ • ^^ ®^' ^" electric
f sin, theihxKe^'rbfna t^^^^^^ '-/-«.
filling the whofe space fo™r,^^Sccupied''bv ^t'^ '"{
gases. Cavendish weighed the gCfie'a'nd'a'C the
^. II.
explosion, and, knowing the wi^iorK* „<• »v
he found that the weight Is ZT^ \ *K ^^'^= ^^^«^>
same as that Ke lases Jhf.h ^'''' J?'"^"""! ^^^ *e
above-mentioned yearftheex^rt^^^^^^^ Since the
been made the subject of clref,.^TP?^''.'?".°'^''^'^'''>»»
by many chemists^rnd the resu tT.i" k'*"^ experiment
composition of wlte^; llTm-Sdlfe' ^rofta?^!
!iy. [Lesson
IV.] SYNTHESIS OF WATER 3,
ginally „sed by Cavendish. We use for this purpose a
El%oZZ^fj graduated, ctrong glass tube'^cXd a
Eudiometer (a, Fig. , ,), open at one end and closed
at the other, whilst through the glass at t.,e top are
melted two platinum wires. Thil tube is first filfed
with mercury, and inverted mouth downwrrds over a
trough filled with this metal (Fig. n). Hydrogen gas is
meLueT^sunnofi''' "'f ,*"''"' ^""^ '•>« vo'lumfadmkted
measured (suppose equal to 100 volumes); oxveen eas is
next admitted, and the volume of the two mfxed eases
measured (suppose that 75 volumes of oxygen are added)
In making this experiment, care must, however be taken
that the temperature and atmospheric pressure are car^
fully measured by means of the thermometer W and the
thaTThe t«l?'h '•"T '" the figure; it is also^4cessa5
that the tube be not more than half full of the Msponi
mixture, as great heat is evolved by the comSon
whkh^Te^soS !t"f,'" '^P'"^'°" °' volume'c^ct 'f";
Kcct^V'Th^ *t^ ^-- ?-i tha^^o'^;S°
nas occurred ; the water produced will be dennc,>p!J
occupies exactly i^voZmpf ^^'f °"' "^^^^^ ^^"^ed
unite withTofLy^^^^^^ ^' '/°^"^^^ °^ ^y^'^^^^
ux oxygen to form 2 volumes of steam, hence
the density of steam or weight of i volume is il±? = g
D2
36^ ELEMENTARY CHEMISTRY, [Lesson
The most striking method of demonstrating the com-
position of water analyticaUy is by splitting I up into ka
trS ""T ^M"- ^^ "'^^"^ ^^ ^ ^"^^^"t of voltaic elec'
ncity. For this purpose we will fill a glass vessel
(Fig 12) with water acfdulated with sulphuric acid to
T^\'^^^ ."2"^""' '^^ aectricity, and bring two tes^
tubes fil ed with water and in^rted'into this visel over
two small platinum plates attacW to wires of the same
metal passing thrr ^.h the caoutchouc stopper at the
Fig. 12,
bottom of the glass ; on connecting these with the ter-
mmals of a battery of three or four of Grove's elements
an evolution of gas from each plate is noticed : that dis-
engaged from the plate in connexion with the platinum
end of the battery is found to be pure oxygen ; whilst that
coming off from the other plate connected with the zinc
end of the battery, is pure hydrogen gas. If the two
tubes be graduated, it will be seen that the volume of the
Hydrogen is a very little more than double that of the
oxygen; for, owing to the oxygen being rather more soluble
IV.]
DECOMPOSITION OF IV A TER.
37
in water than hydrogen, we do not thus get quite the exact
proponions. In order to collect the detonating mixed
gases evolved by this electrolytic decomposition of water
an apparatus represented in Fig. 13 may ^e employed.
Oxygen being 16 times as
heavy as hydrogen, and these
gases combiningto form water
m the proportions by volume
of one volume of the former
to two of the latter, we now
know that the proportions by
weight in which these gases
dst in water must be as 16
. 2. It is nevertheless most
i ijportant that this calcula-
tion be verified by direct ex-
periment. For this purpose,
use is made of the fact that
copper oxide when heated
alone does not part with any
of its oxygen, but when heated
in presence of hvdrogen it
parts with as much oxygen as
will, by combining with the hydrogen, form water, being
itself wholly or partly reduced to metallic copper. If,
therefore, we take a known weight of copper oxide, heat
it, and pass pure hydrogen over it until it has parted with
all its oxygen, and if we collect and weigh all the water
thus formed, and likewise weigh the remaining m jtallic
copper, we shall have made a synthesis by weight of water.
For the loss in weight of the copper oxide is the weight
of oxygen which has combined with hydrot^en to form
water; and the difference between this weight and that
of the water formed, is the weight of the hydrogen thus
combmed. The arrangement used for this determination
IS represented m Fig. 14. The hydrogen evolved by zinc
froni sulphuric acid in the bottle on the left hand is puri-
fied from any trace of arsenic, sulphur, and moisture
Fig. 13.
38
f
ELEMENTARY CHEMISTRY, ILesson
which it may contain by pass-
ing through the U tubes,
numbered i to 7, Fig. 14, con-
taining absorbent substances.
The tube No. 8, containing a
very hygroscopic substance, is
weighed both before and after
the experiment ; and if no in-
crease occurs, the dryness of
the gas is insured. The gas
then comes in a perfectly pure
state into contact with the
heated copper oxide contained
in the bulb A. This first bulb,
which is accurately weighed,
is placed in connexion with a
second bulb B, in which the
water formed by the reduction
of the oxide collects ; any
moisture which may escape
condensation in this bulb is
retained in weighed drying
tubes, 9 to 12, containing frag-
ments of pumice moistened
with sulphuric acid. Most
careful experiments made ac-
cording to this method, carried
out with many precautions
which cannot here be detailed,
have shown that 88-89 P^^^ts
of oxygen by weight unite
with irii parts of hydrogen
to form 100 parts of water.
Free oxygen and hydrogen
combine together, when a light
is brought in contact with
them, with so much force that
IV.] PHYSICAL PROPERTIES OF WATER. 39
sion occurs from the sudden expansion caused by the great
heat evolved in combination. If we fill a strong soda-water
bottle one-third full with oxygen and two-thirds with
hydrogen, and then bring a flame to the mouth, the gases
combine, producing a sudden detonation like the report of
a pistol. Many fatal accidents have occurred to persons
who have carelessly experimented with large volumes of
this explosive mixture. In order to exhibit the great
heat evolved by the combination of the two. gases, the
oxy hydrogen blowpipe is employed ; in this arrangement
the gases are contained separately in two caoutchouc bag§,
being only brought together at the point at which the
combination is desired, so that all danger of explosion
is avoided. The flame thus produced* is very slightly
luminous, but its temperature is so high, that the most
difficultly fusible metals, such as platinum, may be easily
melted in it, whilst iron wire held in the flame burns with
beautiful scintillations, forming an oxide of iron. A piece
of chalk or lime placed in this flame becomes heated to
bright whiteness and emits an intense light, often used
for signal purposes.
Water exists in nature in three forms : in the solid
form as ice, in the liquid state as water, and in the gaseous
form as steam. At all temperatures between 0° and 100°
C. it takes the liquid form, and above 100° it entirely
assumes the gaseous form (under the ordinary atmospheric
pressure of 760 mm.). The melting point of ice is always
found to be a constant temperature, aEd hence it is taken
as the zero of the Centigrade scale ; water may, however,
under certain conditions, be cooled below o*^ C. without
becoming solid ; still ice can never exist at a temperature
above 0° C. • In passing from the solid to the liquid state
water becomes reduced in volume, and on freezing a
sudden expansion (from i volume to 1099) takes place.
That this expansion exerts an almost irresistible force is
well illustrated by the splitting of rocks during the winter.
Water penetrates into the cracks and crevices of the rocks,
N
V ■*,
f^S=: 1 ilil|?ri::;„^£s
40
lifi
ELEMENTARY CHEMISTRY. [Lesson
[nfn f!^"^ """^I ^^\?^S' ^^^^^' *^^ '•^ck is ultimately split
into fragmen s. Hollow balls of thick cast-iron can thus
easily be split m two by filling them with water and
closing by a tightly-fitting screw, and then exposing them
to a temperature below o^ C. *' s "^cm
In the passage from solid ice to liquid water we not
only observe this alteration in bulk, but wTnodcTtha
oc'rT Thtts"^'' -^r^^o^, or disWpearance '?heat
oc»,ure. This IS rendered plain by the foUowin? simnli.
expenment :- Let us take a kilogram TwTef at the
f wf^-'^fK" ' "'^^ ""°*^' ■''■"S^^™ °f water af 79°!
he me"n *;^,^o*^';'?P«'^t"'-e of the mixture will b4
,V,f 1^^?' A 3^ • 5 '. ■'i however, we take i kilogram of
ice at o and mix it with a kilogram of water at 7o»
we shall find that the whole of the ice is melT^'but that
s exac«v^o'?^r„?.^ """ '^.=""l"S => kilograms ' of Uter
lined nth.'w°*f\°'''^'.' 'he whole of the heat con-
hnf hi . hot water has just sufficed to melt the ice
duced hL'^L'"^ *" temperature of the water thus pr5
the hauid T/tJ^ '^-^ "'^' '? f^^^'^g fro-" the solid to
xne iiqu d state a given weight of water takes im ni-
renders latent ]v^,t so much helt as woufd suffice toTaise
7Q»C TheT;%°l '^f'r'^' ^'^Sht of water through
I?, /*' , "^f"' '""* "/■^'ater is therefore said to be
of h;,»^-*u ^^^^"^ '^^^==^*' o'' becomes solid, this amount
form LI'Llh' "f "''^']; *° ''^^P *« *««'■" the Hqu"d
I?,!?' 5 therefore well termed the heat ofliouiditvt.
Zl7^\°' '^"•''^'?<' ^^"^'l''^- A similar lapSce
of heat on passing from the solid to the liauid ^^^^%
t''hy?'.'^;r°'"''°" °^^^' °" passing frZ the Cid to
the solid fonn, occurs with all substances; the amount of
the n'a'Jurn? tf"^ l^'""' °^ ^^"•^^'^ varies, however with
tv.]
EXPANSION OF WA TER,
41
ter, we not
notice that
ce of heat,
ing simple
Iter at the
:er at 79°;
tire will be
ilogram of
ter at 79**,
1, but that
of water
heat con-
It the ice,
thus pro-
e solid to
:es up or
e to raise
r through
aid to be
imount of
' through
s amount
he liquid
utdity, is
pearance
tate, and
liquid to
mount of
ver, with
showing
»btaining
ulphate),
urbed, it
retains the liquid form, but if agitated it at once begins
to crystallize, and in a few moments becomes a solid
mass. If a delicate thermometer be now plunged into
the salt while solidifying, a sudden rise of temperature
will be noticed. Similarly water at rest may be cooled
down below 0° C. without solidifying, but if agitated it at
once solidifies, and the temperature of the whole mass
instantly rises to 0° C.
When water is heated irom o*" to' 4°, it is found to con-
tract, thus forming a striking exception to the general
law, that bodies expand when heated and contract on
coolmg; on cooling from 4° to 0° it expands again : above
4°, however, it follows this ordinary law, expanding when
heated, and contracting when cooled. This peculiarity in
the expansion and contraction of water may be expressed
b^ saying that the point of maximum density of water is
4 C. ; that is, a given bulk of water will at this tempera-
ture weigh more than at any other. Although the amount
of contraction on heating from 0° to 4" is but small
(i volume of water at 4° becoming i-f 0*00012 at 0°) it
yet exerts a most important influence upon the economy
of nature. If it were not for this apparently unimpor-
tant property, our climate would be perfectly Arctic, and
Europe would m all probability be as uninhabitable as
Melville Island. In order better to understand what the
state of things would be if water obeyed the ordinary laws
of expansion by heat, we may perform the following ex-
periment. Take a jar containing water at a temperature
above 4°, place a thermometer at the top and another at
the bottom of the liquid. Now bring the jar into a place
where the temperature is below the freezing point, and
observe the temperature at the top and bottom of the
liquid as it cools. It will be seen that at first the upper
thermometer always indicates a higher temperature than
the lower one; after a short time both thermometers
mark 4° ; and, as the water cools still further, it will be
seen that the thermometer at the top always indicates a
lower temoerature than that chn«7« ' -
4* ELEMENTAIiY CHEMISTRY. [Lesson
temperature .fThe ton lav-r nV <^°°1'"?. ?°es on till tlTe
which a crust of icefs Se2 but If 'tf ' '° °°' ^^'"^
water be sufficiently lar<rp Th. ', " "*® "^^s of the
at the bottom Tnevy refu'cld ^0^^'"? °^ *^ ^^'^'
csely the same phenomenon occurs ^n tt "f""''? P^'^
lakes and rivers • » tho «.,.f,L . .'" '°^ freezmg of
by cold windlfand thus becom.W I' " ^'"^'^^^^y =°°l^d
hghter and warmer waerrise^'"f ^^^l^V^^'' whilst
goes on till the temDeraturn\lf fi, I "JP'^ "' P'^t^^: this
to 4°, after which Zsurf^f.°l,^^ "'''°'^ ""^'^ '= reduced
much it be Bpiled as it ifX"^ ^r u'^^"" ''"''^' however
water at 4°T Hence rV ;. ^^^ ¥^'^'' '''^'> the deeper
massofwlterr^faTnU hetSerature^^^^^^
become heavier as it cooled dowf?nth»f '*• • ^^^ water
continual circulation would be keotuo rn°.^. P°'?'' ^
mass was co6led to o° wh^n L-j^i ? """' the whole
would ensue. Thus our ht^.,^ ^'''•^""" °^ ">« whole
verted into sol[rmasses of' ice"* Xch Th"" ^' '=°"-
warmth would be ouite in,,,ffii? ' .^. "" *^ summer's
hence the climate of nur„^^?' thoroughly to melt;
approach in a^verit^^hat ofThe ^0^^ ^°"^ "'^•>'
water does not freeze\?« „LZ !r • ?"^ regions. Sea-
of the ocean, whTch prev^^^ ^h. '">,^,'°/''" S-^^^' <l«ptb
cooled down to the f^eSL'fc *^°'^, fr?™ ever befng-
very deep lakes never' freei"^ as Jh!.'?'^'''^' '" ^"S'^-^
whole mass never gets reduced to 5\.''^'"P-^««e of the
In the first P^celZTeleT.^^^^'^T^.^^Tr^^
to boil, or eni-ers into eiullitiZ-LTt ■ ' ".•^^g'ns
engagement of water^at or steim Im' ff, 'T"^ ^'^
most heated surface take.: niLt T' ■ "" *''^ ^°wer or
water is heated inTe ass riSt I *"' " '^^^ ^^«» when
passage from the hwfd to th^^ ^*' ''^'"^- I" t^s
• Ti, • . ^ ^ *^ gaseous state, a large
.h«S'LX«dSt?a?rbe'.r'?£:='^-"'«" " «»«M«-b.y low., L,
IV.]
LATENT HEAT OF STEAM,
43
quantity of heat becomes latent, the temperature of the
steam given off being the same as that of the boiling
water, as, like all other bodies, water requires more heat
for its existence as a gas than as a liquid. The amount
of heat latent in steam is roughly ascertained by the fol-
lowing experiment. Into i kilogram of water at o°, steam
from boilmg water, having the temperature of ioo°, is
passed until the water boils : it is then found that the
whole weighs 1-187 kilos., or 0*187 kilo, of water in the
form of steam at 100° has raised i kilo, of water from
o^ to 100°; or I kilo, of ateam at 100° would raise 5*36
kilos, of ice-cold water through 100°, or 536 kilos,
through 1°. Hence the latent heat of steam is said to be
536 thermal units.
Whenever water evaporates or passes into the gaseous
state, heat is absorbed, and so much heat may be thus
abstracted from water that it may be made to freeze by
its own evaporation. A beautiful illustration of this is
found in an instrument called WoUaston's Cryophorus;
it consists of a bent tube, having a bulb on each end, and
contaming water and vapour of water, but no air. On
placing all the water in one bulb, and plunging the empty
bulb into a freezing mixture, a condensation of the vapour
of water in this empty bulb occurs, and a corresponding
quantity of water evaporates from the other bulb to supply
the place of the condensed vapour : this condensation
and evaporation go on so rapidly that in a short time
the water cools down below 0°, and a solid mass of ice is
left in the bulb. By a very ingenious arrangement this
plan of freezing water by its own evaporation has been
practically carried out on a large scale by M. Carrd, by
means of which ice can be most easily and cheaply pre-
pared. This arrangement consists simply of a powerful
air-pump (a. Fig. 1 5), and a reservoir (b), of a hygroscopic
substance, such as strong sulphuric acid. On placing
a bottle of water (c) in connexion with this apparatus,
and on pumping for a few minutes, the water begins to
boil rapidly, and the temperature of the water is cooled
( f
m
44 ^^SMEATA/iy CffSMfSTJty. [Lesson
^o W by iu omi evaporation as to freeze to a mass
aqJroufvapourir!JlJe^n'''"f^''-V^'« "^ ^t^am or
aii; thus w^W thatTa '?,«' '^'''=" ""P."^^" '° ^^e
room for some days, .he wholeftf T" ^ *"''' '" »
evapo^te. This ^o^ :^t:l ^^Z ^'^^y
Fi^. 15-
temperatures is called the e/ash> f^^. « ^
aqueous vaDour- if " "'\^^^'^^ y»'^<?, or /'<?«j/<7«, of
quantity o7S is pS aLrf."'"^' ^^^^ ^ ^^^^
meter, by the depress&hfch Ih. t^ "^"'""7 l^ ^ ^^r°-
thus given off is^cap^we of e Jr^^^^^^ o/ the vapour
column (as in Fiff o) If wL jl/n "?, T'' ^^^ mercurial
water thus nlaced ?r!'fhJu ^^^"^^^y ^^eat the drops of
the columnTf'me c^^^^ shall notice'that
water is heated trthP^^^t ^ ^'''^^' ^"^ when the
barometer tu^^ L° atftffi.te^'Teie/^l
7
IV.] TENSION OF AQUEOUS VAPOUR. 45
that in the trough, showing that the elastic force of the
vapour at that temperature is equal to the atmospheric
pressure. Hence water boils when the tension of its
vapour is equal to the superincumbent atmospheric pres-
sure. On the tops of mountains, where the atmospheric
pressure is less than at the sea's level, water boils at a
temperature below 100**: thus at Quito, where the mean
height of the barometer is 527 mm., the boiling point of
water is 90°- 1 ; that is, the tension of aqueous vapour at
90*° I is equal to the pressure exerted by a column of mer-
cury 527 mm. high. Founded on this principle, an instru-
ment has been constructed for determining heights by
noticing the temperatures at which water boils. A simple
experiment to illustrate this fact consists in boiling water
in a globular flask, into the neck of which a stopcock is
fitted: as soon as the air is expelled, the stopcock is
closed, and the flask removed from the source of heat;
the boiling then ceases; but on immersing the flask in
cold water, the ebullition recommences briskly, owing to
the reduction of the pressure consequent upon the con-
densation of the steam ; the tension of the vapour at the
temperature of the water in the flask being greater than
the diminished pressure. All other liquids obey a similar
law respecting ebullition; but as the tensions of their
vapours are very diflerent, their boiling points vary con-
siderably.
When steam is heated alone, it expands according to
the law previously given for permanent gases ; but when
water is present, and the experiment is performed in a
closed vessel, the elastic force of the steam increases in a
far more rapid ratio than the increase of temperature.
The following table gives the tension of aqueous vapour,
as determined by experiment, at different temperatures
measured on the air thermometer.
46
ELEMENTAny CHEMISTRY. [Lbsson '
Tension of the Vapour of Water.
Tension in
millimetres of
mercury.
I
Temperature
Centigrade.
Tension in
atmospheres,
I atmosphere
= 760 mm. of
mercury.
0-927
2*093
4'6oo
6-534
9165
12-699
'7*391
31*548
54*906
91*982
148-791
233*093
354-280
525*450
760-000
differ from 760 mm the tPm^L^^ ^^^ ' '^ *e height
under that presTr^ tm'Z S^r."^ 'H""-'^' boilfng
vessel is here employed becauseT'f, T ?■ u^ ""^'^
does not always boil at r«;» ;t f ^ '^ '°""<i 'hat water
the atmospheric te^tTb^'ytVr^'''''''^''' »''°"gh
molecular action iialoffous to col,»=" I ""^'"S '° s°nie
and water. ""ogous to cohesion between the glass
Pure water and ice, when sepn J., i„
found to possess a blue colour f^ ■ '^'^^ »"^«es, are
glaciers Md lakes of S^S„h i' *"'] ="^" '» *e
pure water the chemist is oblSed tn J^f.^^^' '° °^t^'»
-ater (that is, to boil the'X'lntfn.VIf .^^^P""?-
IV.]
DISTILLED WATER,
47
formed by the condensation of the steam thus produced),
as all such water contains more or less solid matter in
solution derived from the surface of the earth over which
the water flows ; this dissolved solid matter is left behind
on boiling off the water. Solid matter in suspension can
be got rid of by the simpler process oi filtration through
paper, sand, &c. An arrangement for distillation on a
small scale, as used in laboratories, is seen in Fig. i6; it
consists of a glass retort in which the impure water is
placed, connected with a condenser, made of two glasg
tubes, between which a current of cold water is made to
circulate. The distilled water is collected in the flask
Fig. 16.
placed at the end of the apparatus. Rain-water is the
purest form of water occurring in nature, but even this
contains impurities derived from the dust, &c. in the air,
and no sooner does it touch the earth's surface than it
dissolves some of the materials with which it comes in
contact, and according to the nature of the ground over
which it passes becomes more or less impure. All fresh-
water on the earth's surface has been derived from the
ocean by a vast process of distillation, having been de-
posited in the form of rain or snow from the atmosphere.
All the rain-water ultimately passes in the form of
spring-water, or river-water, into the sea, carrying with it
48 Elementary CHEMISTRY, [lesson^
s^Quelljfe Tthif/^"' ^Y'"^ " ^^ percolated. In con-
r^^„1 i / ""* <:°n"nual accession of soluble salts and
rlXred Jr-l 7.T- ^^ r''P°"''°"' »»•«= sea-wL''e^s
renaerea salt; it contains about -ic narts nf cr^iiA «,«♦♦
28 of which consist of common illt"^^ sod um chS
m solution m 1,000 parts of water. cniorme;
stancerwIfhthT" ^^"^'■^' '°'^''"' ^°' chemical sub-
stances with which we are acqua nted. Most salts ar^
soluble tc a greater or less extent in water.^d a^ den^
sued again m crystals when the water is evTpor^ed • w^
are unac<^uamted with any simple general law rep-^lVinf
the quant ties of salts taken up b/w«S ; t mo!t ca ef
he solubihty IS p-eater in hot than in cold wate7 Water
Zat°o>7^Z^- V^'- '°'''^ '''^"= '» comLTnati^as
water of ciyslaUtzatton in many salts ; when this wafer
IS driven off by heat, the crystal fails to powder GasS
nitur.'^lf/'j':^ '" *?'^'' '" l"^"''''^^ varying with the
nature of the gas, the temperature, and the Dressur^ Vn
which the gas is subjected. '^It is solely Vcon^Tuence of
he presence of oxygen derived from the air dissolved .°n
the water of lakes, rivers, and seas, that fish are enabled
tfels^th^'o*' '^^P'r^^r : ^^ 'he water passe! throu|h
their gills the oxygen is token up to purify their blood.
Hydrogen Di-oxide.
■Symbol HjOj.— This substance has received the name
of oxygenated water, as it easily decomposes into oxTJ^n
and water : it is found to contain twice as much oxvfen
?o^v"'h'*°''i''°"''?'"S °^^ P"'^ by weighr"l hydrofen
by thrsvmbol 'H°oT!f" ' ''^"5?' 'f-efepreseTwIter
H n ^^Tt »°' l^yd^gen di-oxide will be written
H, O,. It does not occur in nature, but is artificiallv
?hSlc1'd"A"!r ''--/'■-ide Ba '0 fw^h'S
cmoric acid, H. Clj ; an exchange takes place between
^vW»'^"U'^ ^'^^ hydrogen, giving rise to hydrogerd"
oxide and barium chloride. Thus ;'urogen ai-
Ba I O,
ciJh.
v.]
NITROGEN.
49
H)drogen di-oxtde may also be prepared by passine
carbonic ac.d gas throigh barium di-oxlde suspended "n
water, when banum ca.honate separates out is a white
fn rdutio'lf tIV" '^T^ ?"" "y'^^^Sen di-oxide remains
equatioiT- °° " '■«P'"«^«"«ed by the following
Ba O, + H,0 + CO, = Ba CO, + H, O^
The aqueous solution of the di-oxide is ,-oncentrated
by allowmg the water to evaporate under the rece^er of
an air-pump ; the liquid after a time becomes thkk but
.t cannot be entirely freed from water. HyZgen dtoxide
IS chiefly characterised by the ease with which i bses
3- r%h7^'"i\^'= eas is slowly given off at 20°, but a?
100 C. the evolution of oxygen becomes very rapid In
consequence of the readii..:- with which it gives off
oxygen, hydrogen di-oxide acts as a powerful bleachine
agent, rapidly oxidising and destroying vegetable colour^
ng matter. A remarkable decomposition occurs when
this substance is brought in contact with ozone, comrnoS
oxygen and water being produced. Another imerSe
reaction occurs when silver oxide is brought togethe? wkh
hydrogen di-ox.de; as the silver oxide is reduced o
formid ' '" ''^'"' ^""^ "=°'"'"°° ""yg^" ««
LESSON V.
NITROGEN.
Symbol N, Combining Weight 14, Densitv ml —
Nitrogen exists in the free statfin the airf of whichTt
constitutes four-fifths by bulk ; it occurs comWned in the
bodies of plants and animals, and in various chemica!
compounds, such as nitre, whence the gas derives Ifs
name (generator of nitre). It is best obtained from thi
a.r by taking away the oxygen with which it is mTxed^
for this purpose we mav bum , ,,,».-» ^c _i. ^» '";".=" •
JO ELEMENTARY CHEMISTRY. [Lesson
bell-jar filled with air, the mouth of which is olaceH in ,
phosphorus and oxygen, called phosphorus pent-oxide at
water leavir;-''."' '^''' '°?" ^"''^'''^ ^"'^ <Sssolve in 'the
^ftK 'f^ ? t..e nitrogen m a nearly pure state. One-
fif h of th.^ original volume of the air, consisting of oxygen
will h,ve disappeared. Nitrogen may also be frepared by'
passing air over red-hot metaUic copper, which combines
with the oxygen, forming solid copper oxide, andTavhS
the gaseous nitrogen in a pure state. Nitrogen is lis!
formed when a current of chlorine is passed Through an
ex^ss of a solut on of ammonia ; nitrogen gasTevolved
and sal-ammoniac remains behind in solution. If the
chlorine be present m excess, a most dangerous and ex!
plosive compound is formed.
Nitrogeri is a colourless, tasteless, inodorous ?a«
slight'y lighter than air (specific gravity 972?a°r bel^!;
10). It does not combine readily with bodies, and is f
rZi?r?/"''K""?' ".«i*f .'"PPorting combustion no?
animal ife,nor burning itself: it has, however, no poisonous
properties, and animals plunged inlo a jar of thfs gas d"l
simply of suffocation from the want of ixygen. N toogen
can be made to unite with both oxygen and hydZfn"
when combmed with the latter it foris a powerfufalSe
^^k^'^Z"'"', ^"^ "v'**^ *''^ *'°'l' elements it forms a
strong acid, nitrtc acid.
The Atmosphere.
« Jh^. ^*'?9=P'>2'-e.is the gaseous envelope encircling the
S?.k' "^i" '^°"= ""'«« *e ocean of air at the bottom of
tT^ ,1 I ^^- ^^ ""^^.^^ ^^"^ of *e existence of
»nlV'^"7!u'"°''* '^P'^ly' "'<i experience the resist-
ance offered to the passage of our bodies, and also when
the air is in motion,'giving rise to a wind. We noticed"
^^n!f,T.f '^ ^l^osphere if we withdraw the a r fro^^
fw fu ^^^ Yy^^ ^^ ^ powerful air-pump, for we then find
that the hand ii pressed down with a fo?ce equal to ro«
kilos, on a square centimetre, or nearly 15 l^s. on every
(i
-\^.
''. [Lesson
placed in a
>mpound of
nt-oxide, at
solve in the
tate. One-
: of oxygen,
)repared by
I combines
md leaving
fen is also
hrough an
is evolved,
n. If the
IS and ex-
)rous gas,
air being
, and is a
istion nor
poisonous
IS gas die
Nitrogen
lydrogen ;
il alkaline
it forms a
cling the
jottom of
stence of
Jie resist-
Iso when
otice the
air from
then find
to 1-033
3n erery ,
v.]
THE A TMOSPHERE,
51
square inch. The total atmospheric pressure which the
human body has to support hence amounts to several
tcMis, but this pressure is not felt under ordinary circun -
stances, because the pressure is exerted equally in every
direction. The instrument used for measuring' the pres-
sure of the air is termed a Barometer (see Fig. 9, p. 30),
and the average pressure at the ser>.-level is equal to that
exerted by a column of mercury 760 mm. high. 1 he air
being elastic and having weight, it is clear that the lower
layers of air must be more compressed than those above
them, and hence the density of the air must v-v at dif-
ferent heights above the sea-level. The density -i the air
being thus dependent on the pressure to which it is sub-
jected, the higher strata of air become extremely rarefied,
and it is hence difficult to say exactly whereabouts the air
ceases, but it appears that the limit of the atmosphere is
about 45 miles from the level of the se?. If the whole
atmosphere were of the same density throapJiOut as it is
at the earth's surface, it would only reach to :^ height of a
little more than 5 miles above the sea-level. The weight
of one litre of dry air at 0° and under 760 mm. of pressure
is 1*2932 grams.
Respecting the chemical composition of the atmosphere
we have to remark, in the first place, °tl at the air is a
mixture, and not a chemical compound of its constituent
gases, although, as we shall see, these occur throu;Thout
the atmosphere in almost unvarying proportions. T^e
grounds for commg to this conclusion are, first, that i*' ive
bring oxygen and nitrogen together in the proportions in
which they are found In air, no elevation of temperatur.
or alteration in bulk occurs (as \j invariably the case when
gases combine), and yet the mixture acts in every way
like air; secondly, that the relativcquantities of the two
gases present are not those of their combining weights,
nor of any simple multiples of these weights ; and thirdly,
that although in general the proportions of the two gases
are constant, yet instances not unfrequently occur in which
tiiis ratio is different from the ordinary one. The most
E 2
52 ELEMENTARY CHEMISTRY. [Lesson
convincing proof, however, that air is not a chemical
compound is derived from an experiment upon the solu-
bility of air m water ; when air is shaken up with a small
quantity of water, some of the air is dissolved by the
water; this dissolved air is easily expelled again from the
water by boiling, and on analysis this expelled air is found
to consist of oxygen and nitrogen in the relative propor-
tions of I and 1-87. Had the air been a chemical com-
pound, it woula be impossible to decompose it by simply
shaking It up with water ; the compound would then have
dissolved as a whole, and, on examination of the air ex-
pelled by boiling, it would have been found to consist of
oxygen and nitrogen in the same proportions as in the
original air, viz. as i to 4. This experiment shows, there-
tore, that th^ air is only a mixture, a larger proportion of
oxygen being dissolved than corresponds to that contained
in the atmosphere, owing to this gas being more soluble in
water than nitrogen.
There are many ways of determining the amount* of
oxygen and nitrogen contai^ied in the air, the best of
these being by the eudioiueter ;* by means of which the
composition by volume is ascertained. For this puroos"
the same arrangement is employed as that used in" the
eudiometnc syn.hesis of water (Fig. 17). A quantity
ot air sufficient to fill the tube about one-sixth full is
introduced into the eudiometer previously filled with
mercury ; the volume of this air is then accurately ascer-
tained by reading off with a telescope the number of the
millimetre divisions on the tube to which the mercury
reaches, whilst the height of the column of mercury in
the tube above the trough, together with that of the
barometer and the temperature of the air, are also read
off. Such a quantity £>f pure hydrogen gas is now added
as IS more than sufficient to combine with all the oxygen
present ; and the volume of this gas, and the pressure
exerted upon it, are then determined as before. An
• From eid«,i, clear weather, and m^'tpok, a measure: a measure of the
clearness or punty of the air ; that if, of the quantity of oacv«n whJ.K ;.
com^oi. - ^^— — -
len iiave
v.] EUDIOMETRIC ANALYSIS OF AIR. 53
electric spark is now passed through the mixture, care
having been taken to prevent any escape of gas by pressing
the open end of the eudiometer against a sheet of caout-
chouc under the mercury in the trough. After the ex-
plosion the volume is again determined as before, and is
found to be less than that before the explosion, the whole
of the oxygen and part of the hydrogen having combined
Fig. 17.
to form water; the diminution, therefore, represents
exactly the volumes of these gases which have united.
We know, however, from our previous experiments upon
the composition of water, that 2 vols, of hydrogen always
unite with exactly i vol. of oxygen to form water : hence
one-third of the diminution in volume must represent the
oxygen which has disappeared, and, therefore, the volume
of oxygen contained in the air taken. An example may
make this clearer, buppose the volume oi air taken
r
54 ELEMENTARY CHEMISTRY, [LESSON
amounted to loo vols, and that after the addition of
hydrogen the volume of the mixture was 150 vols. ; after
the explosion 87 vols, were found to remain, that is,
63 vols, had disappeared ; then -1 « 21 will be the volume
of oxygen contained in 100 vols, of air.
Analyses of air collected in various parts of the globe
thus made with the greatest care have shown that the
relative quantities of oxygen and nitrogen remain the
same, or very nearly the same, from whatever region the
air may have been taken. So that whether the air be
derived from the tropics or the arc! 'c seas, from the bottom
of the deepest mine or from an elevation of 20,000 feet
above the earth's surface, it contains from 20*9 to 21 vols
of oxygen per cent.
When we know the composition of air by volume, and
the relative densities of the two constituent gases (14 for
nitrogen and 16 for oxygen), we can calculate its compo-
sition by weight; we thus find that in 100 grams of air
23-16 grams of oxygen are mixed with 76*84 grams of
nitrogen. It is important to control this calculation by
experiment ; for this purpose a large glass globe furnished
with a stopcock k rendered vacuous by the air-pump and
then weighed ; a tube of hard glass filled with copper
turnings and also furnished with stopcocks is likewise
weighed. This tube is then heated to redness in a Ion?
tube-furnace, and connected at one end with the empty
flask, at the other with a series of tubes filled with caustic
potash and sulphuric acid, for the purpose of completely
Ireemg the air passing through them from carbonic acid
and aqueous vapour ; the cocks are then slightly opened,
and air allowed to pass slowly through the purifiers into
the hot tube, where it is completely deprived of oxygen
by the hot metallic copper, which is thereby oxidised -the
nitrogen passing on alone into the empty flask. After the
expenment is concluded, the cooled tube is again weighed
and
uuant
the increase over the former weighing gives tt
- -• cs ; ■«—■«- sxivivaa-*, ill WCigUl Ui il
I
the
iiiC
i
Lesson
ition of
. ; after
:hat is,
volume
e globe
hat the
ain the
ion the
air be
bottom
•CO feet
SI vols.
le, and
(14 for
:ompo-
of air
ims of
ion by
nished
ip and
copper
kewise
1 long
empty
caustic
jletely
c acid
Jened,
s into
xygen
I; the
er the
ighed,
!S the
il IRS
v.]
COMPOSITION OF THE AIR,
5S
globe gives the nitrogen. The mean of a large number
of experiments thus made shows that 100 parts by weight
of air contained 23 parts by weight of oxygen and ^^ of
nitrogen.
In addition to the two above-mentioned gases, the air
contains several other important constituents, especially
carbonic acid gas, aqueous vapour, and ammonia gas.
We have already noticed (page 14) the important part
Fig. 18.
which the carbonic acid gas of the air plays in the phe-
nomena of vegetation, this gas being the source from
which plants obtain the carbon they need to form their
tissues. The quantity of carbonic acid present in the
air is very small compared with the quantities of oxygen
and nitrogen, being only about 4 vols, to 1 0,000 of air ;
nevertheless the absolute quantity of this gas contained
in the whole atmosphere is enormously large (viz. about
3,000 billion kilos.) The quantity of carbonic acid con-
tained in the air can ,.-e found by drawing a known volume
of perfectly dry air (not less than 20 litres) through
weighed tubes containing caustic potash ; the increase
}r» weip-Vit of the tubes fives the weia"ht of carbonic Ecid
56 i'^LEMENTARY CHEMISTRY, [Lesson
contained in the air drawn throup-h F,v ic cu .1
described in the larger manuals. '^"■^'^•"c acid are
Aqueous yapour is contained in the air in -inanffi^o
varymgu, diiiferent localities and at diffe ^nt t?mes and
depending mainly upon the temperature of the Sr A^
at a given temperature cannot contain more than a cert^'n
quanity of moisture in solution; and when it has uke"
fog^oVxi^rirt'ife^cre^i^f'r^^^^^
and hail; when war^ air^lTer/y tden'^ th'moUture
when the temperature is ab Je theTeezfng Um""'^
crystallizing as snow-flakes if the temperatur^ Ee below
[Lesson
shows the
: aspirator,
e of water
passage of
two tubes
le steeped
:ompIetely
bulbs, in
c potash ;
huric acid
tie potash
onic acid
inder dif-
2 to more
:losed in-
present is
to reduce
possible,
acid are
uantities
nes, and
iir. Air
1 certain
IS taken
ted with
the air,
'hen air
jposited
a mist,
1, snow,
loisture
osition,
ture, it
, and a
IS rain
int, or
below
v.]
MOISTURE IN THE AIR.
$7
that point. Hail is caused by the congelation of raindrops
m passing through a stratum of air below the freezing
point. The quantity of rain thus deposited is very larpe :
I cubic metre of air saturated with moisture at 25°^ C
contains 22-5 grams of water, and if the temperature of
this air be reduced to 0° C. it will then be capable of
retaining only 5-4 grams of water vapour; hence 17-1
grams of water will be deposited as rain. The air in
England is often saturated with moisture, whilst the
driest air observed on the coast of the Red Sea during
a simoom contained only one-fifteenth of the saturating
quantity. Instruments for ascertaining the degree of
moisture or humidity of the air are termed hygrometers.
Tho deposition of dew is caused by the rapid cooling
of the earth's surface by radiation after sunset, and by
the consequent cooling of the air near the ground below
the temperature at which it begins to deposit moisture.
The amount of aqueous vapour contained in the air at
any time can be determined by the apparatus used for the
estimation of the carbonic acid, for the moisture must be
removed from the air before the carbonic acid can be
absorbed, and the increase in weight of the tubes filled
with pumice-stone moistened with sulphuric acid gives
the weight of aqueous vapour. In general the air contains
from so to 70 per cent, of the quantity necessary to saturate
It. If the quantity be not within these limits, the air is
either unpleasantly dry or moist.
The next important constituent of the air is ammonia
which is a compound of nitrogen and hydrogen, and only
exists in comparatively very minute quantities (about 1
part m 1,000,000 of air). Nevertheless it plays a very
important part, as it is mainly from this ammonia that
vegetables obtain the nitrogen which they need to fonn
their seeds and fruit ; for it appears that plants have not
the power of assimilating the free nitrogen of the atmo-
sphere. Other substances which occur in the atmosphere
m very small quantities rnay be considered rfs accidental
imnurities^
\ w» «r^^
\jt.A\.i.i.x: uigaiiic matter ia liie
■7'
58
ELEMENTARY CHEMISTRY. [LESSON
aware of the existence of^^^.h „^""^ '""• We become
stances when enteric a crnwH»,^^"''= P""'«scent sub-
air; and it is probawl thafZ'' "7°"" '^'°'" "'^ ^'■esf'
of marshy and^'oth^^d^tri tf s o'l'^rVet^f '''°^",
some omanic imDuritv At r..lo^T i? ^^ presence of
6ut little%ertain DWge J^ this' ^ub^cr '^ "' P-°^=f ^
present in fresh air, but ILerallv X»-' , •' P,.'""^ '' ^^°
of towns and dwell ne ronmf 3 ''f^"-' "\ *^ '^'ose air
by the organic mane?, &c"n' S^a 1° "' ;^^=°«P°f '°"
how it is formed in nature, unless it be bv th. T ^""^
of atmospheric electricity. ^ *^ discharge
I LESSON VI.
COMPOUNDS OF NITROGEN WITH OXYGEN
^^^'^l^^^^l^S^^^:^^^^ ^'--1 compounds
LTO;:^^^?s;*'''"=°°'^'"'»^t^""''^ ''=*■« of N. -»■« of o
3 Nitrogen Tri-oxide *' ,0 " .. 32 —
. 4 Nitrogen Tetr-oxide ^ *' »» 48 —
5 Nitrogen Pent-oxide " -a »» »» 64 —
It will be seen that the oxveen containpH ;n"fi
P°""ds is in the proportion of the numbers 2 T^ TT^
one and the same quantity of nitrno-o,i . „ \i V ' 3' ?' 5' '"
first time, we meetVth a^trikW fxaAnl Af Tif' /"'' *^
[Lesson
at extent
become
ent sub-
he fresh
ilthiness
Pence of
possess
e is also
:Iose air
position
)t know
scharge
pounds
■6 of o.
|2 —
.8 —
'4 —
o —
' com-
h 5, to
or the
^aw of
, while
irts of
i that
some
(thus,
at no
ity of
iated
ished
VI.] DALTON'S ATOMIC THEORY. 59
experimental facts. Dalton endeavoured to explain these
facts by his celebrated Atomic Theory. He asked him-
self, Why do the elements combine only in multiples of
their several combining proportions ? and he answered
the question by the 1 allowing supposition.
Matter is made up of small indivisible portions, which
are called Atoms (a privative, and re/xi/o) I cut). These
atoms do not all possess the same weights, but the rela-
tion between their weights is represented by that of the
combining weights of the elements ; thus the atom of
oxygen is taken to be 16 times as heavy as the atom of
hydrogen, and the weights of the atoms of nitrogen and
oxygen as 14 to 16. Dalton further assumed that che-
mical combination consists in the approximation of the
individual atoms to one another ; and, having made these
assurnptions, he was able to explain why compounds must
contain their constituents in the combining proportions or
in multiples of them, and in no intermediate proportion.
Let us take, for example, the compounds of nitrogen and
oxygen ; the lowest of these consists of one single atom of
oxygen combined with 2 atoms of nitrogen, or with one
double atom of nitrogen, as it contains 16 parts of oxygen
to 28 of nitrogen ; thus, (n)(n)® J and we therefore
write its foi-mula, N^ O, and call it nitrogen mon-oxide.
^^l^^''^J'^^Vo^xri^. that can be formed must be produced
by the addition of another atom of oxygen to this ; thus
we get ®®®® = No O2, or nitrogen di-oxide. The
next must be formed by the attachment of another atom
of oxygen, and thus we get{^)0(o)g)(o) = Nj O3, or
nitrogen tri-oxide. The next possible compound is
NXNj(0X0X0X0j=:N,04
or nitrogen tetr-oxide ; and the next
= N.O
SI
6o • ELEMENTARY CHEMISTRY, [Lesson
planation of new facts * P^^'^t^uy suited to the ex-
the molecular weight of water. 2 -f-io _ i8, gives
Combining Volumes of Gases,
one: inasmuch a^sii::^"J°",';'''° ^Z ^ ^^J^ f ™P'e
'•» the gaseous state «4 &^/ ^/f 'Zv ''""'"'^
'^.erghts; or, what is the 3ame hW he atom. tT.!^
gaseous state all occupy the same spfce't
alike "r'orfZgL'i^ -^g^ -re
the density kKUIn'g w: ght'jr^Urt^^^^^^
H; or, nitrogen is 14 time! hea^lVlaTS^^ f^hl
to the la* m.„tioMd on par™, r«K«fnJ il / ^•■'. '^7 *"' "" '"^opfOM
vapours, as instead of hav'^nf the r deS es^^en J. "t'l °/ "T^T^ gaVes or
.n5 fSS Xi'la;St"se'?s?l'nXTwY '" *' ^=- "' Pl-P^on^
to be in accordance with the ab?ve law Sh " ^ «"■?« ^' 'k"! required
.uch a. ainc and mercury. ^l^SX'-TX^\^Z:^%i^'^
X
It
VI.] COMBINING VOLUMES OF GASES, 6i
density of chlorine is 35-5, that of sulphur vapour 32, and
so on. Remembering this fact, it is easy to calculate the
absolute weight of a given volume—say one litre of these
different gases— when we know that one litre of hydrogen
at the standard pressure and temperature weighs 0*08936
grams. Thus i litre of oxygen, under the same circum-
stances, weighs 16x0-08936= r43ograms
I litre of nitrogen weighs 1 4 x 0*08936 = 1-251
„ chlorine „ 35-5x0-08936 = 3-172
„ sulphur vapour „ 32x0*08936 = 2-860
With respect to compounds, we find that the density of
a compound gas is one-half its molecular weight; or the
molecule of a compound gas occupies the space of 2 atoms
of hydrogen.*
Thus the density of water-gas, or steam, H„0, is -- or
2
9; that is, it is nine times heavier than hydrogen; the
density of hydrochloric acid, HCl, is ^^ or 18-25; that
of ammonia, NH3, j or 8-5 ; that of carbonic acid, CO^
44
— or 22.
2
Hence the weights of i litre of these compounds (esti-
mated at 0° C and 760 mm.) are as follow:
I litre of steam weighs 9 x 0*08936 gram,
ammonia ^ „ 8-5x008936 „
„ hydrochloric acid „ i8-25Xo-o8936
„ carbonic acid „ 22X008936 „
The symbol for water, HgO, therefore, not only indicates
that It IS composed of 2 parts by weight of hydrogen and
16 of oxygen, but also that 2 volumes of hydrogen have
united with I volume of oxygen to form 2 volumes or one
molecule of water gas. The symbol NH3 denotes that
3 volumes of hydrogen and i volume of nitrogen have
• The exceptions to this law are mentioned under the several compounds.
■<5» ■ ELEMENTARY CHEMISTRV. [Lksson
t"he' s'Aol™ Cltrs' thatT'","' ^' °^-'?'"onia, whilst
acid ^ contain x vormeXhlori^^'andfo'/h'^r""™
We have seen that o» »> J. i ^ ^ °' nyarofifen.
unite with 32 parts of oxvLrr„%*'^ ^'^'S*^* of nitrSgek
the. density' of tWs compS is h'^ever"^ f°A '
penment to be ic- hpnrA .>o ' "^^^^er, found by ex-
consisting of ,4 parts ^ weight oTtt--^'^''^''* h°'
^s 4teE °^iiZlS;r!!L^tT ^T'' ^
K-rsi:rKortf|^^^^^^
the union of the nitro^n inH '^---oxides, fc.med by
illustrates the ^n:^Xe:^r:rj^rfA^'- ^'«- '^
a glass globe filled with air is ffirn?! ? 'i • ^""^ Purpose :
wires, from the extremities of Si I"''* '"'° ««aUic
induction coil can be Tssed thrn i, ^^ 'P?'''' fr"™ ^
-Pid discharges l>av?1o^'iu'S"tt f^i:;- mt'^L!''!
^w^
[Lesson
nia, whilst
irochloric
\ydrogen.
nitrogen
di-oxide ;
^d by ex-
ht is 30,
to 16 of
> formula
together,
3 do so i
ough a
oloijred
lOticed.
ned by
Fig. 19
rpose ;
letallic
om an
ter the
utes, a
VI J PROPERTIES OF NITRIC ACID, 63
portion Of the oxygen and nitrogen have united to form
a compound gas having a reddish brown colour wh°S
^ni ^if if-^'J^'^??^^'^^ ^y ^°^di^g ^ sheet of white
paper behind the globe. These red fumes have the p^wer
(like ozone) of liberating iodine from iodide of potassium'
stfrrh tl P"P'' ^^r^ ^" ^ ''^^^^ °f this a a?d
starch (see page 17) becomes at once blue when brought
passed fcl'/i"^' '^°"^^ ^^^^^ '^^ sparks hfve
t^hroui whth ^ ^'' '"'"i^ ^^ P^^^'^' ^^ P^^^^ -'"t »^ the air
called^ nitTpi. \ 'P^'^' ^-'^ P^^'^^' ^ '^^^ substance
called nitre, or potassium nitrate, is formed ; and from
^rlrslir^^''^ compound, called nitric acid, can be
i^Sf.«- • ^^'l substance is formed when flashes of
ifil^i"/ P/'' •^"'l"^^ ^^^ ^^"» ^^^"& ca^-ied down to the
earth s surface in the ram. Nitric acid may be considered
^n f,^°";P°""^ of 'Nitrogen pentoxide with water; and, as
all the other nitrogen oxides can be prepared from it we
raSon '' '°" "^'^ ''^ properties and mode of prepT
Nitric Acid, or Hydrogen Nitrate.
SymbollA'^0^, Molecular Weight 63.--Nitre, or potas-
Slum nitrate, is generaUy formed by the gradual oxidation
nL^ir^?° •' ^'^^"'^^ ^^^"^^ ^'^ Vr^slc^ of the alkaH
potash. Spring water, especially the surface well-water
of towns, frequently contains nitrates in solution, owing to
mtf^L^^^'^'S^^'r^^ soil containing decomposing animal
matters, which by oxidation yield nitrates. For th^
reason, water containing nitrates is unfit for drinking
purposes Potassium nitrate, kNO, (commonly called
saltpetre), occurs as an incrustation on the soil in various
localities, especially in India; and sodium nitrate!
^^^03'i!r.,^h^li saltpetre, is found in large beds on the
coast of Chih and Peru. Nitric acid is obtained by heat-
!5f..^''H'<fn^^^\^^'^ ?"lP^""^ ^^^^> °r hydrogen sul
phate, H,SO, ; when nitric acid, HNO3, and hydrogen
Snctir"l'"^P^^^'"' ?^^^*' ^^^ f°^'"^d. The decom"
positions here effected may serve as a type of a verv large
64
KNO
Nitre and
ELEMENTARY CHEMISTRY. fLESSON'
/fifif r^f r.««.^ • ^.^i>^f place with one atoui or :^s eom7m-
lent of potassium in the nitre Thesf* Hn.r ) t ^9^"^^.
tions may be reorespnfpH f« 1 f r ' "oi^posi-
a/^er^e chemical change hTs"?at„"Jlfc:, rs-"^"^"''
'j + ^2 Sa = H NO. + HK SO or
&lphunc Acd giv. Ni.ric Acid & kydrogen S;.iiil S^Jhaw
SifcombtT'and'thatthe''^ 'k^?^''^^ "^'^'^^ -'h
exchange ofVdrogen'for potaS ^'^ ^^^"^ ^
(5^]
<["h so,
\K)N0,
or by a straight line, thus—
H
NO3
HSO4
K
Les^n
'omposi'
ig in an
.nents ;
ogen in
eqttiva-
3mposi-
[uation,
relative
her the
ements
O4 or.
iulphate.
Dounds
i when
ely the
It with
it of a
of its
above
S O .
2-f-64
I
Thaps
actual
VI ] PREPARA TION OF NITRIC A CJV, 65
This signifies that, if we require 63 parts by weight of
nitric acid, we shall require to take exactly ,0^1 pL^rts of
hive' M6Vn ^r') ^^r'^^^^'^ ^^•^' ^^^ ^hat ^^e shall
nave 136 i parts of hydrogen potassium sulphate formed
Do"rHr/ '^- ' "T^"''^' '' '''^'y ^^ calciUate the pro-
portions of ingredients needed to produce any given
qua.^tity of nitric acid. 'ygi>en
i'ig. 20.
Nitric acid is prepared on a small scale by placin- about
cqua weights of nitre and sulphuric acid in a stopp^^^^^^^
retort, which is gradually heated by a Bunsen's burner, as
l^'nZ'Lf''' ^^^/'5"c acid formed distils over, and ma; be
collected in a flask cooled with water. On a large scale
this substance is prepared in iron cylinders, into which
ttfrT.\''i "'^P ^""^ ^"^^^ ^'^ ^'''''SK the nitric acid
being collected in large stoneware bottles.
Nitnc acid thus obtained is represented by the formula
r»,rl V. '" a strongly fuming liquid, colourless when
fZ% ^-^ '"'"'f^- '^'Shtly yellow from the presence of
lower oxides of nitrogen. Its specific gravity is 1-51
at i« ; It does not possess a coi.-tant boiling point, as
It gradually undergoes decon^osition by boiling ind
m/: . m
66 ' £Z£UEJVrAJiy CHEMISTRY. [Lesson
less water, a stronse' ac id thU 1v ' ^" "'"""^ ^"'^
mixed with more witer^ w, if *" .^"'"^^ °^«'' ! "hen
this constanTcom7osi;:io„Ts at'aird'^t^f ^'"^ °?^ ""
tains 76 per cent, o'f oxygen ^fS'some o"^ 'whic^'eaTi?;
tin into this hquid"'dnut:dtraZl°e'S'"r:7Fume''
are immediately P-iven off ;,nH ^v.^ 1 * i ^ ^" ^""^^^
iiiliiiflsi
solution of ferrous subhate ?eSn"^ °1,'°,''' '"^''"'^^ ^
duced wh.re the two avers' J\2.'-A^ black rmg is pro-
acid ' nrPspnT M-; . y^'^?^™ "qu'd meet if any nitric
by the ^proces; ^iZ ^^"^1°""^. ^"A metallic oxides!
fi;.i?xrciufdt';'a:s Thrrri'Sri^ar^^^^^
for^:^rju™res°'vt";^i,f^'^^
several rnetfls "^ ^^^ """ '''^ '"-^"tioned under the
acfdi'cr "^ °f '"^ing'' Erullftmu s'-solut :;^' ?e"d ' All
oxygen, aid ^^^^^^^t:"^^^ ^^^^
"ufs. These acids may be regarded as water, g \ O,
ac
Lesson
d under
acid is
ng con-
O3, and
ed with
; when
;ver till
id con-
t easily
This is
pper or
fumes
idized ;
ilutior,
matter,
■esence
ng the
^sts for
ited an
ng the
■face a
is pro-
nitric
3xides,
nerous
lolublc
e arts
ler the
ies of
acids
1 have
. All
:ment.
n tains
i oxi-
lie,
VI]
ACID BASBS AND SALTS.
f
in which part of the hydrogen is replaced by the oxygen-
ated group of atoms ; thus nitric acid may be represented
as H J ^- Whe^ the rest of the hydrogen of an acid
is replaced by a metal, as for instance when sulphuric
acid acts upon zinc, the acid character of the substar -
disappears, and a salt, called zii^e sulphate, is formed,
thus : —
Salts are likewise produced when certain hydroxides and
oxides are brought into contact with acids ; thus if the
solution of potassium hydroxide (caustic potash), obtained
by the action of the metal potassium on water, is added
to nitric acid, the alkaline or caustic properties of the
hydroxide as well as the sour taste of the nitric acid dis-
appear at a certain point ; the solution becomes neutral,
that is, it does not change the colour of either blue or
red litmus, and the salt potassium nitrate is contained in
the liquid : thus —
The soluble hydroxides which thus act upon acids are
terried alkalies, and have the power of turning red litmus
solution blue. In the same way many metalhc oxides,
called basic oxides or bases, act upon acids tp form salts ;
thus silver oxide dissolves in nitric acid, and neutralises
its acid character, forming soluble silver nitrate, thus—
11 !°
■f 2
NO,) H)
+ 2
NO
A ^ ^ O
Ag S ^^•
V 2
68 ' ELEMENTARY CHEMISTRY. [Lesson
Nitrogen Pentoxide, or Nitric Anhydride.
.^/.«3./NA,orNg^2Jo.-This oxide of nitrogen
,Trf"rv'.M Prepared directly from liquid nitric acid; but
found to be nitrogen pentoxide. The decomposition tikes
place in two stages, in the first a yellow liqu d cSled
nitroxyl chloride, NOj CI, is formed ; thus- ^
NoJ + S ! =NOa CI + Ag CI + O,
and this acting upon another molecule of silver nitrate
forms mtro|;en pentoxide ; thus—
fei^°?^cr"'°!5'''^ ™^"'. ^' + 3°" and boils at + 45" • it
N8:!0+gi0=N0,j^^N0,j^_
The fact that the composition of nitrogen pentoxide is
ex^SnllW^l'lf™"'^ ^^?» may^e^'aTcertLlned
experimentally by determining the quantity of nitrosen
contained in 100 parts of nitrogen pentoxide, which is
first converted into nitric acid by tfie aid of ' Jate. as
oxrd'^t'thus. ""° ''^"^ ""'^'' '^y '^^^""'^"' ^'A i^'»d
Pb O + 2 NO3 H = Pb 2 NO, f H-0.
We thus find the nitrogen tr weigh ;':■.•^-^ parts and
hence the oxygen 100- 25-9:„ or 74-07 parts! We then
wish to know what is the simpHs. relation lA whi^h the
combmmg weights of nitrogen an. ,g.n are comained
in this compound ; in other wo.-ds vnat .., the ratio of the
>^
[Lesson
nitrogen
icid; but
ite, silver
a white
lalysis is
ion takes
id called
3,
r nitrate
CI.
■ 45" ; it
es with
VII.]
NITROUS OXIDE.
69
3xide is
Ttained
itrogen
hich is
ite** as
th lead
:s, and
e then
ich the
tained
of the
number of atoms of nitrogen present to the number of
those of oxygen This is ascertained by dividing the
tt7e^3'e^entr;fcP"^^^^ ^°"^^^^^^ ^^^''^ ^'
-2^3 = ,.853 and 7^7^4-6294.
senf^nV^^'" ""l ^^^ ?''^^^' °^ ^*°^s °^ nitrogen pre-
sent to the number of atoms of oxygen is th.it of the
cond^^^^^ Jhlf .1' ^'''^f' ^^ ^^^^ of 2 L%.990. Hence w1
n?nm. ? ^ ^ ^^^ ^""J"^ ^^^^*^ ^^ between the number of
fh^ cr L^f-%^^'' ^""^ """"y^^^ respectively is that of 2 to c,
,n ^^'.^^i^.^^fference whic:i is noticea being due to ihe
unavoidable errors which accr^mpan- -very experimental
Al^h^' n^lf ^^^\!?^^-f?re, terme^d errors 1/ elp7ZTf.
nitric^HH h' °/^d^\°f^ nitrogen may be obtained from
less of ,/. > depr^^^^g 't of Its hydrogen, and more or
iess 01 Its oxygen.
LESSON VIL
Nitrogen Monoxide, or Nitrous Oxide,
Symbol y^^O, Molecular Weight 44, Densitv 22 i\
obtamed by heating ammonium^ nitmte, NHfNS; or
NO* I ^> '"^ ^ fl-'^s^ such as that used for the production
of oxyg ,n, and is best collected over warm water (see Fig.
21). The salt de-->mposes on heat-ng into nitro<-en mon-
ri'v^^^^^^^^^^ NH,N03==N,0+/h,0; or'am^^::>Zm
s a c lo fr ^ 'f" ^°^°^^^<^ - d water. Nitrous oxide
aste. ? k . '^^iT^^e^^is possessing a slightly sweet
taste , 1 IS somewhat soluble n cold water one volnmf*
of water at c^ dissolving 1-305 volumes of tL gas S
one volume - water at 24° dissolves only o 6of vok .ne
-.trogen nionoxide differs from all such gases x hich ve
lave Drfv nimlv^noc.-^^^^^ x «^'' 8f.=>es vnicn v.e
expos?d''I&~"''''r''^' '""'""^'' ^^ it liquefies when
cxpobed either to ^reat pressure or to nn in?.*r^=^ j^.-.- ..
70 ■ ELEMENTARY CHEMISTRY. LLesson
o her wo?H°,1l."^'^ pressure, it forms a colourless 1 quid (in
liSe cooTed~beIor-,^i°c» n^H-f 'f' °° ^'^^ '^ ""'^
mli<:« p., ,1, -5 "5 ' " solidifies to a transparent
reldn^jks' a^nrf'l'lL°^ ""T*^ ^^^"^ P'"°S«<1 i"t° "i'^ous oxide
rekindles, and the wood continues to burn with a brighter
Fig. ai.
tiTyi^rvot's'^L^i^vis'tc^^^^^^^^^^^
to effect this decomposition a tolerably high temperatu.^"s
[Lesson
of about
to - 88"
iquid (in
■ gas is I
. If this
isparent
n vacito,
las beei)
us oxide
brighter
ingi» m
ygen ;
id on
t also
t that
5)and
; and
ure is
VII.]
NITROUS OXIDE
7i
necessary,— the same products of combustion are produced
as if the combustion went on in the air. When inl
nitrous oxide produces a peculiar intoxicatii
the human frame ; hence it has been called lL
The composition of nitrous oxide may be c\NLt.^^ „,
follows : a bent tube (Fig. 22) is filled with the %y gas
over mercury up to a certain mark on the tub^, glmall
pellet of metallic potassium having been previously intro-
duced into the bent part of the tube j this is then heated
by a spirit lamp, or Bunsen's burner, while the open end
of the tube is closed with the thumb under the mercury,
to prevent a loss of gas by sudden expansion caused by
the combustion. The potassium burns in the gas, uniting
Fig.
J2.
with the oxygen to form solid potassium oxide, whilst
the nitrogen remains in the tube. On removing the
thumb and allowing the tube to cool, it will be seen
tnat the volume of nitrogen is exactly the same as the
volume of nitrous oxide taken ; hence this ^as contains
Its own volume of nitrogen. But we know by experi-
ment that the weight of one volume of the gas is 22 so
that if we subtract from this the weight of one volume of
nitrogen (viz. 14) we shaU obtain the weight of oxygen (8^
contained m one volume of nitrogen monoxide. Hence
we see that two volumci of nitrous oxide are composed of
two volumes of nitrogen and one volume .s^^gen or 44
%
7^ ■ ELEMP^TARV CHEMrSTkv. fLESSON
parts by weight contain 28 of nitrogen »nH ,e. c
gl^'s formula is therefore KO^ThftlA ""y^^"'
^ ^■qiJM^ ide (air = ,) is rcVj- j^J'^u"^" gravity
mrfaph ,W2 grams! ^^ ' '•°°' '='"^- ^' ° anS
Zf''"'/"^ NO, Molecular WeW,t ,0 75. v
colourless gas obtained by actXuDon '""'^ '5— ^
i tLtmg upon copper turnings
^^^^tir ^^^^^^^^^^
and collecting it oJe^^^erS^nT^!]- 3..
3Cu + 8HNO, = 3(Cu3N03) + 2NO + 4h'o
^:^^ '"' S'- -PP- -^rate, nitrogen di-
co,^^*rwtro"4l'n"ir°c'o!rnerd'^T' '\^ ">'<>= «
gas, forming red fumes tZchZl ^J^^^ T^ "^'^ 'a"er
and by this property irmavh^H^'^j'^ "?'".'''='" «ater,
other gases. AUhou ,h nitric n '^''""g^'^f'^d from al
volume of oxyeen anrl ^T ""^'^ contains half ics
weight than n1So'"deTdo.?j:«r '"; P^°POrtion by
posu,o„ ; thus, .gnited pho%horus,-«ni'es3 burn ng' veTy
/
Lesson
oxygen,
gravity
o° and
1 5-— A
irnings
sgas
1 di-
: ; in
atter
ater,
I all
ics
I by
om-
om-
r'ery
/
«B«
NITROGEN TRIOXIDE.
extinguished on plunging
n
VLI.]
brightly, is v.^.xuiiuibnea on plunging it into nitric oxide
\2\l ^^'^'"/u °? ^ ^^** ^^^ "^^ybe determined ac«^
ng to the method described under nitrogen m^^m-
one volume of nitrogen dioxide yields hflf a voUime of
oS"/.'th^ ^1^ ^' one 'volume of ni'rogeTcHf
of this ef^ t "IT^l °^«"^^'" '°"^^^"^^ '"^ one volume
ui mis gas is i5--7 = 8: or two volumes of nitrogen
dioxide weigh 30, and are composed of one volumf of
nitrogen weighing 14, and one of oxj^en weS 16
Hence m accordance with the law mentioned on d 61
respecting the densities of compound gaserthe formula
of this oxide should be N O and not ivj n ' fi? ^?^"^."^^
DroDerties csi thA !r!.o it • ^^ ^'Pi- the physical
p operties ot the gas likewise, compared with those of
nitrous oxide, seem to indicate that this latter has a more
Kee'nfn the1^'"'T.= ^^"^ ^T'' oxide has not™'
liQuM IttPn.^ T'^ ^°"?' ^""^ ^°^s ^°t condense to a
liquid at temperatures and pressures at which nitrous
oxide readily hquefies ; nitric oxide is dec^mposerw^^^^^
greater difficulty by heat than nitrous oxide, aZ therefore
supports combustion less easily ; and it is a genemUaw
that in a series of similar bodies the more comKed be
the constitution of one member, the more reS does i?
The specific gravity of nitric oxide (air = i) is ro^8
Mtrogen Trioxide.
Symbol N2O3, Molecular Weight 76, Densi/v '8_
rh,s substance ,s prepared by mixhig four vowi of d^
fumS wwth ~ } ' ""* ''™ *^^'^^ combine to form red
umes, which condense to a volatile indieo-blue coloured
.quid, the same blue body is obtained by addi.^w^ter
to mtrogen tetroxide apd drying the distillai ovxr falcium
i
74 ' ELEMENTARY CHEMISTRY. [Lesson
of liienicjicid, thus ; "loxme, with formation
'^As.Ojij. 2 HNO, + 2 H,0 = N,0, + 2 H,AsO
Arsenic trioxide and nitrir ar.H or,,4 . •,. *"
trioxide and arsenic acid ^"'^ "^'"^'' >"<=''* ""'"8^"
Nitrogen trioxide dissolves in ice-cold w^t,.r f
nitr t"e W ' '^"^ ,=°J''"'"'"S "itrotstcid T/'hydrS
and dec^ompo's^" wlr "Jl^e^w ?°"P°""'' '^ veryZsSf fe"
acid and S oxide, "h^s- ' " ''^™'=^ '"'° """<=
3HNO.-HNO, + 2NO + H,0.
to lucVe1?yfe^pt|i'>°"^-'^ "^' "o*--' "« "able
obtained by^t^trn^pota sfulnPS" K No""' ^T.- ''
one atom of oxveen • the^arr^ fif^ ' ^ "^s' "''"<='> '°ses
gen trioxide ^^\i>^t^Z^^^:^t:^X^.
n8Jo + 2HJo=.,noj^^H|o
same^";o1ittT"nit°^^%rolU° toV t = '" «''<=
will be noticed that nitr!'"cW forms siLrniri'^'?.'- ''
•t ?: of aTeSrKoTei" "^^^^^^^^^ F^^
end in " ite,» whikt ac?ds wL ''''P°"'''"S '"^'«"i'= ^^Its
salts ending in "ate?' """'"' '"'* '" " '<= " ^""n
A'/'/rff^fw THroxide or Hyponitric AaK
Symbol NO,, Ar^/^^«/<z^ ly^ /^^ g „ .
This substance forms the greater ua« of fht "^ ii^T
brown fumes evolved when nitric ox irit LI * '^^'''^'"^
the air ; it is, however" best prenaJ^d !fv .""^P" ,'"'°
nurate in a hard glass 'retort ,'7rd"oxidt o^r^ «^'
VII.] PREPARATION OF AMMONIA. 75
nitrogen tetroxide are produced by the decomposition of
the nitrate, thus :
2 (Pb 2 NO3) = 2 PbO 4- 4NO2 + O2.
Nitrogen tetroxide, NOg, solidifies at - 9° to long
prisms ; these on fusing yield a yellow liquid, boiling
at 22°. Owing to the fact that the density of nitrogen
tetroxide is 23, its formula is considered to be NO, and
not N,04. ^
NITROGEN AND HYDROGEN.
Ammonia.
Symbol NH3, Molecular Weight 17, Density 8'5.—
Nitrogen and hydrogen form only one compound, viz.
Ammonia ; they do not readily unite when brought together
alone, but do so under certain circumstances, especially
when water is evaporated ; the nitrogen of the air then
combines with the elements of the water, forming small
quantities of ammonium nitrite, a compound of ammonia
and nitrous acid, thus :
Na + 2H2O = N2H4O2, or NH4 NOg.
Ammonia is chiefly obtained from the decomposition
of animal or vegetable matter containing nitrogen and
hydrogen, being formed either gradually at the ordinary
temperature, or quickly under the influence of heat ; thus
when horns, or clippings of hides, or coal is heated, am-
monia is given off; hence ammonia was known as spirits
of hartshorn. The name ammonia is derived from the
fact that a compound containing ammonia, called sal-
ammoniac, was first prepared by the Arabs in the deserts
of Libya, near the temple of Jupiter Ammon, by heating
camels' dung. Guano, the dried excrement of sea-birds,
and the urine of animals, likewise contain large quantities
of ammonia. Ammonia and its compounds are ow, how-
ever, mainly obtained from the animoniacal liquors of
the gasworks : coal contains about 2 per cent, of nitrogen,
which, when the coal is heated in close vessels, mostly
L»->JP1tMfetH&L-!-
76 ELEMENTARY CHEMISTRY. [Lesson
moniacal liquor and thi^ni,'',-"' " ^^^''^ '° ^is am-
sal-ammonro'f Commerce &ai„\T"'^''' ^''- ^he
■ 9 HNO3 + 4 Z„ = 4 (Z„ .NO,) ^ 3H,0 + H^N.
chlorate, NH.HCI or NH nT"!^*^' ""^ ^""'onia hydro-
3 nvi or JN H,CI, and an excess,or two parts
Fig. »3.
w'hicf t're'o^crrtTs' ?ei'''''"^ T'^^ decomposition
•equation : ' " represented by the following
CaO + 3NH3Ha = CaCl, + aNH3 + H,0.
.mS an7;lten""'"°"'^'= «'^^ -'"«■» ^'"oride, and
•I
y~*^
SSON
coal
am-
. the
icent
d is
ia is
lask
dro-
arts
VII.]
AMMONIA,
77
Ammoniacal gas is colourless, and possesses a most
pungent and peculiar smell, by moans of which it can be
readily recognised ; it is lighter than air, its specific
gravity (air =. i) being 0-59, and it may be collected by
displacement, the neck of the bottle intended to receive
the gas being turned downwards, as in Fig. 23. A cylinder
tilled with quicklime is here placed between the flask
f;
p-3n.
and the bottle, for the purpose of completely drying the
ammonia. A simpler arrangement is shown on Fio- ^'y;ia ■
a layer of powdered quicklime placed in the upper part of
the flask itself serves to dry,the gas. Ammonia may also
be collected over mercury, but not over water, as it is
extremely soluble in this liquid, one gram of water at 0°
absorbing 0-877 gram, or 1149 times its volume, of'
m
w
*^.r.
o- \t. ^^
IMAGE EVALUATION
TEST . ARGET (MT-S)
1.0
I.I
lU
\M III U 1 1.6
Pnotogmphic
Sciences
Corporation
23 WEST MAIN STREET
WEBSTER, N.Y. 14580
(716) 872-4503
#
iV
,v
«^
'0"j.
'9.
y.
^
xP
78 ELEMENTARY CHEMISTRY. [Lesson^
ammonia, under a pressure of 760 mm. ; whilst at 20° the
same weight of water absorbs o 520 gram, or 68ri time?
Its voUime, under the same pressure. The solution of
ammonia gas in water is the common liquor ammoniae of
the shops, which has a specific gravity of about o-88o.
Ammonia gas, as well as the aqueous solution, possesses a
strong alkaline reaction, turning red vegetable colours
blue: it unites with the most powerful acids, forming
compounds called the salts of ammonia (see p. 213), which
'''ig 24.
closely resemble the salts of the alkaline metals ; hence
Uie name of the volatile alkali has been given to ammonia.
1 He action of ammonia gas on nitric acid may be thus
represented —
NH3 + NO3H = NH4NO3 ; or ^^^ \ O.
On exposure to a pressure of seven atmospheres at the
ordinary temperature of the air (about 15° C), ammonia
condenses to a colourless liquid, boiling at - 38-5° • and
VII.]
AMMONIA,
79
this liquid, if cooled below- 75°, freezes to a transparent
solid. An elegant application of the principle of the latent
heat of vapours has recently been made in the case of
ammonia in M. Carry's freezing machine, Fig. 24. This
consists essentially ot two strong iron vessels connected
in a perfectly air-tight manner by a bent pipe ; one of these
vessels contains an aqueous solution of ammonia satu-
rated with the gas at g°. When it is desired to procure ice,
the vessel a containing the ammonia solution (which we
will term the retort) is gradually heated over a large gas
burner, the other vessel B (the receiver) being placed in a
bucket of cold water : in consequence of the increase ol
temperature, the gas cannot remain dissolved in the water,
and passes into the receiver, where, as soon as the pressure
amounts to about 10 atmospheres, it condenses in the
liquid form. When the greater part of the gas has thus
- been driven out of the water, the apparatus is reversed,
the retort (a) being cooled in a current of cold water,
whilst the liquid it is desired to freeze is placed in the
interior of the receiver (b). A re-absorption of the am-
monia by the water now takes place, and a consequent
evaporation of the Jiqupfied ammonia in the receiver : this
evaporation is accompanied by an absorption of heat
which becomes latent in the gas ; hence the receiver is
soon cooled far oelow the freezing point, and ice is pro-
duced around it. • j u
The composition of ammonia may be ascertained by
leading the gas through a red-hot tube, or passing a series
of electric sparks through the gas, when it will be decom-
posed into nitrogen and hydrogen, which wil je found to
occupy together a volume twice as large as the ammonia
taken, and to be mixed together in the proportions of
three volumes of hydrogen to one volume of nitrogen.
Hence the formula NH3 is given to the gas.
The salts of ammonia will be described together
with those of potassium and sodium (page 213). The
compound ammonias will be noticed under Organic
Chemistry.
'.'
*
r
80 ELEMENTARY CHEMISTRY. [Lesson
LESSON VI IL
CARBON".
't fyj'^^J^^'^^ Combining Weight i2.-Carbon'is the first
solid element which we have to notice ; it is net known
m the free state, either as a liquid or as a gas. Carbon
Iferemarkable as existing in three distinct forms, which,
iMHitward appearance or physical properties, have
noting in common, whilst their chemical relations arc
idAjUcal. These three allotropic forms of carbon are'
(i) Diamond, (2) Graphite or Plumbago, (3) Charcoal-
these substances differ in hardness, <:olour, specific
gravity, &^., but they each yield on combustion in the
air or oxygen the same weight of the same substance,
carbonic acid, or carbon dioxide;* 12 parts by weight-
of each of these forms of carbon yielding 44 parts by
weight of carbon dioxide. Carbon is the element which
is specially charactenstic of animal and vegetable life,
as every organized structure, from the simplest to the
most complicated, contains carbon : if carbon were not
present on the earth, no single vegetable 0/ animal body
such as we know could exist. In addition to the carbon
which is found free in these three forms, and that con-
tained combined with hydrogen and oxygen in the bodies
of plants and animals, it exists combined with oxygen as
free carbon dioxide in the air, and with calcium and oxy-
gen as calcium carbonate in limestone, chalk, marble,
corals, shells, «&c. The fact has already been noticed that
plants are able, when exposed to sunlight, to decompose
the carbon dioxide in the air, liberating the oxygen, and
taking the carbon for the formation of their vegetable
structure ; whilst all animals, living directly or indirectly
•Although the term "acid," as iv^ have already seen, strictly denotes a
hydrogen salt, yet the word has been applied so long to a few other com-
pounds containing no hydrogen, such as carbon dioxide, &c., that iLssie
Oodics arc uiiiveriallv known by the naincj. carbonic acid, &c
i.'
I> <
4
"?>
♦.•
k
■ - i
4
\'
VIII.]
CARBON,
8i
upon vegetables, absorb oxygen, and evolve carbon di-*
oxide. Thus the sun's rays, through the medium of plants,
effect deoxidation or reduction, while animals act as oxi-
dising agents with respect to carbon.
The element carbon not only combines directly with
oxygen, but also with hydrogen, forming a compound
caUed acetylene, CgHg. Carbon forms with • oxygen,
hydrogen, and nitrogen a series of more or less compji- '
cated compounds very much more extended than the
series formed with these bodies by any other element ; so
that these compounds are considered as a separate branch -'
of the science under the name of Organic Chemistry^ #
%\
Fig. 25.
the Chemistry of the Carbon Compounds. The proper-
ties of the majority of these compounds will be examined
in a subsequent chapter, owing to their complexity ; hence
till then it will be better to postpone the consideration of
several of the properties of carbon.
The Diamond was first found to consist of pure carbon
by Lavoisier, in 1775-6, by burning it in oxygen, and col-
lecting the carbon dioxide formed ; it occurs crystallized
in certain sedimentary rocks and gravel in India (Gol-
conda), Borneo, the Cape, and the Brazils. Diamond occurs
crystallized in forms (Fig. 25), derived by a symmetrical
geometric operation from a regular octahedron, known as
G
^
o
82 ELEMENTARY CHEMISTRY. [Les'son
belonging to the regular system of Crystallography (see
p. 192). The specific gravity of diamond varies from 3*3
to 35 ; it is the hardest of all known bodies, and when
cut possesses a brilliant lustre, and a high refractive power.
In addition to its employment as a gem, the diamond is
used for cutting and writing upon glass. We are alto-
gether unacquainted with the mode in which the diamond
has been formed : it cannot, however, have been pro-
duced at a high temperature, because, when heated strongly
in a medium incapable of acting chemically upon it, the
diamond swells up, and is converted into a black mass
resemblittMppke.
GrapJ^^yXii Plumbago, crystallizes in six-sided plates
which have n^relation to the form in which the diamond
crystallizes, uraphitfe occurs in the oldest sedimentary
formatibns, and in granitic or primitive rocks : it is found
in Borrowdale in Cumberland, and in large quantities in
Siberia and Ceylon. It has a black metallic appearance
(whence the familiar name black lead), and leaves a mark
when drawn upon paper. The specific gravity of graphite
is2"i5 to 2*35. Coarse impure graphite maybe purified
by heating the powder with sulphuric acid and potassium
chlorate ; a compound is thus obtained which, on being
heated strongly, decomposes, leaving pure graphite in
a bulky and finely-divided powder :" this powder when
strongly compressed forms a coherent mass, from which
pencils and other articles can be made. Graphite is used
for polishing s&faces of iron-work, and also for giving a
protecting varnish to grains of gunpov ler. Graphite is
produced in the manufacture of iron ; it occasionally
separates from the molten pig-iron in the form of scales.
Charcoal is the third allbtropic modification of carbon.
It is obtained in a more or less pure state whenever animal
or vegetable matter is heated to redness in a vessel nearly
closed ; the volatile matters (compounds of carbon, hydro-
gen, and oxygen) are thus driven off, and the residue of
the carbon, together with the ash or mineral portion of
the organism, remains behind. •*
VIII.]
CHARCOAL.
83
The purest form of charcoal-carbon is found in lamp-
black ; it also occurs as wood charcoal, r oal, coke, and
animal charcoal. This form of carbon docs not crystal-
lize, and is hence termed amorphous carbon : it is much
lighter than either of the other two forms, the specific
gravity of powdered coke varying from i-6 to 2'o. Char-
coal appears at first sight to be lighter than water, as a
piece of it floats on the surface of this liquid \ this is,
however, due to the porous nature of the charcoal, for if
it be finely powdered it sinks to the bottom of the water.
This porous nature of charcoal enables it to exert a re-
markable absorptive power, of which much use is made
in the arts. Charcoal is thus able to absorb about ninety
times its own volume of ammonia gas, and about nine
volumes of oxygen. In the process of sugar-refining, use
is made of the property of charcoal to absorb the colour-
ing matters present in the raw sugar : the kind of char-
coal best suited to this purpose is that obtained by heating
bones in a closed vessel. Charcoal is also used a^j a
disinfectant in hospitals and dissecting rooms, &c. It
appears that the putrefactive gases when absorbed by
the charcoal undergo a gradual oxidation from contact
with the oxygen of the air taken up by the charcoal, and
are thus rendered harmless.
Coal is a form of carbon less pure than wood chaicoal.
It consists of the remains of a vegetable world which
once flourished on the earth's surface : the original woody
fibre has undergone a remarkable transformation in pass-
ing into coal, having been subjected to a process similar,
in a chemical point of view, to that by which wood is
transformed into charcoal. It has not, however, lost the
whole of its hydrogen and oxygen, and it has at the same
time become bitumenized, so that for the most part all
the vegetable structure has disappeared. There are many
different kinds of coal, containing more or less of the
oxygen and hydrogen of the original wood : cannel coal
and boghead coal contain the most hydrogen, and anthra-
cite coal the least. The alteration in composition which
G2
.^\
mmm
mm
I
I
I
F '
84
JE.LEMENTARY CHEMISTRY. [LESSON
wood has undergone in passing into the various forms of
coal is seen from the following table :--
Compositions of Fuels (ash being deducted).
Description of Fuel.
1 Woody Fibre . . .
2 Peat from the Shannon
3 Lignite fiom Cologne .
4 Earthy Coal from Dax
5 Wigan Cannel . . .
6 Newcastle Hartley . .
"7 Welsh Anthracite . .
Percentage Composition.
Carbon.
52-65
6o*o2
66*96
74'20
85-81
88-42
94-05
Hydrogeh.
Nitrogen
and Oxygen.
5-25
5-88
5*25
5-89
5-85
5*61
3-38
42*10
34* 10
27-76
19-90
8-34
5*97
2-57
COMPOUNDS OF CARBON WITH OXYGEN.
Carbon forms two compounds with oxygen, viz. ;
Carbon Monoxide, or CO.
Carbon Dioxide, or COg.
Carbon Dioxide (commonl/c ailed Carbonic Acid).
Symbol CO2, Molecular Weight 44, Density 22.—
Carbon dioxide is always formed when carbon is burnt
in excess of air or oxygen. It is best prepared by acting
upon marble, chalk, or other form of calcium carbonate,
with hydrochloric acid. On pouring some of this acid
upon pieces of marble contained together with some water
in a flask, a rapid effervescence from the disengagement
of carbon dioxide gas at once occurs, calcium chloride
\
ESSON
rms of
TOgen
).'cygen.
2*10
776
9'9o
B-34
5*97
2-57
:id ).
f 22. —
s burnt
' acting
bonate,
lis acid
>e water
gement
ihloride
VIII.]
CARBONIC ACID.
85
being left behind in solution in the flask. Fig. 25^
shows the mode of collecting this gas by displacement
of the air. The decomposition is thus represented :
Ca CO3 + 2HCI = CO2 + HgO + Ca Q\.
Calcium carbonate and hydrochloric acid give carbon
dioxide, water, and calcium chloride.
Carbon dioxide occurs free in the air, and in the water
of many mineral springs. The quantit)' of this gas present
in the air is nearly constant, and amounts to about 4
Fig. 25rt.
volumes per 10,000 of air this quantity, though relatively
small, is, taken altogether, very large, being about 3 bil-
lions of tons in weight, as can be easily calculated if we
know the weight of the atmosphere and the density of
carbonic acid.
\ It is also evolved in very large quantities from the
craters of active volcanos, as well as from fissures in the
districts of extinct volcanic action.
' ^ Owing to the evolution of carbon dioxide in respira-
tion anoTin the burning of coal-gas, &c., this gas is always
found in larger quantities in dwelling-rooms than in the
open air. When the air of a room contains 010 per cent,
of this' gas, it is certainly unfit for continued respiration,
'
86 ELEMENTARY CHEMISTRY. [Lesson
not only on account of the deleterious effects produced
RnV votik r;^'' '^h,' "'^° ''<^'^^"=^' '°eether ,^ith thTs
,-,,H?-f,i ^ °'^ animals, and these matters act in a pre-
itfent&r^P'"'/''' ''"^,'"'= ''^°'=« 'he necessit/?or
bliW nes r^rh'""*H?"-'^ °^ dwelling-rooms and public
Duildmgs. Carbon dioxide gas is also given off in the
process of fermentation ; it occurs frequently at the bottom
of old wells and forms the choke-damp of tVe coal m neT
Compounds of carbon dioxide with lime or magncsia™uch
as limestone or calcium carbonate, ^^ | Oj, and mag-
nesian limestone, &c., occur plentifully in nature some
ako'colS.T'jf "'-"'-"Chains, "balcium carbonate
also constitutes the main portion of coral, a substance of
which whole continents are being built up in the Pacific
Carbon dioxide gas is colourless and inodorous but
possesses a slightly acid taste ; it is .-529 times heavier
than air and s tolerably soluble in waterrfut is all
expelled by boiling, one volume of water, at 0° di" solving
'Iso'rt""-?!''"^^' "'}"l'''* ^°° oAly oVTrolumf
^t thl 7 . ™'"™^ °*^ ""^ gas absorbed by water
at the same temperature is found to remain the same
under whatever pressure the gas may be measured AsOie
volumes occupied by any given quantity of l^s measu ed
h" s cleaf^htt thPr''"''^f ^"^ in versely^s thie pressure^
m. tf !f ^^ weights of carbon dioxide thus absorbed
Tder fhr?""'""^' ^° *^ P^^^^"'^-'- Thus, for instance,
temnerSurf n^JT °^ ' ^'""T^ere and at' the ordinar,^
I c^Q m n- ^Z"" ^^^''- °f ^a'^'' dissolves i cbc. or
I 529 milligrams of carbon dioxide. So under a ores
temoemturfr,?,'''''' .' '=^=- "^ ^^'^ -'" ^'"'e «ame
of^'itmn. \ ^ "^ ' '='"'■ (""easured under the pressure
d oxide fr'^ °' ' X .•529=3-058 milligrams of carbon
dioxide. The increased quantity of absorbed carbonic
acid under increased pressure is seen when a bottle of
soda-water or champagne is opened ; the pressure being
VIIT.]
CARBONIC ACID.
87
diminished by removal of the cork, a brisk effervescence
and escape of the dissolved gas occurs. The same rela-
tion IS found to hold good when many other gases are
dissolved in water under varying pressures.
The aqueous solution of carbon dioxide reddens blue
htmus paper, and when placed in contact with a metallic
oxide, such as calcium oxide or lime, CaO, ^ives rise to
the formation of salts such as calcium carbonate : this
aqueous solution may be considered to contain a true
acid, the real carbonic acid, ^2^ | Og (which, however, has
never yet been isolated), and the reaction which then
takes place may be thus represented ;
^^0,4-
CaO:
CO I ^2 + H2O.
Carbonic acid and calcium oxide give calcium carbo-
nate and water.
The red colour produced by the acid on litmus paper
disappears on drying, owing to the decomposition of this
true carbonic acid into carbon dioxide and water, thus :
C^' \ O2 - CO2 -f. H2O.
Carbon dioxide gas does not support the combustion of /
bodies in general, such as wood, sulphur, or phosphorus ; /
but certain metals— for instance, potassium and magne- \S
Slum— heated in the gas, are able to decompose it, burn- If
mg in It, and uniting with the oxygen to form oxides^
while the carbon is liberated. ^
Carbon dioxide can be condensed to a liquid by the
application of great pressure, or by cooling the gas to a
very low temperature : liquid carbon dioxide is a colour-
less and very mobile liquid, which is remarkable as being
found to expand by heat more than the gaseous form of
the same substance, 100 volumes of this liquid at 0° be-
coming 106 volumes at 10°, while 100 volumes of the eas
at 0*=
must be heated to 16-4° before they expand to 106
rairniii
riniT -ni'iwr
88 ELEMENTARY CHEMISTRY, [LessOxW
volumes ; hence this body is an exception to the rule that
liquids expand by heat less than gases, and at the same
time forms an excellent Illustration of the fact, that liquids
expand proportionally much more when submitted to a
high pressure than when under a low one: thus, the expan-
sion of water above ioo° is much greater than that below
ioo°. The boiling point of liquid carbcn dioxide is- 78°.
At a still lower temperature it freezes to a colourless, ice-
like solid. At 0° the tension of its vapour is 35*5 atmo-
spheres ; and at 30° 73-5 atmospheres. The liquefaction
of carbon dioxide gas can be effected either by evolving
the gas in a strong closed vessel, so that it is either con-
densed by its own pressure, as is the case with ammonia
in Carry's freezing machine (described on p. 79) ; or by
pumping the gas by means of an ordinary forcing syringe
mto a strong wrdught-iron receiver, kept during the pro-
cess at a temperature of o'. As soon as the volume ot gas
pumped in amounts to about 36 times the volume of the
receiver, each stroke of the syringe produces a condensa-
tion of the gas which is pumped in ; and thus the receiver
can easily be filled with liquid. If the stopcock be then
opened so that the liquid is forced out, a portion at once
assumes the gaseous state ; and so much heat is absorbed
by this sudden transition from the liquid to the gaseous
form, that a portion of the liquid is solidified and de-
posited in the form of white, snow-like flakes, which can
be collected by allowing the stream of liquid to flow into
a thin brass box with perforated sides.
^ Solid carbon dioxide t'lUs obtained is a light, snow-
like substance, which, owing to the bad conducting
power iox heat of the gas which the solid substance is
constantly giving off, may be handled without damage,
although its temperature is below — 78° C. Ifj however,
♦he solid be forcibly pressed between the lingers, so that
the substance really comes in contact with the skin,
a sharp pain will be felt, and a blister like one produced
by touching a hot iron will be produced. This solid
carbon dioxide is much used for the production of v ;ry
VIII.] COMBUSTION OF THE DIAMOND S9
low temperatir :ff ; for this purpose it is mixed with clhei,
and the mixture brought
into the vacuum of the air-
pump, whereby a tempera-
ture as low as— 100° C can
be obtained, and large quan-
tities of mercury may easily
be frozen.
The composition of car-
bon dioxide may be ascer-
tained with great exactness
by burning a known weight
of pure carbon, such as the
diamond or graphite, in a
current of pure oxygen gaS;
and weighing the carbon
dioxide produced. 1 he ap-
paratus for the synthesis of
this gas is represented in
Fig. 26. The weighed quan-
tity of diamor'd, placed in
a small platinum boat, is
pushed into the porcelain
tube, which can be strongly
heated in the furnace. One
end of this tube is connected
with a gasholder and drying
tubes, A, B, C, by means of
which pure and dry ojfygen
gas is supplied. The other
end is connected, as is seen,
with a number of tubes, and
bulbs desUned to absorb
the carbon^ioxide formed
by the combustion : the tube
D and the bulbs E contain
a solution of caustic potash,
and the other tubes F are filled with pumice-stone, and
%
J
BllilWIiWriigBI
90 ELEMENT A R Y CHE MIS TR Y. [Lesson
sulphuric acid. The bulbs and tubes are carefully weighed,
and then the apparatus is filled with pure oxygen, and the
tube slowly brought to a red heat. The gas passes gradu-
ally through the system of tubes, and carries along with it
the carbon dioxide formed by the combustion of the
diamond : the gas is wholly absorbed by the potash in
the tube and bulbs, whilst any moisture which might be
given off from the bulbs is taken up by the tubes F. The
oxygen gas is dried as it enters and also as it leaves the
apparatus ; so that the gain in weight which the tubes
have experienced gives exactly the weight of carbon
dioxide formed by the combustion of the carbon of the
diamond. Usually the diamond contains a small quantity
of ash, or inorgnnic matter ; and this weight must be
subtracted from the original weight of the diamond, in
order that we may know the exact weight of pure carbon
burnt : for this reason the diamond is placed in a platinum
boat, which caA be withdrawn and weighed affer the
experiment, and thus the amount of ash determined.
Another precaution that must be taken is, to fill the
greater part of the red-hot tube with porous copper
oxide, in case any trace of carbon monoxide (CO) should
be formed by the incomplete combustion of the carbon :
this gas would pass unabsorbed through the potash if
not oxidized to carbon dioxide by the copDcr oxide. In
this way it has been shown that 100 parts of carbon
dioxide consist of
Carbon .... 27*27
Oxygen .... 7273
Carbon dioxide
lOO'OO
If w^ divide 27*27 by the combining weight of carbon
27*27
and 72*73 by that of oxygen, we have — ^ — ^=2*273 ^rid
72*73
—-^ = 4*545 ; or the relation between the number of
atoms of carbon and that of those of oxygen is that of
*'
/■-"
,
IX.]
CARBON MONOXIDE,
91
I to 2 : so that the formula of carbon dioxide is COg.
Hence the gas should contain its own volume of oxygen ;
for 44 parts by weight of carbon dioxide, occupying a
volume equal to that occupied by 2 parts by weight of
hydrogen, contain 32 parts by weight of oxygen, which
hkewise occupy a volume equal to that of 2 parts of
hydrogen. That this is the case can be experimentally
proved by burning charcoal in a known volume of oxygen
in excess, when it is observed that, when the gas has cooled
after the combustion, no alteration in its volume has
occurred: hence the volume of carbon dioxide formed
must be precisely equal to that of the oxygen used in its
formation.
LESSON IX.
Carbon Monoxide, or Carbonic Oxide Gas.
Symbol CO, Molecular Weight 28, Density 1^. — When
carbon burns with a limited supply of oxygen, carbonic
oxide is formed. The production of this gas in an
ordinary red-hot coal fire is often observed : oxygen of
the air, which enters at the bottom of the grate, combines
v/ith the carbon of the coal, forming carbon dioxide ; this
substance then passing upwards over the red-hot coals,
fiarts with half its oxygen to the red-hot carbon ; thus .
C02+C=2CO.
This carbon monoxide on coming out at the top of the
fire meets with atmospheric oxygen, with which it at once
combines, burning with a lambent blue flame, and re-
forming carbon dioxide. Carbon monoxide gas in the
pure stete caja be prepared by passing a slow current of
carbon dioxide over pieces of charcoal heated to red-
ness in a tube by means of a furnace, as represented in
Fig. 27 : it may likewise be obtained in the pure state
from several compounds of carbon. Thus, if crystallized
wqililllMI
92
ELEMENTARY CHEMISTRY. [Lesson
oxalic acid be heated with strong sulphuric acid, a mixture
of equal volumes of carbon monoxide and carbon dioxide
gases is evolved : this latter can be easily separated from
the former by shaking the mixed gas up with caustic soda
solution, when sodium carbonate will be formed, half the
volume of the gas will disappear, and the remainder will
be found to be pure carbon monoxide. This decom-
position of oxalic acid results from the fact that sulphuric
acid has a strong tendency to abstract water, or th(j
elements of water, from the bodies with which it comes
into contact : thus the oxalic acid, which may be repre-
iv',''
Fig. 27.
y sented as Cg H.^ O4 (see p. 366), being deprmcd of the
^ elements of one molecule of water, vvhich are^aken up
by the sulphuric acid, yields a compound, Cg (\ which
cannot exist alone, and immediately splits up i^ COg
and CO. Carbon monoxide can also be prepa\d by
heating formic acid, C H, O2 (see p. 348), withl^ul-
phuric acid : here, as with "oxalic acid, the elements o(
water are removed, and pure CO is thus evolved.
Carbon monoxide is a colourless, tasteless gas, which
\
IX.]
COMPOUNDS OF CARBON,
93
has not been condensed to a liquid ; it is a little lighter
than air, its specific gravity being 0*969 (air=»i) ; it is but
very slightly soluble in water. It acts as a strong poison,
producing death when inhaled even in very small quan-
tities, the fatal effects often observed of the fumes from
burning charcoal, or from limekilns, being due to the
presence of this gas. When heated in contact with oxygen,
carbon monoxide takes fire, burning with a charac-
teristic lambent blue flame and forming carbon dioxide.
In contact with caustic potash at a high temperature,
carbon monoxide produces potassium formate, thus :
^|o +
CO = CHKOj.
Caustic potash and carbon monoxide give potassium
formate.
The composition of this gas can be ascertained by
combustion in the eudiometer v^ith oxygen. 100 volumes
of carbon monoxide and 75 volumes of oxygen yield on
passing the electric spark 125 volumes, of which 100 are
found to be absorbed by caustic potash, and hence are
carbon dioxide, the remaining 25 volumes being un-
altered oxygen. Hence the volume of carbon dioxide
produced is equal to that of the carbon monoxide taken,
whilst the volume of oxygen needed is half as large. But
as carbon dioxide contains its own volume of oxygen,
carbon monoxide must contain half its volume of oxygen ;
or two volumes of this gas weighing 28 contain one volume
of oxygen weighing 16, and hence 12 parts of carbon by
weight : therefore its formula is CO.
i
COMPOUNDS OF CARBON Wi:
HYDROGEN.
\
These compounds are very numerous ; they are known
in the gaseous, liquid, and solid forms. A still larger
number of substances exist containing carbon, hydrogen.
<*4iU \}A.j"l^\,llf .Viiii S\H
..•i ..l« t^r\w%^¥tw\^c v\%¥fr\m^t
H'^^iU.iX.S J^::.zv
o — *
94 ELEMENTARY CHEMISTRY, [Lesson
organic ccmpoundSy and they are more numerous than all
the compounds of the other elements put together. Many
of these are found to be formed from the bodies of plants
and animals, and their properties are considered under
the division of Organic Chemistry^ or the Chemistry of
the Carbon Compounds. We now have only to describe
some of the simplest of these compounds.
'*
Methyl Hydride^ Light Carburetted Hydi^ogen^
or Marsh Gas.
Symbol CH^, Molecular Weight i6, Density 8.— This
is a colourless, tasteless, inodorous gas, which has not
been condensed to a liquid. It is found in coal mines,
and known undet the name Qi firedamp; it also occurs
in stagnant pools, being produced by the decomposition
of dead leaves— whence the name marsh gas ; it is one of
the constituents of coal gas, &c., and is evolved in many
volcanic districts. Mnrsh gas may also be artificially pre-
pared by heating sodium acetate (see p. 351) with caustic
soda, thus :
Sodium acetate and caustic soda give sodium carbonate
and marsh ga*?.
It cannot be obtained by the direct union of its ele-
ments, but \ s formed when a mixture of the vapour of
carbon disulphide and sulphuretted hydrogen gas are«
passed over red-hot metallic copper, thus :
8 Cu + C S2 + 2 H2 S = CH4 + 4 Cu2 S.
Marsh gas burns with a blueish-yellow non-luminous
flame, forming carbon dioxide and water ; with a limited
supply of air it yields several products, amongst which
is acetylene^ C2H2. If mixed with ten times its volume
of air, or twice its volume of oxygen, it ignites with a
sudden and violent explosion on the ai">T^lication of a
IX.J ACETYLENE AND OLEFIANT GAS. 95
light, and hence the great damage produced by the escape
tt^ f • '""/u^^ '^'?^'-. '^^^ composition of marsh gas
^ ascertamed by explodmg it with oxygen in the eudio-
^^if ; \^''^''^% «^ this gas and 3 volumes of oxygen
yield 2 volumes after passage of the spark. On absorbing
by potash the carbon dioxide produced, i volume of
oxygen is found to remain. Hence of the 2 volumes of
oxygen needed to burn the i volume of marsh gas. i has
gone to umte with the carbon, and i to form water with
the hydrogen. It is thus seen that 2 volumes of marsh
gas contain 4 volumes of hydrogen weighing 4 (as water
contains 2 volumes of hydrogen and i of oxyVn), and as
much carbon as is contained in 2 volumes of carbon
CH ' k 'p^';n'? ?v '' ^y ^'^^^' '' ^^^ h^^^^ the formula
*^"4 ^s given to this gas.
Acetylene.
of^4Thnl^.'nH'Tl^'' ^^' ^' ^^""'^^ hy the direct union
ot carbon and hydrogen at a very high temperature
For this purpose the carbon terminals of a powerfif fflt
"^^L^TV^l ^.'-'"r?^' '"^^^^^^ '^ ^^ aCosph rf of
hydrogen. At the high temperature thus evolved, a direct
union of carbon and hydrogen takes place, and acetv^^^^^^^^^
>?'T^\ ^^^^^'^^^^ ^^ ^ colourless gas, which burns
with a bright luminous flame, and possesses 'a disigreeabk
and very pecuhar odour ; it is -produced in all cases of in
complete combustion, and its smell may Se noticed whe"n
wircttarmeT^s ' T'^ '^"^- ^LyleT c^l^nes
witn certain metals, such as copper and silver • and the
compounds thus formed are distinguished by the ease w^th
which they undergo explosive de^omposidon This gas
likewise unites directly with hydrogen, forming the nixt
substance, ethylene, Q H^ -f H^ = C^ H,. ^
Ethylene, Heavy Carburetted Hydrogen, or Olejiant Gas.
^^r't^i bl^J^J^I'^^^^K ^/^Sht 28, Density. 14.-
=..^- o«^ « v,i>iaiiiwu On me aestructive distillation of
.'
MMWI
96
ELEMENTARY CHEMISTRY. [LESSON
coal, and is an important constituent of coal gas. It is
obtained in the pure state by heating i part of alcohol
(spirits of wine), C2 Hg O, with 5 or 6 parts by weight of
strong sulphuric acid ; as in formation of carbon mon-
oxide from formic acid the elements of water are sepa-
rated by the sulphuric acid, and Cg H^ is evolved as a
gas. This gas is colourless, but possesses a sweetish
taste ; by exposure to a high pressure at a temperature of
— 110° it has been condensed to a colourless liquid. On
bringing it in contact with a light in the air, it burns
with a luminous smoky flame, forming carbon dioxide and
water. When mixed with three times its bulk of oxygen
and fired, it detonates very powerfully, i volume of ole-
fiant gas requires 3 volumes of oxygen to burn it com-
pletely, and yields 2 volumes of carbon dioxide ; so that
I volume of oxygen is needed to combine with the hydro-
gen. Hence this gas contains twice as much carbon as
marsh gas, with the same quantity of hydrogen ; we must "
therefore write its formula Cg H4.
defiant gas combines directly with its own volume of
chlorine gas, forming an oily liquid, Cg H^ CIg ; and owing
to this property it has received the above name.
Coal Gas,
The gas so largely ujed for illuminating purposes, and
obtained by the destructive distillation of coal {i.e^ by
heating the coal in large closed retorts so as to decompose
or destroy the coal, the volatile products of this decom-
position being condensed and collected), is not a simple
chemical compound, but a mixture of a large number of
distinct substances. In order to prepare coal gas of good
quality, cannel or some highly bitumenized coal is heated
ill a closed retort : volatile bodies are thus formed and
expelled, while a residue of (impure) carbon is left behind
as coke. The volatile products of this decomposition may
be distinguished as tar, ammonia, water, and gas. The
tar contains a srreat variety of substances, from some of
IX.]
COAL GAS.
97
which the well-known aniline colours are produced Tsee
The^'c'^^iTs^^^ chiT"^" ''^"";^ ^^-"^ thrnlJl^oge^'n
D 2ri? tLT ^^i^^ source of ammoniacal saltl (see
tion before it is sent ou^ from^he ^LwoH,^ tk P"?''?^-
proportion of the ingredi^nTs orefenMn ;. J^^ '■^'^"'"'
greatly according il 'the'tnroT" oa, emplL"d''and
retarfrL^--5.~^
Illumi-
nating
power ;
in
Candles
per 5
cubic
feet.
Composition in ioo Volumes.
Hydro-
gen.
H
Marsh
Gas.
CH4
51*20
41 '53
Heavy
Hydro-
carbons.
Equal to
Olefiant
Gas.
CaH4
'arbonic
t-»xide.
CO
Nitrogen,
Oxygen,
and
Carbonic
Acid.
Canrelgas
Coa gas . .
34*4
13 'o
25-82
4760
13*06
305
(22-08)
( 6-9/)
7-8s
7-82
2-07
The value of coal gas, as regards its ilium
inatir^ power,
■+==
98
ELEMENTAR V CHEMIS TR K [Lesson
is ascertained by comparing the light given off by the gas
burning at a certain rate, usually i^ cubic feel per hour,
with that of a sperm candle burning 120 grains per hour.
Thus the cannel gas is said to be equal to 344 candles,
and the coal gas to be equal to 13 candles.
Structure of Flame.
It will be convenient here to mention the nature and
structure of tiame, and the principle of the Davy lamp.
Flame consists of gas in a high state of ignition. When
a jet of burning hydrogen is plunged into oxygen, the
flame of hydrogen in oxygen is seen. This is caused by
the ignition o? the particles of hydrogen and oxygen,
owing to the neat evolved in their combination. A
similar flame of oxygen in hydrogen is seen when a jet of
the former gas is lit in an atmosphere
of hydrogen. The temperatures of
flames differ as much as their illumi-
nating powers, and the hottest flames
do not necessarily give off much ligjit:
thus the oxyhydrogen flame, which is
so hot as to burn iron or steel wire
like tinder, can scarcely be seen in
bright daylight. I n order that a flame
shall give off much light, it must
contain solid matter, which becomes
heated up to whiteness. If a piece
of lime be held in the oxyhydrogen .
flame, it becomes strongly heated,
and gives off an intense light : so
also if we -bring solid matter, such as
powdered charcoal, into the colourless
flame of hydrogen, it becomes luminous. The difference
between the non-luminous flame of marsh gas and the
luminous flame of defiant gas is due to the fact, that
in the latter carbon is separated out in the solid form,
whereas in the former all the carbon is at once burnt to
Fig. aS.
,ESSON
he gas
r hour,
r hour,
indies,
IX.J
STRUCTURE OF FLAME.
99
re and
lamp.
When
;n, the
sed by
xygen,
n. A
I jet of
sphere
ires of
illumi-
flames
iliglit:
hich is
t\ wire
een in
1 flame
must
jcomes
1 piece
drogen .
leated,
it : so
;uch as
ourless
ference
nd the
:t, that
I form,
urnt to
carbonic acid. The flame oi a candle consists of three
distinct parts— (i), the dark central zone or supply of
unburnt gas surrounding the wick ; (2), the luminous zone
or area of- mcomplete combustion ; and (3), the non-
luminous zone or area of complete combustion. If we
bring one end of a smaii bent piece of glass tubing
(Fig. 28) into the dark central zone (i), the unburnt gases
Will pass up the tube, and may be ignited at the other
end, where they escape into the air. In the luminous
part of the flame the gases are not completely burnt, and
carbon is separated out in the solid state ; and it is to the
presence of this carbon that the flame owes its luminous
power. In the outer zone the supply of oxvgen is greater,
all the carbon is at once burnt to carbon dioxide, and the
flame here becomes non-luminous.*
Fig. 29.
Fig. 30-
The effect of allowing a complete combustion to pro-
^m.1i Ti ''''''^ throughout the flame is well seen in the
small Bunsen gas-lamp, now universally employed in
LmaTril ^" ^^i? l^^Ppig.29) the coal gas issues
liom a small central burner (a), and passing unburnt up
. * The optical difference between t>>ese twn r1acc« «f a
in sne paragraph on bpectrum Analysis (see p. ~28jj7' '" "
H 2
■f '
too ELEMENTARY CHEMISTRY, [Lesson
the tube {e) draws air up with it through the holes Uf) •
he mixture of an- and gas thus made^an be lighted at'
the top of the tube, where it burns with a non-l urn nous
perfectly snriokeless flame : if the holes (./) be closcrthe
gas alone burns with the ordinary brigh smoky flamo
rhe blowpipe flame (Fig. 30) ma/also be divided into
two distinct parts~the oxidizing ffame ia\ where there is
excess of oxygen, and the reducing flamV^), where there
!S excess of carbon ; and these are distinguished by the
same properties as the outer and inner mantle of the
Fig. 31.
Fig. 3*
candle flame. Ever)' mixture of gases requires a certain
temperature to inflame it ; and if this temperature be not
reached, the mixture does not take fire : we may thus
cool down a flame so much that it goes out, by placing
over It a small coil of cold copper wire ; whereas, if the
coil be previously heated, the flame will continue to burn.
The same fact is well shown with a piece of wire gauze
containmg about 700 meshes to the square inch : if this
be nela close over a jet of eras, and the
rra c 1 i f
rx.]
CYANOGEN,
loi
sible to remove the gauze several inches above the jet, and
yet the inflammable gas below docs not take ffre the
tiame burning only above the gauze (Fig. 31). The ml
talhc wires in th.s case so quickly conduct ..way the hTpt
that the temperature of the gas at the lower side of the
gauze cannot rise to the point of ignition. This simple
principle was made use of by Sir Humphry DavyTh s
safety-lamp for coal mine.. It consists of an oil Tamp
^Fig. 32), the top of which is enclosed in a covering of
wire gauze; the air can enter through the meshrs of the
gauze, and the products of combustion of the oU can
escape but no flame can pass from the inside to the out-
sido of the gauze ; and hence, even if the lamp be placed
in a most inflammable mixture of firedamp and air no
Ignition is possible, although the combustible gas may ake
, fire and burn inside the gauze. It is, however, Then ad!
visable that the miner should withdraw, to avoid rfsk of
exp osion of the gas from the gauze thus becoming ove?
heated and inflaming the firedamp which surround! ,t
1 he compounds ot carbon being generallv of a mnr**
comphcatecTnature than the precedin^g one /they wiH be
Chemistr7 ''''' '°""^'''^ ""^^^ '^' ^^^^ of 'o^anic
CARBON AND NITROGEN.
Cyanogen Compounds, -Z?,x\,on and nitrogen do not
unite together, but if nitrogen gas be passed over a white
hot mixture of charcoal and potassium carbonate a
remarkable compound termed Potassium Cyanide KCN
IS formed, thus : ^>**iiiue, jvuin,
K2CO3 -f. Ng + 4 C - 2KCN + 3 CO.
From this substance a large number of bodies can be
prepared, all of which contain the group of atoms CH
.^c r^^TX^^^lt'l'^J}'^^ ^"d. P<^.^"Jiar properties : to'
j,,„„j.. ...v. ,.«„,c cyanogen is given, irom its formine
a number of blue compounds («iia.ot blue, and y«Z
loz ELEMENTARY CHEMISTRY. [Lesson
I produce). Cyanogen combines with metals to form
cyanides^ and in this respect resembles chlorine ; and it
belongs to a class of bodies termed compound radicals^
of which we shall have to speak hereafter.
Cyinogen compounds are prepared on a large scale for
various purposes by heating nitrogenous organic matter,
such as clippings of hides, hoofs, &c. with iron and
potashes, a double cyanide containing iron and potassium,
called potassium ferrocyanide, or yellow prussiate of
potash (see Organic Chemistry, p. 375) is formed.
The most important compound tormed by cyanogen is
one with hydrogen (analogous in composition, to hydro-
chloric acid, H CI), and called hydrocyanic acid^ or com-
monly /r^/jj/V acid^ HCN. This substance is prepared
by acting on potassium cyanide with dilute sulphuric acid
in a retort. Hydrocyanic acid mixed with water distils
over, leaving potassium sulphate in the retort.
If the aqueous distillate be shaken up with mercury
oxide, the hydrogen of the hydrocyanic acid is replaced
by mercury, and mercury cyanide, Hg | ^J^', is formed,
which may be obtained by evaporation in the form of
white crystals.
Hydrocyanic acid is prepared puBe and free from water
by passing sulphuretted hydrogen gas, H2S, over dry
mercury cyanide, hydrocyanic acid and mercury sulphide
being formed, thus :
' Hg|^^ + H2S = 2(HCN) + HgS.
Mercury cyanide and sulphuretted hydrogen yield h'^dro-
cyanic acid and mercury sulphide.
Hydrocyanic acid thus prepared is a volatile liquid,
boihng at 265", and solidifying at - 15°; it is the most
poisonous substance known, one drop of the pure acid
being sufficient to produce fatal results : much care must
the efore be taken in its preparation not to inhale the
en in small quantity, may produce death.
vapuui, vvhu t.,
/
of
X.]
CHLORINE,
103
It possesses a peculiar and characteristic smell of bitter
almonds, and occurs in small quaatities in the kernels
and leaves of many plants.
Cyanogen Gas, or Di-cyanogen, ^ \ , can be easily
obtained as a colourless gas by heating mercury cyanide.
It is best collected over mercury, as it is soluble in water.
It condenses to a colourless liquid when exposed to a
pressure of about four atmospheres ; it is inflammable,
and burns with a beautiful purple flame, forming carbon
dioxide, COg, and free nitrogen.
Cyanogen forms a large number of compounds, some
of them of a very complicated constitution, and connected
with other carbon compounds, under which they will be
considered.
LESSON X.
We now pass to the consideration of a group of ele-
ments which resemble each other closely, and posress
strongly marked and active properties : viz. Chlorine,
Bromine^ I Oilmen and Fluorine,
CHLORINE.
Symbol CI, Atomic Weight 35*5, Density 35*5.
Chlorine was discover- \ in the year 1774 by Scheele :
it does not occur free in nature, but can easily be pre-
pared from its compounds. It is found combined with
metals forming chlorides ; of these sodium chloride, sea-
or rock-salt, is the most common : to obtain chlorine from
this, it must be heated with sulphuric acid and manganese
dioxide, thus :
2 Na CI -f- 2 SO.Hg + MnOo
. = 2 CI + Na2S04 H- Mn SO4 -f 2 HgO.
Sodium ':hloride, sulphuric acid, and manganese dioxide
give chlorine, sodium sulphate, manganese sulphate, and
water.
f—
^
'^^ """»
1
(
104 ELEMENTARY CHEMISTRY, [LESSON
If one part by weight of salt to one part of manganese
dioxide be mixed with two parts of sulphuric acid and
two of water, and the mixture brought into a large flask,
the chlorim; gas is given off regularly upon the application
of a very slight heat : m order to obtain the gaipure it
maybe passed through the water contained in awash-
bottle before It is collected for use. Chlorine is a green-
yellow gas whence its name (xX«/t>or), possessing a most
disagreeable and peculiar smell, which, when the gas is
present in small traces only, resembles that of seaweed
but when present in large quantities acts as a violent
irritant, producing inflammation of the mucous mem-
brane, and even causing death when inhaled. Calorine
gas when submitted to a pressure of five atmospheres at
the ordinaiy- tenjperature is condensed to a heavv yellow
liquid but It has not yet been solidified. This gas cannot
be collected over water or mercury, as it is soluble in the
former (i volume of water dissolving 2-37 volumes of
clUorine at 15 ), and combines directly with the latter
forming mercuric chloride. It can, however, be easily
collected by displacement, as it is nearly 2*5 times as
heavy as air. If metals in a finely divided state are
brought into chlorine gas, they take fire spontaneously,
forming metallic chlorides: thus powdered arsenic
antimony, or thin copper leaf, burn when thrown into
the gas.
The most remarkable property of chlorine is its power
ot combimng with hydrogen to form hydrochloric acid •
when these two gases are brought together in equal
volumes, they combine with explosion on bringing a
flame into contact with them, or on exposing the mix-
ture to sunlight. Chlorine is even able to decompose
water m the sunlight, combining with the hydrogen and
liberating the oxygen. Several experiments illustrative
of this property of chlorine may be mentioned. If a
burning candle be plunged into this gas, the taper con-
tinues to brrn, but with a very smoky flame, the hydrogen
alone of the wax entering into com.bin^<^ion wifu -
X.1
CHLORINE,
105
chlorine, whilst the carbon is given off as smoke or soot :
the same effect is produced when a paper moistened
with turpentine (a compound of carbon and hydrogen)
is held in a jar of chlorine gas ; the hydrogen of the tur-
pentine at once combines with the chlorine, formin*-
hydrochloric acid, and the carbon is liberated ;— so much
heat is given off by this action that the paper frequentlv
takes fire. ^ ^ j
The well-known bleaching action of chlorine also de-
pends upon its power of combining with the hydro^-en
of water and liberating the oxygen. Dry chlorine gas
does not bleach ; we may enclose a piece of cotton cloth
or paper coloured by a vegetable substance, as madder
or indigo, in a bottle of dry chlorine, and no change of
colour takes place, even after the lapse of many weeks :
if, however, a few drops of water are added, the colouring
matter is immediately destroyed, and the cotton or paper
is bleached. Here the chlorine combines with the hydro-
gen of the water; and the oxygen at the moment of its
liberation (when it is said to be nascent) combines with
the vegetable colouring matters, forming compounds des-
titute of colour. Ordinary free oxygen has not this power
—not at least to any great extent ; and it is a frequent
observation that bodies in this nascent state have more
active properties than the same bodies when in the free
state. This difference depends upon the fact that the
molecules, or smallest particles of an element which can
exist in the free state, do not consist of the individual
atoms, but of a group of atoms. The molecule of a
cornpound body contains two or more dissimilar atoms,
whilst that of an element contains similar atoms. The
molecules of all bodies in the gaseous state, whether
simple or compound, occupy the same volume. Thus, free
oxygen is | q ; free hydrogen | ^ ; free chlorine j ^} :
similarly, free cyanogen is j ^^. Now, the moment an
element is liberated from a compound, the single atoms
lo6 ELEMENTARY CHEMISTRY. [LESSON
unite together to form a molecule, and the elementary
body makes its appearance in the free state : if, however,
substances are present on which the element can act
chemically, they are decomposed by the chemical attrac-
tions of the liberated atom, which are more active in that
state thai when united to form a molecule.
Chlorine is unable to bleach mineral colours : the dif-
ference between printer's ink, coloured by lampblack or
carbon, and writing ink, . vegetable black, is well illus-
trated by placing a sheet of paper having characters
written and printed upon it in a solution of chlorine in
water.
^ Chlorine gas is largely used for bleaching purposes
m the cotton, linen, and paper manufactures. It is
sometimes used jn the form of a gas, but more usually in
combination with calcium and oxygen, forming the article
called chloride of lime (a mixture of calcium chloride,
Ca CI2, and calcium hypochlorite, Ca ClgOg), or bleaching
powder. Chlorine is also largely employed as a disin-
fectant and deodorant, its action on organic putrefactive
substances being similar to that upon organic colouring
matters. ^
CHLORINE AND HYDROGEN.
Hydrochloric Acid, or Hydrogen Chloride,
Symbol HCl, Molecular Weight 365, Density i8'25.—
This substance, the only known compound of chlorine
and hydrogen, is obtained when equal volumes of chlorine
and hydrogen are mixed and exposed to the diffused light
of day ; the gases then combine, and form an unaltered
volume of hydrochloric acid gas. If the light be strong,
this combination takes place so rapidly that a violent
explosion occurs, owing to the sudden disengagement of
heat consequent upon this combination. The volume of
hydrochloric acid formed is equal to that of the chlorine
X.]
HYDROCHLORIC ACID.
107
rn^ of'l'uT'' ' °"^ molecule of hydrogen and one mole-
thus • ""^ ^'""^ ^"^^ molecules of hydrochloric acid,
Hydrochloric acid may, however, be more easilv pre-
pared by heatmg common salt (sodium chloride) and
FiG. 32a.
sulphuric acid in a flask, as seen in Fig. 32^. The gas is
hrst purified by passing through a wash-bottle contain-
ing a little water, and then is either collected bvdisolace.
iucat ^ll uie gas is required) or passed into' water (as
io8 ELEMENTARY CHEMISTRY. [Lesson
ne^der'""^ ''"^ '^' ^^"''^ '^ ^ '°^"'^°" °^ ^^"^°"^ ^^^^ is
Na CI + H2SO4 = HCl + H Na SO4.
Sodium chloride and sulphuric acid give hydrochloric
acid and hydrogen sodium sulphate. "yarocnionc
Hydrochloric acid is a colourless gas, 1-260 times
heavier than air; it fumes strongly in damp air c^m!
Urv^erfJ^.r^"'"^^' ""^ ^^^ a^sLngly "c?d re^ctio^.
It IS very soluble in water, one volume of this liquid at
15 dissolving 454 volumes of the gas ; this solution is
the ordinary hydrochloric or muriadc acid of the shop
w7 ^^'^^'""^ of 40 atmospheres the gas forms a limpid
n K*r. ^^ ^^^ ^^^'^ ^^ collected over mercury, and its
solubihtym watdr strikingly shown by allowing a few dU^
of water to ascend to the surface of the mer?ury in con!
tact with the gas : a rapid rise of the mercury in the ^ar
immediately occurs. A saturated solution of hydrochloric
st'rondvTnT "^'^ '^'. specific gravity of r^ '; itfum ^
TrTt^A li^ • '"' ^''f "^^^^ ^^^^^d i" a retort, loses at
frfn ^y^/?^hlo"c a^^d gas, but after a time an aqueous
acid distils over at the ordinary atmospheric pressure
containing 20-22 per cent, of HCl, and boiling con!
stantly at 1 10°. If the distillation be'conducted tfnde? a
diminished pressure, the acid boils constantly at a lower
^^^^T'^'v''^ ^"^^^' ? composition which is different
^L ^ A u "" u-"f. P""'?^ ' ^^^^^ the constant acids thus
potained by boiling the solution of hydrochloric acid gas
wr^''^^''/^''""^ ^^ considered as definite compounds of
HCl and water. This fact holds good for many other
stlnnf h' t"'^^"' 1^'^^^' ^^- ' ^'''- '^^' re^i^^e^s con-
stantly boiling at the same temperature, and having
constant compositions, are obtained on distillation the
composition and boiling point varying, however, 'with
ducter'"""^ '''' ^^^ distillatiSk has beek con-
rnltT""°"^^"^"^^.^J^'.°^ ^y^'°^^^ ^^^lo^'de (commonly
called muriatic acid, from murm hr!•n-^ -rn ^^^i^^
times
X.]
HYDROCHLORIC ACTD.
109
(see p'^^SS MorA' '"^""f^""^ of sodium carbonate
everv'^week in JJ^ V ?k 1'°°° '°"' °' ''''^ ^'^'^ are made
add^hnrnr J South Lancashire district alone. The
The arrangement represented in Fi? -xx is adant^H t«
show that, when gaseous hydrogen chb^iie^ifplss ^d ovS
**'«. il.
formed, ru"f"'" ''^^'''^' ^^'^ ^^ chlorine gas are
4 HCl + MnO, = CI, + 2 (H,0) + MnCI,.
0=1- ri^n^^i':-K h^,'s 'r^u'^t::
//
I
no ELEMENTARY CHEMISTRY. [Lesson
li^lST'f "'"P*^^'*'."" "f hydrogen chloride is best deter-
mined by decomposing the aqueous acid in the dark by
means of a current of voltaic electricity, by an arrance-
ment smnlar to that shown in Fig. ,3, and coUecUng the
gases (hydrogen and chlorin. ) evoWin a long tube?afte?
It (Tih.! fifi °f ?°'"P°s'"on to go on for some time. If the
tube thus fi let^ be opened m the dark under a solution of
potassium iodide, the solution will rice in the tube the
iodine being liberated, the chlorine combin ng with he
potassium, until e:;actly half the tube is filled with liquid •
the remaining gas is found to consist of hydrogen If
the mixture of electrolytic gases, which can with^care be
end, h^P.'" ^ J^°"«i '"•'^having very finely drawn out
ends, be exposed to the action of daylight, or of a bnVht
artihcml light.'such as that of burning magnes urn vfie
immediate combination of the two gases will ensue an^
on opening one of the ends under water this hquij tni
completely fill the whole of the tube, show ng that Z
component gases were present in exactly the proport on
thelv^ter" ^"''^^^^"''^^'^^ -"d gas, wLch dSves iS
Nitro-hydrochloric Acid, or Aqua Regia.
.^-S^?"'" ""='3ls, such as gold and platinum, and many
int i «^,nrP°""^.!; '""^^ '•'= certain sulphides, whicTdo
ratllv n™''^ m either nitric or hydrochloric acid sepa-
rately, are readily soluble m a mixture of both of these
t^rm1:-f?^'"'i^ "P?u "^""'."g- This mixture has b«en
termed Aqua Regia because it dissolves the t^oble metalsl
and Its solvent action depends upon the fa« ^haT h
contains free chlorine, liberated by the oxidizing ac "on of
The mfl°" 'k*^ ''^^'■"^^? °^ ">■= hydrochforic acid,
f rn, ?nihu T^' r '"'T'Ly "'"^ 'hii free chlorine to
1 V ^ Th "^ cWprides and the sulphides are decomposed
by It. The nitric acid is reduced to nitrogen dioxide and
this combines with a portion of the chlorine to form the
compounds N O CI and N O Cl^ which are hbemtSl a!
Lesson
it deter-
dark by
irrange-
ing the
)e, after
If the
ition of
be, the
ith the
liquid ;
en. If
:are be
!vn out
bright
11 wiie.
le, and
lid will
at the
)ortion
Ives in
X.J
CHLORINE AND HYDROGEN
many
ich do
sepa-
these
• been
etals),
liat it
ion of
acid,
ne to
posed
2, and
m the
sd as
III
yellowish gases, condensing to a dark yellow, very volatile
liquid when they are led fnto a freezing mixture: The
same compounds are formed by direct combination when
tr.fh;T''r?'''Kp- ^'^"^'^^ ^"^ ^^^°""^» are mixed
together. If chlorme is present in excess, N O CL is
^^l T^'^^' ^P'^\ '' P^°^"^^^ ^^'^ the oxide^ of
nitrogen is present in largest quantity.
COMPOUNJS OF CHLORINE AND OXYGEN.
Chlorine and oxygen do not unite directly, but thcv
may indirectly be made to form the following compounds^
Compounds of Chlorine and Oxygen. CorresRonding Adds.
Chlorine Monoxide, CI, O, yieIdin£r[^-^>*5'*^'^''<'«' ^"<A or 1„ ^, ^
^XHydrogen Hypochlorite]^ ^' ^
Chlorine Trioxide, CI, O3, yielding|2*'5''^«* ^"'f* or 1 « ri n
'^XHydrogen Chlorite /*l*-lt>.
Chlorine Tetroxide, CI, O4
(Chloric Acid, or \rr r^,r^
Wydrogen Chlorate /" ^I O3
[Perchloric Acid, or ) rr /^, ^
Wydrogen Perchlorate (" CI O4
todll'twnif^t^^'^^'* ^l^ ^^^^^» corresponding respectively
f^e stlre ' "°' y^^ ^^^"^ prepared in the
Chlorine Monoxide.
Symbol Q\0, Molecular Weight 87, Density 43-c.-
Chlorine monoxide is obtained by the action of chlor ne
upon mercuric oxide-the chlorine combining not o"ly
With the metal, but also with the oxygen, thus-f
Hg O + 2 CI, = Cl^G + Hg CI2. *
anS'^cticThti^^e^^ ^'^^^'^^ ^'^^ ^'^^"^^ — ^^^
It IS a colourless gas, which mav be condensed by
•- •.-■ a icu ii4Uiu, wmcii iS very
me
.♦^s
"2 ELEMENTARY CHEMISTRY. [Lesson
ox^S^istr""*""""'^ ""'"' ''"^'^''^^ '»"> chlorine and
cold so?:,ir 'of '/^^r ^so'j'f "^^ '"* '■"'° .^^ -i""'- ^^n"
Wa CIO, known as sodium hypochlorite, thus : """'*
2NaHO+Cl,= NaC10 + NaCl+H O
as bleachmg powder (or chlmide of me ?s foimed "
Hy?^ht;^rd"^^-;r.'orMt.\^'~^^^^^
quantities for bleaching purposes aid L '!l""""S'°"'
all absorbed, and bleaching powder formed ThA ^^r "
may be thus explained : *'""'°^'^ lormed. The reaction
, 2 Ca H,0, + 2 CI, = . H,0 + Ca CI, + Ca CI, O,.
and'Srhv^Schlori^'"'^ '''' ^^'''-' -■-"« chloride,
the^a?;Tcl,'j'rstt?lrbet'' fcp-r ?["r^ °/
upon the fact that if hy^drochLlraddt's L'T^I
X]
HYPOCHLOROUS ACID.
bine together forming water whilst thl^.M • ^^'^ *'' ^.°"^-
The copper suIphato^uXg^es no c^,^^'^^^^
an indefinite length of time Hv th?i ^^ ' «ind acts for
powder is now bfing mar^.u^e'd irCT-mh^t"'"'
HypoMorous Add, or Hydrogen HypochloriU.
miSrtlfh"dlilPe-niJfic\c"d1„°d" .?^''„ 'j/P-'^'oHte be
hypochlorous acfd comes ov.r^ltJfi"'^' "^ r'"';°" "^
po.essin,a pecuHa.- ..e.ir/d p'o'J^^Jte^lf^i'^"';^^:
Na O CI + HNO3 = Na NO, + HOCl
andft'chYo^ous acid' "t^'iT^ ^'^ -d'"- "i«rate
fore in the same relltion^rrhl °''°'" ''"''' ^"'"'''' ^'''"^■
acid to nitrogen pentoxrde or ai ThT T"""'''^ "' "''"<:
dioxide. Hydrochloric add L "^^--bonates to carbon
acid with the'^volut.'on of'c^tt tZr" ''yP°'='"o'ous
libe"r:?e? hX^h.^^L^ a^^i'd' C^. !,"f"f • -"' ^^^^
can be used for the ofpnlitf^ the calcium chloride,
from the hypochlorftes • '^^ f h" "^ hyPochlorous acid
process of bleacWng for '-he rt.^''^ are employed in the
ing powder to libel,/ 1 "^f^omposttion of the bleach-
cloth^ Thi; s accomnli.h' ,''?'°""" '" "'^ ^bre of the
to be bleached tn HlS ^t T '^'""^ "^« e°°='«
then passing them through .in .^\^''5'"«, P°""'^'-. ard
phuric acid. wh"r?bv the hI? ,':>'^'-'"=>'loric or sul-
of the cloth : hence' he bia hTn^' ^T'f^^ '",•'»« ^^-^^
after the goods have t^ea" soured"' or r °"^ •^''''^'«=
acid. ^^ soured, or dipped m the
"W^
iH ELEMENTARY CHEMISTRY. [Lesson
Chlorine Trioxide,
' cfr^%?'^l'- P^od"ced by the deoxidation of chloric
c^c d, HLIU3. It IS connected with a series of salts called
chlor, es, just as hypochlorous oxide is with . e hypo-
ch&is NrtK"^^" '''"'' ^^ "'^^^^' ^"' ^^^'"^
Chlorine Tetroxide^
^rf(^r!fi ^k^u'' ?' ^ ^^^^ y^"^^ &as obtained by the
action of sulphuric acid on potassium chlorate. It con!
denses to a red brown liquid, and is a very dangerous
substance, as it is liable to sudden decompLS, pro-
b.T?hV^';T'''!;^"'^'"^P^°^^°"«- ^' '^ s«J"ble in wafer;
but the solution does not yield any peculiar silt^ on
Chloric Acid, or Hydrogen Chlorate.
Symbol H CI O3. If excess of chlorine be passed into a
warm and concentrated solution of caustic potash, potas-
sium chlorate and potassium chloride are formed thus •
3 CI2 + 6 K H = KC103 + 5 K CI + 3 hJo.
The potassium chlorate can be easily separated from
he more soluble chloride by crystallization. Chloric acM
bfivHrnfl ^P-r^'''^'^-^^^ decomposing potassi,im chlorate
by hydrofluosihcic acid, whereby an insoluble potassium
compound is precipitated, and chloric acid remains in
solu ion ; or, by adding sulphuric acid to barium chlorate
msoluble barium sulphate being precipitated, thus :
Ba 2 CIO3 + H2 SO4 = Ba SO4 + 2 (H CIO3).
Chloric acid solution may be concentrated in vncuS
over sulphuric acid to a syrup, but it decomposes on
further evaporation ; it acts as a powerful oxidizing aiient.
and vvhen dropped upon paper it produces ignition, part-
mg with Its oxygen. *, F«*n.
X.]
PERCHLORIC ACID.
w
this gas. The coxnl^^hiJ f T ' .^"yenient source of
by detcrminin/the^we Z S "''°"' ^"^ '^ ascertained
«*c.a, VIZ. ^^^2 J o, IS as yet unknown.
4
Perchloric Acid.
Symbol HCIO4, Molecular Weight lon-r ^.^rx.
at this stage, a new sa t wiU t'oTd^be''^ 'T^".
composiJr„'fK'cio'"'''lt''^'"r™ P!;^<^'"°"te, and its
• the chlorate by treatment ih^h^ ^ If'?' =^P='f«ed from
HCIO,. It has a spedficSrof i 78 at^.?'.^ "5 5"''''
P^^».tJirinfagLf[£^^^^
rpVd^a^^iifrdiF"' *^°^ -^" ^^^
water Corns a?h^tk ofi?iiauld h'J'r" ^""''" '^""'«<* """
and containin; I, , l!L''3."if foiling constantly at 203».
--= ,-j t-. v.=.,L. ui nciu^and thus nof
I 2
'■V-'-g
lie ELEMENTARY CHEMISTRY. [Lesson
corresponding to any definite hydrate. This hydrate can
thus ^ ^ ^°'""^ "" '^^"''^" °^ ch Jrous aad^
3 H CIO3 = H CIO, 4- H,0 + CI, + O,.
Perch one acid is by far the most stable of the acids
derived from chlorine.
Chlorine heptoxide, Cl^O^, corresponding to perchloric
acid, is at present unknown. ^ pcrcnioric
eac^h^m^emt^f ^"^-^l^""^ form, as Seen, an unbroken series,
oxygen r ^ ^'"^ "" ^^^ ^'^'' ^^ °"^ ^^^"^ «f
H CI, Hydrochloric acid.
H CIO, Hypochlorous acid.
H CIO2, Chlorous acid.
,H CIO3, Chloric acid.
vH CIO4, Perchloric acid.
COMPOUND OF CHLORINE AND NITROGEN.
to Sim' !f ?^''"'^'"^'rS "'^'■ogen, though only indirectly.
which h.Vn'^K''''^'^^^^^'°"'P°""^' '^^ composition of
which has not been a^ yet determined. If chlorine gas is
fuxssed into a solution of ammonia, nitrogen, as we have
seen, is liberated • if an excess of chlorine be employed
' drops of an o.ly l.quid are seen to form, whicn; on beiW
toucned, explode with fearful violence, so that the greatest
caution must be used in manipulating even tracesTthis
body The explosive nature of this compound arises
from the fact that its constituent elements are very loosely
combined, and separate with sudden violence.
COMPOUNDS OF CHLORINE hND CARBON.
Chlorine and carbon cannot be made to unite directlv
with one another, but, by indirect means, four d stinc^
compounds of these elements can be obtained. Ona"of
the most important reactions by which the carbon chlorkics
can be prepared is by the action of chlorine on cerTain
F
i
e
k
a
XI.]
BROMINE.
"7
hydrocarbons, in which fh^ i,*,^
atom for atori, by chlorine ^^f °^^" Z^^" be replaced.
following four st/p-fMT J^ .t'- ^^"^ ^'^^ marsh jras the
by chloifne occurX orma^on"of'''"^r ^^ ^y^"^-
being the last one. '°'"^^^'on of carbon tetrachloride
(i)CH, 4-Cl2 = CH3CI +HCI
(2) CH3CI +Cl3.CHa iHr*
LESSON XI.
BROMINE.
Symbol Br, Combininir Weitrht H^ n -. .
element, which closely rIkembiS rMn '^''-^ 8o._This
and compounds, was discoCred hJ JT'"."? P''°P«'-'ies
the salts obtained by the evan"— ^ ' ' '^^^' '"
does not occur free in nature a^ndt°ilk°/ tf ■"'''^'•- ''
combmed with sodium and malne,,', m • '"ll"""^' '^°'^"''
certain mineral springs In nSl? . u "'^ "^'"^ of
mine, use is made of ?he fact thl f '° t,'^'-" P"^« ^ro-
bromine from its combinations wifh" '^'?"",^ '"'^'^'^^
metallic chloride. The bZ'ne thus ff'?' ^°""'"^ "^
separated bv shaking thp hn^A ■ , ^"^^ ''^''■^ may be
solves the bromine,^,brmi^"'a brIX"' h^'^! "'"'^'''^dis-
addmg caustic potash to th"f eth^rifi f • '°'""°"- ^^
at once disappears he b. omfnT 1^'""°"' "^^ =°'°"'-
formmg the bromide and brZato ^f*""" <:.°mbined,
evaporation of the ether these fit P°tassium : on
Ignition (to decompose the hro^fN "'l'"^'"' »"d after
again be liberated hv^K„ t,!'.?.'"*'/) '.h? bromide can
-.• -- »-wuu 01 sulphuric acid and
««? EtEAfENTARV CHEMISTRY. [Lesson
manganese dioxide, exactly as in the case of chlorine,
2BrK+.H,SO, + MnO,=.Br+K,SO,+MnS0,+3HA
its specific gravity at ^ 7s t^'^^T ^'''^^' mercury);
black solid, and ^4\t 6,»^ I '' f""'"' ^' ' "° '° ^
irritating sme'l resemhlin! \^}\ P°==?^ses a very strong
stink), a^.d, wl,^„Tha,ed Ic ts as °a Jr °""" ^''''"'*"> ^
part of bromine dissolve'.; In ,K„ f ™"S P°'=°" •' °"e
15° ; and this solution possestsfc^° P^"' "^ *^'^^ «
however, in action Tha^rose of cHori^^ [f'''^^'
'ng action is caused by the oxidatfoTnf J*"" f^""^'
matter, the bromine romK,.,; °^'??"0" «' the colouring
water to form kn add r^nlf r'} ^t hydrogen of thi
spending in mode of formi 1 ''ydr°b'-omic acid, corre-
chloric acid. formation and properties to hydro-
Hydrobromic Acid, or Hydrogen Brof,ide. '
Symbol HBr, Molecular Wei-rkt 8i /).„o,v
Hydrogen and bromine do noTunke tol'.f -^ '^°(-~
placed in the sunlight hnf f.° , """« 'Pge'her, even when
bromic acid when msiedthro^?Jhr5"i'' '° '^"^ ^ydro-
Hydrobromic ac"d1s nrenlr^f k .u"''°'P'"^'=«'^'n '"be.
(phosphoric acid) ot^ tfrC™^^''^ ""l ^<=''°" "^ a<:ids
bromine and phospho us ^n cTnt'/A°' vk"'^'' "^^ ''""^ing
violent action occurs WHr^h? "^'j** '^^'^'■' "'•'en a
acid being fonned' th^i f " "'"^ ^""^ Phosphoric
P+5Br + 4H,0 = 5HBr+H3PO,.
and L«™l?o"nJly i'n'^o' s^'a^ ' f °"^ ^""^ --'-"• '
water. When concent^a^H i„ " " "'?'">' ^'''"We m
760 mm. pressure^at i"6° I'nH '"'".^°"' acid boils (under
H .Br. /wo volutes of ti^fstasTon^n V T k"^^"'- °'
unued with one of hydrogen. ' ThraqrouTaddtS
if
(
<
I
s
Iff
Fff
^ilj*«r
XI.]
BROMINE,
119
f^L^::t^!^',f:^ ^^^ ^--^- -^ water. The gas
Oxides and Oxi-acids of Bromine.
Jo^nTme^'ur''"^"" '° ''^"^^ "^ •=•>">"-. although not
Bromine Monoxidt> Rr n ,*e «^«. i
only in aqueous solution "Hs obtained bv^^r' !''°"^'j
bromine water upon mercuric ox^erthus !^^ ^ ^"'°" "'^
HgO + 2Br,+H,0 = 2HBrO + HgBr
^atWlfXtion^'hidrol"'^^ ^^?f ^^'<= ->°"nng
Bromine givS ^th sKItIh^'^ °'"''' ^'"'* ''^^"g ^onm.d"
to bleachfng powder consists nf ~"P°""d analogous
bromide anlc^alcium'hypobromfte ^ ""''""■" °^ «''^'"'"
ob^rd'by'tflTctlSfXhlo''^''"'''^' "^^03. can bo
thus : ^ °" °^ chlorine upon bromine water,
^'• + 3H,0 + sCl = 5Ha + HBr03.
chloric'add'Tmirn met^rKP""'""" " ^^^esponds to
like the co?;espon^^g chSes b^t'^' ^''^ be obtained,
on the metallic r«,VlL ;„ ' ^^ "'^ action of bromine
method of otoinSe broX'eTo/?^;'?.- i"^"^ "^^^
(potassi,,m and sodium) con^,f,L/ ,^ ^""^''"^ "'^'als
'rated ^olutio.. of the metamr V k^ "^""^ ^ "^o"""-
ui.tU carbonic acid bee?ns o .f^""^"^.^"'' "chlorine
bromine ; all the chwfn^ """^P^' and then adding
bromate 'rema ns Hence fr^^"'' and solution of purf
displace chlorine from l».„ ^^^^^^^ *at bromine can
chlorine can l^em " bromr.T"'^' -^'^ "^^g^"' '^''ilst
hydrogen. The bro,^.fI^ !, '^""" "= compound with
same w^^he chTrates '^*^°'"P°=<=d by heat in the
Brc^^mntoxide, Br,'o.. has n^f „»» i^„. ....... .
^f
120
ELEMENTARY CHEMISTRY. [Lesson
Perbromic Acid, or Hydrogen Perbromate H RrO k.
been obta ned bv the arHV^n ,>f k "^^^^^^^^y « ^r<^4> bas
acid, H Clot. '*^°" perchloric
IODINE.
Symbol I, Combining Weight 127. /?<?« c//t/ r ^ 7 t^^ •
but m presence of a soluble iodide it irfreelv Hkffi !i'
forming a deep red or brown solution : ft i elsifv sotyhil'
perties as either of the precedinTerements ,?f n1, T"
added to starch paste largely dikUed with „a?er no blue
colour IS observed until the iodine is set free by the add?
tion of a drop or two of chlorine-water, when a deeo hW
colouration ,s instantly perceived. o^ne acts ^as a
XI,]
HYDRIODIC ACID,
121
Ki^Lfefe. '"' ^'^^" ■" =-^" ''"-"ties, it is „.uch
Hydriodic Acid, or Hydrogen Iodide. '
Symbol HI, Molecular Weip-ht i-.« n •. ^
Iodine and hydrogen mT„ !r"S"' '28, Density 64.—
other by heatfn JXl T^ !'i! ""^^^ '° ""''« wiU each
rated when dauti Surif,. h' = ''^'^""'"'^ ^^^ *« "be-
substance is, however b«fi ^"' S'' ?° '°<l'd«- This
phosphorus i^.dMe^Uh'w'TteJK'''* "^ '"'"« "P°"
PI3 + 3 H2O = 3 HI + H5 PO3.
an fpZX"rouil°c1f '"' "^'^'- P^°''"- "y^riodic acid
^n^cIrnrai^fj^'eSkr'iC-^^^^^^
pressure, and soMifies at - cV ^^t «^' '"f^"" ""^er'
gas shows that hvdriodir arW nx u U *"^'ysis of this
posed of one XrT of hyd oeL ^//r '''°"<^V'- =^
vapour, forming two volumeTof^Srirdk ^cfd."' '"''"^
Oxides and Oxi-acids 0/ Iodine
dol^t^%;:?d^VeSgTSlrt^f^^^^
iodic andTeriodic acids' corrT'^'"° ''"P""^"' ^'^^l
Chloric and percLric acids ^''''"^ respectively with
Mic Acid, or Hydrogen lodate.
Symbol HIO3, Molecular Weight i-,f. -rt.-
which corresponds closelv with rflt ll^rZ^'^. ""d
"-'* '-- «*-*«, may Dc ofa-
^
It ■
122 £^LEMENTARY CHEMISTRY. [Lesson
tained by the direct oxidation of iodine by nitric acM and
also by actmg upon iodine water with chlorine, thus '
^-^3H20-f5Cl=H103-f 5HC1.
chlort^'adr'^'^ """"^ '^^^""^ y^'^^ ^°^^^ ^^^d ^^d hydro.
The alkaline iodates are formed (together with the
Dromateb, by dissolving iodine in the caustic alkalies •
6^ + 6HKO==KI03+5KI + 3H20.
poLtrum rc"d1de"and wa?er ' ^'"^ ^^^^^^^"'^ ^°^^^^'
The whole of the iodine is converted into ioda^e if
chlorine gas be passed into the solution, thus
I+6KHO + sCl = KI03 + 5KCl + 3H,0.
iodine, caustic potash, and chlorine vield nota^inm
lodate, potassium chloride, and water Po'^ssium
an ioTtlTn '^^ ^}^'' ^^yge^co'^biiies with iodine to form
an lodate in preference to forming a chlorate with chlo
nne The iodates of the alkaline metals decomoose on
anH "^ ^'^V}^ corresponding chlorates, yfeM^nTox' en
^Ll ^°^^de rhereas the iodates of the heavy mefals
yield the metallic oxides, iodine, and oxygen ^ ^'
Iodine Pentoxide, I^ O^, or Iodic Anhydride is obtained
to i^t^'' ''^'^^"'^^ ^°^^^ ^y heating'iodic acid, Hio^^
J^f''f'f^'''^\ "^^4' ^'^ J^J^^rogen Periodate, can be
aSd^lL o^'^'^V'^'" corresponciing perchloric acM by the
addition or lodme. It is a white crystalline solid bod v
rndtxTin"Th/P"? "P ^"^^ i^^^- penLxit'wafe^;
ana oxygen. The potassium salt of this acid rr,i«»i,
resembhng the corresponding perchloraS is !>-' >ed t
KI03 + 2KHO + CIj=KIO, + 2KCl+riO
acid"tl&f ^''^' ^^ °" '* "'■"P"'-^'^ "y ''^'"'"S Periodic
Pf
Lesson
cid, and
LIS :
hydro-
ith the
:es and
ies :
iodate,
date if
issium
xi.J
FLUORINE,
123
3 form
\ chlo-
)se on
xygen
neuls
ained
aiOg,
xn be
f
►y the
:
body,
\
vater,
osely
1
2d by
'
; and
■i
iodic
iodine and Nitrogen,
.h^5x -Ta«TyT/p.atdT;Se'"^ - "«
pounds are black powders wh^h ' u"^ resulting corn-
dry state, suddenl/ depose with ''r, ^''T^^^ '" 'he
sometimes even explode spontaneous^ Th" """P"'-'' ='"''
of nitrogen is prepared bv the !.,.??„„ '^^ ^ ''^ ?"■■« 'o^I'de
solution of iodLVn ieorrm°/4!rf .^'<=°'"''''<=
6I+4NH3 = Nl3 + 3NHJ. '
FLUORINE.
combined wi'thXe mS S£m f^-— This element occurs
Ca F„ or fluorspar/rmS.' Tlr'? <''*'<='"'" fl''°ride,
found in Derbyshire iHsTLTif -"'f "^ '" ="bes and
cryolite (3 NaF + Al f\ I J '^ T '^""S^ quantities in
whilst it has betn d«'i^tedT mti 'f """ *" ^'^«>«nland,
teeth, and even in the blood „? "^ quantities in the
remarkable as forminfno comf ""^"""'^ ^'""""^ is
as being extremely'Sffficult rrepareTiJ' °^^«""' ='"'*
Many attempts have been mad? t^K? • / P'.""^ ^'^'e.
free state, but none of the ^mVa u'^'." """""^ *" the
bromine, 'or iodine give Tny resuk 'V'*^!^ ="°""^'
however, of dry iodini unrn hV, ^f ^ ^^ 'he action,
that fluorine h'arbl^n "^^f 'I'J .^^^^^ fl"°fe, it appears
colourless gas which Aneir^l?' ' f ' '^ '°""d '« be a
sorbed by caustk pota.h wi?h th'l f "P°" ■«'''^'' ^"<1 ^^ ''h-
fluoride and hydrogen dioSe ^°™^"°" of potassium
2KH0 + F, = 2KF + H,0^
Hydrofluoric Acid, or Hydrogen Fluorfde
Symbol HF, Molecular Weight J, n v
gas corresponds in comoo^tlfn f '.u T''-^ lo.-This
pounds of^he three pTeced'o' .>° hydrogen corn-
obtained in an exactlv^^mni^ elements, and may be
sulphuric acid^^^t^ci^m'fl^SreThus'f ''^ ^"'"^ "^
124 ELEMENTARY CHEMISTJRV, [Lesson
Sulphuric acid and calcium fluoride give hvdrofluorir
acid and calcium sulphate n>aroMuonc
llydrofluoric acid gas muM be prepared in a leiden or
annum vessel, as dass is mn.VlKr .m.V.iI,.'? u" ?,. ^^^^'^" ^^
mi;,„;e af he terp4u,re of' '".%P, if* !? '' !'""^^
l.po'„'%iir's'.ir';- >' ''-"^« ''■^^' -^ v^x V oSy
fume, nf H,t ' P™'^"?"? P«inf»l Avounds ; and the
the .string acid dfssolvr^w th"'a" h'sine' n^l^l; "f^"
37 percent, of HF P'"'"'^' «''>en the hquid contains
iU pt^eJ^of "S^^^trr''' f- hyl'-oflooric ncid is
tUafrtuorine forms IX hf^^^ ""' '"■''.''•■''/™»^ "-e fact
a volatne coSS'tlfe^^ron^ir^^^^^^^
niainicr bv covering { wXl cri,ct -.i ^.^'^''^ ^'"^P'^^
IS used in metallurglc operat ons ar/fl1?!* fluorspar
name (Juo, to flow): *^^'^^"*^"^ ^^ ^ ""-^i whence us
Xtl.]
SULPHUR.
especinlly a gradado 'f' prop r cs' Thus^chtfr'"'^ '•^"•
Cn:V-9;' anroflXcTof. '^ '^/'^orine is ^33 "f
parent hfnm,'«« i, V i . f^ ^5 » liquid chlorine s trans-
The rLhTnTn^ ^"V "^'^K^'y «^' ^"d iodine is opaque
ine combin ng weight, and therefore the densitv of Sr«
3rL+ lir ' "^^'^ '' ^'^"^ °' chbrlnTalfci iodin:;
2" «- 81-25 ; and in its general chemical deport-
ment bromine stands half-way between th^ nfK„. *
LESSON XII.
SULPHUR.
^S>;;/<^^/ S, Combining Weight 32, /J^^j-//!/ ,2 c„i„i,
occurs both.free and combiid in Se -^ ul^^^^^
free m certain volcanic countries esDe^i;,ilvM cm
pounds termed sulphides, wh™h co^st h f' .1, ^ '^°'"-
ores ,™m which th'e metals are'uTuTob'ainerrhus
PbS, lead sulphide, or Galena; Zn S zinc snlnMH.
mende; and CuS, copper subhi^ ir^ rt,„ A I ' ""^
from which those rn'etah'^fre generally procu^^H ^^q"?",""
also is found in nature, combined ^VhmctaUnndnP^"'
to form a class of saUs called surphates™ of the"e Sm'
sulphate or ffvosum. Ca >^n _i_ V, u /^ ". -i^' caicium.
"■^- "' '-% \ - ii^^-'-, uanuiu Sulphate
ta5 ELEMENTARY CHEMISTRY. [Lesson
pots (Fig 35); th^ sIlFpZ^di ils'ola' ii; Z^'i^Z^'t
thus obui:;.?-fi„\T 'p :.;? br^K :;'i!tl
Ki
iT* :4'
!i
of a fine crystalline pK'"cl'u^VFt'Ts of 'tV^""
in wttuSj-lJXeT?^^ - t"-
are obtained by mdtina: suloh,?r if' ""f '^^ °"^" '"o
allowed to coo/sbJ^ "f c, sts fnT'"''l '"'P''"'' "^^
needle-shaped, prism^^i "cr^s^ wWch ire^'Ji^^nPff "■'"'•
m fom from the natural c^t^SphTrSh^vrfh^i
X'l.]
SULPHUR,
127
crystals of the^naturai 0/.^,^^ 'R''^^'"^ "P '"'^ »«veral
The th.a aaot^irm'iaSo^- ,ff »r^^^^^^^^^
.teJaThtt^r^a"^^^^^^ -H water:
caoutchouc, and has a so/rifir J" °"""^?' ''^^^mWiag
form of sulphur is, however no. n^"^ °' ''^- '^his
hours, at the teinperaZe of /h» ^''^^n^"' J i" a few
the ordinary brittle fwrn of fhli^""' *'"' ™^" assumes
to loo^it instantly chan^efto^Lfe"V *''"^' '^ ''^«<=<1
evolves so much heat fftn 5 "'* '°'™' »nd thereby
III". These peculiarLdifir„f''*K'' t««>Perature up to
sulphur is he'^ted^hr.tlohrti'r":! tPPl-"t /"en
* *""'> -■*'' "^-feiii wuii, at
•
"8^ 'jiLEA,irj,rAJ,y C//^-.,/#rA.,-. [LKSSor,
attains the consistency oY hick (r«.r, S"'""'"'^''' '■'"''
23o» ,t can scarcely be poured out of H '" """,•'" •''''°'"
above 250°. it again becomes flu?H. ml "^ ""-^'"^ '' '''«««d
redd<sh.black coloured th7n linn id' " ' T*^.'!:'""" "^ » dark
c:^:^^^'' '' ^^-■"" -tiir^'^'d'j-^Ts
in ml'''a^;riVo"."~b'.:-;'„^^^^^^^^ heated ■
bining with the oxyLn to form . 1 ■?'""> ""'"e. corn-
called sulphurous acid), SO wMrh '''' •"■ '''°'"'^'= (°ften
possessing the poculia \inM.kn '1^'^^ °'^"' ^ «^«.
which IS evolved when a comr^on ^Jr '"'^°""nff smel
Sulphur combines directly wXchlofl'"'"';'''' '' ^""''■
other elements whilst many metils h?rn' ''■'"■''P".' '""^ """^
as they do in oxygen g7s»n?,,w? 'V'''P''"'' vapour
Sulphur is insoluble in water nnM". '°™ sulphfdes.
but both the natural ocTah^;\^„f°l' °'^T'' ''^"ids.
^.ry^'alline (or prisma ic)va?^;'iisSyf='"f fhe othe;
uisulphide, CS, whiUt ,h^ I ^ aissolve freely m carbon
insoluble in this g ^ When" Tn' ^?™ "^ ="'Phur is
m carbon disulphide, sulDhur crv«!R^"'^ '^?'" '°'«'°n
natural or octahedral forS ^rystallues m the ordinary
COMPOUNDS OF SULPHITR AND OXYGEN
^^:^^:"^^.S^ are known in
H» SO3, Hydrogen Sulphite or Sulphurous Acid and
H, SO, Hydrogen Sulphate or Sulphuric Acid
Ja?;tU^"^«:-^,^^^^^^^^^^ Of ^su,r::e- known.
s^«W?"=sTLtf;? i^-onTSSf
•^^ 2, 3, and 4, are important
t
f
c
XII.]
•sWt
PHUR DIOXIDE.
129
compounds ; the remainin<r bodies ire h... i.vi 1
and do not as yet serve anv m,,.?1 ^ r*"^ ^'^^^^ known,
racturcs. These compL'^dsSblf '" '^' T' ^^ "^^^""■
the hivv of multiple zSx^m^l^l 'r "" '^''^'"^ "^^^""^r
Dalton, (See .^{^/.', p 59 "^ Proportions enunciated by
(0 Hydrosulphurous Acid
(2) Sulphurous Acid
(3) Sulphuric Acid
v4) Hyposulpliurous Acid *
(5) Dithionic Acid .
(6) Trithionic Acid
^l( Jetrathionic Acid .* .*
W Pentathionic Acid
H,S O3
H,S,0,
fl2S',08
H,S,0,
H,S,0,
Sj^'^idfl/ SO.^, Molecular H'dirht (a n v
I his gas is obtained when suln^i.^ic » '^ ^^'j-f//^ 32.^
off in large quantities from vdcLcc^^^^ ""^^ ^^ ^''^^^
prepared more conveniently on S^^ ^' "^^^^^
the elements of water and on^ IrM " y ^^ removmg
from sulphuric acid Lrheat^L ,1 ""^^- u'°^^^
copper oJ- mercury, thus :^ ^iong with it the metals
Cu + 2H,SO,==SO,4-CuSO, + 2H,0.
sulph^K'w^^^^^^^ ^^^^ ^'^'^ -^P^- dioxide, copp.,
theltClter^^^^^^ ^o purify it, and
colourless gas, possessir'^a LPr. ^/.'P^^^^^^ent. It is a
sulphur; it^s^^247 nK^3 heavtrT/ '"'"^^ °i ^"^"^^g
condensed to a colou icss linnfn K ^^^r ^''■' ^"^ '"ay be
under the o. iry a^mo, '?"^^ ^^ ^°°J»"g down to - 10^
below- 76^tnei;LdSs^^^^^^ ^^^^« <=ooled
arrangement for liquefyinTthe ^^^^-^^P^^^^"^ solid. The
consists of the "suarSion fl^asVlnr '"J^^' 36 : it
^vi.ch . connected with a s^tlass^^^^^^^^^^^^^
. . <~"/..ir/.\jAi, [Lesson
,^H .r."""^ '"i'""'o or salt nn.l noundcl i,r Tl
I Wtlon.105 111 1 1 s liihc mill Ml. I ' ' "■ r"^" i> P> I lie Riis
Pincod lH-l„w, whic V- ISO n i""' '"I" ""^ »'"•'" ll.^sk
Wlicn a ,„niJie,:;;:a ,hy7 X
cts^d'Sftfrhe ::^^^^^^^^^^^ •>-<"-? 'aton. is so
duced to -frjo : this is eisMv Ih "7 '" "*'' """y be re-
.l.e liquid upon the bu b of a^ ' "oZu^ ^°"""« '°""= °f
has been wrapped in cotton woo?" ">'-''™<"»etcr which
condtsed,th;b^s'!:onsl°:i;f^^-^^^'-'"f -<= --'X
law of pressures occuDvim^for I '"7!«"°" ^om Boyle's
sure less space than afrund-.h^"'''' '"'='<^'"'^"'s of p,es-
ditferencc LoiW hr " the ]t'^T ^°"'l'"°»s /this
The volume of this ^s fin. T. "l? '^"'P^"'u>e.
sulphur is found ^U'^Xl^J^^ aT'ttflTtht
A
XIL]
SULPHUR DIOXIDE,
= ^:tTLj^^:^^,^::ti of .„,p;;;
clemc.,,.,, , volume of s«lp .u tmX '^Uh'* ^.h! ''""'r
oxyKon to K,yc . volume, of the diox.'llc '"''' "^
bulphur dioxitlc ia very soluble i. witnr , i
water iit lo" dissolving ci ih i *'"^f ' volume of
volume, of thifg^^^'-l^h/ olutio.; of 'th^ '""'•^' '°' ^^^
si,t, (like that ot carbon dioxide n «fif Sa, in water con-
/>////^, or true sulphurous acW If sn "f. f^"''T'' ^"'■
i» decomposed on boiling h^l?^"f '"" ""is substance
dioxide being reproduced thi. \^»' """ ' »"'' ""'phur
If the solution o?7hi^"a; fn water 'h?' ,"5 '." ''' «"•
a crystalline hydrate or.nU?!,^ '"' -S' ''<'*' ''dow t°
havi^Kthecomi;o;?,^l„''i, "s'^T'll/r^" "■^'"■''"=» ""«'
co^Sotrill^fsuLtnr" »'"5?of a series o,
decomposed by the » Uoler'.r^"' ™'"P"""''' «'•= easily
liberated as .\Z tK^s tee' r',';: 'r'''''^''^'"«
b loachmg agent, especially for ,^[k l^T^^n'^'^ " "
which cannot bi bleacheJ b^ chlorine T-""] «°°''*
ployed as an antkhlor iat thr n„r„T v" " *''" ^m-
the excess of chlorine present in'^Z?^ of getting rid of
which paper is made ""^ '^''-■a':''ed rags from
."inner 'exaS'^"p|os1e7o'tha[''!'"^ ^T^ ««« '" a
inasmuch as i? uSftes witS the ixv^rn'\'!!!°""^ •■«=".
colouring matter present form in, 7^ ? ?^ •"= *^«" of
liberating the hydrocen • ,n ?,^ ? sulphuric acid and
by aCinl as a'reducTng'or deoxX;"'^"' ^"'^ '''"^^^^^
chlornie bleaches by oiddntion J- > f^, ^^ent, whereas
an antichlor depends on Thi? ^'^ilarly, its action as
hydrochloric acrds"1hus" " '^"™^"''" °^ «"'ph"ric and
^°^ + ^H.O + 2CI=^^H,SO,-i.2Ha
ni.nlSrofs^uS\"i'ifofol.'"r^'''^-^^'--' '" '"e
tins purpose enom.ousquantUics of i, /""?'' ^'"'^ '°'
Sulphurous acid. H„ SO lit' .°!u""'. ^'oxidc areused.
-f '■■',
m
ill
%"
'32 £^£M£ArrAJiy cjf£M/sr/iy. [leSson
placed, and the i^r^/^i/r^h ''>'^™pn has been re-
replaced by a me al Th^t H^"? ''°"" """"shave been
pWte, H K S O ^s an J5 Hydrogen Potassium Sul-
ks6„ is a ne'utraf sJt st"^',^",' ^°'Ti""^ Sflph.te
Potassium Carboiiite HKCA ^^ ^'7^''"^ Hydrogen
bonate, Kj COj. ' "^^°3, and Potassium Car-
LESSON XIII.
Su/p^r Trioxide, or Sulphuric Anhydride* '
6>wjp/ SO3, Molecular Weight 80 Density An Q t
pnur dioxide dots t.o<- im^^^* ^- ' • -^ '^°'~'S"^-
con.bine directr;witroxygen' to foTL'T^v^
two dry eases he r.!.cc«^ . t. ™ ^'-'s' D"t if these
divided metallic oS,!^'*"" 7"' ''^"»«'' ""d Bnely
white fume of tt sulphu""Z,vt '''^'="' ?"'' '^^"'^
^ar-^gX^\^S?^F^^^^^^^^^
Th^ comSinn' f/^*- •""'"? as a red-hot iron would do
imo%u^tr"Sde'rn^w"attrrilt"Pr^'-^^^i"
wIJx^ anhydnde is meant an oxide which forms
an acid on treatment with
XIII.]
SULPHURIC ACID,
Car-
133
Sulphuric Acid^ or Hydrogen Sulphate.
. ^y**^f>ol H2SO4, Molecular WetP-htQ% -Thic c. u .
IS the most important and vl^Ju\L1a7^ substance
means nearly al! the otW Tnt^ ^ ^^^^ri, as by its
because it is ve^^ Ia4?y^^^^^^^^ ^"^ ^'so
for a great variety o7puSs So vT l^^ "^^""factures
cations of this acid fhlFtlT ^ Y^luable are the appli-
in the slh Uncas^^^^^^^^^ manufactured
per week. Indeed, it has been ^^^ITd'ter ''"^
mercial prosperity of a rn^xr^f^r l^^ u • . * ^^^ ^^m-
great accuracy b/the amoun? S^ ft^i,^" ^"^^^ ^^ ^'^^
consumes. ^ '""^ ""^ sulphu. ,c acid which it
Sulphuric acid was first Drenar*-H K^ ^.v.-n-
pound of iron, oxygen sulDhur JnH ^^ ^'^^'"'"^ a corn-
sulphate or green vUriol^Tht ^f^l' "^^"^^ ^^^^-^us
known as fuming orNordhalsen a^M ^ ^'^
a mixture of hydrogen .win w ' ^^^ consists of
H.SO + SO, '™s%\r o'f''^^^^^^^^^ ,^"-^'^e>
long been superseded by the folio wTn? ^^'' ^^^^^er,
method, which depends unon l^ / ""T convenient
sulphur'dioxide does not comlne ^ith'f '*'"'' ^^'^°"^^
water to form sulphuric acid it fcT u^^ 5^^^^" ^^^
the oxygen when the"l"«er ^'„^^^^^^^^^
form of nitrogen trioxide, N.o" thusT ^ '" ^^^
SO, + H,0 4- N,03 = H,SO, -f. N O
phuS^aclS^LrSidT" "'^^^^" trioxldjyield sul-
^^r^^tSi^j;; S^^^r ^!^-^es u,
another atom ^^^^^^ t^^^^
from the air. Hence"t is clear .haTfh^M^n'" °^ °^y?^"
as a carrier of oxygen hetw^n thtafr anSV'l^'^P'y
indefin tely small auantif,.^f .!,• • *"° "•*= SO,; an
thereforeawt",:!"?,"!"?."/ ""« ■'^"™Sen trioxide &'in^.
"' ""■"■ "' '-0"veri an ir.definitely large
134 ELEMENTARY CHEMISTRY. [LESSON
?huricl^5 *""*""■ '"°'"''^' '^«'"' -<! own into sul-
materials are br^u^lit/ Fi^^'' ;\ t i„°''rT"i """''
add '''^,'r"|-"f ' for 'tlie'LStu'r" ^f Stu'rl'
fn i. ^^^ ''''''^" 'Chambers, of which two are represented
in the figure, are connected tosether hv a wX 1. i
l^a compoimd of sulphur and imn Fo c \ •« p;'/ucs,
furnace (^«). The sulXir nf thl ^' •. ¥ ^^ ^ suitable
beh nd in the fumarp a »™,ii . r,^ '^a"?' remains
is placed in the ceniral oarf of ??" ^?' ^""^aining nitre,
salt^is deco,nposUr.he'a«ion "sute Jc d'thtl^
is maintained by connectini» tL »r,H '','"°™"gn draft
with a high chiiLey not Zwnfn ?he fi/ureh,:;''r •''-.'
of »h.,. j„« on. If the supply of sj^, t h,s,fe„; f^X .o"'''"'""!'^"
formed, having the composition SO ^^O, . , ' ? ' "-""'Po.md «
of w«,r i„,„ It- 1 tOH ' " <'=™"P»sed, on addili„n
«",. to play an impo.tan, V'^n 'rifi^lL^^'S ^^X' Sl^^''^ ''^
I
I
^■11.] SULPHURIC ACID CHAMBERS.
^ii
136 F.LEMENTARV CHEMISTRY, [LESSON
reaching the chimney. The sulphuric acid, as it forms
falls on to the floor of the chamber, and, when the
process is working properly, it is continually drawn off
attammg a specific gravity of about r6o, the strength
being ascertamed by an arrangement shown in (/)
whilst the waste gases passing out of the chamber should
contam nothmg but nitrogen and small quantities of
nitric oxide. In order to obtain from this weak chamber
acid the pure sulphuric acid, U^SO,, the excess of water
must be removed by evaporation : this is conducted, on
the large scale, first, by heating the chamber acid in
covered leaden pans {e), until the specific gravity rises
^° '7?' )^"'^" t^e acid is known as the drown oil of
vitriol of commerce, and then further concentrated in
vessels of glass, or of platinum (as lead is attacked by the
strong acid), until its maximum strength and specific
gravity is attained. The hydrogen sulphate thus obtained
IS a thick oily liquid boiling about 338°,* and freezing
at IO-8 ; Its specific gravity at & is 1-854. It combines >
with water with great force, absorbing moisture rapidly
trom the air : hence it is used in the laboratory as a
drying agent. Great heat is evolved when this acid is
mixed with water, and care must be taken to brino- these
two liquids together gradually; otherwise an explosive
combination may ensue. Many organic bodies, such as
woody fibre and sugar, are completely decomposed and
charred by strong sulphuric acid, whilst others, such as
alcohol, oxahc and formic acid, are split up into other
compounds by the withdrawal of the elements of water
by this acid.
One molecule of hydrogen sulphate unites w'>h one of
water to form a compound, HgSO^ + HoO, which can be
obtained pure by cooling a mixture of acid and water
having a specific gravity of 178 down to 7°C., at which
tnovlS^'L^n '^''' ^y^-TS^njulphate undergoes a slight decomposition, sulphur
^oxide bem? evolved and an aad remaining behind which contains only
2
t
7
C
t;
C
t(
XIII.] SULPHURIC ACID CHAMBERS. 137
temperature rhombic crystals of the hydrated acid are
tormed. The sulphuric acid of commerce frequently
contains large quantities of impurities, especially lead
sulphate from the chamber, and frequently arsenic from
the pyrites and nitric acid, as well as the lower oxidesTf
nitrogen In order to free the acid from these impurities
It must be distiUed and subjected to other treatmen fo;
a description of which the reader is referred to the"arger
treatises. A high temperatures sulphuric acid decom-
To'tht ?/"''"'■ 'lT'!.^.S«2,, oxygen, O, and wX,
H.,0 thus, fa current of the acid be allowed to flow on
to red-hot bncks, and the gases resulting from the decom-
position passed through water, the sulphur dioxide will be
ll^n "-^^'^^',^1^ ^«PPly of pure oxyge^ Ob!
ained Hydrogen sulphate is a dibasic acid ; i.f. it con-
ams two atoms of hydrogen, either or both of which can
be replaced by an equivalent quantity of a metal As
with sulphurous acid, in the case of the alMne metals
we have two salts, thus-KHSO, a.id K,SO " Crur
and lead sulphates are insoluble in water :' hence soK
sa ts of these metals are used as tests of the presence of a
sulphate, a few drops of solution of barium cMoride for
example, producmg an immediate white precipitate of
barium sulphate m water containing the merest trace of
sulphuric acid or of a soluble sulphale. C^lcTum-, stron-
tium-, and potassium-sulphates are but slightly so ubleTn
water, whilst the other sulphates are easily soluble
Some sulphates crystallize as anhvdrous salts, such as
ar?H 5" F?f^'='"™ ^"'Pl^^'^ ; B''S(J„ barium sulphate
and AgjSO, silver sulphate : whilst others require water'
o retain their c^jstalline form, and this water is te^ed
■water of crystallization. The crystals of iron sulDTate
or green vitriol, and of zinc sulphate or white vtoiol con
tain seven molecules of water in the solid form Uust"
copper sulphate or blue vitriol requires but five molerules
to preserve its crystalline form, thus : "^^ molecules
FeS04-t- 7H,0 ^ ^ „
138 ELEMENTARY CHEMISTRY. [Lesson
Hyposulphurous Acid, or Hydrogen Hyposulphite,
Symbol n^^fi^, is not known in the free state The
fsNa S O "" ?v ""r •'yP°»'!lphi«e, such as that of sodiurn!
crystallization. It is largely used in photOKranhv for the
^Z^^^,^, ^T^ "?^ '^««^' 'h^ =«"t possetshfg the pro!
on bv Ae il°hr"^Th' "'^V r"l «:''ich'^have been unacted
on Dy the light. This useful sa t s prepared bv Da<;^inT
a current of sulphur dioxide into a^ S solu^fon o^f
sodrnm sulph.de and caustic soda, and purifying by crys-
tallization the sodium hyposulphite obtarned: ^
2 Na,S + 2 NaHO + 4 SO, - 3 Na.S.O, + H,0.
Hydrosulphurous Acid.
fyfnboj H2SO3. This compound is formed by the >
action of zmc on sulphurous acid, thus : ^
Zn + 2 SO2 4- HgO = ZnSOs + H^SO..
It consists of a yellow liquid, which acts as a far more
powerful reducing agent than sulphurous acid, and at once
Skaches vegetable colouring matters. Hydrosulphurous
of sulnh'u;^ undergoes decomposition with separation
ot sulphur. It forms a series of salts, which are stable
"yptll^tef ' '"' " ^^^"^^^'^ "^^ ^^^^ convert^dlnto
cr.n t!? f ^^'^l not only combines directly with oxy-
gen to form SO3 but also with chlorine to form SOXL
sulpkuryl dtchloride. SO3 not only combines with a mole^
f Lf/T';°J?r '1?^P^""^ ^"^^ «2S0„ but also wth
a molecule of HCl to form SO3HCI, chlorhydrosulpkuric
tlt^^^'^ substance is of interest, because it is alfo pro-
duced in a reaction common to many bodies, which may
Xill.] HYDROS ULPHUROUS ACID. ,39
like the acids, be considered as water in which one atom
chfofnJ Prf «"d a compound of phosphorus and
SoTurc^xSlorrder""" '^'"■°^"' '=h'oHde^nd phos-
PCI5 + H,0 = POCI3 + 2 HCl ;
and if phosphorus pentachloride be added to concen-
trated sulphunc acid, the reaction occurs in two stages,
, (') PCI5 + H2SO4 - POCI3 + HCl + SO.HCl
(2) PCI^-f SO3 HCl = POCI3 + HCl + S6:aj
It will be seen that in both these reactions, one atom of
hydrogt n and one of oxygen is taken out, and one aTom
of chlorine substituted for the group of atoms OH (termed
the rar^ica/ hydroxyl\ Sulphuric acid may, however be
regarded as two molecules of water in which two atoms
of hydrogen are replaced by the group SOg.
S:!
o,
so.
I
Oo or
HOH
HOH
SO
OH
2OH
Expressed according to this last formula we can plainly
SOj
Sulphur
Dioxide.
SO.
|o
Sulphur
Trioxide.
H
OH
Sulphurous
SO
OH
2^ SH
Hyposulphurous
Acid.
SO,
(OH
( CI
Chlorhydro-
SO,
ilpl:
Acid.
so, j ci
Sulphuryl
SO,
OH
OH
Sulphuric
Acid.
SO.
OH
NO,
■i^sviiioriac.
Crystals of the
Lcuden chamber.
I
//
" ^TT'
WXT-TT
. '*° ELE^NTARV CHEMISTRY. [LESSOf.
COMPOUNnS OF SULPHUR AND HYBROOFN
Hydrogen Sulphide or Sulfihuretlcd Hydrogen.
Symbol HjS, Molecular Weight xi. n,n,it« ,, -ru-
pas IS formed when hydrogen Uij/fu"'^ L^rT''"-
snipbur, but it is b st nr/nf«^ u .u "iraugh bo'ling
snlpliuric acid upon ro'^Tlohid/ F%''" °" °^''""''
being also formed, thuLT '"'P''"''^' ^^^^ "°" s^'phate
,FeS + HjSO, = FeSO, + H,.S,
di'vIllnUror'^/if Y'"'"" •^"''"S^ P'''« -i'h ""e of
lion. i.,g. 38 represents a convenient form of
fig. 38.
gas possessing the pecuHarodouT ^ T^.te"' egg^s • tburni
f>n application of a ight with a hlnUh fl™ ' i r"'
water and sulphur dioxide When "nh'^IedTt^'arr™""^'
po.son on the animal economy, evTn iflih.ted w"th l!.?.^
••-^f^i^^i
Xiir.j SULPHURETTED HYDROOEN.
'•♦V^
smell and a sS y ^cid " r.? ' "^^"[.'"S "'?«"'!»'•
volume of watefat o° H 1„? "°" '° /''« "■'''"• One
whilst atJ" ,.„ ,°"°''"^*'*-37 vo)u..ies of the eas
tel l^.a^re^f^-Lo™;.','?^*' '"''^ =?'"''le. Exposed to a
temperature of the nV I fu '"'"^'^" "' 'he ordinary
f ee in nature in volcanic ^^^^""'""i '^^''^e^" """''^
certain spr,nt4 [hus H ,rSf f' *^ *^" "' '" "'« ""''«'■ "f
odour and medicinal uoC^tT'""' °'*^"'^'^ P<='""«^
It is like«-ise generated h,' Ih ""^ P'^/'"'^^ °^ "''^ «^s-
matters, such a! alb?,ml - 'I P"'^?f»"'on of animal
contains sulphur -also ivth/n'''^ or""'" °^ «««'' *hich
P.esence of '^ec;;int°or«U?c ^ir.'""" °^ -'P^^'" i"
tabled eX';%'ra°tintf smallli'^'^P" '"^'^ ''^ —
Known volumeof the ^aswh^n*^? u-'^ ""''"'<= "" ''" »
and h) drojten hberaS^ ' tu^!"^ '"'Ph.de will be formed,
means of a red hot n ati"..™ ■ ''^'^°'"t'°?'ng 'he gas by
-iphur is de,:os!rd,td"Cdr:g"A:e';re''%?bth"' "^'
the volume of hydroo-en obt limS fc r T' ? ^^^^ ^^^^^
that of the gas empbved tnH K """""^ ^° ^^ ^^-^^^ ^o
phurctted hydrogen Sinf?.^ "^^^""^^^ «f sul-
weighfng 3^^ ^ ' ^""^ ' ^^^""^^ ^f sulphur vapour,
lab' ritTlfby^ ^" ^^^^^^^^ -agent in the
metalsinto JrouDs If^f ' ^ ^'^ ^^^^^^^ ^« ^^P^^ate the
a solution o a Copier' ^1^'ro "TT ^^ '^''' ^^' '^'^^^^
acid has been added L-H, ^'^^ ^ '"'^^^ quantity of
of copper sulphide f\hus ""^ ^'^^"'"^'"^^ precip^te
If we do the
«-\ ■ «^>« .
jpiw^ipi
CuSO, + H,S = CuS + H,SO,.
le with a solution of an iron «;.
e, ucc-iuse iron sulphide is soTubl
;e in an
i. ■ '
H^r ELEMEATAHy CHEMISTRY. [LrssOK
. olctV^e^cVha^^^arlhulT °' ^" ^"'^'' '-" -'P^ide is at
FeSO. + 3 KH. + H,S = FeS + K,SO, + a H O
Ken from an acid solution r^ht ''L"''P'""'«*«'' ''ydro-
those which are not ShL'n^^-^^Tr''''^^- ««=°nd,
gen in an acid solution but whth'' ="'P'""-etted hydro-
, an alk-'-ne one or ,hi T ^^ "^ '° precipitated in
sulph, ^ are soluble either In , I ^-agent, as their
to thi. .roup belong the meta?s of t''h;'/f;'"' ^"^^'■'^' '
ttne earths). ^ metals of the alkalies and alka-
Hydrogen Bisulphide, HjS,
cai^lt dtS tatr^fchfei^ ,Lr.-''°» °^
CaS2 + 2HCI = HaS2-f CaCl
tie ffin"''4sti^n. *'&fc„ °L'^^ 7.^'' -"-•> -'^
poses into sufphur and'^uli'hulXthy'd" og'^^.'''^ <1"°'"-
C^r^^;^ Disiilphide.
•^y^^^oiCS^, Molecular IVei'o-ki -yf, n v o
vapour of sulphur be passed ovPrV"^T'^-^ 3^-- ^^ the
volatile compound, CsfTs formic f^'^^ charcoal, a
densed to a heavy coSurlesri?o,1d ""^''^ "^''^^ ^e con-
liarly disagreeable smell boilinl^.f^P'^'o"''^ ^ P^^""
specific gravity of ro^T ci u- !,-^^,'^A^"^ ^^^^ng a
flammable, its Vapou^^ignitPng at x^o^^^^^^^ ''' ^^^^ ^^-
air, forming carbon dioxide .hH ^^t u^^" ^'^^^ with
IS msoluble in water, Cacts as f iP^'^di«^ide. It
. ui acts as a solvent upon gums,
rif
XI V.J
•SELENIUM,
caution. ^ * ^"^ *' 'nust be employed
143
its vapour is,
with
sulphrc^^^^^^^^^^^^^ IZHr^^^y the foregoing
oxygen series ; thus : corresponding bodies in thi
Water, H, O.
Hydrogen dioxide, H. O,.
Carbon dioxide, CO,.
Sulphuretted hydrogen, H, S.
Hydrogen disulphidl H,^.
Carbon disulphSe, &s".' "
Ihese possess not onlv in ar.^i
similar chemical properties IhtfT .^^^^P^^ition, but
seen in many otheV comDonnd.^f ^''"'^^'* relations are
pounds, S,C1, and TCL-Xv ar'et^ '^^°l"^ ^^^ '^^'
current of chlorine gas over mel/rr'f .^^ ^^^^'"^ ^
volatile liquids, the first bo^W^a^i,«'"^f ^"\ ^"^ ^^^
IS decomposed on boiLUg into S^.ct and a"' '^' ''^"^^
LESSON XIV.
SELENIUM.*
Symio! Se, Combining Weight 70- c /5. v
Se enium is an element which •doselv^;<.f''Kf'-^ 79-S—
m Its properties, but it occms in verv sm.ir'''"'Hlphur
was discovered by Berzeliu/ JL f ^ 5"?" quantities ; it
sulphur in certain vSes of s1h'^"k'^ « accompanying
a so occurs free in na ure and u V ^V'^^' Selenium
with metals in certainlremfnerals ?''■."" ^'"'^'""ion
rorm is Obtained ^^^^^^^^^^^S^
"7-'f;, uic moon.
'♦4 ELEMENTARY CHEXIHTRY. [Lesson
^^r^^^t^t^j^:^ r '•«""■- -"'»
of t.,c (ormer variety is 45 that" f '1^ ?'''.''"'""" ^'^^'y
ta line selenium melts at 2 iV ' anrf h ? '''"^'' 47- Crys-
Wow a red heat, eivirijoff a deen i,"''' '" * ''^'"P'-' "r>--
selenium softens ft a tenper.tuX f ,' ?," 7P°"^' ■"'-•°"^
point of water, and remaX ,n n ^ '"'^ ''''°*'<^ ">e boilinv'
time. In a finely dSSstate^'i^n" ?""'"'-'<'" f"^ »°'""
mnted light, selenium has TIIa y "''"'" ''=^" ^y trans-
air with a bright blue flantl'"^"'': ^' "^""^ in the
means of the spectroscope %28.i'A^'k" '"^"""^'^ ^^
{uagnificent and"^ characi^ris u! bln'ds tk ^ '"'" °f
burning selenium is very necnli^r ^}}^- *""«" of
rotten cabbages, and is dife to ?hi /' ''"^'nblmg that of
the composition and proper, es of !vT"°" P^ ^"^ °^'de
yet unknown. Seleni^S^fo"s"[;i'^'^i*ff 'however, as
selenium dioxide, SeO., and i/ ,„T '^'^ '-dphned oxides,
iatter, however, has not as tt hJ •" f '''•*;"^''' ^^'^^■■ this
and salts corresponds wit'h it t''"^'!?'^"^''' '^'« ">^ ^cids
wnh the dioxide, aTweT 'know '. 1)1"", '^''^"Pondmg
the analogous sulphites and ^i'.,'* ""'"^^'y resembiS
called selenites and selenaTes '"'P'^«^^ = they are hence
Selenium Dioxide.
Syiniol SeO^, Molecular Weii^ht .,-. -ru-
pound IS formed when seleninm if 1 "'.5-— This com-
pyre oxygen. It ma^be prepared to".",' '" "?5.''''- °^ *»
nmm in nitric acid r aqua riS^ ' Q ?' ^y °^'dizing sele-
white crytalline ma^^caoaW^^'.f S-'""/'" '^'"^'"^ is *
•and thus forming sTlkt^f^if ^''^^^'^^ ^- ^^T'
solution seeiium is at nnrTA "r^fOa- From th s
sulphurous acid, sul^huVa^cM S^^o^'j^ ^^^^ of
H,Se03 + 2SO, + H,0 = 2H,SO, + Se
sulphUes'"'^''"''^ '''''''"'' -"-P-d closely with the
XIV.]
TELLURIUM,
*45
: Sdenic Acid, or Hydrogen SeUnate.
Symbol HjScO^.-This is best Dreoari^rl K^ f •
selenite with nitre: on addition rff?i^ ^^/"^'"^ *
PbSeO, + H,S = Hi,SeO, + PbS.
Selenic acid decomposes, on heat n< ., i •
oxide, oxygen, and water ;' the meAnf." f '*■""'" "^i-
respond to the analogous silDhaterinH *^ *="»'" "r-
with them-that is, tLy c Wallze in fh/*"^ 'somorphous
have an analogous comDosWon xL^ ^^"^ ^°™^ ''"d
difference between the tZelim?„'. ^he most important
is that the for^r U oxk^zed t^ ;'"v,'Pu"''^''<»^^'«"'™.
action of nitriclcid vXreaf h. 1 ^J^''*'^"' P"'"' by the
fused with nitre in order to reach fh.l''""'' ''1">* «° "^^
of oxidation. ^"^^ '"^ corresponding degree
SeUniuretUd Hydrogen, or Hydrogen Sele„ide
Synbol H,Se, Molecular IVeirht 8it n.„.,;
This gas is obtained by the affion of <^'^°'7i—
selen,de, exactly as si,lnh,,.lf J u ?^ *" ^"<^ up-in a
.'rom a 'sulphX It is*^ a cdo„rl.^f • ^r '^ P^^P''^^^
possessing i tiauseous smell indexhihi?^'"'"''''' ^''''
in every respect analogous o those of t/.."*! f^P^^''^^
sentative. *" °^^ °' "= "Jlphur repre-
TELLURIUM.*
Symbol Te, Combining- WeiM 120 /).w .
s-ng an fnalogy t sulpC aSenSTn''S c^^^U^
** From tellus, the earth.
!
k I
146 ELEMENTARY CHEMISTRY, [Lesson
relations that its compounds are best considered in this
fnT^^nc ,''''''"'"' '^T^J''^'^^^^^ ^°'^ ^«d other metals
n T.ansylvania and Hungary. The specific gravity of
te lunum IS 6-25, and it exhibits a bright whitf metlllfr
Tlw\ u f -^"^ ^^ ^^"""^ 500°, and may be volatilized at
fn thi^ J^eat m a current of hydrogen gas. When heated
m the air, it burns with a bluish-green flame, forming
white fumes of tellurium dio:cide, TeO^ : this compS
iS also formed when tellurium is oxidized by nitric acid,
and the solution evaporated to dryness. With water the
n'^^i nf k'^' /^//«^^^^ acid, H^TeOg, and with metals in ,
p ace of hydrogen, tellurites of the general form, M^TeO,.
VVhen tellurium or a tellurite is fused with nitre ootas
r \?? TPO4 + 2 H2O, and telluriu7n trioxide, TeO„ can
be obtamed With hydrogen tellurium forms a colour-
hTch-/^"' I iT*-'"^ hydrogen, H^ Te, which cannot be
distinguished by its smell from sulphuretted hydrogen.
' Oxypn, sulphur, selenium, and tellurium form a
natural group of elements, each uniting with two atoms
ot hydrogen to produce a series of bodies possessing-
analojous properties viz. H^O, H^S, H^Se, H^Te. Thi
last three members of the group exhibit the same kind of
striking gradation of properties as was noticed in the case
of chlorine, bromine, and iodine. Thus the mean of the
combmmg weights of the two extremes is jiearly the com-
bining weight of the mean, 31±Ji9 _ g^.^ . ^j^jj^^ ^j^^.^
specific gravities, 2-0, 4-5, and 6-25, and their melting and
boiling points show a similar gradation.
SILICON,
Symbol Si, CGmbinitig Weight 28.— Silicon, next to
oxygen, is the most abundant element known. It -does
not occur, however, in the free state, but always combined
I
^»>n^*,y„^
■ TW ii>l»n » . B ! . Mii,i.^:;V:;-u; '•■•?:: . &■
kiv.]
SILICA,
HI
silicates ; and of these Se pr^f^ ¥^?' ("""'"S "Gallic
in order to obtain silicon in .^/ !:"^"Posea.
pound of this subsLce^ith fluorine '.n^"'"' ." '^°'"-
potass.. si..co-fluoride, is hea!;dtX%S^ SuT
. K2SiF6 + 4K = 6KF +si.
InL^h^rrdr^^^Lf^o'ntaTe'^^^^^^^^^ °^ '"«
different moSatbns - amornlfn ^^ "'"'^'u""'' '" "^'^^
crystalline. The granhite for J^? '',• Sraphitoidal, and
heating the broln^^mo ^^^^ powtrTo'7'h'Pr'' ''>
perature, when ^he mass con7r=.?f. j I ^ '"^'^ tern-
more deAse. CrvstaK =.T ^ u' ^^^ becomes much
the mixtur: wh'lSllvrb^lTsUicon with""?"' "^ ^"''"^
mg the mass crv<iftl« ,.f c,;" ^'"'^°" ""* zmc : on cool-
on°the ^"?whi7h latter can ea".ii''t.°""'^ '" ''^ "^^P^'i'^d
in an acid. SHicon thus oh.t • '^ ^^ ^^T^^'' "^^ ^°'Mion
scratch glass • it W I .L v '"^^ -'^ '"^''^ enough to
be fused at a 'temmr/K". " ^'^"'^^ "^ ^'49, and may
cast-iron and sted.*^ ^''""^" the molting points of
^//zV(^?< Dioxide, or Silica.
Symhol Si Oj, Molecular Weie-ht 60 k fi,. 1 t
oxide of Silicon ; .ft occurs in %i!l ' "^ °"'y "^"own
in six-sided prisms or nw^Jn ^ ^"'^ ^'^'^ crystallized
a less pure condWon in'^S '' *\1V^«'-. and exists in
agate^ ^&c. The " l"J^„ „m'' poTaslt^'T'- "'"'' ^°^
iron-sihcates, mixed to.'eSe'r in H ff ' <'*''='"m-. and
'-Ostallized silica, in the form r^f o u-.
q-rtz,has a specific J^^ ^"^^^^^^--^
148 ELEM-ENTARY CHEMISTRY, [Lesson
to scratch glass ; it is unattacked and undissolved by
all acids, with the exception of hydrofluoric acid, by the
action of which silicon tetrafluoride and water are pro-
duced, thus :
SiOg 4- 4 HF = SiF^ + 2 H2O.
Silica is infusible except at the highest temperature of
the oxyhydrogen blowpipe, when it melts to a colourless
globule, and ii cannot be vapourized at any known tem-
perature. Silca in an amorphous condition can also be
prepared, and then exhibits peculiar properties. For this
purpose one part of finely divided quartz or white sand is
heated with four parts of s<3dium carbonate : as soon as
the latter begins to fuse, the silica combines with the
sodium apd oxygen contained in the carbonate, carbon
dioxide, CO2, being evolved with effervescerce, owing to the
formation of a sodium silicate, called soluble glass. If the
fused rnass be boiled with water, it will dissolve, and on
the addition of hydrochloric 2iC\d, silicic acid, or hydrogen
silicate, H4 Si O4, partly separates as a gelatinous mass,
partly remains dissolved in the liquid. If this solution be
evaporated to dryness and heated a little, and hydrochloric
acid then added, silicon dioxide is left as a white powde/
insoluble in acids : this amorphous silica possesses a
specific gravity of 2*2 to 2-3, and can only be obtained
again in solution by repeating the process of fusion with an
alkali, &c. A pure aqueous solution of hydrogen 'silicate
can be obtained by allowing the solution of this substance
in hydrochloric acid to diffuse through a membrane for
some days. For this purpose the solution is brought into
a flat drui.1 or sieve made out of parchment paptr, and
this is allowed to float for some time in a large quantity of
water. The liydrochloric acid and sodium chloride pass
through the parchment paper, and a clear solution of pure
sihcic acid remains behind. The limpid liquid thus ob-
tained may be concentrated by evaporation until the quan-
tity of silicic acid in solution rises to 14 percent ; but this
solution is apt to gelatinize on standing, forming a clear
XIV,
] SILICON COMPOUNDS.
149
fit? 11 ^v^ dmlysts, and it depends upon the fact
that all crystalhzable substances (called crystalloids) can
pass in solution through the parchment pape^wS
gum-hke amorphous substances (^^//^A such i the
gelatinous silicic acid, cannot pass ^' ^^^
Potassium- and sodium-silicates are lar^elv used for
with the silicates of cilcium or lead forms th- sever. ^
descriptions of ?lass (p. 225). several
Siliciuretted Hydrogen,
^fi^'f^^^' ?*' ^^a colourless gas formed by the action
sflicon'' 'tatffi^ "P'^ ^ '•""^^""'^^ of mag^nesium anS
f f g wilht^^^^Tm^^TdTr^^^^^^^^
Silicon Tetrachlaride.
Symbol Si CI,, Molecular Weight 170, i?,r«x/Vv Sc
This compound is formed when silicoi i/Teated 'l^^
chlorme but may be prepared by passing dry chforine
over a red-hot mixture of hnely-divided silifa and carbon
Chlorme alone is not able to decomoosp tili^, carDon.
presence of carbon a change is eff^r?^H . k ' ^"' '"
oxide being at the same timfforaed ' ' ^"^ '"°"-
^•r ,,f' °* "•" ^'^ + <^» = Si CI, + 2 CO.
;5ilica, chlorine, and carbon yield silimn t«r,^i,i -j
and carbon monoxide. Fig w show, ,h» '^'■^*='''o"de
employed for preparing this body, xle m,xtu^e''"„f ?r "'
o receive it s'i;^^°PP'"S 'T "'^ """'^ placed beW
1?,;^ boil,"; i".%°V!!.T^u!J^ - volatfle colourless
-o - j^ ^* """ "'i^'ing a speciiic gravity of
/,'
iS^ ELEMENTARY CHEMISTRY. [Lesson
1*52. It is at once deGomposed by water, silicic and
hydrochloric acids being formed : hence we may see that
this body in the chlorine series corresponds to silicon
dioxide in the oxygen series-, and that in the formation of
the chloride four atoms of chlorine simply replace its
equivalent quantity, two atoms, of oxygen in the silica ;
Fig. 39.
SiOg becomes SiCl4, as one atom of oxygen is equivalent
to two of chlorine.
If dry hydrochloric acid gas be passed over heated
silicon, a new substance is formed together with silicon
tetrachloride, to which the name of silicon-chloroform has
been given, because its constitution is similar to that of
chloroform. This body is SiHClg, chloroform bein^x
LHCI3, and it boils at 36°. It is very inflammable, and
burns with a greenish flame, evolving dense white cloiids
of silica. It is also easily decomposed by water, and at
low temperatures a white powder is formed, having the
composition SigHgOg, called silicon-formic-anhydride.
2 SiHCl3 + 5 H2O = li^g I O + 6 HCl.
By acting on white-hot felspar with silicon tetrachloride,
an oxychloride of silicon ^j^Js | O is formed. This is a
■■%■'
XIV.] BOJ^ON AND ITS COMPOUNDS. 15,
colourless strongly fuming liquid, which, in contact with
water, decomposes mto hydrochloric and silicic acids.
Silicon Tetrafluoride.
Symbol SiF^, Molecular Weight 104, Density 52 -
This IS one of the most singular compounds ot silicon
It IS formed whenever free hydrofluoric acid comes in
contact with either free or combined silica : this is the
cause of he etchmg which hydrofluoric acid exerts up ,n
glass. Silicon tetrafluoride is b.st prepared by heat. J in
a flask equal parts by weight of finely-powdered fl"u or
spar and white sand, with about eight parts of sulphur^
u :u^5 decomposition first occurring is the one bv
tie silicl ;' thus7' "'^"^ '' generated, and this then attacks
\'^^ ^tf2 + H2S04=CaSO, + 2HF.
(2)4HF+Si02 =2H20+SiF4.
Silicon tetrafluoride is a colourless P-as which fumes
strongly in the air ; it do.s not burn nor^upport combus
tion, and maybe condensed by great pressure, or exposure
to a very low temperature, to a colourless liquid ; it is de-
composed by water, but may be collected over mercurv or
by displacement When l.d into water, this gas yields
sihcic acid, which is deposited in a state of finfdivi ion
and a new acid called hydro-fluo-silicic acid, or hydroo-en-
sihco-fluoride having the composition hJ Si FlwhSi
remains m solution : 2 ^^^6, wmcn
3 SiF4 -f 4 H2O = 2 H^SiFc + H^SiO,.
This substance has an acid reaction : the correspond in o-
potassium-and barium-silico-fluoridcs (K.SiF^andBaSiFJ
are insoluble m water and alcohol. ^
BORON.
Symbol B, Combining Weight iro.— Boron combined
With oxygen and sodium is found as borax -- - -
r 11"! r% 'J 1 1 1 1"^
• • • i2 tt i XJLS. V
iiH
'5a SLEMENTARV CHEMISTRY. [Lksson
pho,,s. Bororfs easilv nhf^-""!; "y^''""'^ and amor-
Powder, bv heating tUCo„'tr;n-r''^'^*"T'''°"^
sodium. Crvstalhvfd wL • ^"oxide, EjO,, with
amorphous ^o^^t^Z.^^T^'^^ ^^ ''^«'"ff ^^e
the fused state hav^n^^L„ ^'am.nium-this metal in
which sepamL ou fn ti^5^P""7 °f '"=^°'""g boron,
the metaf cools iast L^ th» '^ co ouriess crystals when
does from i?s so/ution in ir„n^P''"°'r^' ^°™ °^ «'bon
.alli.ed boron ^^T4:Jr^l^^'^'^llr£l- ^rys-
scr^?ch'^hTlrr;^e r'*^" ->-^ en'ouK
crystals whic™ was analv,.^'^"""" "'^ ''""« colourless
was foun,j to be present ^ hi """^ quantity of carbon
have be<5 prepaS' ar^.-'ficiX in"T^'" T^ "^^^''^ *<>
fication. Boron burns wh^nf^ ,^t <^'amond modi-
or in chlorine, fU^,^^i'oSdeZite''V•" °^^^^"
able as beinf onp «f .h«. r ™"e or chloride : it isremark-
with nitrZI, absLhinC '^^^?^'"^"*" *'"'^'> ""'"fe directly
evolution flight °« *" ^^^ *''«" '^'l !•« wit^
Boracic or Boric Acid.
vo&diS''if?':^^V^^^^^?-'" -«- oM
gas escape from the eartT"Vbese JJL/m iet°! ''^"l '""'
known as fumerollp^ r.r- cr.m • steam jets, which are
of boric acirXcfcolIe^n theT"'" ""/" •"«»''*'««
mouth of the jet. By means of tLlfT'r '^^'^ ^^ '^e
jets the solution of bor^rfr L^J • ^eat of natural steam
acid obtained by MH^^'tion .'LT""'"^'^'"' *"'' '^e
acid thus p^paKllmpTrt^- Iv^i^'y^^,.:!" "/ '™''^
Boron likewise occurs L f.sTuZr^ '^ 1-"^°™ ^"s^any.
Thibet, and on thTc^ast of cSr„^ "«'""» ""-'^ -
separate- oJt ^ o^ ^'^^1^^ Ert"r ^^.iS»
it
**<«?**»»#»*»
X.V.] BORON AND ITS COMPOUNDS. ,53
B^O,. Boric acid i. slightly soluble jl JT" a'""^"'
more soluble in hot waf "r • if i.^^ . "^°'d' ^nd rather
tint to the bIowp,pe flame ^HcrayLl^ P<=^""^'- g'^^"
series of bands when evami^.^ k ""*' * characteristic
scope. Metallic borates rtlt'nTnd"'!,"/ "^^ ^P^"™"
con^binations of these borates wKron SoxWe ' Th"'
sodium I >rate of borir aHH ;« , u- i! ./^ inoxide. Thus
.en is replaced bysoX^,' s" NaBO '+ Tuo' ""'tT
fused borax s this salt comhJni^ Vi? ^ ^ ^zO ; whilst
boron trioxide hus 2 NaRO^jT'i^V"^ "'^^^^"'^ ^^
Compoun s similar to thfsktte^sai^t!??^ °' ^"^^^'^^
the sulphates Thu^ m!^!. are known amongst
M Qn J c r^^ ^ Nordhausen su phuric ariH ic
H2SO4 + SO3, ana a sodi- 1 compound Na SO /^n •
known. Manv of thp tv^. oTi;^ p^u"u, i>ia20U4 -f bO,, is
borax, giving coloured ri~«« u^^ are^soluble in fu?ed
largely Led in°hearts^ifffl- ^"""l"^ '^"^ compound is
a blowp^e re 4nt ""' ^""^ '" '^^ laboratory as
BctTnd"^^ 1uSet'°f^ '° '°™ ^ ^'•-''^-*.
;?«<..^V&, BfJ both these °omT ^ ^°"^^V°^^^^S tri-
a method limilar to th|t "aTomed fL'^^h P^'P^'"" "^
ng silicon comDoimH. .„ ^??P'^<* for the correspond-
slilhtly d"C7constilut1kr .h''' r'^'''^'''"'''"^ '^
blance Like s licon a Ln h^, ^^''^''^^ ^ ^""""S ■•«=«"-
hydrofluobork aciZor hin °" u°™lf ^ borofluoride :
and potassium bo;ofli°o'ride'K^^," borofluoride) is HBF„
^l.EMENTA,V CHEMISTRy. [lesson
LESSON XV.
PHOSPHORUS
in combination with oxveen inH^^i • '"'■^' ^"* '* ''<»"nd
t.t.es in the bodies, an7frpechl1v th''r '" H""^^ l"""'
>n the seeds of plants and akn li i ^°"^'' °^ ^"mals,
r.te and apatite^ When bones .Mh "'""■'"= phospho-'
mass is left behind ;tTis is 'ne^ rT' ^ '^'^'"^ ^"''d
(phosphate of lime) AniLl« ..^'''''"i™ Phosphate
necessary, for the formaUon of th '"."• "'^ Phosphate
plants. Plams, again draw .i" 'P'"^^' &<:■> ''■■om
whilst soils der ve'their nhosDh./L'f"PP'y ^"""^ *« =o".
existing in the oldesr^ranite fe kT., '"1^" q"^"t"ies
of which the fertile so1 s hav. h' ^^ "'^ disintegration
phorus appears also to be a v-" Pwduced, Phos-
the brain and other cemres of^^r"''^''^ '"^''^'''^n' '"
was accidentally discove ed by Brlnd'tT H^^r" ^'
•669; but Scheele, in 1769 poLed nf,. ?if "''.'"burg mg
Tihosphorus in the bone^ LnS °'" ,"'^ existence of
carefully. "^^' ^"'' exammed its properties
mix'ng?t':™h t^o'Eof'itT P^r^^?" '^°"--«''. by
and ,5 to 20 parTs of wa e^*^ "i,,*«'&"?t of .sulphuric acid
poses the bonla.sh, forr^ ^g cald^mlfc ^""^ '^^^°"'-
which separates out as a whf- ins^lnh^ '%'"' ^yPS""",
the greater part of the nW.,1, '"^°'."°'« Powder ; whilst
into solution^ in combfnalTwr Valciu^ '°"" ^^^
hydrogen, forming calcium hTdt„ ^' °'<ygen, and
commonly Icnown^as i/^ft^/ 1^ ^T^fe L^lf
Uil
IBIL^'
.'fJj:^M.S»a
XV.]
PHOSPHORUS.
'55
is drawn off clear, evaporated down to a svnm ^n^ fV,
the water in yeZw drops whflsth-''''';>^t'"iV"^ "'"'^^
behind in the'retort trStci^^ZCXif "'""'"
mable and oxIdTzable subsCce ''and .^^"^'''"^'^ '"1^:^-
ma ches Phn/,,*''" ^"."'Po^i""" for the tips o/ludlr
pTrl^m1o,id!'r S^,-;?,^^^^^^^^^^^
and consistency • but at low T» '" ^.PP^arance
brittle. Itsspecificlravitvl. ,.|"'P^'?*!'>-«s « becon.es
white-^fnies cons5^trnrof;f:;^|/J°,^^™'^^^^^^^^^ tg
formmsMospLZ's7mol%Tvo J^^ combustion, and
dride). The ienition of^w^i; * ' ^°\ Phosphoric anhy-
fricti.^n prbVlwr,:n5e7n\rU:t;7th^'V"^^'
cause this substance to iVnil . i ^^^ ^^^^ "lay
taken in handlTng phosSi ^T^FT ^^^"^"st be
cut under water ^Jj^^^P^o^s, and it should always be
is its iSteVafLl^fnlnfSeJ.^^^^ ''"'^•^^'■' ^••°'" ^^-' "^ht. and /... T ,..„_
■
156 ELEMENTARY CHEMISTRY, [Lesson
actiny chemically on it (such as hydrogen or carbon di-
oxide), It IS found to have undergone a very remarkable
change, bemg wlioily converted into a dark red opaque
substance, aivogether insoluble in carbon disulphide. The
weight of red substance produced is exactly equal to that
of yellow phosphorus used. This is called red or amor^
phous phosphorus, and differs much in its properties from
the yellow modification, especially in its inflammability,
as It does not take fire in the air until heated to above
200 , when It becomes reconverted into the ordinary form
and burns with the formation of phosphorus pentoxide!"
Ihe specific gravity of amorphous phosphorus is 2-14.
1 he sudden conversion of yellow into red phosphorus can
be shown, by heating a small piece of ordinary phos-
phorus in a dry tube with a mere trace of iodine ; com-
bination at once occurs, a small trace of volatile phos-
phorus iodide IS formed, and the remainder of the phos-
phorus IS converted into the red modification. The red
or amorphous modification of phosphorus Ci^ri also be
obtained m a cystallized form by heating red phosphorus
in a tube with metallic lead. The phosphorus dissolves in
the i^elted lead, and on cooling separates out in crystals,
which possess a bright black metallic lustre, and have a
specific gravity of 234.
Phosphorus forms two oxides, phosphorus trioxide,
I'a^a* and phosphorus pentoxide, P2O4.
Phosphorus Trioxide, or Phosphorous Anhydride,
Symbol V^O^ Molecular Weight no.— This oxide is
formed when phosphorus is burnt in a limited current
ot dry air, when it undergoes slow combustion. It forms
a white non-crystalline powder, which combines with
great energy with water forming thereby phosphorous
actd, or hydrogen phosphite, H3PO3. This Icid is like-
wise formed when phosphorus is allowed gradually to
"n'lS^iBBB gg
XV.]
PHOSPHORIC ACID,
157
PC1, + 3H,0 = H,P03 + 3HC1.
nff^''„H''"'"^ '^'? '°'""°" "^^ hydrochloric acid is driven
no;itH ' °" .^°°''"g' "ystals of phosphorous acid are de-
posited. There are two classes of metallic phosohites •
the one contains those which correspond to pDorous
uy metal ; and the second those n which onp ;dtnm ,>„i„
of hydrogen has been thus replaced "the Funeral form^
of the two will therefore be M,H PO and MH PA ^
letter M denoting an atom of a^monatlmic Si '' '^^
Phosphorus Pentoxide, or Phosphoric Anhydrtde.
Symbol V^O^, Molecular Weight 142.— This s, i,«»n.»
air'or"ot;en'" Phosphorus bufns btightlyt excesT'f
which "aSs moi",ure"wl h XTtmTt "^"a* "7^^^'
ing hydrogen phosphate oT phospho k°a id^H %^"™;
aspirator. The whte powder '^fiSff °^ ^ ^""°*'' °f
Shaken out of the g.^wTelVteraS irct "^e^te'a!
Trihydrogeu Phosphate {Tribasic Phosphoric Acid).
Symbol H3PO,, Molecular Weight qS-Wh^n !i,
receding compound is brought infn".L?,.7^.^^."._*«
preceding compound is brought into contact a
great heat is evolved, and cLnin;H-^!''f?KL'
with water,
piaiuc Wiift
II
IS8 ^i-EMENTARY CHEMISTRY. [Lesson
P205+3HjO = 2(H3PO,).
nil ^l^o r^i,^^ u "^ """<-i<tii>, constitutes the main sourre r\i
all tlie phosphorus compounds If hnn*. ooi, ?^'"/""^^^ p*
treated with sulphuric rdd and Jh^c. i .-^ ^^ frequently
If sodium carbonate be adr^ v1 t.^ ^ « i ^-
added until the solution ceases 't^rJ^ '^f.^^^^onate be
neutral sodium ifhos^hatP ■ \t,:l^J rnombtc or co7nmon
by the symbol NaHPo' *^f composition is represented
of crystal ^T^^""^ molecules of water
Trihydrogen Phosphate . . H PO
Dihydrogen Sodium Phosphate .' H,VpO,+ ,2 H,0.
XV.] PYROPIIOSPHORIC ACID, ,59
Hydrogen Df-sorli ni Phosphate . HNagPO. + H O
Tri-sodium Pho ,,nate .... NaaPO, -h 12 H,6.
The three . ;; s of hydrogen in trihydroeen phosohatd
HNaNH^pJ, ;• ydj^gen-sodauu-ammonium Phosphate,
All these substances are distinguished by givine a
/^/W precipitate with solution of silver nitrate cfnsistln^
of tri-si ver phosphate, K^.VO, ; and by producl^rwi^h
ammonia and magnesium' sufphate a white crvs^aHne
precipitate of ammonium magnesium phosphate-
NH^MgPO^ + aHaO. .
fini^riu" ^'"'"'^^^ "^ phosphates can readily be detected by
Pyrophosphoric Acid, or Hydrogen Pyrophosphate. ■
Symbol Ht¥fi,.-lStna^^ic phosphoric acid be boated
for some time to 2,0°, a crystalline mass of pyrophosphoric
acid IS formed and water is Uberated ; hus : ^"°^P"°"*=
2 H3PO, = H,PjO, + HjO.
This acid is tetrabasic, the four atoms of hydroeen bein?
replaceable, either all or in part, by metals ??h,,^ff
common sodium phosphate be heated tiredness wa'.ef
s driven off, sodwm Pyrophosphate, Na.RO, rem™^ns
2 NajHPO, = HjO + Na^P^O,.
7r^!^My}^ ^^^\ i' '^'''°'^^"? '" ^^'^^ i* ^^^ be re-
pass back t'ofh. f ? "?' '""^^ "P ^'■'^' "?»»' «° ^= to
pass back to the state of common phosphate (exceot on
give^Tth'lif'' ''"l""^ °^ it^. solution)/ This Since
g ves with silver .i.trate a white precipitate of silver pvr(>
pliosphate, Ag,P,0, : and thus this class of nhosohlto
i6o ELEMENTARY CHEMISTRY, [Lesson
S^ "^A Io^SI'h^ ^'-^ ^^^. P^^^eding or tribasic phos-
phates- A so-called acid sodium pyrophosphate, having
the composition Na^H^P^Oy, is also Lown. ^ ' ^
Metaphosphoric Acid, or Monohydrogen Phosphate, '
. 6>/«^^/ HPO3, is obtained in the form of a transnar^nf
anLmmf^'"'''' i^-^^' Na(NH,)HPO„ is heated, water
NapSTs left ^'l^'T"" ?^^ ^"^ ^'^^^'^^^^ metapho\phlTe,
Aal^Ug, is left .-this dissolves unaltered in water forming
one of a third class of phosphates termed JS^ZT
Phates ox metaphosphates.Tht solutions of thSe saks
Ses'of'Sbvth' '''V"''' °f ^^^ two pre"^;^?
withiolmionl of Li ' P'^^,"T& gelatinous precipitates
wim solutions of calcium and silver salts consstinp-'nf th^
metaphosphates of these metals. cons..ting of the
From the above it is seen that three. modif^cp ions of
phosphoric acid are kno^vn. or, rather, thr d fferenf
we have-' ^"^"^ "^^ '' ' ''^'^ '' metallL s;Us'^^S
an^Jl^dYu'^p^L^^^^^^^^^ -^^> H3PO,.
P P^O^^l^.i'^'^!?^^'' phosphate, or pyrophosphonc acid,
t; f ^' i ^^^'"""^ pyrophosphate, Na^P.O,
(3) Monohydrogen phosphate, or metaphosphoric acid
HPO3, ai-^ sodium n-etaphosphate, NaPOa.
n.f/A''^ the above hydrogen phosphates can be ore-
pared by passing sulphuretted hvdrogen throucrh w^f^!:
contammg in suspension the correspo1.ding silver s'JL^;
(3) 2 (AgPO^) + H,S
- H4P2O7 -f 2 AggS).
rmm
»»wwiii|ii|p(jp ii ym^j
XV.] r'HOSPHORUS AND HYDROGEN. x6i
Hypophosphorous Acid,
Symbol H3PO2. — In addition to the phosphates and
phosphites, a class of salts termed Hypophosphites is also
known. The composition of hydrogen hypophosphile is
represented by the formula HPH2O2, and that or sodium
hypophosphite by NaPHgOg ; and these saUs may be
supposed to be hydrogen or sodium metaphosphate, HPO3
and NaPOg, in which one atom of oxygen has b^en
replaced by its equivalent, or two atoms, of hydrogen.
Sodium hypophosphite is obtained by acting with caustic
soda on phosphorus, when phosphuretted hydrogen gas
is evolved, and a solution of hypophosphite remains
behind.
PHOSPHORUS AND HYDROGEN.
Three compounds of phosphorus and hydrogen are
known— PH3, a gas; PgH^, a liquid; P^Hj, a solid
substance.
Phosphuretted Hydrogen,
Symbol PHg, Combining Weight 34, Density 17. — This
gas is obtained in the pure state by the decomposition
of hydrogen phosphite, or hydrogen hypophosphite ;
thus :
4 H3PO3 = 3H3PO4 + PH3, '
But it is generally prepared by the action of caustic potash
on phosphorus :
3 KHO + P4 + 3 H2O = 3 KPH2O2 + PH3 ;
potassium hypophosphite being formed. It is a colourless
gas, smelling like putrid fish.
Each bubble of the gas thus prepared takes fire spon-
taneously on coming into contact with the air, forming
singular rings of phosphoi as pentoxide, which expand as
they rise. This self-inflammability of the gas depends
upon the presence of small quantities of the liquid hydride
P2H4, which may be condensed to a volatile and very in-
flammable liquid by passing the gaseous hydride through
a tube cooled by a freezing mixture.
,f
•mrmm
mm
t62 £LEMmTAJiy CHEMISTRY. [L.sso.v
PHOSPHORUS AND CHLORINE.
water, it sinks down as a heat/^n k \ ^^^"^ ^^^°^« into
fosed, hydrogenlkoldhUe 22 ?,^^^ ^s gradually decom-
formed (see d iU^ t?^ ^a ^^^'■ochloric acid bein?
is 1-45, -d^tJ^b^^-^^^^^^^^^^ ^-vity of the trichiS
chloride rapidly absorbs cWorineLs' .nJ^^'^^^""' ^"■
into the pentachloride, a yelEh slhVI t k .'' ^^^^^^ted
IS also fprmed when Dhosnhorn • u ^ substance, which
chlorine: Phos|Lru^s p?nuS^!o Le^ "" '^^T "^
presence of excVss of wkter ?r rmfn . .^^^^"^Posed in
phate and hydrochloric acid kT^k ^"^^^^^S^" P^os-
quantity of 4ters present a HouJ^.'^ °!5^^^ ^^"^^^^^
^^j/^^/^r/^,. is formed haWn^ ?hi^ ^^""."^^^ phosphorus
boiling at iio%. ^^^^'.^^^^^g the composition PCl30,and
Th,c ,^^^^^6+^205= 5 POCI3.
bring silver chloride and nWnh^ ''"?i'^ '■> "'"^ i'' we
we get nitroxyl cWorfde (^elf "' <»^y=Woride together
, NO, / „
3 Ag %^ O + POCI3 = 3 NO.Cl + Ag3P0,.
Co^rresponding compounds with bromine are likewise
ar.^UsSe;e&t7?hi?r^ '7T' -'"Pounds;
P2S3 and P,S„ corresDond n .n ° ?^ ""^'^ compounds
I'^O; and P,0 The oxid ern"P*''"'5? «'"'» the oxides
ever is as /eVunknown '^'"•'•^=P°nd'ng to P,S, how-
^
••mmmimw^s
'rjfwr
XVl.J
ARSENIC,
i6%
LESSON XVI.
ARSENIC.
Symbol As, Combining Weight 75, Density of Vapour
150.*— Arsenic closely resembles phosphorus in its che-
mical properties and in those of its compounds, although
in physical characters, such as specific gravity, lustre, &c.,
it bears a greater analogy to the metals : indeed, it may be
considered the connecting link between these two divi-
sions of the elements, antimony and bismuth being closely
connected with it on the one hand, and phosphorus and
nitrogen on the other. Arsenic is sometimes found in the
free state, but more frequently combined, chiefly with
iron, nickel, cobalt, and sulphur. It is also contained in
very small quantities in many mineral springs. In order
to separate arsenic from any of the metallic ores in which
it occurs, the ore is roasted, or exposed to a current of
heated air in a reverberatory furnace ; the arsenic com-
bines with the atmospheric oxygen, forming arsenic
trioxide, AsgOg, which is carried in the state of vapour
from the furnace into long chambers or flues, in v/hich the
irioxide (commonly known as arsenious acid, or white
arsenic) is deposited. Metallic arsenic may be preparec*
from this oxide by mixing it with charcoal and sodium
carbonate, ad heating in a closed crucble, the uppp ■
part of V hich is kept cool : arsenic condenses in the coo^
part of 'vis apparatus as a solid with a brilliant g^^y^ha
Irstre. n urnishes in the air from oxidation; it :.,. a
sperific gravity of 57 to 5*9 ; and when heated to dull red-
r^si>,it volatilizes as a colourless vapour without undergoing
fus- -anci this vapour possesses a remarkable gariic-
lil; smeh Arsenic when heated in the air takes fire, and
, ^.'^j' i_ volume occupied by an atom of (gaseous) arsenic weighing 75 is only
Half of tha^ orcupied by the other elements genemlly : in this re- ct arseuic
M 2
11 JT^^T/" """"'^'"'- »■"»»
OXIDES OF ARSENIC.
(o'^X.S^a/ rr. Tf r^en a. known,
As,0,. '^^'''^' ^s«^3; (2) Arsenic I entoxidi,
Arsenic Trioxide,
burnt in the air or i^oxyten^!f,M.™"' ^''«" ''^^^^'^c Tl
by roasting arsenical pyrftesFeslV' f ""''"? P'^'P^^d
•s 3'6. It exists in two distlnrf f„ ' '? 'P'='^'fi= g'-avity
the V treous: it occurHn he fi ' t ™Hi« '''■^'''''''"' '^^
m bnlliant octahedra, and in tif^ modification crystallized
parent glass-like sol d devoid nf"°°"J ??• ^ ^'^mi-'rans.
this form of the substance on l.L-"^"'"^ *'"'""f«: ■
tnoxide IS feebly soluble in wa£r . ,t '>:• Arsenic
may be considered to contain Tr,^ i the ;>..ution (which
hydrogen arsenite, H AsO Ini ^"^"'""s acid or tri-
acid) has a feebly acid Won uT"', '" Phosphorous
in hydrochloric acid, andfs f?eelv ..^^ m''^? '"°''^ "-^^dily
the alkalies, arsenitesbein Worm j'"Mt '" ^°'""o'is of
M3ASO3: thus, tri-silver arfen^fi^^ a l''^^S^"^™"o'-m
hne arsenites are soluble fn wa Ir ^ .t^'^^?'' "^^^ '''ka-
the alkaline earths and wf'i'!.?^ °^ '^« metals of
water Sodium arsenite Is SseJh"2fn^'':i'"'°''!'^'^ '"
Scheeles green and emerald ^reenlL '"^° P'',*"''"^ ••
taming arsenic trioxide and ??„ I compounds con-
made in large quam Wes for ^^'' ''°* °^ "*'cl> are
Ai! the soluble™ es are d^£,%T"' ^? '^ P'^ment.
best antidote is ^^^^^Xy%.^l.tlS.y^T^^,:^
XVI.] ARSENIC PENTOXWE. 165
(c.rr\r nxide^ or magnesia, which form insoluble arsenites,
Inrthus preven the poison from entering into the system
When heated to about 220° C. arsenic trioxide vo atihzes
v^hout melting, forming an inodorous and colourless
viDoTr ^t is occasionally met with crystallized m long
needles of the same form as the crystals of the correspond-
ing oxide of antimony (see p. 255).
Arsenic PenioxiUe.
Symbol As A. Molecular Weight 2io.-J^^ oxide
rcor^monly called arsenic acid) is obtained by acting
&etioxide with nitric acid evaporatmg to dryness
'ind heating to a temperature of 27f . It forms a non-
crvstainne white powder, which, when strongly heated,
crysiaiiiiie wmuc y > Dowder is dissolved
decomposes into AsgOgand Ug. ^"^^ P""*"/"' ^_:- „^:^
hv water, and the solution yields crystals of arsenic acid,
or tTrhydrogen arsenate, H^AsO. : the metallic compounds
correspondfng to this are ^^^^^ f r^,f ' ^",^;;^^^^^^^^
the corresponding tribasic P^^^p^^^f ^^Pj^^S^ ™Tline
sition, whilst they are identical with them in crystauine
form. Thus we have—
Trisodium Arsenate NagAsO^ -f 12 H,a
Hydrogen Di-sodium Arsenate . H Na^As O4 + 12 H,0.
Dihydrogen Sodium Arsenate . H2NaAs04 + H^O.
Trihydrogen Arsenate . . . . Hg As O4.
With solutions of magnesium and ammonium together,
Se arsenates, like P^osp^ates form an in^^^^^^^^
cipitate, having the composition NH4 Mg AsO^ + 6^^^^^^
ra-iir oaium magnesium arsenate). The arsenates ot the
Ska^-e metals are soluble, those o the other mevas
insoluble, in water. Ti -s Iver arsen^/. 'If^^ZT^^Ue
salt of a brownish-red colour, whereas tri-silver a.s.n//^
has a bright yellow tint. Arsenic acid acts as . poison,
but it is less powerful than arsenious acid.
Iff ••
.66 ELEAfENTAf^y CHEMfST.V. fL-cssoN
mdeeSbecn prepared bvSf^ J?'. •u'^-'^^A^O* have
solution in water thevrnlsf*^ ^- "■'basic salt ; fiut on
on.y the characTeJlltKtre'^triS^^fa.''' """^ P'^'<^""
ARSENIC AND HYDROGEN.
Arseniuretted Hydrogen.
hydrogen, andTo 'ammonia ^T"'^', ^Z P'^o^PhurettiS
an alloy of arsenic a"d^°?nc'with„"?^K '^>' ''^5°«Posing
a^°'r^rtsrSn€i^^^^^
ArseniurettS hydrogen burn1f°TK'° l,<=°'°«less hq??d
deposits arsenic upon a cold hnnV^ t ^'""^"^ Aame, and
a red heat it is deposed imoL^^'*^ '" ^''?'"« •' below
^ Arsenic unites wiS^dilorin ° tf""-'' ^"^ hydrogen,
form arsenic trichloride tZ?^' .^™'"'n«. and iodfne, to
trichloride is a coSesfvoUn 1'-^"^ 'C'-''''**- The
which decomposes n confer I'L'^ '"»""*' foiling at 132°
and hydrochC acWs ' """^ ^^^^'^^^ yieldingtrsenious
ARSENIC AND SULPHUR.
suIphMe, 'Si%^ t7Z^Zl 'f,--^Arsenic Di-
by Passiag a stream' ot?.^bur^K"yS„ t^^^
XVl.J
DETECTION OF ARSENIC.
167
the acid solution of the corresponding oxide, when it is
precipitated as a yellow powder. The arsenic sulphides
form with the sulphides of the alkaline metals compounds
bearing the same analogy to the trisulphide and penta-
sulphide that arsenites and arsenates do to the trioxide
and pentoxide : in short, these compounds are sulphur
salts, the arsenites and arsenates being oxysalts ; hence
they are called sulp kTixsQViiiQS and jw/^Atarsenates, thud :
As2S.,-h3K.^S ----- 2K3ASS3;
As./);, t^ 3 K.^O — 2K3ASO3.
Detection of Arsenic.
Arsenic possesses characters of so peculiar a kind, that
its presence even in very minute traces can be detected
with certainty. From its solutions it can be precipitated
as sulphide, by the aid of sulphuretted hydrogen : and
this sulphide, when dried and fused in a small test tube
with a mixture of potassium cyanide and sodium car-
bonate, yields a ring of metaUic arsenic : on heating, the
metal is oxidized to the trioxide, which deposits in minute
octahedral crystals. These, when boiled with water, yield
a solution giving a bright green precipitate with neutral
copper solutions, and a bright yellow one with neutral
silver salts. Arsenic in solution may be also detected by
the evolution of arseniuretted hydrogen, on adding zinc
and sulphuric acid to the solution to be tested : on burn-
ing the gas, arsenic is deposited in the metallic state upon
a piece of cold porcelain held in the flame. This mirror
dissolves in solution of sodium liypochlorite ; and if
treated with nitric arid, and the solution neutralized,
yields with silver nitrate solution a red precipitate of tri-
silver arsenate. Many compounds of arsenic heated on
charcoal in the inner blowpipe flame give a garlic odour
of arsenic. Solutions contaming arsenic boiled with hydro-
chloric acid and clean copper deposit a coating of arsenic
unon thft cooDcr : this coatinsr, on drvinff and heatinsr in a
., -•?•
'68 EZ.EAf^:,rAI,y CHEMISTHV. [Lesson
other reactions, the present of th.-'' ^^ ""'="' ^"^
arsen,cmaybedetect'ld,^ftheStv r'^'i P''«'°" °'
however, be taken to ensure ^y^lT'' ^^^^ '^^e must,
logical experiments, of evert tra^f""' '" «"?!> toxico-'
reagents used. ^ "^" of arsenic in the
phl'u^^anT^^^^^^^^ between nitrogen, phos-
ing compounds are examined ff^tu ^^^'^ correspond-
ed chlorides have l^^^^^^^Z^l^^^^^ ^^-^
N2O3
» P2O3
ASaOg
N205
P205
AS205
NH3
PH3
ASH3
NCl3(?)
PCI3
As 03
atom o?eac\"of tteo^^^^^^^ ^^T'-^^' that is, one
of replacing, three atom, nf if ^^"'"^^^^^^ 'o, and capabll
bismuth (set pp 254 fc7Whl,> ^"^.T^-"^' Antimony and
a striking rese'Pblitia^^^
Atoms and Molecules,
proc"es*/s fak/fePSd^ni'tr -'^7 "^^^ «» '^''e-ical
One of these laws tells Ss^wVh'TP'^ ^alterable laws,
to form compounds in p?ooort^!,'r.^'"^ ""*'« together
combining weights or I'^stoXmuuL'"'''??^^'* by their
iln "■ '"^''Pl^in this f^cTwe assume .^-^^.^ ''"^''''•
made up of very small partcles whfrh ^" "^Wer is
indivisible and which are termed ^/f ^re chemically
of each elementary substancf ^ff» °""' .^"<* *e atom
of every other. Kw the atoms if 1'^^?*'^"^ ''^°'» t^at
and chemical compounds aTfnJ^.^K.u^'"^"' *""« =J*e,
of unlike .toms. Hence ^he^^n^''"'^^PP''°=''mation
pound consist of a group of atomf^^lP^""='^* "^ ^ corn-
group of atoms ; this group which can
XVI.]
ATOMS AND MOLECULES.
169
be divided by chemical but not by mechanical means is
termed a Molecule.
The smallest particle of. ah element in the free state is,
however, not a single atom, but a group of atoms mechani-
cally indivisible, or a molecule. This explains (see also
p. 105) why elementary bodies act more energetically and
enter more readily into combination at the moment of
their liberation from a combination (in the nascent state)
than when in the free state.
When chemical changes occur it is the molecules which
react upon one another and the change consists in the
change of position of certain atoms contained in the
groups. When an element is set free from a compound
the liberated atoms join together to form molecules, unless
some body is present with which the element can com-
bine. As we have seen (p. 105), the molecule in the free
state occupies the same space as the compound, that
occupied by 2 parts by weight of hydrogen.
Hence it follows that the same volumes of different
gases simple as well as compound always contain the
same number of molecules, and this explains the well-
known fact that all gaseous bodies obey the same law
of expansion by heat, and of alteration of volume by
pressure. In order to obtain the molecular weight of any
body which is volatile, without decomposition, all we have
to do is to determine how many times heavier the gas is
than hydrogen, and to multiply this number by 2.
Density of
the Gas or
Vapour.
I
35*5 .
62
150 .
100 .
Hydrogen ,
Chlorine . .
Phosphorus .
Arsenic . .
Mercury
dolecular
Atomic
Weight
Weight.
2
71 .
• 35*5
124 .
. 31
300 .
• 75
200 .
. 200
iH
■■'^ If we divide this molecular weight by the atomic weight
we obtain the number of atoms contained in the molecule.
The molecule of Hydrogenj Chlorine^ and most of the
other Elements known in th^
atoms. Phosphors and arUtcT' "'^'^ ""'«" ^
atoms m the molecule whShf' ^T^^'f > contain 4
mercury, and of some oihir voL n^ molecular weight of
the atomic weieht nr 7k„ , '^.'"^'als is the same as
contains only onTatZ. ^' "'"'^'"'^ °f "-"e elements
of a^^|s:1eS°;^rr"r^■^'"^-p--
compound. ^"^^^ ^^^ enter into a chemical
-mUnd^tdf wS^hTafolcu^V^^ ^-P'« -
f"t<^^^^sLri\?.^,ii^^^
Chemical \ change ^oes !,„ ^^^^'^^ ^hich occur when a
/-.W^, but fof theTke of 7mTJr '"^^i"^ ^^^^'«^-
atomic formulcE. simphcity we frequently use
Thus if we write KCIO — v:^^ i r^
potassium chlorate splits UD~imn nt.^-"^^ ^^'^"^^ that
oxygen ; we know, however^thTt ?h i«=^*^^^^ "^^^"d^ and
place in two stages. ' ^ ^^^ decomposition takes
(0 2 KCIOo = KCl 4- Kr\r\ i ^
of ty elS'of compiTundlak^'X''^" T '"°'-"'e
We can now explain why oxide nf 'In ^ '" '^'^ reaction.
Jo.de when bro^ht to/et^^^fd^- ^^^^^^
. Silver unites but feehlv win, „ '
'S easily decomposed on heatin?^ti;' ^"'^ ""'^^ °f ="ver
for hydrogen dioxide, and the afo'/^"^ ^°^^^ ^°°^
Sliver oxide unites «^th that from ,.?^ °J5>'^?" from the
T^s^t ftrn^5 A^"^^e=lSi^Vr
(p. 49); themoleclirXV/e cS-lfe? ol^^
XVI.] QUANTIVALENCE OF ELEMENTS, 171
one of which is readily separated, and this combines with
the loosely attached atom of oxygen contained in the
molecule of hydrogen dioxide, thus :
Ozone. ^l^l^^ Water. Free oxygen.
Quantivalence of the Elements.
If we compare together the compounds of the pre-
ceding elemen s with hydrogen, we find that these exhibit
a distinct difference in combining power. The first group
embraces coaipounds, of which the molecule contains one
atom of hydrogen combined with one atom of the element
In the second, the atom of each element is combined with
2 of hydrogen ; in the third, 3 atoms of hydrogen are
present; whilst the fourth group contains 4 atoms of
hydrogen in the molecule.
Hydrogen.
(I)
(2)
(3)
Hydrochloric
Acid.
h| cij
Hydrobromic
Acid.
H
Br
Hydriodic
Acid.
Hydrofluoric
Acid.
I ?! ?i
Water.
Sulphuretted
Hydrogen.
Seleniuretted
Hydrogen.
H
B!
Se
Telluretted
Hydrogen.
Phosphuretted
Hydrogen.
Arseniuretted
Hydrogen.
H
H >As.
H
Marsh Gas.
(4)
Siliciuretted
Hydrogen.
Hi
^^Si.
H ">
IMAGE EVALUATION
TEST TARGET (MT-3)
^
^
O
K^^
u>.
/.
C/j
1.0
I.I
1^128 |2.5
IS IIS
1!^ 1^ 12.0
1.8
1.25
1.4
1^
^ .
6" -
►
V]
s'^
m
^ ^^
<p
4
l>
7
Photographic
Sciences
Corporation
23 WEST MAIN STREET
WEBSTER, NY. 14580
(716) 872 -4303
'^":^'
^
'%'■
4^ my
i/.A
hi
same relations »v^ «-....,
(0
Chlorine
Monoxide.
These same relat;-n« ^«^-ILesson
Hypochlorous
Acid.
H
CI
Arsenic
^nchloride.
CI
CI
(2)
Hypobromous
Acid.
(3)
Carbon
Tetrachloride.
rseni(
chlorid
^)
I)
O.
Arsenic
^ri-iodide.
Hence it is rl^^a.- *t, ^
cer^in groups. The eSu oftl'^fi^ *"« elements into
atom for atom with hydro~n .1 ** ''"* 8™"P combine
jjuwer. ihe members nf .(.„ ^°"v one comhinm^
"••niay be termed Sf L?h ,?™"'^ «^°"P ^re Z3
powers and reqni/^;,^^^^ Pf^^ses 2 corZ^^^g
i>&Ser-S|#' TSrdSS
The elements belongK^^r'f''-""^'"^ 'he elements
'uustrate this quantivalence, 'oUowmg equations
w
' [Lesson
n the com-
i any other
lUS
nts into
combine
i^«/ ele-
iibining
'valent,
ibining
iration,
ire tru
sih'con
nee of
ments.
ti and
One
\ and
td are
ttions
I
XVI.] QUANT/VALENCE OF ELEMENTS. 173
S
3s{g + 2As|cL
6HC! + As2|s
H*
H
H
H
<^ g + ^8hc{g+.o{
H
H
In like manner the metallic elements can be divided
into classes according to their equivalence, their power of
combining with chlorine being taken as a measure of
their quantivalence, few compounds of metals with
hydrogen being known, thus :
Potassium Chloride
^<i«a!
Calcium Chloride Ca
(CI
I CI
(CI (CI
Antimon> Trichloride Sb^ CI Tin Tetrachloride Sn \ 9
\r\ i Cl
^ " i CI.
The monad elements unite amongst themselves to form
only few and simple compounds; but if an element
possessing more than one combining power enter into
combination, the number of possible compounds becomes
larger. Chlorine and hydrogen form only one compound,
in the case of oxygen and hydrogen on the other hand we
are acquainted with two compounds. In hydrochloric
acid the two single combining powers of the two atoms
are saturated by mutual attachment; if one atom of
monad hydrogen attach itself to one of dyad oxygen, one
of the combining powers of the oxygen atom is left unsa-
turated, and this may either combine with hydrogen to
form water H— 0~H, or another atom of oxygen may be
attached, and this again may saturate itself with hydrogen,
and we obtain hydrogen dioxide H— O— -O— H. In a
■a^^*"
«>aybeSSt:'li°?^tl'°l°'°"-"'^^ °f chlorine
i C1~H .
Cl — o — H
a-o-o-H •
CI — — — o~H
Cl-0-O-O-O-H-
»nd also the oxi-acids of phosphorus:-
H— P— O— o— H
••' HO-
H — P
\
HO
HO
O - o - H
P-O-O-H.
Others with five such a oms Th.?^ "^"^ ^*°«^s» but also
cMonc ac. "nUe ..ee^^ .^-~^ a.a h,...
Bt . ^^"3 + HCl = NH n
Phosphorus trichloride absorb, i .
is converted into the pemachloriHrp.^?^ ''^^°'^^' ^d
These compounds, howeler ^m ^ -^^'^ + CL = pq.
■quid state : when thev a^e hf "^^ ^?'' '» the^solid d?
the 2 molecules from which t&,"'? decompose into
some cases this decomw.s1tion%:?1!^ ^^"^ ^^ed. I„
chlor.de absorbs ammoS tW?u^ "^^^y ^een, silve?
pound AgClNH„ but "his cnml°''^.™<* '^"^^ th^ com^
composes into chlorMe o' suZ'^^nH*^ '^''^" heated d™.
Other compounds, such as pemLMn f^^T' amm, aia.
appear to volatilize withouf d.^^ °''"^^. °^ Phosphorus
case It can be proved tha, t^»''°^'™' ''"' '" tWs
comams the molecul^of 3U3 J^^" 1= ^ '"'"'"^e and
and free chlorine. The ^^or/^fe''-?^'^^^^^^
XVI.] QUA'NTI VALENCE OF ELEMENTS. 175
accordingly, does not obey the usual law; thus the
vapour of chloride of ammonium, if it consisted of similar
molecules, must posses^ the density of 2675. In fact,
however, its density is only the half of ^is ntimber, for 4
volumes contain i molecule of ammonia and i of hydro-
chloric acid ; hence its density (or the weight of i volume)
. 36-5 + 17
IS ^ ^J -f- = 13-37.
4
Not only can the elements then be considered as possess-
ing varying quantivalence, but also those groups of ele-
mentary atoms which act collectively as elements ai^ jto
which the name of compound radicals is given. Tmie
radicals consist of two or more atoms of dyad, triad, or
tetrad elements whose combining powers are not com-
pletely saturated by their mutual combination. Thus nitric
acid may be considered as water in which i atom of
hydrogen is replaced by the group NOg,
H|0 NO.J0..
This is a monad radical, the three combining powers
of the nitrogen atom are united with oxygen ; two ator s
of oxygen possess 4 combining powers, and hence one of
these remains free or unsaturated, and the group NOg
can take the place of a monad element. In like manner
the constitution of all the oxi-acids and also the hy-
droxides can be represented. These compounds contain
the group OH ('water minus one atom of hydrogen) ;
. this group may be considered as a monad radical, and
has received the name of HydroxyL That this radical
plays the part of a monad element, such as chlorine, is
seen in the following equations :
2 HCl + Nag = Hg -f 2 NaCl.
Hydrochloric acid and sodium give hydrogen and soditim
chloride :
■'% 2H0H4-Na2= Hg-f 2NaOH.
^Water and sodium give hydrogen and sodium hydroxide
^Bj^huric acid and the sulphates contain the group SOg
//
i;6
^l-^MENTARV CffEMISTJiV. fLESSOK
This is a /^^^ r«,//<ra/ — o — S n
so \ ^^
^^2 1 OH
SO \^^
^^2 1 OH
SO \ ^K
i>0, I Q^
"* (CI
Pofci PO
(CI
(OH
( H
( H
(OH.
V A J, III rA
Roman nu4mls Xve tSfs™!::;? '^A> P'^'^'°^ *e
not monads, thus : ^°°' "^ *ose which are
in IV
H, O, N, C, NO,, SO, PO, &c.
LESSON XVII.
THE METALLIC ELEMENTS.
m^KtesHhte^^^CtrT. *?- "- -»-
and only fifteen of the Jauer ^Z ^«''' °^ "'^ ^""er,
however found in smairqurntks^7."5f"y metals are
these and their compounds are h^^' fi^.l *^ Properties of
m this work we shaU only consMer tt ''"°^'? •' ^° *«
and commonly occurring meSs '"°'" ""P°rtant
mfsa^el^f^rcS^^^^'i^^^^^^^^^^
and .s not founded or^Z'^^'^^^ ^^y.
xvii.] THE METALLIC ELEMENTS, ijy
arsenic and antimony may, in some respects, be considered
as metals, and m others as non-metals.
All metals, with the single exception of mercury (a
liquid), are sohd at the ordinary temperature ; they pos-
sess a high power of reflecting light, caushig the br&it.
glittering appearance known as the metallic lustre : thev
are opaque, except in the thinnest possible films, when, as
in the case of gold leaf, they allow light to pass ; they are
better conductors of heat and electricity than the non-
metals, and, as a rule, they have higher specific gravities
than these. The metals differ widely from each other,
both m their physical and chemical properties, and are
accordingly adapted for different uses : those metals
which are lightest exhibit the greatest power of union
with dT^ V ^^^^''^' ""^^^^^ ^M^%o oxidation
Physical Properties of Tie Metals,
specific Gravity— Tht following table, giving the
specific gravities of the most in portant metals (water at
o L= loo), shows the great variation which they exhibit
m tnis respect i~-~
Iridium
Platinum
Gold .
Mercury
Thallium
Palladium
Lead .
Silver .
Bismuth
Copper
Nickel .
Cadmium
Cobalt .
Manganese
Table of Specific Gravities.
21-8
21*5
19*3
13 "596
ii'9
ir8
ii'Z
io*5
9-8
8-9
8-8
8o
Iron . . .
Tin . . .
Zinc . .
Antimony .
Arsenic
Chromium
Aluminium
Strontium .
Ma-^nesium
Calcium ,
Rubidium ,
Sodium ..
Potassium .
Lithium .
N
7*3
7-1
67
59
5*9
256
254
175
158
1*52
0-974
0865
0593
178
ELEMENTARY CHEMISTRY; [Lksson
Fusibility,— TYi^ melting points of the metals differ even
more widely than their densities ; mercury fusing at 40^
below zero, and platinum only melting at the highest
temperature of the oxyhydrogen blowpipe.
Table of Melting Points.
Mercury. . , . . — 40°
Tin -f-235°
Bismuth . . . ... 270°
Cadmium .... 315**
Lead . .
Zinc . .
Antimony
334''
423"
425'
Silver -f i,ooo*
Copper 1,090**
White Cast Iron . 1,050°
Grey ditto . . 1,200*
Steel. . . 1, 300° to 1,400**
Wrought Iron 1,500° to 1,600°
Some of the metals can be easily converted into vapour,
or volatilized : thus mercury boils at 350°, arsenic passes
into vapour even before it assumes the liquid form, whilst
Cotassium, sodium, magnesium, zinc, and cadmiunfi, can
e distilled at a red heat. Even the more infusible of the
metals, such as copper and gold, are not absolutely fixed,
but give off small quantities of vapour when strongly
heated in a furna,ce.
The colour of most of the metals is nearly uniform,
varying from the bright white of silver to the bluish-grey
of lead ; cepper is the only red-coloured metal known,
whilst gold, strontium, and calcium, are yellow. In
ductility, or the power of being drawn out into wire, and
malleability, or the power of being hammered out into
thin sheets, the metsds differ considerably. Gold is the
most malleable of all the metals, being capable of being
beaten out to the thickness of the ^^V^^^ P^rt of an
inch : it is, likewise, the most ductile metal. Other metals
possess this property in lesser dfe^ee, whilst some, such
as antimony and bismuth, are brittle and may easily be
powdered. Hardness, brittleness, and tenacity, are phy-
sical properties of great importance, in which, the metals
differ widely.
V
TRY; [Lksson
»79
xyu.-\SPECmc HEA T AND A TOMIC HE A T.
Specific Heat and Atomic Heat.
When equal weights of different bodies are ra!.*^
art *dfffer™t """"'''■ °^^/P«' o^^^rVtlrl^^y
;o'sses?df^^er43 /^'C^ '' ^L^^"' ^°^^.
IS 31 times as large as that reamVpH fr» ^.o.-^^^i.
platinum through the same im^rj "'^^ ^ ""'"s- <>'
.A4*. A.«/ of pfatinum ^^iidT^Tor o-ol^'^tL^^
wuter being taken as the unit. The specific he=.'f ^f .1?
caU:ulating 'thr fee tto^r^^^iT^f^r^r^^^^^^
the atomic weights of the metals that th^ m.^i,^ ^®
pressing the capacity for heat of he atoms are S^/n T
or the metals all possess tie sameatJ^HZ,-^^"^^- '
clearly seen if we multiply theTp^cificTeats of ;i,J^'! }*
by the corresponding atomic we^hts- thus * ^"^
Lead . .
Platinum
Silver . ,
Tm . ,
Zinc . .
Specific Atomic
Heat. Weight.
0*031 X 207
0-032 X 197-5
0*059 X iq8
0-054 X 118
0*095 X 65-2
Atomic
Heat.
= 6'4I
= 6-37 '
6-39
a meTn's^T'ch^"^^^^^^^ ?^ ^P-ifio heat
ascertaining'i?1n att^^ ^S Tnthr''^* %''^
newly discovered metal thaS; cht%^ t^^^^^^^
N 2
t/
•4^
E»*
1 80 ELEMENTARY CHEMISTRY, [LESSON
whether it most resembled lead or the alkali metals : if it
was to be classed as a dyad with lead, its atomic weight
must be 408; if it was placed with the monad alkali
metals, its atomic weight would be = 204. Thf
specific heat of thallium was, however, found to be 0*033 J
and if we divide this into 6*4, the common atomic heat ol
the metals, we get the number 194— a number muck
nearer to 204 than to 408. The difference here noticed
between 194 and 204 is due to the great difficulty of
accurately determining the, specific heat of bodies and
the errors which arise from the variation of physical
condition.
The following non-metals have the same atomic heat
as the metals ;
Nitrogen.
Chlorine.
Bromine.
Iodine.
Selenium.
Tellurium.
Arsenic.
Nitrogen and chlorine are, it is true, not Vf ^wd
solid state, but their atomic heats can be c:- *
the molecular heats of their solid ccmp
elements in the solid stale possess the same t.
in their compounds; and hence the molecui
sum of the atomic heats of the combined elenu
shown in the following list :
Specific Molecular
Heat Weight
0-089 X I43'S ~ 2 X
0219 X 58*5 = 2 X
0107 X iI9*I = 2 X
0102 X 189 = 3 X
00423 X 454 = 3 X
o*ii8 X 488-6 = 9 X
Silver chloride, AgQ . ,
Sodium chloride, NaCl .
Potassium bromide, KEr
Tin di-chloride, SnClj .
Mercuiic iodide, Hg Ij ,
Platinum potassium )
chloride, KgPtCle ( '
'n the
from
the
'OS
;he
is
6-4
6-4
6-4
6-4
6-4
64
?"ss.
TRY, [Lesson
me atomic heat
lOt Vf ^wD 'n the
XVII.] DISTRIBUTION OF THE METALS. 181
The remaining elements have all an atomic heat smaller
than 6*4 , thus the atomic heats of sulphur and phos-
phorus are 5*4 ; of fluorine, 5 j of oxygen, 4 ; of silicon, 3*8 ;
of boron, 27 ; of hydrogen, 2*3 ; and of carbon, r8. In the
case of these elements the atomic heats are calculated
from the molecular heats of their compounds in accordance
with the above-mentioned law, as the following examples
show ,
Molec.
Molec.
Heat.
Spec.
Heat. Weight
Ice, Ha O . . 0*478 x i3 = 86 = 4f 2X2*3.
Mercuric ox-)_._,ov. ^ ^ .
ide,HgO jo-048X2i6 = 10*4 = 6*4+4.
1>x?dtAs,03">'^5Xi98 =24*8 = 2X6*4+3X4.
Calcium Car-I ^, , . « .
bonaie,CaC03r202X 100 = 20*2 =6*4+ 1*8+3X4.
Potassium sul-)^.,^^^^,^, , ,
phate, K^SOj )oi96X 174-2 = 34*2 -2x6*4+5-4+3X4.
Carbon hexa-) ^ ,, « . , ,
chloride, CaClfl j°' '77X237 = 42*0 = 2 X r 8+6 X 6*4.
Occurrence and Distribution of the Metals,
Only a few of the metals occur ^n the free or uncom-
bined state in nature; in general they are found combined
with oxygen, sulphur, or some other non-metal. These
metallic compounds exist most variously distributed
throughout the earth's crust ; some are known to occur
in only one or two localities, and even then only in minute
quantity, whereas others are found widely distributed in
enormous masses. As is seen by reference to the table
on p. 9, the metals aluminium, iron, calcium, magnesium,
and sodium occur in very large quantities, forming, when
united with oxygen and silicon, the whole mass of granitic
rocks composing our globe ; but it is not from these
sources that the metals in question can be obtained for
p iL fK^ f
Ij MI |H *H
i82 ELEMENTARY CHEMI^THY. [LESSON
the purposes of the arts. For this object we employ other
combinations, found in smaller quantity, from which the
metaJs can be more easily extracted than from the
silicates ; and these compounds are termed the metallU
ores. ^
The heavy metals and their ores generally occur in<:er-
spersed throughout the old granitic or early sedimentary
rocks in the form of veins or lodes, which are cracks, or
fissures, running through the rock in a particular direction,
and filled up with a metallic ore. Other ores, such as
ironstone, are found an ongst the more recent sefiimen-
tary formations, having been deposited in large masses,
probably from aqueous solution.
Th« consideration of the occurrence and distribution of
the ^a.vious metaUic ores belongs to the science of geology;
the study of the modes of procuring the ores is the pro-
vince of the miner 2SiA engineer; whilst the processes by
means of which the metal itself is obtained from the ore,
although mainly dependent upon chemical principles, are
generally classed as belonging to the branch science of
metallurgy.
Classification of the Metals.
The metals can be conveniently grouped into classes,
in which the several members possess certain properties
and general characters in common.
Metals of the Alkalies. — i,
3, Caesium, 4, Rubidium.
3»
Potassium-
Lithium.
Class I.
2, Sodium. ^^ ^^ ^^
(6, Ammoniu n. j— The metals of this class are rnonova'lent ;
they are soft, easily fusible, volatile at higher temperatures ;
they combine with great force with oxygen, decompose
water at all temperatures, and form basic oxides, which
are very soluble in water, yielding powerfully caustic and
alkaline bodies, hydroxides, from which water cannot be
expelled by heat. Their carbonates are soluble in water,
and each metal forms only one chloride. Ammonium,
w
WK [Lesson
n.] CLASSED OF THE METALS.
183
n, decompose
N H|, is added to the list of alkaline metals proper, from
the general similarity of the ammoniacal salts to those of
potash and soda.
These metals and their compounds are closely ana-
logous in their properties, and they exhibit a remark? ble
relation as regards their atomic weights : thus sodium,
which stands between potujsium and lithium in proper-
ties, has a combining weight which is the arithmetic mean
of the other two, ^^i-? « 23 ; so, too, rubidium, standing
half-way between caesium and potassium, has a mean
atomic weight, 33 -r 39 _^ gg
Class II. Metals 0/ the Alkaline Earths.— i, Calcium^
2, Strontium. 3, Barium.— The metals of this class are
divalent ; they cannot be reduced by hydrogen or carbon
alone ; they decompose water at all temperatures, pro-
ducing oxides, which combine with water to form hy-
droxides, from some of which the water can be driven
off by heat. Their carbonates are insolut' ■*. in water, but
soluble in water containing carbonic acid in solution.
Class III. Metals of the Earths.—i, Aluminium.
2, Yttrium. 3, Erbium. 4, Cerium. 5, Lanthanum.
6, Didymium.— With the exception of aluminium, these
metals are hardly known in the free state, as their com-
pounds occur so rarely that they are not employed for any
useful purpose, and their properties cannot be considered
in an elementary work. The oxides of this group are
insoluble in water ; and they cannot be reduced to the
metallic state by hydrogen or carbon. Aluminium decom-
poses water at a high temperature.
Class IV. Zinc Class.— i, BeryUium or Glucinium.
2, Magnesium. 3, Zinc. 4, Cadmium. 5. Indium.— These
metals are divalent ; they are all volatile at high tempera-
tures, and burn when heated in the air ; they decompose
water at a high temperature, or in presence of an acid
and "brm only ^ ne oxide and one chloride. '
//
i:
R
184 ELEMENTARY CHEMISTRY, [Lesson
Class V. Iron Class. — i, Manganese. 2, Iron. 3, Co-
balt. 4, Nickel. 5, Chromium. 6, Uranium. — These are:
not volatile at the temperature of our furnaces ; they de-
compose water, like the preceding class ; and they form
several oxides, chlorides, and sulphides.
Class VI. Tin Class.— i, Tin. 2, Titanium. 3, Zir-
conium. 4, Thorium. 5, Niobium. 6, Tantalum.— Tin
is the only one of this class employed in the arts. These
metals decompose water at high temperatures and in
presence of alkalies : the four first form dioxides and
volatile tetrachlorides, and are tetravalent and closely
connected to silicon. The three last are very rare metals,
and appear to be pentavalent.
Claims VI L Tungsten Class. — I, Molybdenum. 2, Tung-
sten. — These metals are of rare occurrence ; they decom-
pose water at a high temperature, and form trioxides and
volatile hexachlorides.
Clasr VIII. Antimony Class. — i, Antimony. 2, Bis-
muth. 3, Vanadium. — The metals of this class are tri-
valent ; they form the junction 'between the metals and
metalloids, and they closely resemble arsenic, phosphorus,
and nitrogen in their properties.
Class IX. Lead Class. — i. Lead. 2, Thallium.— Heavy
metals, allied in their general properties to the two first
classes. Lead is divalent, but thallium is monovalent.
Class X. Silver Class. — i. Copper. 2, Mercury. 3,
Silver. — These metals do not decompose water under any
circumstances ; they are oxidized by nitric and strong
sulphuric acids ; each of these metals forms two basic
oxides which, except in the case of copper, are decomposed
by heat alone. Copper and mercury are divalent ; silver
is monovalent.
Class XI. Gold Class. — i, Gold. 2, Platinum. 3, Pal-
ladium. 4, Rhodium. 5, Ruthenium. 6, Iridium. 7, Os-
mium. — These metals are not acted upon by nitric acid,
but only by chlorine or aqua regia, and the oxides are
reduced by heat alone ; and they with silver and mercury
constitute the noble metals. Gold is trivalent, and pla-
ijr"
?K [Lesson
XVII.]
ALLOYS.
f
im.
Iron. 3, Co-
These are:
aces ; they de-
and they form
mium. 3, Zir-
antalum. — Tin
learts. These
atures and in
L dioxides and
It and closely
ry rare metals,
num. 2, Tung-
; they decom-
1 trioxides and
lony. 2, Bis-
class are tri-
le metals and
c, phosphorus,
Hum. — Heavy
D the two first
lonovalent.
Mercury. 3,
iter under any
c and strong
ns two basic
e decomposed
valent ; silver
inum. 3, Pal-
dium. 7, Os-
)y nitric acid,
10 oxides are
and mercury
lent, and pla-
J85
tinum is tetravalent. The remaining members of this
group always occur together with platinum, and are there-
fore termed the //^//^r/^*^ »2^/^/j. .
Chemical Properties of the Metals,
The metals combine (i) with each other to form alloys •
(2) with the non-metals to form oxides, sulphides, chlorides'
&c. In the alloys the metallic appearance and properties
are preserved, whereas in the compounds with the metal-
loids the physical properties of the metals as a rule
disappear.
Alloys.— lYiQ compounds formed by the metals amonirst
themselves are not so definite as those which are formed
by union with 9 non-metal ; nevertheless the alloys are
largely used m the arts, as they possess many valuable pro-
perties not exhibited by the metals separately. Thus gold
and silver are too soft to be used alone as a medium of
currency, but the addition of 7-5 per cent, of copper gives
an alloy of the requisite hardness. Then copper is too
soft and tough to be wrought in the lathe, but when alloyed
with half Its weight of zinc it forms a hard and most use-
ful substance known as brass. Gun-metal, or bronze, is a
hard and tenacious alloy of 90 parts of copper and 10 of
tin Bell-metal, a still harder alloy, contains the same
metals m the proportion of 80 of the former to 20 of the
latter ; whilst an alloy of 33 parts of tin to e^ of copper
possesses a white colour, takes a high poHsh, and is known
as speculum-metal, and employed for the reflectors of
telescopes. For making printing type a peculiar alloy is
employed, containing 80 parts of lead to 20 of antimony :
this possesses many properties necessary for type metals,
which are found to belong to no single metal or other
The chemical composition of the alloys is not <;o
definite or so well marked as that of the other metallic
compounds, but they may frequently be obtained in ciys.
tais, in which the constituents are contained '
••« «^^
bHVyliildi
l-.»»
i86 ELEMENTARY CHEMISTRY, [Lesson
proportions. The melting point of an alloy is often much
lower than the melting points of its constituent metals.
Thus lead melts at 334°, bismuth at 270°, tin at 235°, and
cadmium at 315° ; whereas an alloy of 2 parts bismuth,
I of tin and i of lead, melts at 95° to 98° C, and one con-
taining 8 of lead, 15 bismuth, 4 of tin, and 3 of cadmium,
softens at as low a temperature as 60*, and is perfectly
fluid at 65° C. The alloys of metals with mercury are
termed Amalgams,
Physical Properties of the Metals.
Hydrogenium.—Th^rQ are many chemical reasons
for supposing that hydrogen is the vapour of a highly
volatile*^ metal, and although the gas has resisted all
attempts to liquify or solidify it by pressure, it is found
possible to absorb hydrogen in certain metals. Thus,
for instance, metallic palladium takes up no less than 982
volumes of hydrogen gas, forming a veritable alloy of the
metal with hydrogenium, or hydrogen in its solid form.
From the increase in bulk (from absorption of hydrogen)
which the palladium undergoes when placed as the nega-
tive electrode in acidulated water the density of hydro-
genium has been found to be 0733 ; it has also been
shown to conduct heat and electricity, and to be magnetic,
in these respects acting as a metal. Other metals than
palladium, such as platinum and iron, possess this same
power of condensing hydrogen, but to a less extent. The
fact that red-hot platinum and iron are porous for hydro-
gen may be explained by the absorption (or occlusion) of
this gas on the one side of the metallic tube or plate and
its evaporation at the other side. Absorbed hydrogen
(3 volumes) has been found in the mass of a metallic
meteorite (Lenarto), whilst in terrestrial iron carbonic ox*
ide gas is chiefly found to be absorbed Hence we may
conclude that the Lenarto meteorite had its origin in an
atmosphere in which hydrogen gas predominates. (See
Spectrum Analysis.)
^. [Lesson
s often much
uent metals.
at 235°, and
rts bismuth,
Lnd one con-
of cadmium,
is perfectly
mercury are
xyii.J METALLIC OXIDES.
187
cal reasons
of a highly
resisted all
, it is found
als. Thus,
;ss than 982
alloy of the,
solid form,
f hydrogen)
is the nega-
y of hydro-
s also been
»e magnetic,
metals than
s this same
ttent. The
» for hydro-
cclusion) of
)r plate and
i hydrogen
a metallic
arbonic ox*
ice we may
trigin in an
ates. (See
Compounds of the Metals with Non-metals.
U Metallic Oxides,— OY^y^^n acts very differently on
the different metals. Some metals, such as zh^c'maye"
Slum, and calcmm, take fire when heated, and burn with
the evolution of intense light ; whilst others, such as go d
and silver, do not combine directly with oxygen, and are
a^nLtSc^^^^^^^^^ ^^^^^^ byinXeitme^n^
The oxides differ widely in properties and composition:
they may, however, all be represented as water in which
the hydrogen has been replaced by metal. Thus the mon-
oxides may be considered to be water in which either
each atom of hydrogen is replaced by a monad, as IC.O
AggO, or the two atoms of hydrogen are replaced ^ a
dyad, as BaO, Zn O ; whilst the higher oxides I?rregarded
as two or more molecules of water, in which the hydrogen
is in like manner replaced by its equivalent of metal. The
most important of these higher oxides are the sesqui-
oxides, such as alumina, Al^ O3, and ferric oxide, Fe„ O, ;
he dioxides, such as black oxide of manganese Mn O*
the trioxides, as chromium trioxide, Cr O,; ^
The oxides may be divided into (i) Basic oxides •
^^)fero^desj {3) Acid-forming oxides} If o^apS
of the hydrogen m water is replaced by metal, the result-
ing compound is termed a Hydroxide : thus by the action
of potassium on water hydrogen is liberated and caustic
potash, ^ I O (potassium hydroxide), is formed. The
hydroxides of the dyad metals may be considered as two
molecules of water in which one atom of metal replaces
two atoms of hydrogen, thus calcium hydroxide is^^ \ O,
Js^'lmfnTAf'n """'"^'P^^^^^ ^" *^^ sescjuioxides'such
as alumina, Ala 0„ may be reoresented as «?v m«u^,'i«« ^.
■■■Il l ' H i .
--r-j^ y Ui
^aautB'
183
ELEMENTARY CHEMISTRY. [Lesson
water in which half of the hydrogen is replaced by a
hexad group, thus :
Tl
Aluminium hydroxide Alg ) ^
(or Hydrate of Alumina) H g ) ^o- ^
When soluble in water these hydroxides have a strong
alkaline reaction; that is, they turn red vegetable colour-
ing matter, such as litmus, blue. Several oxides unite
directly with water to form hydroxides, thus :
BaO + «jo-^^Jo,
This barium hydroxide does not part with its water on
ignition^ whilst others, such as copper hydroxide, decom-
pose on boiling, thus :
Cu I O, - Cu O 4- HaO.
The most characteristic property of the basic oxides and
hydroxides is their power of neutralizing acids and form"
ing salts. This is accomplished by an exchange occur-
ring between equivalent quantities of the metal of the
oxide and hydrogen of the salt, thus :
'^
The classes (2) and (3) contain more oxygen than the
basic oxides. The peroxides yield oxygen on heating with
oxiacids, and either chlorine or hydrogen dioxide on
treatment with hydrochloric acid, thus :
Mn O2 + HaSO^ = Mn SO4 + Hs,0 -f O,
and Mn02+ 4H CI = Mn CI2 -f 2 HgO -f Q\,
Many metallic oxides form acids when brought into
contact with water, just as is the case with the oxides of
the non- metallic elements.
i!0+^H"'|0-H|0 +
'»10;
|o,.
XVII.]
METALLIC SALTS.
189
2, Metallic Sulphides,--.Uet2iU combine directlv with
sulphur to fonn sulphides ; and these occur freStlTS
nature, forming many of the metallic ores T^ese com
pounds resemble in composition the correspondhiToxidTs
and hydroxides and may be represented as sulohure ?pH
hydrogen, H„S, in which the hydrogen is ryiacedbvff^
equivalent 0/ metal. Other sulphiles coi^eK to^he
acid-forming oxides and form compounds witrthe basic
suphides termed supho^salts. Thus we have sodfum
.ui& ^h^l' sodium oxide, Na,0 ; antimony pei™
sulphide, SbjjSg; phosphorus pentoxide, P«0. • sodium
sulph-antimoniate, Na3Sb04, sodium phosp^at^ Najir
The sulphides of the metals of the alkalies and all'^^in!:
earths are so uble in water ; those of the reSeM
are almost all insoluble in water, but some S" tSsoluhl^
tory this diflFerence in the solubility of the sulphides ?s
employed as a means of separating the different me?;ds in
the processes of chemical Analysis '*'"^*^®"^ "^^tals in
A\ p '!?'^/''^'*' "^^^ ^^ ^°^"^ed in various ways •
of^ali Sthusf "'^'^"^^^^ °^"^^^^^ ^- the^^^drogen
Zn + H4SO4 « Hg + Zn SO4.
J^^V}^ ^'^'f^ combination of an acid-forming oxide
SOs 4. Ba O « Ba SO^.
SiOj + CaO-CaSiO,.
Sb 4. Cls « Sb CI,.
antend\ hyte^^ -^ '"etal between
l^r^i^^ replaceable hydrogen in an acid is exchanged
r metal, a normal salt is said to h^ f^JtA excnanged
for
i *
i^ . ELEMENTARY CHEMISTRY. [Lesson
K I SO, is a normal salt ; ^ | g^^ ^ ^^.^ ^^^
<rJ^L^,?''*i ** """"ber of atoms of replaceable hvdro-
the number of acid salts which this acid is caoable of
f^rmmg: thus we have Na.PO,; Na,HPO,rNaH.P0.1
HsPO^. .
nofm^^ijf ti.r, h ° •'' ^°'^'^ \y '^^ combination of a
normal salt with a basic oxide or hydroxide, thus :
The constitution of the other classes of salts will be he4t
metlhW^^^ '^' '^'?^^ descriptions Man^^^^^^^
metallic salts when crystallized contain a definite nuXr
(4) Metals also unite with nitrogen, phosDhonis hnrnn
XVllJ.
CR YSTALLOGRAPH Y,
191
LESSON XVIII.
CRYSTALLOGRAPHY.
Most chemical substances, when they pass from the
hquid or gaseous mto the solid st.te, assume some defi"h^
8*°"««"= f?""."-- are said to ^O'W/w, c^staJs are
produced when a substance, such as nitre is HU.ni„Ii '^
water ahd the solution allowed grlduaUy o e^^i^^te
or when a body, such as sulphur, is melted and allowed to
sohdify by cooling ; or when a volatile substance such as
lodme or arsenic tr oxide, is vannrirpH ,t^ .u *
condensed on a cool surgce! Ky' n^tu^V^US
minerals exhibit very perfect crvstallin^ ^;™. occurring
ignorant of the mode iS^whitth ci^'tS^are i^mh^?
//
I (^""' '
192 ELEMENTARY CHEMISTRY, [LESSON
solution, for example, the smallest visible particle possesses
the complete form of the largest crystal, and simply
increases in size without undergoing any change of form.
It has been found possible to arrange the many thousand
different known crystals in six systems^ to each of which
belongs a number of forms having some property in com-
mon. In order to classify these different crystals, the
existence of certain lines within the crystal called axes is
supposed, round whicb the form can be symmetrically
bu'lt up. These axes are assumed to intersect in the
centre of the crystal, and pass through from one side to
the other.
ij/, or Regular System. — Three axes, all equal and at
right angles. — The simplest forms of this system are (i)
the cube (Fig. 40) ; (2) the regular octahedron (Fig. 41) j
Fig. 40.
Fig. 4f <
(3) the rhombic dodecahedron (Fig. 42); and (4) the
regular tetrahedron (Fig. 43). The following are a few of
the substances crystallizing in this system — diamond, alum,
common salt, fluor-spar, iron pyrites, and garnet.
id, or Quadratic System, — Three axes, all at right
angles, one shorter or longer than the other two. — The
simple forms of this system are the first and second rit^ht
square prisms (Fig. 44 a and b), and the first and second
Tigiit square octauedfa (Fig. 45 a and b). In the first
RV, [Lesson
tide possesses
1, and simply
lange of form,
nany thousand
each of which,
operty in com-
t crystals, the
i called axes is
symmetrically
tersect in the
m one side to
equal and at
system are (i)
Iron (Fig. 41) ;
XVIII.J
CRYSTALLOGRAPHY.
and (4) the
g are a few of
iamond^alum,
arnet.
all at right
ler two. — The
i second ritjht
5t and second
In the first
F'g- 4a-
f'ifr 43
*"»g. 44 a.
Fig. 44 b.
Fiar ,g jm
— o- tj •»•
o
* «. 4S Ai
I
mmm$
194 KLhMEiMAKY CHEMJSTRY, [LESSON
square prism the axes terminate in the centre of each of
the sides, and m the second the axes terminate at the
intersection of the sides; and this is reversed with re-ard
to the octahedra. Some of the common substances wtich
crystalhze in this system are-yellow prussiate o. uo.ash
zircon, and tin dioxide. ^ '
3^, or Hexagonal Sjys/em, — Four axes, three equal
and m one plane, making angles of 60°, and one longer
Fig. 46.
or shorter, at right angles to the plane of the other three.-
Ihe regular six-sided prism (Fig. 46), the regular six-sided
Fig. 47.
Tig. 48.
pyramid (Fig 47), and the rhombohedron (FiV. 48) are
the common forms of this system. Quarts, ^calc^^n
TRY, [Lesson
entre of each of
errninate at the
rsed with regard
ubstances which
)Siate Oi po.ash,
es, three equal
and one longer
le other three.—
egular six-sided
Rg.48.
(Fig. 48)^ are
irt2, calc-spar.
^VUA.J MONOCLINIC SYSTEM,
beryl, corundum, graphite, ice (whose hexagonal form i«
seen . snow crystals), &c. crystallize fnTh?L'ag?ni^
a Aghf:^^^^^^ unequal, and
system are th^ right oc^Xdrn^ }^^ V'^^^^ ^" ^^'«
^^-^- 49 and 50), ^^ .^it^r^^Z f^^.
f»fi- 49
Fig 50.
barlui: %tph^,:'':;^'S to''''''"^^ ^- found-nitre,
Fig, 52.
two cut OnP anrkf^A^ ^Ui; i- _ ,
to .he ^■^"^:;^n;;^^i;^^'^^:^
O 2
T
mmi^tm^
196 ELEMENTARY CHEMISTRY. [LESSON
octahedron (Fig. 52) belongs to this system. Many sub^
stances crystalUze in this system : amongst the most
common are— sulphur deposited from fusion, sodium car-
bonate and phosphate, ferrous sulphate, borax, and cane
sugar.
6M, or Triclinic System.— Three axes, all unequal, and
all oblique. — The doubly- oblique octahedron and the
doubly-oblique prism (Fig. 53) are the leading forms in
Fig. 53.
F»? 54-
this system. Copper sulphate, boric acid, the mineral
albite, potassium bi-chromate, and a few other substances
aife found to ciystallize in this system, the forms of which
are in general very complicated. The crystalline form
o( copper sulphate is shown in Fig. 54.
I Under one or other of these six divisions all the known
forms of crystals can be classed.' In every distinct crystal
belonging to any one of these systems, in which the axes
are not all equal, or all at right angles, certain relations
exist between the lengths of the axes, and these have
certain mutual inclinations to one another. These rela-
tions and inclinations vary with diflferent substances, but
are constant for the same; so that different bodies all
crystallizing in the same system, as a rule, have diflferent
relations between the lengths of the axes, and these
<«^~<.>^ii.. 1 Jirr *. •_ «?^ •• . _ _ -•_ _
gwsiwiau/ ii<*vc: Uiiivrczii iMCiiitaUuita tO OiiC aiiOiuct*
TRY. [Lesson
XIX.]
POTASSIUM.
»97
Certain substances exhibiting a similarity in their
chemical constitution are found to crystallize in the same
forms ;-the8e are said to be iso, rphous: whi st Xn
the same body occurs crystallized lu two different s%^ms
It IS said to be dimorphous. Examples of these pS;
relations between chemical composition and cry Se
lorm will be given later on. ^-ry&iaiiine
LESSON XIX,
Class I— Metals of the alkalies.
Potassium.
Sodium.
CiESIl
Rubidium.
Lithium.
Ammonium.
potassium.
C AllUiUCt*
Symbol "K. {kalium\ Combining Weight 391, Specific
Gravity oS6s.-The metal potassium was d^overed in
the year 1807, by Sir Hu^nphry Davy, who decomposed
the alkali potash into the metal, hydrogen, and oxygen bv
means of a powerful galvanic current. Before this time the
alkahes and alkaline earths were supposed to be elemen-
tary bodies. The metal is now prepared by heating
together potash and carbon to a high temperature in
an iron retort. The carbon, at the high temperature, is
able to take the oxygen from the potash, forming carbon
monoxide, which escapes as a gas, whilst the metal
potc^ssium, which is volatile at a red heat, distils over,
ifte preparation of this metal is attended with many
aimculties, anr^ requires special precautions, as the vapour
wlr.^^'"'^/'^* °"^y *^^^s ^^^ w^e" brought ir contact
wiin the air, but decomposes water, combininir with the
uxygen aaa liberating hydrogen : hence the metallic vapour
up
198 ELEMENTARY CHEMISTRY. [LfiSSON
must be cooled by rock oil or naphtha, which contains
no oxygen. The metal thus prepared must be distilled
a second time, in order to purify it and free it from a
black, explosive compound, which invariably forms in
the ongmal preparation, and has caused several fatal
accidents.
Potassium, thus prepared, is a bright, silver-white
metal, which can be easily cut with a knife at the or-
dinary atmospheric temperature; it is brittle at o'', and
melts at 62''-5, and does not become pasty before melting;
when heated to a temperature below red heat, potassium'
sublimes, yielding a fine, green-coloured vapour. This
metal rapidly absorbs oxygen when exposed to the air
and gradually becomes converted into a white oxide!
rhrdwn into water, one atom of potassium displaces one
of hydrogen from the water, forming potassium hydroxide,
or potash, KHO. This takes place with such force that the
heat developed is sufficient to ignite the hydrogen thus set
free, and the flame becomes tinged with the peculiar purple
tint characteristic of the potassium compounds, whilst the
water attains an alkaline reaction from the potash which
IS formed. Potassium also combines directly with chlo-
rine and sulphur, and many other non-metals, evolving
heat and light.
Sources of the Potass iiun Compounds.
The original . source of potassium compounds is the
felspar of the granitic rocks of which the earth is com-
posed, as these contain from two to three per cent, of this
metal. Up to the present time, this source has not been
used for the manufacture of the potassium salts, as no
cheap and easy mode has yet been made available for
separating the potash from the silicic acid, with which it
is combined in felspar. Plants, however, are able slowly
to separate out and assimilate the potash from these
rocks and soils; so that, by burning the plant iid
extracting the ashes with water, soluble potassium sail is
77? K. [Lesson
XIX.]
POTASSIUM OXIDES,
199
obtained. Tliis is the crude potassium carbonate, called
when purified by re-crystallization, pearl-ash; and it is
from this substance that a large number of the potas-
sium compounds are obtained. Some of the other
potassium salts, such as the nitrate and chloride, are
found m large quantities in various localities as deposits
on the surface, or in the interior, of the earth. Potass: mi
chloride occurs m beds, together with rock salt, in M .s-
lurt in Germany. Another inexhaustible source of p , -s-
Slum compounds (which, however, has only just begu.. lo
be utilized) IS sea-water : a plan has lately been proposal
by which those compounds can be obtained from the sea.
Potassium Oxides.
Potassium combines with oxygen in three proportions
forming three well-defined oxides of the formulce--
(i) Potassium monoxide . . . . K,0; ^
(2) Potassium dioxide K O •
(3) Potassium tetroxide . . . . KgO .'
Potassium monoxide, KgO, is obtained by allowing thin
pieces of the metal to oxidize- in dry .ir : it is a grlyish-
white, brittle substance, which melts a little above red
heat, and volatilizes only at a very high temperature.
This oxide combines with water with evolution of great
heat producing potassium hydroxide, or potash, from
which water cannot again be separated by heat The
reaction may be represented ag an exchange of hydroeen
for potassium, thus : ^ j'uiu^ca
KgO-f H20 = 2(KHO).
The dioxide and tetroxide are produced when notas-
sium IS oxidized at high temperatures. ^
Potassium Hydroxide, or Caustic Potash, HKO,
IS obtained as above, or more conveniently prepared bv
tolling one part of notnssfnm /^avK^^^f/ 5.:^u .....1 •'
■ Sj-
200 ELEMENTARY CHEMI:y FRY. [Lesson
parts of water, and adding slacked lime prepared from
two-thirds part of quicklime. In this reaction caldum
rttV P? "^^T' *?."?''-' P°*^s^ remaining in solution.
Jf an ^HH ''^•"'^' ^^'"^ '5°^^^ '^^^ ^«"^^^^«^e «" additic^n
of an acid, is evaporated in a silver basin to dryness
fused by exposure to a stronger heat, and cast into sticks
m a metalhc mould. Thus^repared, caustic potash is
v v^hite substance, soluble in half its weight of water
and acts as a powerful cautery, destroying the skin. It
.s largely used in the arts and manufactures for soap-
^u^rpoTes.^ '' employed in the laboratory for various
Potassutm Carbonate, K2CO3.
This salt receives the commercial name of potashes
or pearl-ashes, and is imported in large quantides from
Russia and America. The crude substance ?s prepared
by boihng out the ashes of plants with water and
evaporating the solution to dryness: a pure sah may
be afterwards obtamed by separating the impurities by
crysralhzation. The leaves and smlu twigs^ of plants
contam more potash than the stems and lar|e branches
Potassium carbonate can be obtained perfectly pure bv
heating pure potassium tartrate to redness, and separa
ting the carbonate formed by dissolving in water. This
salt absorbs water from the air, or is deliquescent and
s, therefore, very soluble in water; it also turns red
1. mus blue, or possesses a-strongly alkaline reaction.
Hydrogen PotassUwt Carbonate {Bicarbonate of Potash)
HKCO3. '
This substance is formed when a current of carbonic
acid gas, CO2, IS passed through a strong solution of the
a'id H ?^o''-- ^'Tl ^' ^°^^^^^^^^ ^^ d'basic carbonic
am, n^^Kd^, m which one atom of hydrogen is replace(^
V?K [Lesson
XIX.]
GUNPOWDER.
20 1
by one of potassium. It is a white salt, not so soluble
t'est^paplT"^ <^arbonate; the solution is Aearly neutral to
Potassium Nitrate {Nitre, or Saltpetre), KNO3.
This important salt occurs as an efflorescence on the
soil of several di/ tropical countries, especially tha' of
India. It may be artificially prepared b/the p^cess Cf
nitrification, m which animal matter (containing nitrogen
LXfh. !f r'^P'} ^^^'? '°^^^^^^ ^ith wood?ashesind
lime to the action of -e air : the organic matter gradually
undergoes oxidation, nitric acid being formed; and this
unites with the hme and the potash to form nitrates The
salt IS obtained from both of these sources by boiling out
the soil or deposit with water, adding potassium carbonate
o decompose the mtrate of calcium, and allowing the n^tre
?S^"''- °^'- ^'^'^ crystallizes in rhombic prisms
It dissolves m seven parts of water at 15°, and in its own
weight of hot water. It contains nearlV half its weSht
of oxygen with which it parts on heating with carbon or
other combustible matter.^ For this reasoI,rit?e?s laryy
used m the manufacture of gunpowder and fireworks
Gunpowder
aSd'l'nlnW ^T., '""'""^'^ T'"'"^ °f "'"-e. Charcoal,
and sulphur. The genera! dec< Tiposition which occurs
when gunpowder >s fired may be*^ expressed by saying
tha the oxygen of the nitre combines with the S
coal, formmg carbonic acid and carbonic oxide, whils,
he nitrogen is liberated, and the sulphur combines with
the potassium Hence gunpowder can burn under wier
or m a closed space, as it contains the oxygen needed
for the combustion in itself; and the greaf exofosive
power of the substance is due the vident evolution
of large quantities of gas, and . .apid rise of"emperatire
causing an mcrease of bulk sudden and ^r™ "^„fwf
202 ELEMENTARY CHEMISTRY. [Lesson
occurs in the Ssionil! ^'''''^P°'*^'°^ ^^^^^^ actually
has been ex^eted above ""^ "^
an equation. The foUowfnV tnwf " be represented in
Nit^e .
Charcoal
Sulphur .
English
and
Austrian.
Prussian. Chinese
75
^5
lo
ICO
75
757
13-5
14-4
II-5
9-0
French.
75'o
12*5
12*5
lOO'O
lOO'O
lOO'O
Potassium Chloride^ KCl.
crystallizes in cube, "ike fod?,?^*!'.' ' 1," ^'^''^^t^'- = *'
much employed for the PreDara^on^lt' *"^ '^ "°*
salts. J- " 'or tne preparation of other potassium
Potassium Chlorate, yiCXO .
ofTwsTal^havi b''ee°n"aLTH P°'^=^«°/the production
It is manufaXed'S fhrfc'S/te "■^)-
calcium chlorate madp h« 1,,? scale by decomposmg
with excess of chS bv mtl ^^"?«^ •">* '""'' »? Uml
thus : <:'"onne, by means of potassium chloride,
Ca2C103 + 2KCI=Caa, + 2KCI0,.
xixj POTASSIUM SULPHIDES. - 203
soluble cLium%hlorideS„ttsoJv^^^' "'"^' ""«
Potassium Iodide^ KI.
rating and igniting the soSS mass to JeC' '^'''°"
Potassium Sul^/uite, K2SO4,
is contained in the ashes of both spi o„^ 1 j ,
and is only slightly soluble in water A t. ^U"* ?'^'''
termed hydrogin potassium sutohS'e %kIc^^, '"'P^'",^
phate of potash), is a soluble saJ?nhft'i„i^-°t(°'' '''^"'-
of the maliufacture of n°tric Idd. "^ '" ""^ P^'*^*
Potassium Sulphides.
poSXisr^r^i^^'j" I™ -r com-
not used in the StT ^^^'"^ ^^'^^ ^ ^^i-l. ^d are
of ^cSStashCin "fs iSuJT^ ^^^ ■"'° - -'»«-
hydrogen p'otassiursi/p^^de! HK^f it Sr' ''"^'^
General Characteristics of the Potassium Compounds.
the fl^;Cd 1rsp°X^'!frT"'/ "''"^' =°1°- to
i<H ELEMENTARY CHEMISTRY. [Lesson
solution of a potassium salt is mixed with an excess
2 fKaf+P.ri "* '.?■}.•* (3) . potassium-platinum chforide
cri-stakt,h3' 7'!''"' P'-«':'P««es in small yellow cubica
crystals, when platmum chloride solution is added to a
t±^hh?h1''nnr-=""- .'"'^"^ reactions se??e to dis^
imguisn the potassium salts.
SODIUM.
cfiZi'l^-,'" %l!fj'"''}'f''"'^i'^'"^ ^"?'" 23, specific
Lrravtiy o g/.—This metal was discovered bv Sir H Davv
■mniediately after the isolation of potassium by the d7
composition of soda with the galvanic curJem It can 4"
procurid more easily than potassium by reducing the ca^
bonate m presence of carbon, and is now manufactotd
especially magnesium and alum nium The aoparatus
Xr'^ for the. preparation of this metal is the same
35 that used for potassium : the metal distils over when
condensed, and drops into rock oil. Sodium isTsUver"
^^'^le^'flln^' °i^r'^ temperatures, and melttag
at 95 6 , It volatilizes below a red heat, yielding a colour-
aoidrvT''- ^'''" V*"™"" "P°" "*«^^ it floats, and
rapidly decomposes the water with disengagement of
hl^^V"' ^''- ^'"^ '■°""«<1- If the watfr^b^hot or
be thickened with starch, the globule of metal become
so much heated as to enkble the hydrogen totakefire
The compounds of sodium are very widely diffused
Analysis, p. 282); they exist in enormous quantities in
the primitive granitic rocks (see p. o), ^ut thev are
mos readily obtained from sea-water! ^hich contains
saltttoTthfr'- °^=°""™ ')'""''' (commonTs'ea
salt), or from the large deposits of this substance which
occur m Cheshire Galicia, &c. Sodium carbonltrwas
formerly obtained from the ashes of sea-plants or ke1p7as
potassium carbonate is still prepared from the ashes of
XIX.]
SODA MANUFACTURE,
205
land plants; but at p esent the sodium carbonate is
?rKa'Lr"^ ''"'''^' "" ^" enormously large scal^!
Sodium Oxides.
There are two compounds of sodium and oxygen
Wn-Sodium Oxide, Na,0; and Sodium Dioxide"
Sodium 0^/V/^, Na^O, is formed when sodium is
oxidized in dry air or oxygen at a low temperature, a
white powder being formed : this takes up moisture with
great avidity forming HNaO, sodium hydroxide' ox
soda from which water cannot again be separated by
heat alone, but which can again be converted into the
oxide by heating with sodium ; thus :
HNaO-f- Na = Na20-f H.
Sodium Dioxide, ;^^^0^, is a yellowish-white powder
which is formed when sodium is heated in oxygen to
200 C. : It is soluble m water, but the solution readily
Sodium Hydroxide, or Caustic Soda, NaH O,
is a white solid substance, fusible below a red heat anrl
^^t'rt' '1 \V^-' corresponding potassiWorS^d
f, llv .il^'''^"^^^ '^ T^^^'^ ^^^^ ^s ^ caustic, is power:
fully alkaline, and is largely used in soap-making The
manufacture of solid caustic soda is now carried on on a
large scale, by boihnglime and sodium carbonate together
with water, and evaporating down the clear solution :
Ca -h Nag CO3 -H H, O = Ca CO3 -f. 2 (Na H O).
Sodium Chloride {Common Salt), NaCl.
It is from this salt that ahnost all the other sodium
compounds are prepared. Sodium chloride occurL i«
r-H-. ,.-
206 ELEMENTARY CHEMISTRY. [Lesson
parts of water' at. c^.nJ^^ '" ^5?"' **<> ^^ » halt
fn hoS'ii cold^^ater. '''''' ""' '^'"°'"= sensibly more
Sodium Carbonate, '^2.^0,0^.
trCs "' ^'■°''''''' "^'^* "''^ "^ divS into
sa/4afrcteoe{r?.o^tr^^^^ - --«™
(i; ^alt-cake process, --1\i\% process consists in fK^
Fi^ rfi !^„ f, furnace called the Salt-cake Furnace
sufhlw'e the'sfr*/"'^ ^'^- 55 t»>e elevati^rof
tionLo towefs, oA"cX^^l|;7;^h^tke°'orTr!:'^^^^
XIX.J SALT-CAKE PROCESS.
moistened with a strea. of water • n.« .. i. i <• .
vapours are thus condc sed anH Vr! *''?''' "^'"'^ a^'d
airV up the chimney. A drawil^'of Z t/"'' ''*"'"''
mem of £e kind is ^ven t'^^S^^^l'^^^^^,^^^
Fig 55
Fig. 56
^xt'feetin'S b^thf/"'^^ '"^ *?-- B, which is
it meets wUhthldescenHfn.^f ^ ' f^?'"S "P •'''^ *»*«
falling waTe^ When^th "5 ''" '"^^' ?"°"'^'' "^""^"t "^
makers are^comn4l/-f"°'±'i-l_P^^''?'"«n' the alkali-
_—,.,.. ^v.- wnuciisc at icasi 95 percent.
2o8 ELEMENT A R Y CHEMI:STR Y. [Lesson
of the hydrochloric acid g.^i they produce; and so pcr-
Icctly is this condensation as a rule carried out, that the
escaping gases do not cause a turbidity in a solution of
silver nitrate, proving the absence of even a trace of the
acid gas. After the mixture of salt and acid has been
«-«#
Fig. 57.
heated for some time in the iron pan, and has become
solid, it is raked by means of the doors {ad) seen in Fig. 55
on to the hearths of the furnaces at each side of the de-
composing pan, where the flnnie and heated air of the fire
I? K [Lesson
XIX.J SODA-ASH PROCESS. 20a
^^^^^:^^^''''''''' '"'^ -«»■"- sulphate and
and purification of the samo • ?» « ^l u ■ s«P«ation
whicK the salt-cake undeSoes n It? n» ''"'"'"' ^'^^"ee
is its reduction to sulDhfdf ht l •■ P* -^^S? to soda-ash
coal or slack 7 '"'P'"^^' •'V Seating >t with powdered
NajSO, + C^^. Na^S -f 4CO.
or limestone (caldum carbonate)': " ^'"'"« '' *"*' '•>^"'
Na,S + CaC03 = Na,C03 + CaS,
Fiff. 58.
Fig- 59-
mfxtureTf Ie™f T '", P''^^''^^ <=^^i«d »" « "nee; a
aid se^en LnH^, I ,°/ ^^"-'^^ke ten parts of limestone,
in section ?n^^'T '^i'"^ "^'^ ^'^'^'^^ ^«'-«'^« (shown
fuses and L 'C' 5^' '!"'' '" ^'^^^''°" '" ^ig. 59), until it
;uses ana the above de,-omnnsi>,nr, ;=, „„~ri„r7 ...u._ ;,.
raked out into iron wheelbarrows to cool. This process
210 ELEMENTARY CHEMISTRY, [Lesson
is generally termed the black-ash process, from the colour
of the fused mass.
The next operation consists in the separation of the
sodium carbonate from the insoluble calcium sulphide
and other impurities. This is easily accomplished by
Itxtvtatton, or dissolving the former salt out in water. On
eyaporatmg down the solution, for which the waste heat
of the black-ash furnace is used, the heated air passes
over an iron pan (see <^, Fig. 58) containing the liquid.
On calcining the residue, the soda-ash of commerce is
obtained.
No less than 200,000 tons of common salt are annually
consumed in the alkali works of Great Britain, for the
preparation of nearly the same weight of soda-ash, of
which the value is about two millions sterling. The soda-
ash of commerce contains from 48 to 56 per cent, of pure
caustic soda, Na,0, as carbonate and hydrate, the re-
mainder being impurities, consisting generally of sulphate,
sulphite, and chloride. If soda-ash be dissolved, and the
saturated solution allowed to stand, large transparent
crystals (monoclinic) of the hydrated carbonate, of the
formula Na^COg-f 10 H,0, separate out: this substance
is commonly known as soda-crystals, and is much used
for softening water for washing purposes. Sodium car-
bonate also occurs in small quantity in certain localities
as an efflorescence on the soil, and in the beds of dricd-
up lakes.
Hydrogen Sodium Carbonatey or Bicarbonate of Soda
HNaCOj, '
is obtained by exposing the crystallized carbonate in an
atmosphere of carbonic acid gas. It is a white crystalline
powder, which on heating is readily converted into sodium
carbonate. The bicarbonate is chiefly used in medicine,
and for the production of effervescing drinks.
Sodium Nitrate^ NaNOj,
is found in large beds in Peru and Northern Chili, and
STRY, [Lesson
f, from the colour
separation of the
calcium sulphide
accomplished by
out in water. On
h the waste heat
leated air passes
ining the liquid,
of commerce is
salt are annually
Britain, for the
of soda-ash, of
rling. The soda-
per cent, of pure
hydrate, the re-
rally of sulphate,
issolved, and the
LTge transparent
arbonate, of the
: this substance
d is much used
s. Sodium car-
:ertain localities
e beds of dricd-
bonate of Soda^
:arbonate in an
vhite crystalline
ted into sodium
ed in medicine,
inks.
hem Chili, and
211
XiX.] SODIUM SULPHATE,
termed soda, or Chili saltnefr^ Tf • * ^"
quantities and used as a mTn,- ^^^"^P^rted in large
paration of nitric acid LTncr .k ' ^""^ ^J'^ ^'^ ^^^e pre-
of nitre. For this IttS^^uVos^^^^^^ "^'^^)' ^«d
solution of this salt is mixed with /hnf . concentrated
of potassium chloride^^ on coolfn^ "^"""i^'^^^ solution
separates out in crystals, and sSn ^r'l^f'''^"'' "^^^^^^
in solution. ' ^ sodium chloride remains
Sodium Suiphate,n^^^,0,-\^,^^^^^
anhyTrrsTtat'e'^TsT-cake^^n^"''" '^!*^> ^"^ "^ the
m n^ mineral springs, and is used ^'n'r^-" '^^ ^^'^' «'
sau-^^it is emplf^, in t^^^u^S^' ^^^J-s
^ Amongst the other more important salts of sodium
Sodtum Jiyposulthite Na q u r. .
foned under the compounds 'of '.ufnht + *?»0' •"«»■
(P- iS8) : Borax, Mq, + ZTaf^ '"'-^" phoiWus
sulphide, NajS a soli We si? f^™^*^*?- '5^ '' Sodium
sulphate with carbon, i'^«« «S ^^ ""^^"""S ""e
(see p. 148). ' •^''"""" silicate, or soluble glass
General Character islics of the Sodium Ccnpounds.
am/iXti-o'SlJf^rn'rt^,^ thf --Ption of th.
compounds can be detect^ hv t J P"'^^*" ^ "^ sodium
which they impart to the flame^ Th/f ""'^^ .^"ow tinge
■s distinguished by one fine bri^^ I P>>f '"•'"' "f sodium
>n position with th^ dark scJar line called D.""'^ '"^'"''^^'^
P2
212
ELEMENTARY CHEMISTRY, [Lesson
CiESIUM AND RUBIDIUM. '
Cae=i33. Rb = 85-4.
nnanHti^c -ru ' ^^^"ougn generally occurring in small
found in many :\her\";ring ^fsS W-v^^ ^.^
an< other old plutonic silicates as wl?!^, t^ °'u'"'<'^,
rubid^m saUs- ie %rp?eTely°'pS"a"d Tv'^nT't?"''
sSfn/t ™'^'"''"™ "^^ isom6"us wit^^th/co^f
spending potassium compounds. The f„«»H l-ki -j
of these metals are easily decomDoseH htt^ ^Worides
current, and the metallic element deposited'^ Ae galvanic
s?r" r''1'';^P"^'* "^y ^^'J""'"" w a cirbonae polt
Slum. Rubidium is a white metal wi^vi! '-j, ^ ,
goes oxidation; its specie L^kll^^^ rapidly under-
greenish-blue vapour ^ ^ '^^^ ^""^ '^ ^^^^^ ^
LITHIUM.
-Thi^tne^ii fff'"'''^^ ^'^/^^ 7, ^9/.^^. ^r«z.//y 0-50
ride by el te'TL'lf^r ^^,^r P?^"^ *^^ ^"^^^ch^o^:
uy ciecincity. it is of a white colour, it fuses at 180",
^TRV, [Lesson
f.
•60-61 by Bunsen
Llysis (see p. 280).
nd potassium in
previously been
They are found
:urring in small
ed in the mineral
: they have been
kinds of mica
s in the ashes of
fee, and grapes.
>tassium by the
which they form
m, caesium, and
ted by platinic
with water, the
etals. Caesium
reater solubility
I- The salts of
with the corre-
fused chlorides
)y the galvanic
d. The metals
bon, like potas-
rapidly under-
and it forms a
c Gravity 0*59.
the fused chjo-
t fuses at 180",
XIX.] AMMONIUM SALTS, #
and is the lightest metal knnwn tk^ 1-4.1. •
formerly supposed to be ver7?;re on,v t^ f"' ''^"'
occur in three or four minprafr l » ^ ''^'"^ known to
has shown that this is a ^Mdy-istr bu?ed?K .^"^^^'-^
occurs in small quantities in ,lm^Hii*^'^ substance: it
tobacco, and eve^rhuman blood 'k'^wTn^inV" ■"'"?,'
contans large auantitiee nC Ik?, ' -^^ ^P'^.'"g "n Cornwall
chloride. UtL^tt^'^'hemical relations « '""^ 1°™ °'
the class of alkaline and aSnie^fh met^s the If^T
carbonate, and phosohatp hf^ino- ^„?" "^^^P^ the hydrate,
water. A 1 the vffie l^iZ^..'^''^^ sparingly soluble in
nificent crimson dnget"^ ^ "^^g-
AMMONIUM AND THE SALTS OF AMMONIA
maTcoU'enfeXttnitr^d^'t the ammoniacal salts
or sodium in the alkaline «lt/ "" *'°'" °^ Potassium
ammonium is formiaf thus? • ^"'■'■''P°"'''"S =''" °f
Potassium Chloride, K Q.
Potassium Sulphate, BSO4.
Potassium K\r.
Hydrosulphide H/^
Ammonium Chloride, NH^ Q
Ammonium Sulphate, jJh*!s04.
I Hydrosu"l^ide ^H*)s
The radical ammonium ^^4 1 i,^ .
the free state • it i. \ ^1^'^ ^'"^ ^'^^^^^^ ^'^
metallic lusfe,Vhichctno^';w^J"^^^^^^^^^ ^^^'^^^^^ a
-ci at a low ^^r.;:^:.^''^,-^^^^
0'
7
214 , "Elementary chemistry, [l
into ammonia? and hydrogen. An amalgam of ammonium
can easily be prepared by placing sodium amaS IT
a s9l.ution of ammonium chloride . soLm c&e I
formed, and the ammonium wrJch is thus iTeraf^d unit.,
with t e mercury to form a singular light SmS^^
mass, which rises to the surface of the liqu d b^t soon
decomposes into ammonia, hydrogen, and mercuo^
Ammonium Chloride, NH^Cl,
«mmi«^'"?''i^''' '^ Dbtained by neutralizing the distilled
ST^M ""^^ ^'^r' ^^ ^^^ gas-works (sef p 07 wUh
hydrochloric acid, and evaporating the liquor to dryness
-^^sublimmg a mixture of the commercial sulphate ol
iti^pnium with common salt. The sublimed salt foL,
a tough fibrous mass; it is easily soluble fn water T^^
CTKStallizes in arborescent forms composed oTcrvsSs
belonging to the regular system. On heatiW \L^\^.tv
completely without melting. ^' '^ volatilizes
Ammonium Carbonate,
rsJ^l f^vf^if^'^^*' (NH4)2C03, is a very unstable com-
Snn .f'o^''^ decomposes on contact with air, with evoS-
Ind ^ilT'^'l'^' ^y ^"^^^^S a mixture of sa -ammonkc
and chalk a white transparent salt sublimes whiSi k th.
carbonate of ammonia of commerce This ^s however
a compound of ammonium carbonate and carbon dS
(NH,), C3O3 or l^^)^^ I o, ; it smells of ammonia, and
fnto^Jh^ hT """"^ "^'^^^^^^ ^"^^ ^^^ ^'""^ the air passing
mto the hydrogen ammonium carbonate or bicarbonate,
NH^ I CO3. This latter salt is amorphous with the corre-
sponding potassium compound, and occurs frequently in
Ammonium Nitrate, NH4NO3,
LllJln^^'^ ^^ neutralizing ammonia with nitric acid, ani
crystallizes in long transparent elastic needles. It is
'mitm\
RY. [LES5 0N
of ammonium
amalgam into
m chJoride %
berated unites
bulky metallic
luid, but soon
nercury.
g the distilled
e p. 97) with
or to dryness,
tl sulphate of
ed salt forms
in water, and
i of crystals
^ it volatilizes
instable com-
lr,with evolu-
al-ammoniac
which is the
is. however,
rbon dioxide
mmonia, and
e air passing
bicarbonate,
ith the corre-
requently in
'ic acid, ani
dies. It is
XIX.] AMMONIUM ^ULPHWE^^^m^^
very soluble in water, and wh^n 1,00* a ^BKf^
decomposes into ..^ ^^Z ^S^^jl^,!'
Ammonimn Phosi^tes,
The normal salt, (NH J, PO wm^^^A u , "^
acid and ammonia are mixeS fn . ^ ^^^^ Phosphoric
when on cooling the ^al^sfnl^ concentrated solution,
do:ing it loses altn?a VL?d"f ^et^iJ^r^^^^ p^'^
which crystallizes in the monSk system ? t^*'
this solution the salt NH. H PO ?c 7 J ^? boihng
crystallized in quadraUc pS 'a H^^^^ "^^^ ^^
ignition a residue of metanl^Lh ■ ^^^5 ^^^^^ ^^^^^ on
sodium phosphate, nS!n?HPo' '"'''^' ^«"^°nium
is a substance' muJh u^e^dt l^ptpe'ex^S^^^^
Ammonium Sulphate, (NH J^ SO4. -
Phuri" Tc d Klwlt^r .'"It Ir^^^^"^^ ^y ^^^-S -^■
sulphate is largefye^^^^^ "^^"Z? native. ^ The
a i^anure. ^^ ^n^P^oyed for alum making, and also as
Ammonium Sulphide (NH ) S
. If dry sulphuretted hydrogen and exces., c^ a.
niacal gases are brought together at ^I'l^f^ ^^^^ a»^«»o-
separates out in colouress crvst^l«^~ A.^^^^^^
temperature the sulphide losesTHlndt '^^ ^'^^^^
a crystalline mass of t^^hydrfsul^lhl^^^^ ^"^^
volatile body, which decomposefat^^^ ^ ^^^^
and sulphuretted hvdrocren An o ^ ^?^^ ammonia
body is much used in th^'l^i^ ^"^^^^^^ solution of this
The salf« nf '^'^"^P"/"^^ ot ammonium and water
Jimmonia when thev are X.^, »?"?•, ?""?«"' smeUof
Caustic alkali. Th'^-,.^H^!'S^!? .^i''. P"?'"=. "nie or a
itmic
Caustic aIkarTh:'a^?,^--^-ustic^^
i«*-«WW»»|«».,i«tite,,i
■''.™rT''"'-~*'
IHJHyt'if''
**
i
216 ElEMENTARY CHEMISTRY. [LESSON
?ni°Dot'arr'S!.'' '"":!"'''"' ^!"* ^«^'''"''''= *c correspond.
iaV!iraH^ii::rte^c-^ - =iP
Hydro xylamine, NH3O, or N ^ H
(H
, This substance which may be regarded as a romnnnn^
intermediate between ammonia andCte^or as amSa
^^yaroxyi (UH), is a base uniting with p-ids to form a
^WWdined series of salts. Hyd^xylami^ll^nc^b^n
isola«ed m the pure state, but its aqueous solution hl^
been prepared, and forms a colourless, inodorous hanid
possessing a strong alkaline reaction/ On SLt?^^^^
^^^.r.f '^'' ^'" P^^^^^ °^^^ unchanged, wffthTre
mamder undergoes decomposition with formatinn %
ammonia. Hylroxylamine ?an be prep"y^^^^^^^^^
tl(us Nol R^°" t^''^"" °^^^^ aW^nascerhydrS
thus .NO + H3 =7 NH3O ; and also by the reduction of
Hydrochlorate of Hydroxylamine NH«0 HCl
PhosDhate " '* ,^"»0 " NO,
i-hosphate „ „ (NH3O), H3 PO,.
b. described fn d>e paS Sing « ortehemt'?.''''' ' "«^ I"""" »"'
'^^^^^
XX.]
CALCIUM,
217
LESSON XX.
Class II.~Metals of the Alkaline Earths.
Calcium. Strontium. Barium.
CALCIUM.
Symbol Ca, Combining Weight 40, Specific Gravity 1-58.
Calcium forms a considerable portion (see p. 9) of the
Plutonic rocks of which the earth is composed, and occurs
Vx^JtZll ^rS!^'^''^ ^°^"^^"^ whole mountain-cha"ns
Thi^'f? ^'I'^^^^'.^E'"?"' ^^^ mountain limestone.
I^ .M^ -i ""^i^'T '' obtained by the decomposition of
he chloride by the electric current, or by heatine the
iodide with sodium; it is a light 'yellow metal ^hch
easily oxidizes m the air, and when heated in air t burns
bdng'foSf ed ^^"^'^ ""^'^ ''^ ""^ "^^ ^^^y ^^^^^ °^ ^^^^^^
Calcium Oxide, ox Lime, k 0.~Pure lime is obtained
by heating white or black marble to redness in a vessel
exposed to the air. Lime is prepared on a large scale for
Lrhnnf. f ^ "Jm"' T^P^'"'' ^^ ^^^^^^^^ limSstone (the
caibonate) m kilns by means of coal mixed with the
stone ; the carbonic acid escapes, and quick- or caustil
/r;«. remains. Pure lime is a white infusible subTtance
which combines with water very readily, mvintr off ^tell
heat, and falling to a white powder cklfed cilcti^hy
droxide, or slaked lime. Ca O H^ O. The hydme is
pS rolfh /" T^^ ' P^^^ °^ '' dissdv^'g?n%3o'
parts of cold, but only m 1300 parts of boiling water, and
forming //^.-«,^/,^, which, like the hydrate, has a great
power of absorbing carbonic acid from the kir. It is in-
deed partly owing to this property that the hardening or
»etting of mortars and cements made from lime is due
^ortar consists of a mixture of slaked lime and sand : a
gradual combination of the lime with th-i
•1 •
i»»»^ iNlilMMalllKitlMsiii,
21 8 ELEMENTARY CHEMISTRY. [Lesson
and this helps to harden the mixture. Hydraulic mor-
tars, which harden under water, are prepared by carefully
heating an impure lime containing clay and silica • a
compound silicate of lime and alumina appears to' be
formed on moistening the powder, which then solidifies
and is unacted upon by water. Lime is largely used in
agriculture, its action being, ist to destroy the excess
of vegetable matter contained in the soil ; and 2dly to
liberate the potash for the use of the plants from heavy
clay soils by decomposing the silicate.
Calcium Carbonate, or Carbonate of Lime, Ca CO, --
This salt occurs most widely diffused, as chalk, lime-
stone, coral, and marble ; many of those enormous
deposits being made up of the microscopic remains
of mihute sea-animals. Calcium carbonate exists crys-
taUme as calc-spar, or Iceland spar (rhomboheural
or hexagonal system. Fig. 48), and also in a different
form, arragonite (rhombic. Fig. 49); so that this sub-
stance is dimorphous. The carbonate is almost insoluble
m pure water, but readily dissolves when the water con-
tains carbonic acid, giving rise to what is termed tern-
porartly hard water. Such a water deposits a crust of
calcium carbonate on boiling, owing to the escape of the
carbonic acid. The well-known evil of boiler crust is
caused by these deposits. The formation of such a crust
may be checked, if not avoided, by adding a small quantity
of sal-ammoniac to the water, soluble calcium chloride
and volatile ammonium carbonate being formed. Water
hard with dissolved carbonate may be softened by the
addition of lime suspended in water in such quantity that
the excess of carbonic acid is neutrs'Jzed.
Calcium Sulphate, CuSO^.— This occurs in nature as a
mineral termed Anhydrite, and combined with 2 H„ O as
selenite, gypsum, or alabaster. It is soluble in 400 parts
of water, and ^ a very common impurity in spring
water, giving rise to what is termed permanent hardness,
as It cannot be removed by boiling. Gypsum when
moderately heated loses its water, and is then caUed*
XX.] CALCIUM COMPOUNDS. 2,9
plaster of Paris : this when moistened takes ud two
atoms of water again and sets to a solid mlasMd^s
therefore much used for making casts CmS
Calaum Chlortde, CaCl,.-This soluble saUil formed
Td^f eTo 8l^°'irt5:"'' '? ^^''^'^^ '° hvdrochtoric
acia (see p. 84) : if the solution be then evaporated
me, Ca Uj + 6 H„ O, are formed. When these are dried,
the subs ajice still retains 2 H, O, and forms 1^ porous
mass which takes up moisture with greatTiditr^d
is much used for drying gases. When thrn^'ss^s
more strongly heated, it fuses and parts with^ Z
Bleaching Pow<Ur,ox Chloride of Lime,C^Ci^C!,zC\0,
°^ ^^ \ O CI,'* ^ Mixture of calcium chloride and calcium
hypochlorite, and is obtained by the action of chlorine
upon slaked lime see p. 113). If a clear snlnfinn ^f
bfeaching powder is\eJd m&\ im^i qu^tity "f oxi,te
of cobalt or of copper, the oxygen of Sie hypochforite
B gradually evolved, and calcium chloride left behind
This decomposition depends upon the fact that hiffh^
oxides of the metal are at first 4med ; but these decW^
pose under the influence of heat, and give off oxyZ
regenerating the lower oxide, which again attacks ShS
portion of hypochlorite ; and thus tile process bSom«
continuous. It is not improbable thaHhe act?o„ of
manganese dioxide in facilitating the evolution of oxyeen
from^potassmm chlorate may ^depend upon a sK
Ca/cium Fluoride, or Fluor Spar, CaF* Found
Ctystalhzed in cubes in Derbyshire and Cumberland
When hea ed with sulphuric acid, calcium sulphate 4d
^stdtTl ""-^t' P; '^^^ '"% ^°™^'»- I' i* sometime^
rSpar" is deritir'"""" °' '"^'^^' '^^^"'^^ ''^ """«
me1;^o°nf/'?l/^^i'"i??J?!?J?°"°'l^°f <='!l""?' may be
- "*«»«WII»»»»*Wl*-
I
^»«> ELEAfENTAH Y CHEMiSTR Y. [Lessor
Calcium pmtamlZfde C f S „ L7 n" ^"■'•" P" =°'') ' ""^
number of distinct brUtfnefbvwhi.T'^ '^''"'""'''"K »
tins metal can be easil^ asSi '/dTsee^V^ne")! °'
STRONTIUM.
-VcwW Sr, Combining Weight 87-5.
speciei;cspecknyX«;fefr"^ u ""'V ^ ^w mineral
the sulphate StronXm^^^^^ •''^ carbonate, and «/«/,«,.
titles in ce tai„S";^,^i'/*i=^ °^="" [» minute quan-
white colour -x^Tw^Z^t \ P« metal has a yellowish-
ofelecS'on theS'^lf IY rt>e ''"'°" "^ ^ ^'""ent
closely in its nro JrH.; f •?"''^' L' "-e'cmbles calcium
When heated in*^ the a^i C??'^"- ^''^^''^ '^ ^•54-
strontia ' '^"'"*' formmg the monoxide
Strontium Monoxide, or Stroutin «:, n ti ■ • j .
unLtZtal^r ti^nf^ ^ "■^- ^ ' heal^^ 'it
sorbs carboniT acij wi'th avldL tI"" '" *^'^'"' *"'' "''-
employed in the am rH';f "' °^ "''l "'''^ ^^ich are
strontium is a very rharacTenVn. f / ^he spectrum of
c^^^e^e^yTd" S3?S f-^^^'-Se
calcium aKium "alts.^ '^''''''^' *^"° '" P'^^^"" °f
XX.]
BARIUM,
331
BARIUM.
^y^Mys^ Combining Weight lyj.
Wum minerals bcins: the su^^'hl'^ "^ '""" """""""n
the carbonate, or v,itlrfu. tEc mVal f"^"" '^'"'' ""'l
yet been obtained in the cnhir„„. f f' ^^""^ has not
powder may be prepared rnfsLi^'^' ''"'''■« '"«'''««
former metal,, whTch'^t elo,e?y ?e/emb?e', ll'*^ '° ""« ^'^^
Bapum Monoxide, or .ff«rL Co T»,''\P''°P*'"'"-
forming this oxide is to dec m^^l.,^,?' ^^^ '"'" "'ay of
■s a greyish porous mLsrwhkh fus« "/'T t^ ''^^^ '«
ure, and takes up water with evoTuH^l'' r'«'"TP"a.
formmg a crystallfne hydrMe H fti n V/ J"!!?'' ''eat.
hydrate is soluble in twenty oarf," „r "», + ^ H, O. This
so ution on exposure to The a?r r'.^Ci?"'!'^''^''' and the
acid, and becomes milky. ' '^^P""'' *''«<"•'» carbonic
inf TurrTnf o/txysen ^17^^? ''^'^l» '' Senfly heated
together to form TSifxTde con7,° ^"'""ances combine
oxygen as baryta: this addWon^f ^'"'"8/"''='' as much
ever, evolved at ^ higher temS^Lt"^^ of oxygen is, how-
proposed to use this decomSl 7 = \"'' " ''a' been
of oxygen from the air For'^th ' °^ ^°'' *« manufacture
dioxide Ba O, has b?e„ reduced to'^^^'o^A^' *°°" ^' '^e
IS lowered, and air passed over fh.K^' '*"* temperature
takes up oxygen, passing into B=. n^"^'?' .">" again
decomposed by a' fcighLr^emperftur?" T^'^ ^S^'" '»
process has, however hp,>\, '?nperature. This interestinc
There are no saTts So4 c<^""i"° ' *" ^°'^ '" practice!*
Barium a/^«V*, BaTl Th?. ""^i"? .'° ""'^ ""^e.
the most important comno;m/ I u°'^'''e salt is one of
in flatscales conta nW t'^o alom, ^J""" •' "' ^Tstallizes
prepared by dissolvinf the naZt ^ T^'^""" ^' «ay be
chloric acid, and it is ifreelv^cln carbonate in hydro-
Phuric acid. ^ ^ "^^d as a precipitant for sl
«3 ELEMENTARY CHEMISTRY. ^Lesson
s^rs"S;orfnT4nr^' '4'^^ °V'he most b^oS
-••-/^-d. is .ar/ei?ir^ed to lULate wlifeTaV''"'
««W b/2 No''%'r,°':if' ".^"^ °f bariim'are Ae
o"Sd'&\lVhetlf:p|fUAU"^^^^^^^
on addition of wate? into hUroxide Ba H h 'flTH'"'
Class III.— Metals of the Earths.
ALUMINIUM.
Symholi^, Combining Weight 27*4, Specific
\ Gravity 2*6.
atoinium chloride over Siaum"^It*^IS,,^
FrSr^t'Su",? i^*^ ^^^ both ta Engla^n^'l
rrance, and, from its lightness (specific gravity 2-6) and
A'K lLesson
XX.] metal:^ of the earths. „3
of o';& irs^u■il„^?a'^"elraf f^/o^ ""^'^ P»"'°-
^ W««, AI, C„ specific gr^ti^ v? !!!¥i?[f.,r*- ,
oxide of aluminium known. It ocSir^^AlTi ^ " ""^ """^
pure and crystalline state a. V^f i "*''^' '" ^ nearly
andinaless'pure sta? It ^nZ''"^^'^:''^-^ ^"-^^4
by addmg ammonia to a soIutiS;- 0^12^^ '^XT^
c.p.tateof the hydroxide A>» o, falls down and tWs "
bemg heated yields a white am«rr.K ' " ""s on
alumina. This sub«»n^» • ^'"O'Phous powder of pui«
acids, but the hydratels e^ Jm/"?%''- '^^ ^'f^<=»^^ by
fixed caustic aS[es' SiL't","^ '" "^'^^ ""^ '» '^e
commonest alum ilum sal^fl^f th f ^ "^"'^ '"^^ •• *e
tions have an acid reaction "f , ''^^'"■ns and their solu-
dyeing and calfctpSg as 1 morl'n/"^"?^ ^"^ *°
power of forming msnl. hf» !^ mordant, as it has the
vegetable coSg miuer anffif ' 'f «> /^i.. with
permanent by fixint it in fK„ "I renders the colour
Cannot be ^^sheTlu such P^' °^ '^^ ='°"' «° "'^ it
Aluminium chhride MC?Z" "^'«^me<l/'"A
body, obtained bTheath^^ J"'.^- V°H''^*'''*« '"Md
charcoal in a current of cflorin^"'"'' of alumina and
manufacture of the met^ "* «^ ' " " "^^d in the
on1ta'^:t:.ra^|So?^^f -olublesaU
clay, by acting unon it Jfth '^l^^er by decomposing
mixture of silfca f nd ^l■^?^ '"'P'";™ *"'* = the soliS
goes by the n^e of afuZakT Tlf^^" '!"" f'^'^'^^
pounds of alumina are howe^r It T'*^ useful com-
double salts, which Xmf^T ' ,^ ^"™5' ^ series of
alkaline su phate, cZT. ""^ /"'P''f « ^^s with the
/.g.^« te. SsThrc^t^^fcTi^'^'irr
gether, and allowing the comZ^ sulpWs to-
it is usuaUy obtainfd f^m^CSf '^•V*'' crystaUize, but
6*«**
«4 ELEMENTARY CHEMISTRY. [Lesson
dually undergoes oxidization when the shale is roasteH »h
cluen=rr-a^i^^^^^^
of potassium, ' containing ammonium instead
(NK,\|4SO,4.24H3 0,
There i^ % I?' '"' l"''*^^ °^ ^ potassium sa t ^
and manganese are substituted for tne 'af^ T, T'
common alum : all these alums occur iS reguu'; octL
hedra, and cannot be separated bv crvstiliitfri u
present in solution togelhen ^ "ystaUization when
J:}^^ '^ an aluminium silicate resulting from the disintP
gration and decomposition of felspar by the action of ^f^
and water, the soluble alkaH bei?g wished aw^y. ° The
formula of felspar is ^3|' o.. Kaolin or porcelain
Sd""^.!/^/""" *^'" °^ crystallization, and a^^
irivw'Tfr, '^"' "" "^ '^'='=<=t«<l *l>en in solution by
= f ?sots?ri- cU fso^ ayrr;^!
S:ra?eltXretrbCr ' ""'^ -"^^^ ^^^^^^
TRY, [Lesson
XX.] GLASS AND PORCFLAIN.
225
^ -S, PORCELAIN, AND EARTHENWARE %
^^^'^^'^^^'l^^^ - - have seen,
t^arths are soluble in aciH^n^^^^n^'^^ ''^^^
pounds oi the two are Wnh?h, "^^'^^^"^ ^ whilst com-
5o not assume rcmtaiw"^ water and acid., and
hen fused is temied a i^/^cc ?^^ ^"^^ ^ compound
.^scriptions of Xs usefTn'tJ^T ^'^^^^"^ ^^«^^^ent
;;; "^^^^!^^^' -posed or
^ ^ ^iTrarcC'r ^""^'^"•'^ °^-'-'- of potassium
f ; ^ta^ia^TS ^""'^'"'"^ ^"'-'- '-^PO'as-
fuslbre, whilsTfhf «col'n"' "^'"^^ °^ ^'^=s are easily
infusible : the addUbn" of^x^^ of fc '•= '""^'^ "^^^
specific; gravity, and the lustr^^ffK , """reaies ;th ,
fusibility. The common T' J^% ^^^I't' ^^'^ -^ ii
ateg.neraUymadeorZtriass rhn',f°^^"=''''''" "»«
ratus a sor-a-Iime-glas" " to b4 4eferfed "", ' ""^^ '
l'me-g.assis much employed wherelrfM; ,.," 'V^ P.°'^^"-
hard glass is needed as fnr^nJff" ? dmcultly fusit.e or
combustion tuber?or orgI,^re^"f f '" *^ -"anufecture °f
fourth description of Plasf Is an^lir'^ ^-°?^ P" ^99). The
fcates, employed fof purDoses?/ kTV"'^ of various
hneness of tL'glass isZTco ^equ'nce*' "'°'"- ""'^
car^is'^SllJThelSn'-f''-^^^^^^^
as m the Vocess^ of manSfact/ri'"''^ '"^''.i"'*' ^^ "'ell
"als are melted together'^Jh^r^a" e rfA^If/i^.^'^A-"-
226 ELEMENTARY CHEmSTRy. [Lesson
of " cullet " or broken glass of the same kinH a f. .x,
glass articles have been blown LtTcf .1 "^^^^^ *^^
exposed to the nroce^ nf " JI r "^^^ ' ^^^^ "^"^t all be
otherwise they ^a'e so brittle ^'fo^g; '' ?^"T ^°°^"»^ '
breaking with the slightes touch o^l^tf^^J' ""''^T^
contraction of the different n^H-a k ?. J*^^ irregular
coohng. The foUoti^^^^^^^^^^
the chief varieties of glass composition of
Ingredients for various Glasses,
Crown Glass.
Quartz Sand . .100 parts-
Mild Lime . . ^6
Soda Ash . "
24
Sodium Sulphate 12
Arsenic Trioxide \ '
Cullet .... 100^
Bohemian Glass.
100 parts.
Pure Sand .
Pure Pearlashes. 60
Chalk .... 8 :
S""^^ • ... 40
Manganese Dioxide j „
Mirror Plate.
Pure Sand . .
Soda Ash . . .
Mild Lime . .
Arsenic Trioxide
Cullet ....
100 parts.
35
5
100
Flint Glass.
Pure Sand . .
Red Lead . . .
Pearlash . , ,
Nitre ....
Cullet . . 50 to
100 parts.
20
40
2
100
»
Coloured G//tw.— Certain metal ic oxides nossess thp
quantity Thus ferrous oxide produces a deep ereen
colour (bottle-glass), whilst the*^ oxides of mSgfnese
impart a purple tint to glass. These facts are n^^^^use of
n the preparation of colourless glass ; for as ft ?s difficult
to obtam materials perfectly free from iron, which impart
fslddedT^';,';^ 'r" ""r'i^ °f ""anUnese dio^xide
IS added to the mixture, and the violet -olour thus pro-
wlif <^?'"P'^'"e"{ary to the green, and a nearly colour-
less glass IS the result. The addition of arsenic^WnvM^
^"^ .
»nic trinv'rlp
XX.] PORCELAIN AND EARTHENWARE. .,7
S The '^fourfott^'^'"^ '^^^ fe— '<> ferric-
adding certata -ox des ?o Th'ir'""*', "« ™"«^d by
quantity of cobalt oxklef ^Mst^lro.,',' ^"^^ ^^ ^ ^•^"
ruby-red colour, and feSic ovirl. ? n ""'^^ y^V^n% a
bling topaz. °^'°^ ^ y^'Io" colour resem-
porcelain and earthenware rnnSf J M- ^ " '°™s of
in fact clay, in a moTror~purlS °' "'""!!"'"■"'
some substance which fuseHf ? k^ ? '^' "^o^ered with
f'^rms a glaze, givinga smcofh I ^^^ t^njperature, and
material together fnd H^^= ^^"^ ^<* binding the
nature of the bakek clay "'"^, """'e'-acting the pSrous
lain the finest whfte or China rL P''""?cture of ^rce-
the gradual decompos tion of & whlr;""V"S f™"*
mon earthenware a coloured cllv™/' ?! ^' 'P'' "»« <^°">-
glazeused for porcelZ^ffenL^ ^''^^'"P'°>'«'^• The
spar, the b.scuit^r ^rous 4re bt^i';^^'?^'^ P?*''^^«=<1 ^1-
containing this substanci Tusnend"! f^^^ '"''^ -" ^^^"^^
strongly fired. The artic?es?hSs ro.lH *°'? ^"<* *>'«"
chemical purposes, as VWs elale w1?h\f 5^" J'^ "=^^ '■°'-
Th?- ^^' «?«l!--«-^e tbe%rcaTd"4"a?t%W»^^^ 2^
The mode of obtaininir \W^^ ^T • i^'^^e" is used.
some common salSL?uL^^^^^^^ ^^ *^^«^ing
heated ware, when Ue slfrvl^^^^^^^^^^
decomposition on the heated cnrfo!! -^^^ undergoes
a fusible silicate upon i? ^XnH^ • ^' ?u"'''^^ ^ ^^P^sit of
to moisture. ^ ' ^^ rendermg the ware impervious
Q 2
ELEMENTARY CHEMISTRY. [Lesson
LESSON XXL
Class IV.—Beryllium. Magnesium. Zinc
Cadmium.
-^tlRYLLIUM OR GLUCINUM.
Symbol Be, Atomic Weight 9*3.
This rare metal is found in the mineral Beryl
AI2 iBcs I ^J2- Jt is a light white metal (sp. gr. 2*1), closely
resembling magnesium. It forms a monoxide, Be O and
forms a series of soluble, colourless salts, which have a
characteristic sweetish taste, whence the name Glucinum
by which the element is sometimes designated.
magnesum.
Symbol Mg, Combining Weight 24-0, Specific
Gravity 174.
This metal occurs in large quantities as carbonate
along with calcium carbonate, in dolomite or mountain
limestone; and also m sea-water and certain miS
springs as chloride and sulphate. The metal itself hTs
only recently been prepared in quantity ; it is best obtained
by heating magnesium, chloride with metallic sodium
sodium chloride and metallic magnesium being formed,'
Xh ISf^V • °^ t ^^^^' Z^''^ ^^^°"^> ^"d fuse! at a low
red-heat ; it is volatile, and may be easily distilled at a
bright red-heat; when soft it can be preLe™ wre
and with care It may be cast like brass, although when
strongly heated 111 the air it takes fire and burns Jfh"
dazzhng white light, with the formation of its only o^de
magnesia. The light emitted by burning magneZm wlr'^
is distinguished' for its richness in cher..ir.uZ.^!!t^I]l^
STRY, [Lesson I ''^'''^ ^^^^^SIUM COMPOUNDS.
siUM. Zinc
229
Magnesium does not oxidize in drv air • if ,« «ni 1 ,
acted upon by cold water but morlL^i^i 1 u^^ ^^"""^'y
it rapidly dissolves in su!phunraL\^^^^^
with evolution of hydrogen hydrochloric acids,
Magnesium Oxide, or Mamesia M<r n Art.. , •
knoTO as calcined m»Ll?^^'^r"'''* •'" ""^dicme, and
form the m4Sm«?fcKf-vi' """** "'"^ acids to
alkaline reaafon ?h!?^l'^"' '"^°^' not possess a strong
are :— '^^^"'°"- ^he most important sa.ts of magnesiuiS
Magnesium Chloride, M? CL a fu.iiH» c,u „t,» • j
l..r .U ^oIati^.es, an^let^g":^ U^o^rife Jlj^
Surrey, and contains seven atoms of water of crSllf
.on; .t .s now largely made from dolo^te by separ "tfn;
orms'"^th7he all",'F''""'= , l""" MagnesiuL''^:iph"a"tl
the a kri ne !^fl„wi'",\'"'P'?^'*^,' '•""'^'^ =^"5, in which
water of "vs.iS,W ""^^1 ""?/'?" "^ °'-« ™°l«'--"le of
water oi crystallization ; tb s Me SO. K Sr> -la u r. •
the potash double salt. 's ou< Kj^Ui + 6 Hj O is
Magnesium Carbonate, MffCO fs on .Voni. ui
he%duMltv"of"th"'"'"? distingulh'ef from' hes ' b"
me solubility of the carbonate in ammonium .u^.:°I
230 ELEMENTARY CHEMISTRY. [Lesson
as well as by the ready solubility of the sulphate in water
Magnesium forms an insoluble double phosohate with
ammonia, MgNH, PO, + 6H,0 ; and it isSs formle
metal is usually estimated.
ZINC.
Symbol Zn, Combining Weight 65-2, Specific
Gravity 6*8 to 7*2.
Zinc is an abundant and useful metal, closely resembling
magnesium in its chemical characters ; but it is much
more easily extracted from its ores than this latter metal.
The chief ores of zmc are the sulphide or blende, the
carbonate or calamine, and the red oxide. In order to
extrkct the metal, the powdered ore is roasted, or exposed
to air at a high temperature, so as to convert the sulphide
or carbonate into oxide ; the roasted ore is then mixed
with fine coal or charcoal and strongly heated in crucibles
or retorts of peculiar shape ; the zinc oxide is reduced by
.he carbon, carbon monoxide comes off, and the metaUic
zmc distils over, and is easily condensed.
Zinc IS a bluish-white metal, exhibiting crystaUine struc-
w ''a\ '^ u "i*^^ ^o ^y^ ordinary temperature, but when
heated to about 130° it may be rolled out or hammered
with ease whilst if more strongly heated to 200°, it is
again brittle and may be broken up in a mortar. Zinc
melts at 423 , and at a bright red heat it begins to boil,
and volatilizes, or if air be present it takes fire and bums
with a luminous greenish flame, forming zinc oxide. Zinc
IS not acted upon by moist or dry air, and hence it is
largely used in the form of sheets, and is employed as a
protecting covering for iron, which when thus coated is
said to be galvanized Zinc easily dissolves in dilute
acids with evolution of hydrogen, and it is thus used as
the oxidizable portion of the galvanic battery. Brass is
a useful alloy of one part of zinc and two of copper :
German silver is an alloy of zinc, nickel, and copper.
Ztnc Oxtde, Zn O, is the only known compound of this
^*^
'STRY. [Lesson
sulphate in water.
; phosphate with
is in this form the
•5*2, Specif
losely resembling
; but it is much
this latter metal,
le or blende^ the
de. In order to
asted, or exposed
vert the sulphide
•re is then mixed
jated in crucibles
de is reduced by
and the metallic
crystalline struc-
rature, but when
Lit or hammered
:ed to 200° it is
a mortar. Zinc
it begins to boil,
;s fire and bums
:inc oxide. Zinc
and hence it is
employed as a
thus coated is
lolves in dilute
is thus used as
Lttery. Brass is
two of copper;
nd copper,
mpound of this
XXI.] ZINC AND CADMIUM, 231
metal with oxygen, and is obtained by burning the metal
h'a'LrthCcS^^^
a.o£ous^^^^^^^^^^^^
but loses th>s colour on cooling ; it dissolvS easili ^1'
"^i^S^^ ^- -'- I' i= -^ -a Snt"
The most important sahs of zinc are •—
ike thtlattrrTar^T^ "'* '"agn^esium s^Ipharand;
aLine iulphates ' °'"'"' ^ ''™' °' double^salts' wifh
stafS'fo™7/t^h ^'^ ^ "[hite soluble deliquescent sub-
rinfnat^;ttiam"inT.''itnrof^^^
green colour which a solmion of cohlu '^^i '•^"'^•'''' ^^^
to zinc salts when heated b^L^'thfbloVS' "".''"'
CADMIUM.
^J^fo/Cd, Cm*/«.V ireigiizi2, specific Gravity 8-6
aur'tiH ': t l°„T!r?i'^.^'>' ■•-'■^ ™etal, occurring in small
. ...„,, ,.„^ ^,j^.3_ .jj j.^ chemical relations it
232 ELEMENTARY CHEMISTRY. [Lesson
closely resembles zinc. It is, however, more volatile than
the latter metal, and therefore distils over first in the pre"
paration of zmc. Cadmium is a white ductile metal,
meltmg at 315°: ,t may be easily distinguished and
fnSf5^'r/'''li^yy^"^^^"^ ^ ^''^^' yellow sulphide
insoluble m hydrochloric acid. The metal takes fire when
neated m the air, forming a brown oxide, Cd O. The
chloride and sulphate are soluble well-crystallizing salts.
Ladmium iodide is occasionally used in photography, and
the yellow sulphide has been employed as a pigment!
INDIUM.
X Symbol In, Combining Weight 113*4.
, A metal lately discovered by means of spectrum analysis
in certain zmc ores. Its compounds impart a blue colour
to Hame, and its spectrum is characterised by two fine
mdigo-coloured^ lines, seen in the Frontispiece. The
properties of indium and its compounds have as yet not
been fully examined ; it is, however, a soft white metal
resembling cadmium.
Class V.
Manganese.
Iron.
Cobalt.
Nickel.
Chromium.
Uranium.
manganese.
Syjnbol Mn, Combining Weight 55, Specific Gravity S'o.
Manganese occurs in nature as an oxide, and it can be
obtained, though with difficulty, in the metallic state h\
heating the oxide very strongly with charcoal. The
metal IS of a reddish- white colour; it is brittle, and hard
enough to scratch glass. It decomposes water at the
ordinary temperature, with evolution of hydrogen • it can-
I
XXI.] MANGANESE OXIDES. 233
not be preserved in the air witliout undergoing oxidation
and must be kept under naphtha, or in a sealld tube ;"t
IS slightly magnetic and, Hke iron, combines with carbon
and sihcon. Metal.c manganese is not used in the arts
large scale, and used m the manufacture of steel. Some
of Its oxides are used for the purpose of evolving chlorine
from hydrochloric acid, and also for tinting glasf a purpk
Manganese forms several well-characterised oxides '
{I) Manganous oxtde, or manganese monoxide, Mn O is
a basic body, furnishing the series of well-known m4^!
ganpus salts m which the oxygen is replaced by 1?s
equivalent of another element, or of a salt radical ■ th ..
Mn O, Mn Cl« Mn SO,, Mn 2 NO3. (2) Mang^TLd^ox
manganese sesguioxide, Mn, O3 ; 'w^ich alsS formfsalts
but of a much less stable character, and occurs in nature
Z^, Mnfo .'rrL/1^!^ ^«^angano-manga;^
' .' "■?'-. '^^"tral body, corresponding to the
Sfte' °U^%;°^ r\''"^ °""""'e i" naturf as haus!
mannite. (4) B/aci oxide, or manganese dioxide, Mn 0„
fnZ'^ substance occurring as the ore of manganese
i i? ^ "^,?'' pyrolusite and varvacite. (5) Manganese
hMoxule, Mn, 0„ a dark green heavy liquid obtaTf^d by
S^angTnal''™"^ '"'' ^"'^'^""'^ ^"<1 "P- P°'--™
nW^Tf^t ^?"'"i^' Mn O, is a greenish powder
obtained by heating the carbonate in absence of air -it
ranMlv"",','^ f "^^ ^ '"'^" 9^ pink-coloured salts, and
S In tk' "^^F""' P"=''"S into a higher state of
oxidation. The hydrate is precipitated as a white gela-
tinous mass, when an alkali is added to a Solution of
a manganous salt : this, however, rapidly becomes brown
owing to absorption of oxygen. Of ihe manganous sall\
the chief soluble ones are, the sulphate, Mn SO, + \ HO
a pmk-coloured crystalline salt, prepared by act ng on the
dioxide with sulphuric acid, oxygen gas being evflved-
Ivin vj
2 + HgbO^ = Mn SO4 + O H- Hn O,
234 ELEMENTARY CHEMISTRY. [Lesson
and the chloride, Mn Cl. + 4 H^O (a salt obtained by crys-
tallization from the residues in the manufacture of chlorine
from the dioxide and hydrochloric acid).
Among the insoluble manganous compounds of imoort-
ance are the suiphuie, MnS, obtained as a flcsh-colourtd
preciDitate by the addition of an alkaline sulphide to a
ioluble manganous salt, and the carbonate, Mn CO..
which occurs native, crystallizing like calc-spar in 1 horn-'
boliedra, and prepared as a white powder by precipitatinir
a manganous salt by an alkaline carbonate ^ *^ »
Manganese Scsgmoxufr, Mn^Og, exists in nature as
braunite, and may be prepaied artificially by exposinL^
manganous oxide to a red heat. It forms a series of
somewhat unstable salts, of which the manganese alum
IS one of the most interesting, being isomorphous with
common alum, in which MngOg is substituted for A1,0,
Manganese Dioxide, MnOj, is the common black ore of
manganese and is termed pyrolusite by mineralogists ; it
can be artificially formed by adding a solution of bleach-
mg powder to a manganous salt. This substance yields
one-third of its oxygen when heated to redness (see p. n)
forming the red oxide, 3 Mn 0^= Mng O, -f O,, and gives
up ha f Its oxygen when heated with sulphuric acid (see
above). It is largely used for the manuf^icture of chlorine
Manganic and Per-manganic Acids, When an oxide
of manganese is fused in the air with caustic alkali a
bright green mass is formed, which yields a dark green
solution : this contains potassium manganate, KoMn O
which mriy be crystallized, and is isomorphous with
potassium sulphate and chromate. If this green solution
be allowed to stand, it slowly changes to a bright purple
colour, and hydrated manganese dioxide is dcposilted —
hence its common name of mineral chamelion : it then
contains a new salt in solution, viz. a permanganate,
KMn O4, which may be obtained in the crystall ne state
by evaporation, and is isomorphous with potassium per-
^ffi^'rf Ik- ^^a P^^^^"!-^^ of a few drops of acid at once
eflects this decomposition of the green solution. On
?K [Lesson
ained by crys-
ire of chlorine
ids of import-
flcsh-colourtd
sulphide to a
ite, MnCOa,
ipar in rhoni-
precipitating
in nature as
by exposing
s a series of
iganese alum
orphous with
dtor AI2O3
I black ore of
eralogists ; it
9n of bleach"
stance yields
ss(seep. 13),
^2> and gives
iric acid (see
5 of chlorine,
icn an oxide
Stic alkali, a
I dark green
:e, KgMnO^,
'phous with
een solution
>right purple
deposited,—
ion : it then
manganate,
tall ne state
assium per-
Lcid at once
lution. On
xxri.]
JMN.
23s
^^^^^^ P?tassiu. pe.
substance Is MaZaZsTM^^^2}''^'t\^ '^ ^^"""^^^ 5 this
decomposed on Vl[Z ^fdvfnf' ^"«'^^- ^' '' ^^«'>y
oxygen contains much ozono nn^ ''''y^'"/ ''^"^ »« this
ozonised air is to uour ^trnn ''" ^J^y method to prepare
sium permanganate "^' '"'^^""^ ^^'^ "pon potas^
a part^nSl'^^eri'^ ^ give up
they are now largc4 uscVas di«; f .'"'"^^"^^ "^^"^^ and
Condy's liquids, as well .^hn"^''^^^"^'' ^"^ J^^o^n as
ratoryfortlepirporesorvote'^^^^^ ^" '^^ '^bo-
ManganeseischieflvM! "^""^""^ftnc analysis.
sulphid'e, and by ^e^^^^^^^^ ^^ ^^^ flesh-coloured
ganate, a most deSeTeac^^^ '^' ^^'^'^^ '^^'""^ "^-^n-
LESSON XXII.
IRON.
Symbol Fe, Combinine: Weurht cf. c^ -^ x-^'
Irnn ic «f n "^ ^^^^.i'^^/ So, ^S>>my?f Gravity r^
iron is of all metak tho *« „* • v / o-
The uses of iron were lon^ ,?nt ' ""P""''"' «<> mankind,
the age of iron imDlemenT. K """'" *° "'^ """^n race
bronze and ston.. C^^i,,ir""^ Vr^<:^i.<^A bv those of
small quantity on the Sr h i ""? ^"'^'^ ""'y '" "ery
occurring in those peculiar ^^rLn"''^"^;!' ^'™°^' ^""^ely
stones, which PosseCn extSSria^"Sn'' ""''^°"'
whIf^druron1;a^„'d^'?i:?ir5™''-- 's a see-
and skill which the ear1„^,T %" "'"'""" "^ knowledge'
The iron of commerced sts'fnlree"^ 4''' "°^ P°"«*
hibifng very different pr^pSies anrf l"^*?' '^°™'' «"
Jetn.calco„stitutionsVre:;^-^^P:rr.^^^^^^^^^
of lorw74'taS o^r rjl' *l--"<' '- compound
, ^ -,__-„.„^^ .^, ^,iix-uori aiid silicon, and
236 ELEMENTARY CHEMISTRY, [Lesson
the third a compound of iron with less carbon than that
needed to form cast iron. The modes of manufacture of
these three kinds of iron arc essentially different, and will
be best understood when the properties of the metal have
been described.
Pure iron in the form of powder may be obta'ned by
reducmg the oxide, moderately heated in a current of
hydrogen ; it must, however, be retained in an atmo-
sphere of hydrogen, as finely-divided iron takes fire and
burns to oxide when exposed to the air. A button of
pure iron may be prepared by exposing fine iron wire
mixed with some oxide of iron to a very high temperature
in a covered crucible, the oxide retaining the traces of
impurity which the wire contained. Iron has a bright
white colour, and is remarkably tough, though soft, an
iron wire two mm. in thickness not breaking until when
weighted with 250 kilogs. The pure metal crystallizes in
cubes : iron which has been uniformly hammered exhibits
when broken, a granular and crystalline structure : this
structure becomes, however, fibrous when the iron is
rolled into bars ; and the more or less perfect form of the
fibre determines to a great extent the value of the metal.
This fibrous texture of hammered bar iron undergoes a
change when exposed to long-continued vibration, the iron
returning to its original crystalline condition ; and many
accidents have occurred in the sudden snapping of rail-
way axles, owing to this change from the fibrous to the
granular texture. Wrought iron melts at a very high tem-
perature : but as it becomes soft at a much lower point,
it can be easily worked, especially as, when hot, it pos-
sesses the peculiar property of " welding ; " that is, the
power of uniting firmly when two clean surfaces of hot
metal are hammered together.
Iron and certain of its compounds are strongly
magnetic, but the metal loses this power when red hot
regaining it upon cooling. Contact with a magnet induces
temooraiy magnetism in a bar of pure iron, but a bar of
steel becomes permanently magnetic under the same cir-
'. [Lesson
an than that
nufacture of
:nt, and will
metal have
obtaned by
I current of
1 an atmo-
ces fire and
\. button of
e iron wire
temperature
le traces of
as a bright
gh soft, an
until when
ystallizes in
*ed exhibits,
icture : this
the iron is
form of the
f the metal,
indergoes a
ion, the iron
; and many
)ing of rail-
>rous to the
y high tern-
lower point,
hot, it pos-
that is, the
iaces of hot
re strongly
len red hot,
net induces
ut a bar of
le same cir-
XXII.] FERROUS COMPOV. 'DS
. butV heated it ofidiies '^uh [£ '""'';"P.°'«aneously ;
scales of oxide, and when more Xf°?"*^i''*" °^ ^^^^
air, or plunged into wJinT.! ^ k"^'^ '«^''"^'' '" "»
mation of tie same Wade" |xlde' \T'' *'"' ""= f"''
does not lose its brilliancy; but if a trace'o^'^K*™"
acd >s present, and access of air is oe^iLrf tt'^"""
begins at once to oxidize at the surfar/orT '"' 'J"* "■°"
a hydrated sesquioxide Irnn ^^ ^' "^ '° '■"''' Arming
red heat, liberaSne hvd^o.rpnL^''"'"?""*' ^'^^m =« a
black oxide prSSVyXcotetd T'^ ^"^"""^ ">e
Iron is tetravalent • if f^rm-^ u !'°"°'^'''°" in oxygen.
combining p'^wers to a second .f'°" ■" J"'"^'^ ^V t^o
J^errous !«?/, ; (2) X^Zl^^' ^"""S "se to the green
two atoms of ron are^nif^ L /"''"'"f^'^' '" «'''i='>
and thus a hexad erouo ?, n.L "* .''T'""'"^ PO^^r.
yellow ^.mV salts arl derived."^ ,"' ""^'"^ ""^
Ferr<>t4s Co,fii>otmds.
with which it absorbs oxWenLl" ' * ^'^^^ readiness
oxides Hydrated ferrousSVe H o^ •"',1"'' ^'?^''
as a wh te precioitate wh^n r,!., t^ '-'a. is thrown down
soluble ferrous S' this w(fi?^^f ""^ =°^^ '^ ^'•^^d to a
°^^'-d in --Pfeie absetf oro";^rasTt «'^ '^
:'Si*;=xfd^e!' ^^ii^o^idrc-oif"^^? p-'p"- °'f
p. 22I), and giv^s the pecuHar Hnf r" ^ ""' .S'^" f=««
The ri^«.t imiortam K'Ks '^aUsreT '°'*'"^'*"-
members of the group which Jre'tttravaTeit.""' "'""*"' *"''''" '° ""« "'">"
II
238 ELEMENTARY CHEMISTRY, [Lesson
Ferrous Sulphate {Protosuipkate of Iron)^ Fe SO^
-h 7 H, O. — This soluble salt, sometimes called green
vitriol^ is obtained by dissolving (i) metallic iron, or
(2) ferrous sulphide, in sulphuric acid ; and is also pre-
pared by the slow oxidation of pyrites, Fe S^ :
(1) Fe -f H, SO, - Fe SO, 4- H, ;
(2) Fe S -I- H, SO, - Fe SO, -f H, S.
The solution thus obtained yields on evaporation large
green crystals of the salt. It is largely usecf in the manu-
facture of several black dyes, and is one of the consti-
tuents of writing-ink. Like all the ferrous compounds,
this s^lt easily takes up oxygen, producing a new salt
called ferric sulphate.
Ferrous Chloride^ Fe CI,.— When dry hydrochloric acid
gas is passed over hot metallic iron, ferrous chloride and
hydrogen are formed : the hydrated chloride is also pro-
dured when iron is dissolved in aqueous hydrochloric
acid, green crys'als being deposited, having the com-
position, FeCla + 4H30.
Ferrous Carbonat^ Fe CO3.— This is .ai. insoluble com-
pound, and occurs largely as a mineral called spathose
iron ore, which is isomorphous with calc-spar : it also
occurs in a less pure form, constituting the clay iron
stone, the ore of iron from which a large proportion of
our iron is prepared.
Ferrous Sulphide, Fe S, an invaluable compound,
formed by fusing equivalent quantities of sulohur and
iron together, is employed in the laboratory for the
generation of sulphuretted hydrogen (see p. 140). A di-
sulph de, P^e S^, called iron pyrites, is found in large
quantities, and is much used in the production of sulphuric
acid (see p. 134).
Ferric Compounds. •
Ferric Oxide, or Iron Sesquioxide, Fe^ O,. — ^This oxide
occurs native, as the minerals red haematite and spe-
cular iroa ore, whilst, combined with water, it forms
^. [Lesson
«), Fe SO4
ailed ^/-^^^
lie iron, or
is also pre-
XXII.J
OXIDES OF IRON,
ration large
1 the manu-
the consti-
:ompounds,
a new salt
chloric acid
liloride and
is also pro-
ydrochjoric
\ the com-
oluble coip-
id spathose
ir : it also
I clay iron
oportion of
compound,
ulohur and
•ry for the
40). A di-
d in large
)f sulphuric
• jhis oxide
; and spe-
•. it forms
I
330
so...tio„ o^r a.."^„-'^o^--:.r^-- Z ^/^otllSf
of a ferric salt, when the hydrated cx^de, ^e. j ^ ^
down as a bulky brownish r^A ^r. a , . ^« ' "'
acids, forming Che r"ric"s!t.'^''r' '"^"^'^ '*'^'°J^« i"
by sulphuric Ic^^^T.^fptaie Fe'",so"' ^'"'^ "P^
ar by ^vuiorhlorir ,,~;/-^" •' ^^^O^ 's produr d ;
th. .erricChsr^e chl • drr,h/'^'"''f'' *"^^Cie. Of
anhydrous Salt forms M brilliant r°pH """""r' = ""-'
chlorine gas is passed ov,'rhi^f.^.!i.n'' "y^tals when
of the ferric sX can be r.-d;^!^^^""^ "■°"- Solutions
agents. to the co™?po„d ng^fe?^^^^^^ deoxidizing
latter, n contact wiih ar, .vJhi ^ "*' *'>"'st 'hese
'arric'salts. Thus for insi Z^'?^ f«u^"'' P"*^ '"'o 'he
..as be led througf'a soSr:; fShlorid' "2^"^
oecomes colourless, ferrous chlorW^ ^J^'onde, the liquid
whue precipitate of 'sulphu/isth^^wn' dLn.Tu'': '"" "
Fe, CI, + Hj S = 2 Fe CI, + 2 HCl + S
'^^^z:t^:^-^^^^t^^^ ^ %ht
whilst the ferric- or -/r salts aTpv.ii^P'? beco.aeS dark :
solutions yieH (i) ' deeo reddli^ K ' ''"""■<'' ^ndtheu-
the caustic alkalies ; a^d'^(2U^dt"o bt" ^'^^^^^^ '^"h
potassium ferrocyaAide firrn.f. ^ ^ P^cipitate, with
salts are magnetrwMst'hT^^^n'tra "''' (f"°"=
not magnetic ° ^ ^'•^' salts are
cn'^fallfefMtta°hef^^'an'^"^'th'"^'^°" °<^-- -■■-.
constitutes one o^re mVst'vi^Vo:e"'o°To^t°"''■ ''
oxide foinied when iron is oxidized at » hi k ?' ^' ' ' *
in the air. in oxvin-n rZ •„ '"'^^'' *' a high temper; ture
spondinp- ;, f.S^^"'- °l "? ^<l"«ous vapour. A corrnt
>4, is also magnetic.
^
240 ELEMENTARY CHEMISTRY, [Lesson
Ferric Add— The potassium salt of this acid is
prepared by fusing ferric oxide and nitre together : the v^
mass yields, with water, a purple-coloured solution, and ^
contains potassium ferrate, Kg Fe O4. It is an exceedingly
unstable substance. Neither the acid H2 Fe O4 nor the
oxide FegOg have been prepared.
Manufacture of Iron,
The oldest metho of manufacturing wrought iron
was to r^uoe it at once from the ore by heating in a
wind-fornace with charcoal or coal, and to hammer
out th§ spongy mass of iron thus obtained. This plan
can tomy > j economically employed on a small scale
and with the purest forms <jf iron ore, and has been
superseded by a more complicated method, applicable,
however, to all kinds of iron ore.
This_ consists in the formation of
cast iron as the frrst product^ and
the subsequciit separation of the
carbon and silicon which the cast
iron contains. Cast iron is manu-
factured in England chiefly from
clay ironstone, which generally
occurs in masses, sJtuated in the
immediate neighbourhood of a coal
seam. The clay ironstone (ferrous
carbonate, with clay) is first roasted,
in which operation the carbonic
acid is driven off, and ferric oxide
formed, the ore afterwards being
thrown, together with coal and
limestone, into a blast furnace, the
best construction of which ir seen
in Fig. 60. It has the shape of a
double cone (a b. Fig. 60) built of
strong firebrick and ma:.nnry, and
Fig. 60.
is about fifty feet in height, and fifteen to eighteen feet
XXII.j
IS manu-
MANUFACTURE OF IRON.
241
in width at the broadest Dart tk c •
/he bottom, the air necesiL^'for ^h/^"''" '^ <^'°^^d «
Combustion being supolied in , ■»»'" enance of the
through pipes calledX^^^;"^.) S^hTl'fl '"^='' '''<'*"
fuel and ore, beine cast in f, iu'' ' *"''*' ">«> m xture of
is added continually as ?he h^' •°'' "^ "'^ furnace (d°
and themolter mas^s fs d awn^^ af t^lf' ^'"''^ "o*"
rtlrr °''"" ^°«' "°'^^P °wk be for","""' f° '•'»'
At the lowest part of th^ <:Lr."'?'°r several years.
where the melteS metal and fnZT "„""= '>e««h (h)
being occasionally tapped froml ' ">« ^""er
and cast into pigs in moulds Zh-'^.u"" °^ *« dearth,
l'gh.er slag, which swims on ?he 's.rf»' '^"r^' r''"'' '!>«-
runs continually out from ^ surface of the metal
of the hearth. *" ^" °P«'°& at the upperpi-t
The first chemical chance whirl, ,1,
or impure ferric oxide, und^reoest ^^ ""^^^^ ''•°" »«.
top to the bottom of 'the furnact '^."•!P^"l*S^ fro-n the
porous mass of metallic iron h^lu"' "^ reduction to a
proceeding from the W ?ay^^rs o/ h?' '^"'*= <"''''« ^^
temperature of this portion of ?t,5f"'"«. <=°^- The
much too low to melt the Ln • = !>"™^? '^' however,
down unchanged, together wUh'th?H" "'Tf''^^ «'"ks
until it reaches a Mint at whkh t h. t '*?' ^°'* "mestone,
fhe second change occurs viz tl V"' " S'^^'^*-- Here
impunties of thi ore un?te whh ?h r ''' ''*"'^' ='»<' other
fusible silicate or slag, whilst th^ th limestone to form a
ZT'^rt. ="•»"' "n^eat'^'^ncrwlT?'' "^"^'^^ '"
■roi , a fusible compound, which n,L J " '° '°™ oast
ot the furnace. This, 7„ 0^;™"^,;?°*" 'o 'he bottom
portion of the furnace r?duc?s ,h^. ^^^"^^ .">= hottest
meets, to silicon, and comhln^ ^'-'t^ ."'**> «'hich it
cast iron. ' ' 'Combined with this, it forms
mu* wi?£Te"quan'lly o?'?aX""'" f .,?^'' """^ ^T
contain ; for cast iron °s not^V^'^ ■='"^°" ^^^'^ tb^
pound of these elements wi"h iron Th^ "'^t'"'^^' ^ra-
"> cast iron, (j) as ,. J." Jr"*?: T^« carbon is found
■ " ■ "-^ '-'' srapniic, giving ngg ^^
-M<iMi^l^
M2 ELEMENTARY CHEMISTRY. [Lesson
SsMri'^'^l'™" •• ""* (^^ •" combination formine white
placet ^^^'^J[i^L^^^^^ o?
heat of combustion of the wi,e gases 1^?^^"^ 'n^
escape and burn at the top o^the fur„a;;!^''='i V^"f >
temperature of the blast of arsuSt"the Tr^^^/
J'lf g?s« are collected at the top of t& ft^naS^hv
a hood (E), and pass down an iron v^ iT^f2 ^
::;'" bu^nt?""'" '*•"" " '"^ ^"™-- i^whilh^'th^^'las^^
In order to obtain wroup-ht from ract ,Vnr. fk^ i *.
must undergo the processfs of '"efi^ing '°"^'d'' 'pud''
dlihg. These consist essentially in bnrnine oi.t'^lh.
carbon, sihcon, sulphur, and phosphorus exLZl .5
heated metal to a current of air in a reverber.tnTfi '^ *^^
the melted cast iron becomes ^rt,!o"^lt^^^^l
ox.de, and gradually thickens so as to allow of ftsXini
rolled into large lumps or balls. During tWsm-^es/Sf
whole of the carbon escapes as carbonic oxide^d h^
silicon becomes oxidized to silica, which unUesCh ,hf
oxide of iron, and forms a fusible slae • anv \^>,„^ ? ^
or sulphur contained in the pig irony's 1^„&''^™'
m^ar°r'- ^''^ Y' '^ '^'^ h~r:d°to'^r't,;:
metal coherence, and to squeeze out the liquid slf^^ III
the mass is afterwards roifed into bars or X es ' ^'"'
Another interesting branch of the iron trade is fh.
manufacture of steel. Ihis useful substance is formed
when bars of wrought iron are heated to redness forTr^^
W'bern^ffi*"'' '''"j=°^'= the bar irtS?/ ounZo
have become fane-gramed instead of fibrou' the S,h
stance is more malleable and more eas^y fusible than'
the original bar iron, and is found to cV-rita4 carbon
varying m amount from one to two perce™ Steel do,
sesses several important properties, espeCuy thf no^we;
which rsTfo/ tf '""' "^"""e whL qu41y cK
wnicn hts It for the preparation of cutting-tools, &c. !
K [Lesson
>rming white
rus are also
»nsidered as
working of
jploying the
lich usually
to raise the
the furnace.
furnace by
G), Fig. 60,
h the gases
n, the latter
and "pud-
tig out the
Jtposing the
ry furnace :
h a coat of
>f its being
process the
de, and the
"s with the
phosphorus
oxidized in
give the
slagj and
s.
ide is the
is formed
>s for some
n found to
y the sub-
sible than
in carbon
Steel pos-
the power
:ly cooled,
ools, &c. :
xxiir.j
COBALT COMPOUNDS.
243
fcSS?^'^ea^J!^™?f^ which Z
A new and verv rat.;5 "^^^V"'" mgots.
which i5 both o^higrscie'S?^/ ° P'^P"'"S cast steel
.mportance, is that kl^^'afth^ BeT''' ''"^ '"''"^'ria'
process consists in burning out all fhf'"^KP'''^^*^- This
n cast iron by passing a bfasrof If^t "'If'''?" ^"'' '"'con
the molten metal, and then in Lj™°^P''^"c air through
• a pure cast iron to rfe wroughUrrtr^'^ " quantityTf
necessary to gi,,e carbon enourt fn *"' P'-«Pared as is
mass mto steel : the melted steeH. Ik ~'"'^" *« whole
ingots. In this way sii tons of M !"-^' ""^ "^^st into
operation be converted intoTtPel L.^' "■"" "" at one
Bessemer steel is now larD-elv il 'r"'y "''""tes. The
axles and rails, for MeTlt" ""nT"'"!'' ^"^ railway
for which it is much more fit?.;) ^^ °''^^' Purposes,
so that this process bids Lr f„ *''^? ^""S^t iron
iron indr try. ''^"^ '° revolutionize the old
LESSON XXIII.
COBALT.
Symbol Co, Combinmg Weight c8-7 c^ -^ ^
Cobalt • ' ^A^/A 6^rrtz///,/ 8-5
isasinfusible\7frt'jd':Sr^^^^^^ T'^\ which
magnetic. It is not found natil^^^ W^' ""^^^^^ ^^ ^^^ongly
i^on with arsenic and sulpSur as t^^Tl^ ^^ ^^"^^iSa-
Tm white cobalt, CoAs and o.iT^/'f'"^' "minerals.
The metal dissolves slowfi ,n s^t'^^?' ^^^'^/^e, CoAsS
aacis with evolution of hX^en PthT ^J!^, hydrochloric
are distinguished for the hrifilo * ^^.^^°^alt compounds
are emplo>%d as pigments and ?h '^ "^^ '^^'' ^^^^^^'^ "hey
blue tint to glass.^ There 'are th'^ '""^f"' ^ 'magnificent
monoxide Coo, the sesquL.it c^t' ^^/^^alt, the
nf ' u* ", ^^^ ^o"«er, on solution i^ .%% ^"^ ^" oxide
0* cobalt saI^c «,k:Lu _.^T."?" ^^ acids, forms th^ c^.: J
— . rriji-^ii urc piak when ' — ' - - • " .-"-*'~3
R 2
^drated, and bfue
^'^PW^BHws^W^W^iBliWIi'i
2414. ELEMENTARY CHEMISTRY, [Lesson
when anhydrous ;. whilst the sesquioxide does not form any
salts.. Cobalt monoxide^ Co O, is obtained as a brown
yx)wder by carefiilly heating the rose^oloured hydrate
Co Hj^Og, precipitated by potash in solutions of cobalt •
am.d. Cobalt sesquioxide, Cog O3, is. prepared by adding a
solution of bleaching powder to, a soluble protosalt ; the
oxide C03O4 is abtained by igniting the monoxide in
the air.
Cobalt chloride, Co Q\, is, a soluble salt obtained by
acting on the oxide or on the metallic ore with hydro-
diloric acid : the solution yields on evaporation pink
crystals of the hydrated chloride, or, if further heated
blue crystals of the anhydrous salt. '
The nitrate, Co('NO^)2, and sulphate,. C0SO4, o^ cobalt are
also soluble salts ; the latter is isomorphous with magne-
suim sulphate. Cobalt sulphide, Co S, is a black powder
msoluble in dilute acids. Cobalt compounds can be
easily recognised by the deep blue tint which very minute
traces impart to glass, or to a borax bead, made by fusing
borax into a codourless mass on the loop of a platinum
wire.
NICKEL.
Symbol Ni, Combining Weight 587, Specific Gravity 8-8.
Nickel occurs m large quantities, combined with arsenic
as kupfernickel,. NiAs; also together with cobalt in
spetssj and it is now prepared in considerable quan-
tities for the manufacture af German silver, an alloy
of nickel, zinc, and copper. Nickel is a white, malleable,
and tenacious metal ; it melts at a somewhat lower tem-
perature than iron, and is strongly magnetic, but loses
this property when heated to 35,0°. There are two oxides
of nickel, the monoxide, Ni O, and \^i^ sesquioxide, Ni, Oo:
the former of these gives rise to the nickel salts, which
possess a peculiar apple-green colour. The monoxide is
obtained by heating the nitrate or carbonate, or by pre-
i&a
ga ii m
K [Lesson I xxiii.] CHROMIUM OXIDES.
lot form any
as a brown
ced hydrate^
5 of cobalt ;
by adding a
otosalt ; the
nonoxide in
obtained by
with hydro-
ration pink
her heated,.
3f cobalt are
vith magne-
ick powder,
ids can be
i^ery minute
le by fusing
a platinum
"-ravzty 8*8.
ith arsenic,
cobalt in
able quan-
", an alloy
malleable,
lower tem-
, but loses
two oxides
'de, N ig O3 :
alts, which
onoxide is
or by pre-
245
cipitating a soluble nickel salt with caustic Dot;,c;|, ur.A
heatmg the apple-green hvdrate Ni R A u-^i? u' ^^^
down. The %s^l^<^^^f:Tit^l^^^'t:,t^X^^
adding a solution of bkaching powde? to a so^Xni^ki
i^ii^i^iNUg; , ana the chloride, Ni CL T itp *>r»ihoi+ «;^i 1
!°™^\black sulphide, NiS, insibfelnSu.^' acids
fo^er melafwi '"^^''' distfnguished fro™ thofe ot the
CHROMIUM,
S^mM Cr, C.,«*/„,«^ f^^^^^ 5^.3, sjiecific Gravity 68
occ^r.T;"-^ii;ai:t';=, :r^ r c^jLttiet. z
(whence its name ypQum colnnr^ tk^ ^.k- 'i"^"^ colour
mpftii ic rk^^,^ /y^A*"* colour;, ihe chief ore of this
.Wr^Us'Tt^h 'mTS Slfde'^^^f^ ^ r^r^
chS 'aip^e^S^ 1ote° [r^ostl^^^hr^au^r
munoxiae, t^rU; (2) chromium sesquioxide Cr O • ,'^?
chromo-chromicoxi.If*. CrOCr O . /^^ !!! '• ^ '^s » . 1.3}
Cr O Th*» f„,«^ V ; V 2 ^\i (4) chromium triox de
s^piS|p':^^S%£- .!■: -« »-,;«^^
^rg U3, Crg Clg : the third oxide is a nf^nfril k^^' ^j
246 ELEMENTARY CHEMISTRY. [Lesson
Chromous Compounds.
Chfondum Monoxiii , CrO, is only known in the hydrated
state, -s both it and its compounds absorb oxyeen with
great avidity. The hydrate, Cr H . O^, is prepared as a
brown precipitate by adding potash to the solution of
chromium dichloride.
Chromium Dichloride, CrClg, is a white crystalline body,
which dissolves m water, forming a blue solution. It
is obtained by passing hydrogen over heated chromic
chloride.
Chromic Compotmds.
Chromium Sesquioxide, or Chromic Oxide, Cro O,, is a
dark green, perfectly stable powder, obtained by ignitinc^
th^h-'. oxide, CrgHgOe, formed by precipitating any
soluble chromic salt with ammonia. It is employed as a
green colour for painting on porcelain, and produces the
green of the emerald. A splendid green colour is also
obtained by heating potassium bichromate with boron-
tnoxide : on dissolving in water a grass-green hydroxide
remains behind, which is termed Guignet's green
(Cr^HfiOg).
Chromic Chloride, Crg Clg, the anhydrous chloride, is
obtained as a sublimate, in beautiful violet crystals, by
passing a current of chlorine gas over a red-hot mixture
of chromium sesquioxide and charcoal. These crystals
do not dissolve easily in water, but are readily soluble if
a trace of chromium dichloride is present. The most
ready way of preparing a solution of chromic chloride is
to boil a solution of cbromic acid or a chromate with
hydrochloric acid and alcohol, the red or yellow solution
after a few minutes being changed to a deep greenish-
blue colour. A solution of chromic sulphate, Crg 3 SO^,
may be obtained in the same way, by substituting sul-
phuric acid for hydrochloric acid. Chromium sulphate
forms a series of alums with potassium and ammonium
XXIII.] CHROMIUM SALTS. j^-
sulphates which have a deep purple tint, and are isomor-
phous wuU common aK.m, «? L SO, + .4 H, O. The
tioH'o occurs"'^ ^*'""'''"' - violet-coloured modi,5ca-
Chromic Acid and ChromaUs. '
carboa,1tTjcomr''o°'Jd"Ld' '"T" ""," P°'-'-">
chromate is formed K CrO A-^""* t '°'"'"^ >'^"o«'
the cl,romium compounds a?e' orloarlfn'^ """If '" *'''<=''
ore. This yellow chromatp1?;f ^ ™u '^"'^ chrome-iron
sulphate and manglna" * wi.n ?t°"?*'''' potassium
to a solution of this yellow safti'fffi"" ''"'' '^ ^''''^d
combine with half the bl,f ,1 sufficient quantity to
iJa/irma/^. K, Cr O .L, f ' ^"^^ "^^ crystals of the
used for the preDarStin?n?lt ""t ^^'" ^^" '^ '^^6^7
the solution onKXom^^r'''°f'P'«"'^"'=- ^^ '^
trioxide be added a tht^ l .f 1°'""°? °^ chromium
K.Cr,0.„, crystallizes out Th^' "".■'' f'^-"^^"'^''.
three saItsVay\erepresrn\edIsfolloTsT"''°° °' *^^
W'^'SJO.; (2)
CrOj
CrO.
)
Chromium Trioxidp CrCi \^ -u^ - i . ^
long ruby-red neeSaped ?r^^tabTv1dH- "^^ ^°™ °^
of strong sulphuric acid t\^» ^ \ ^ addmg an excess
bichromfte. '^ The rrvstal, f"<=^"'«'=d solution of the
forming an acid'L'l u K'chTomrc Zcidt"';^ j^ ^f >
excess of sulohuric ariH \i, 1 ^"'' "2<^rO,. The
with concenl^r&atricl."i"^,A%r"°^''',''y ^^^"^'-S
in a current of air [n a elass t'-.h^ the crystals then dried
mium trioxide are ve?y easilt d„ Jh ^Z"'''''^''. °^ ='>~-
presence of organic ^,^rX, .l'l^.i°;„'ff?."'°^'^e in
*«•►**%
248 ELEMENTARY CHEMISTRY. [Lesson
of oxygen, that ignition occurs when alcohol is dropped
on the dry crystals.
If a solution of chromium tri oxide or of potassium
bichromate is heated with hydrochloric acid, chromic
chloride is formed and chlorine liberated ; whereas, if
chromium tnoxide is healed with sulphuric acid, a chromic
sulphate is formed and oxygen gas is given off.
(1) 2Cr03-hi2HCl - CrgClo + eHgO-f-aCla.
(2) 2 Cr O3 + 3 H2 SO, = Cr, (S0,)3 + 3 Og.
The chief of the insoluble chromates are lead chromate,
PbCr04, or chrome yellow, obtained by precipitating
potassium chromate by a soluble lead salt, and largely
useW for dyeing and other purposes in the arts ; silver
chromate, AggCrO,, a characteristic, deep-red coloured
precipitate ; and barium chromate, Ba Cr O., also a yellow
msoluble powder.
Chromium Oxy chloride, or Chromyl Chloride, CrO, \ £!*
■^ / CI
--A compound resembling sulphuryl chloride is obtain^^d
by distilling potassium bichromate, sulphuric acid, and
common salt. It is a dark red, strongly fuming liquid •
It boils at 1 1 6-8°, and has a specific gravity of 1-02 •
and the density of its vapour is 777 (H = i). If potas-
sium bichromate is dissolved in warm hydrochloric acid
large red crystals separate out on cooling : these consist
of potassium chloro-chromate, K CI Cr O3, a substance
intermediate between chromium oxychloride and potas-
sium chromate. We thus have ;
Chromium
Oxychloride.
CroJCl;
Potassium
Chloro-chromate.
OK
CI '
Cr
0,j
Potassium
Chromate.
CrO i^K
The presence of chrorhium and its compounds can be
easily detected by the formation of soluble yellow- coloured
alkaline salts, yielding insoluble yellow lead and silvei
XXIII.]
URANIUM,
249
fugitive, blue colouration wh^^^^^ but very
dioxide is added ^^a verf d iS[et?l"t^^^
acid: this blue colour is due to X f "^'""^ °^ ^^^^n^^c
higher oxide of chromium which hn ^^'^^^^^n of a still
decomposed. ' "^^'^^^ however, is very readily
URANIUM.
^y^nbolV, Combining Weight lie, c^. -^ ^ '
Uranium is a metal ,.,k;^u ^ *"4.
nature, existing coSdTnfl°'''"'"\^"^ sparingly in
pitchblende, U3 0„ and urani ^ ^T"^^^"" '^'^ minlrah,
white colour, and Vt doesToToxidil^f^^^^^ °^ ^ ^^eel-
temperatures, but when stronrfy W^^^ if S' ^'' ^l °^^'"ary
There are two oxides whifh fn^^"^ 'u^"^^^ brilliantly.
are green, whilst the uranfc com^^ ^^ "^^"°"s salts
and these latter solutionr^ve velToTn"'''^' • ^'^ ^^^^^ >
alkali, in which the uranic ?xfdrii? P^^^^P^tates with an
auranateofthebase thus^tlrf?^^' ^" acid, forming
The sulphide is an insoluKrof^ ^" ^l?'^^'^ ^^U^
colour. The chief application nf ^ ye"owish-brown
for the purpose of Cs arnini^'Th""' compounds is
imparts a fine blackfand the "m;,, ' "/^"°"^ ^^'^e
yellow, to glass : uranium cofnJunHl °''''^f ^ ^^^"^^^"1
m photography. compounds are also now used
2SO ELEMENTARY CHEMISTRY. [Lesson
Class VI.
Tin.
Titanium.
Zirconium.
Thorium.
Niobium.
Tantalum.
tin.
■i-i
Symbol Sn {Stannum), Combining Weight 1 1 8,
Spectre Gravity 7*3.
he ores of tin — although this metal has been known
from very early times — occur in but few localities, and the
metallic tin is not found in nature. The chief European
sources of tin are the Cornish mines, where it is found
as tin d" oxide or tinstone, Sn Og. It is in all probability
from these mines that the Pho nicians and Romans ob-
tained all the tin which they employed in the manufacture
of bronze. Tinstone is also met with in Malacca, and
Borneo, and Mexico. In order to prepare the metal, the
tinstone is crushed and washed, to remove mechanically
the lighter portions of rock with which it is mixed, and
the purified ore is then placed in a reverberatory furnace
with anthracite or charcoal and a small quantity of lime :
the oxide is thus reduced, and the liquid metal, together
with the slag, consisting of silicate of lime, falls to the
lower part of the furnace. The blocks of tin, still impure,
are then refined by gradually melting out the pure tin,
leaving an impure alloy behind. English tin generally
contains traces of arsenic, copper, and other metals ; that
imported from Banca is nearly chemically pure.
Tin possesses a white colour resembling that of silver ;
it is soft, malleable, and ductile, but possesses little
tenacity, a wire two mms. in diameter breaking with a
weight of sixteen kilos. When bent, pure tin emits a
TKV. [Lesson
XXIIlJ
TIN,
251
peculiar crackling sound. Tin melts at ,oro a •
sensibly volatile. Tin dnV* nl? 1 •! ,^'^3S , and is not
to the air, whetLrd-- or moist a^^^^^^^^ ^'^ ^"P°^"^«
but if strongly heate. ti^TJ^i' ordinary temperature,
rd"\r' '^'^^^^^^^^
h"/d'ro^?anS ?^^^^ ^^^^^^^
aoid fiso attacks S^^ mVT.I L.k "^''"' ^^^^"^^ • ^^^^"0
fumes being given off a^H c '^^ ^'^f ^^^'"^^ ""rous
white powdi^ There are two'"!J!f ox.de being ieft as a
^e* V.-.^.,T/,^^^^^^^^^^ oxioes of tin.
black powder DreoarpH Kv Kr^*- , ' ^'^ ^''~ ^"*s is a
conditions, possessing totallvV^tr ? hydrate in two
oxidized bi nitric ac^hvZ?^?'' Properties. If tin be
is produced af a wTif^ Sd^'rlXbr^^^^^^ ?^ ''^ ^3,
the other hand, to a soIiitm,r^<- 'v^°'".we in acids : if, on
be added, a wh te preciDSiff^''''''!!'*^ A^'°"'^= "" alkali
oxide, which is reS/fo^^'ricid ''i'Sh'^r?"''=
varieties of hydrated stann.v „ "j r ^°'" °^ these
soluble compound havinrS^'ent'erme^"™ Z''^' '"« '°-
the soluble compound "!„«/" ^cT Cf'' ""''' ""'*
Na, Sn O, + ^ H o fitr™. j u i ". • " Sodium stannate.
sodl, is largelt uledin^lll'''' • °"°S ^'annic oxide with
then'termefi:'^^;^,;";/'^^^^^^^ as a mordant, and
by^:s^f„S^rh?roX^^^^^^^^^
solu^ IslrenS'^' sS + {«t>rrn^ ^
"tin salts" in commenTe • if f, ?,T i'^'''"'*^ *' '*™«d
by passing chlorint^a?^:rS;?tin^f l^Hf ,°^^^^^^
. -- — — ._.^j^..^^^
252
ELEMENTARY CHEMISTRY. [Lesson
less liqu'd, boiling at 120° C. and having a vapour density
nf 9*2. It fumes strongly in the air, and forms a crystal-
Kne hydrate, when a small quantity of water is added,
which easily dissolves in an excess. Stannic chloride is
also used by dyers,.and is prepared for this purpose by
dissolving tin in cold nitro-hydrochlo.ic acid.
Of the sulphides of tin, stannous sulphidey Sn S, and
stannic sulphide^ Sn Sj, are the most important : the
former is blackish-grey, and the latter a bright yellow
crystalline powder known as mosaic gold, soluble in alka-
line sulphides.
Tin can easily be distinguished in solution by the for-
■mation of a splendid purple colour called pmple ofcassius^
forpied when gold chloride is added to a dilute solution
of stannous chloride. Tin is also easily reduced before
the blowpipe in the form of white malleable beads, which
are soluble in hydrochloric acid. The solution thus
obtained produces with a solution of mercuric chloride a
white precipitate of calomel, which on heating becomes
black. Tin withstands the oxidifing action of the air, and
it is therefore largely used in the arts for covering and
thus protecting iron plates, or for " tin-plating," and also
for preparing several valuable alloys, as pewter, Britannia
metal, plumbers' Sv .der, bronze, bell-metal, &c.
TITANIUM,
Symbol Ti, Combining Weight 50.
Titamium is a rare metal, only known in the form of a
grey powder, and resembling tin in its chemical properties.
It is found in combination with iron in the mineral rutile,
Ti Og. The oxides of titanium correspond to those of tin ;
viz. titanous and titanic oxides, Ti O and Ti Og. Titanium
and its compounds are not used in the arts, but a com-
pound of this metal is met with in blast furnaces, crystal-
izing in red cubes, which for some time was supposed to
be metallic titanium, but has since been shown to possess
-0m- -^m^
3ur density
a crystal-
• is added,
chloride is
)urpose by
Sn S, and
"tant : the
ght yellow
)le in alka-
by the for-
' ofcassius^
te solution
:ed before
ads, which
ition thus
chloride a
y becomes
[le air, and
/ering and
" and also
Britannia
xx.„.] MOLY^DJ^NUAf AND TaNCSTEN. .53
the formula Ti Cy, + 5 Ti N x. • .
by its power of unitine at hiA t»Ti "" " ^'=""feuished
oitrogen. * *' ""S" temperatures directly v-:},
wi.i;i^J«?tt"r";rouo*^r^'^{!' ^''■"^"'»' -"^ form
and THORruM marbfadd^d '''''^P™'''''^'^ ^''^CONium
Niobium and TANTiiin:,
metals, the properties „f ,1,^ ^""^ '"'° extremdv rare
jot completely stud 'ed T:ht^rT°\°^ *hich are
being pentavient. ^ ^'^^^ ^'T '•"« '"'"■agoing ia
Class Vli.
]
MOLYBDENUM.
f«^''^Mo,C««^,«,„^^^,^^,^
metal is a grey subs^Twhlch^Sd^"! graphite, Th^
the a.r to mo/yM^num ^rio JSmoO^ °" '•^^""S in
which acts' as an acid fnrm.v,,, -.C^'i ^ yellow powder
mo/^MaUs. The compoSVm^n.'ll^f ' salts^alled
occur frequently, and are not u«ed in .t^''''^"""' «J° not
acd is, however used as a re^n "in V",\ ^o^Y^'c
detectmg small traces of phos^ric add (s f "Tc!;^ ^°'
TUNGSTEN.
^/.«^./W (mi/ra^), o>.^,„,^ ^,,^,, ,3^
with f:r'?J.u:'o°xTdrin%htm&^^ ^r""''" -""'ined
also with lime as L"i^' crwo ^'fr'''^' ''^, ^O^and
been obtained as a greyish-blart n^' J''\'"«al has only
gravity of 17-4. Tungsten is P^^^
the arts : the addition of a JtifP'"''?'* occasionally in
degree of hardnes and otto ISl''^ "?P^«^ * Sre .
Two oxides of tungsten "a^eVn^'^^Jfr^ ^^^^
254 ELEMENTARY CHEMISTRY, [Lesson
W O2, and Tungsten trioxide, W O3. The former of these
IS obtained as a brown powder by heating the trioxide in
an atmosphere of hydrogen ; the latter, sometimes called
tungstic acid, is obtained as an insoluble yellow powder
by heating the native calcium tungstate with nitric acid
i ungsten trioxide forms a viriety of somewhat com-
plicated salts. The sodium compound is soluble, and
has been used to add to the starch employed to stiffen
light fabrics, the tungstate rendering the fabric unin-
namnable.
I
]^ESSON XXIV,
Plass VIII.— Antimony. Bismuth. Vanadium.
ANTIMONY.
Symbol Sb {Stibium), Combining Weight 122, Specific
* Gravity 671.
Metallic antimony occurs native, but its chief ore is the
trisriphide, Sbg S3. The metal is easily reduced by heating
the sulphide with about half its weight of metallic iron
when ferrous sulphide and metallic antimony are formed'
5D2 i>3 + ^63 == Sba -f 3 Fe S. Antimony may also be re-
duced by mixing the ore with coal and heating in a
reyerberatory furnace. Antimony is a bright bluish-v^'hite
coloured metal, cr>'stailiz. ng in rhombohedra, isomorphous
with arsenic. It is very brittle, and can be powdered in
a mortar ; it melts at 450°, and may be distilled at a white
heat in an atmosphere of hydrogen. Antimony undergoes
no a teration in the air at ordinary temperatures, but
rapidly oxidizes if exposed to air when irelted, and if
heated more strongly, it takes fire and burns with a white
flame, giving off dense white fumes of antimony trioxide
A .tirnony 13 not attacked either by dilute hydrochloric or
sulphuric acids : nitric acid attacks the metal, converting
It into white mpoluble antimony pentoxide. Nitro-
nydrochloric acid dissolves antimony easily. The alloys of
TRY, [Lesson
XX r V.J
Vanadium.
ANTIMONY,
255
antimony are largely used in ♦k ^^^
metal (an alloy of lead otf? -^^^ ^^^' Of these fv««
tarn : it conJnf, t^rpe^t-on)^^^ the ZTC^^.
«™es called^ aSti^i^LTS^r^'*' %^ S
arsenic (see p. ,64). A thW oxiHr'"P°"^ '» *ose of
arsenic series : th s is an in,» ^f""*'* unknown in the
the composition Sb'o, ° '"'«™ediate tetroxide havini
Antimony Trioxide*'sh O Xk- .
the important series of sits ^T !? """'^ «"*'« rise to
erne i It is obtained in crvstflMn. ^"y "=«! in medi?
morpoous with the rare form "I "^^^'?"' '^^''^^ ar^fscl
•64). Antimony trioxTdetTallhf"'V"°*'''« (^eet
talhze in octahedra • henro t^. ? °^™ observed to crvs
>so-dimorphous. The bel m^^ °. °^''*'=" *■•« ^^id to be
oxide is by decomposing 'aSn°^P'^t?"■'g "^e pure
alkahne carbonate, when ^^^^•"■"^.'"'^'''oride with an
white powder, thul': ^° *^ °^"'^ '^ Pre^pitatS as 2
IntL'i'ny^trioll'' d' =, "^^ "^ + « Na CI + 3 CO,.
tion of creaC;V°^?tarXt5^:'^„? "^""^^ -* a si.
on concentration the soludn^^H P°'?=swm tartrate), and
« fpotassium ant monrtafef ">'-''^'^ "^ '«'ar
f:!" dissolves in hydrochlori'^ ac d v^ -antimony trioxide
the trichloride, which is rendered' Tl^i"? ^ =°'"tion of
water owa.g to the formatk,r, ^f "•'"'^ ^^ addition of
oxychlaride, Sb O CI, ?hus f ^° '"=°'"'^'«' antimo?^
sba3 + H,o = sboa + 2Hci
Anhmony Pentonde Sh n /
monic Acid), obtained by acting ^^°'""''"^' =^W Anti-
■iitnc acid, or bv dern-^^^^ • ^,°" antimony with strnnl
mony with watLf anTfentl? ?/ P««ac iride of ?n?^
liydrate. It is a light s-riwrX^„^^i'"S "'« .orecmitated
oxygen at a red heat Inrflc^^'' P°^'^'^^'«''';ch loses
■"ediate oxide Sb.O<^'h''A'' 's converted into the in°t?
^ --.vv-,^ "uu cne infe*--
^"Uiaony pentoxide forms
256
ELEMENTARY CHEMISTRY, [Lesson
■I
mi
salts with the alkahes called antimoniates, cc 'responding
to the arsenates, from which antimonic acid, H Sb O3, can
be separated as a white powder. The hydrate obtained
by acting with water on the pentachloride is termed
metantimonic acid, H4 Sbg O7. The acid metantimoriiates
easily decompose into the ordinary antimoniates. The
acid sodium metantimoniate, Na.^ Hg Sb2 O7 -}- 6 Hg O, is
distinguished as being the only insoluble sodium salt
known. It is precipitated by adding a solution of potas-
sium metantimoniate to a sodium salt.
The intermediate tetroecide, Shj O4, is obtain d by
heating the metal or the pentoxide in the air until no
further change occurs.
!^inely-powdered metallic antimony takes fire sponta-
neously when thrown into chlorine gas, witl:. formation of
the chlorides. There are two chlorides of antimony.
Antimony Trichloride^ Sb CI3, is obtained as a buttery
mass by passing chlorine gas over an excess of metallic
antimony, or by dissolving the metal or sulphide in hydro-
chloric acid to which a little nitric has been added :
on distilling the liquid thus obtained the trichloride
volatilizes, and, on cooling, solidifies to a mass of white
crystals.
Antimony Pentachloride^ Sb CI5, is a mobile strongly-
fuming hquidy obtained by passing an excess of chlorine
over the trichloride or the me.al. On distillation it de-
composes into the trichloride and free chlorine.
The sulphides of antimonty Sbg S3 and Sb^ S^, corre-
spond to the oxides, and, like the oxides, are capable of
uniting with the alkalme sulphides co form a "class of
soluble salts. Thus sodium sulphanti tonite is Na, Sb "^u
+ 9 H2 O.
Antimoniiiretted hydrogen ScH^. — Like arsenic, anti-
mony unites with hydrogen to form^a gaseons compound,
SbHg, analogous to AsK^^ arseh''-'J.ted hydrogen. The
gas is evolved, tog^llier with hydrogen, when an anti-
mony salt is brought in contact with zinc and dilute
acid. Like the corresponding arsenic compound, it burns
.'77? F. [Lesson
xxiv.J
BISMUTH,
sition of metallic in^^l%t If ^ ■■•:-' ''^«' w'th depo-
■n medical jurisprudence a^ S °^ T'"''' in>portance
poisonous characters Ha .^. , substances exhibit
•n. their reactions :'sti^"ti'rcarelr""^'' °"" ^"""er
n.H.ate between these t«^ metals' La ?% '° ^'^"'-
cerlainty a very minute ouan?i?v nf ^f* '" ,''^'>=" *■*
'a the body of M ^,imli.^''^""'> °^ ^''hf'' when present
BISMUTH.
i>»&/ Bi, G„;,2,>,,- ,^
This metal is found in? „ ^'"^' G^avify ,)-^.
state, but occurs mr'equenTv'as'rfl^!, '" '''^ "=«-e
reduced to the metalUc state .nrf.C ""'P^'de ; it is easily
wh.te colour. It crystaU^es'in . *^" "^"hibits a pinkish^
can scarcely be dSniuished f^^ "''"'"''"'^^drr, which
26f, and is volatilized ft ith'T" '^" ^s ; it melts at
oxtdize in Iryairat he ordlnlrvf^^'^'"- ^•^"'""' ^^^^ "o
strongly ,t burns with a Ce'fl '!,'"Pf a^"«> but if heated
also takes fire when throvvn int^ ■ir"?'"S ^" ""^^e ; it
.«' Cly Bismuth dissolves easilln •'!^'°""e. gas, forming
IS chiefly used as an !L,?d L? of T ^^^'^ ^'^^ -"^'^J
compounds are also used frnpHi. '^""^''^ "'"^'a' f "s
^0"^"'!^°'" bismuth «;; "n'o^rV"'' ^^ P'S^^nts.
!S a pale yellow powder formp/'^, ^"^ , ^he first of these
' ■ the air; the second o'.deTohl^^" ''^? ""^^^1 i-'' ™^st.d
«■" ■" Potash, and prec oLVin^ ,1!"^'' by dissolving the
acid and heating : it'^Ts a .Sdfsh h P""'°^'''<^ ^y nitri!
'he correspondin? ai lm«, ""'"■°"'" po'.vder. Like
o"de form with^the I H '' ''TP"-'"^' bi.smuth ren
Poi^tanc soluble salt of bism^.it ' ^^ °' '" ''^" mo^t im-
- black insoluble compou,S"'".L":!/f/^^'.¥''. ^H^. U
258
ELEMENTARY CHEMISTRY, [LESSON
obtained by heating the metal in chlorine. One of the
most striking peculiarities of the bismuth compounds is,
that solutions of the salts become milky on the addition
of water, owing to the formation of insoluble basic com-
( NO3
pounds. Thus Bi s OH is formed as a white powder
(OH
used in medicine by adding water to a solution of the
normal nitrate ; and an oxichloride Bi O CI is precipitated
by adding water to the trichloride. MetaUic bismuth is
easily reduced from its compounds, before the blowpipe,
as a brittle bead.
I VANADIUM.
Symbol V, Combining Weight ^I'l,
This is a very rare metal : its compounds occur in small
quantity in certain iron ores, and also in combination as
lead vanadate. It form.s an interesting oxide^ termed
Vanadium pent-oxide^ Vg O5, which yields salts called
vanadates^ isomorphous with arsenates and phosphates,
and also an oxychloridc, VO CI3, corresponding to phos-
phorus oxychloride, PO CI3.
Class IX.— Lead. , Thallium.
LEAD.
*
Symbol Pb {Plu7ttbum\ Combining Weight 207, Specific
Gravity 11 '3.
Lead does not occur free in nature ; all the lead of
commerce is obtained irom galena, or lead sulphide, PbS.
The mode of reducing lead from this ore is a very simple
one ; t..e galena is roasted in a reverberatory furnace,
with the addition of a small quantity of lime to form a
fusible slag with any silicious mineral matter present in
fRV. [Lesson
a white powder
'/t^ 207, Specific
xxivj
LEAD,
259
phur bums off as sulnAr^H w^ ""'^^f P°"'°" ^^e sul-
behind : after Ae late of ^.t' ^""^.^^^ oxide is left
eluded and the heat '^f ,£1 ? ""^^^^ '.""e the air is ex-
Phate and oxide foLedhnS^*"^ '^'^^ • *e lead sul
sulphide, giving off sSllu';°lffirP^°^f *? remaining
lead behind, thus " ^ "^^ ^""^ '®'^"'>ff metallic
W Pb SO, + Pb S = 2 Pb + 2 SO
(2)2PbO+PbS = 3Pb + sb^
wh^hu"e^trcted'byl^rcetr^l''r"'''-°f-'v^^^
is a bluish-white c2ur?5 S ^nH^"'^ ""r^" .^7i. Lead
be scratched with the nail if m'av h-!? '°'^^ '''^' " m^'X
or hammered into pl«e. bu p"sL ' s 5ft7l" °"' '°''"''
elasticity, and a wire 2 Aime n; j^ '"'^ tenacity or
load of 2 kilos. S S at «f '^'"l"' ^'l^^" '^''^ ^
perature volatilizes, thoush not"fn' "^ ^' ^ '''«''« '<='"-
enable it to be distilled ^ quantity suf cient to
. The bright surface of the metal r«m,- '
'n. dry air, but it soon becomS ttlnf ?!.'"^ Permanent
owing to the formation of a film nf^i?^'''^^ '? """'St «'>,
tion proceeds rapidly i„ nresS,c5 of ^ ' and this oxida-'
weak acid, such as carbonic or acet.V ? ""^" ''"^""^X °t
from air lead also preserves it?^I^«' J" P."""^ «">*«■• ^eed
lead-oxide is formeTand hi-i h f ^ "' ?•"■ '''' P'^'^"''
water a fresh portioA of metal tf^'^^/l'Shtiy in the
This solvent action of wate^^^'l ^^P°'^<^ ^°' oxidation.
importance, owin^to the comSf" 'f ^"^ 'I f "L^''^^ of much
and the peculiarly poisonous action nf'''^ water-pipes,
upon the system w£en taken ^T- ^ '?^'* compounds
for a length of timr The smaU auant.f'";"" 'l"?"""^^
contained in all spring and rTver «^T^ ""^'" '^"'
tant influence on the action „f ,1 3^'^^'=''"'= ^" 'mpor-
'aining nitrates or chlorides ,rl Ik, = ''"' "^^^'^ ^on-
««th lead, whilst fhosXrd waUf ^l°'?"'*™"«''o"
or carbonates may Jner"^. ZTl^^^^^T^S sulphates
^^ - ---^--uj^iii iiiiu cuniuct with
S 2
26o
ELEMENTARY CHEMISTRY. [Lesson
lead without danger, as a thin deposit of sulphate or car-
bonate is formed, which preserves the metal from further
action. If the water contains much free carbonic acid,
it should not be allowed to comj into contact with lea<1,
as the carbonate dissolves in water ccHitaining thi^ sub-
stance. The presence of tead in water may easily bo
demonstrated oy passing a current of sulphuret ed hy-
drogen through a deep column of the acidihcd water, and
noticing whether the liquid becomes tinged of a brown
colour, owing to the formation oi lead sulpliide. Three
compounds of lead and oxygen are known.
1. Lead Monoxide^ or Litharge, PbO, a straw-coloured
fowder, obtained by heating lead in a current of air : it
fupes at a red heat, forming scaly crystals termed Litharge
or Massicot. Lead oxide is soluble in caustic potash, and
is deposited from a hot solution in tlie form of rhombic
prisms. This oxide forms with acids the important series
of lead salts, which are generally colourless, and of which
the soluble o^es act as violent poisons. Lead oxide com-
bines wiih s.lica to form an easily fusible silicate, or
glass : thus eartlren crut:ibles in which the oxide is fused
are rapidly attacked. A white hydrated oxide is obtained
by precipitating a soluble salt of lead by caustic potash,
and this if heated yields the oxide.
2. Lead Dioxide., or Pnce-coloured Oxide, Pb Oo. — This
Oxide is a brown powder obtained by passing chlorine
thr ugh the hydrated monoxide, or by digesting led lead
with nitric acid. Lead dioxide does not form s dts with
acids. When heated it yields half its oxygen ; and acted
upon with warm hydrochloric acid, chlorine is evo.vdd,
and lead chloride is formed.
3. Red Oxide or Red Lead, a compound of the two
last oxides, having the composition 2 Po O -|- Pb Og. It is
obtained by exposing massicot to the air at a moderate
red heat, oxygen being absorbed. Red lead is chiefiy used
in glass making (see p. 226). When treated with dilate
nitric acid the lead monoxide dissolves, forming soluble
lead nitrate, leaving the puce- coloured oxide behind.
T/iV. [Lesson
XXIV.]
Z.SAD OXIDES
gen ; and acted
rine is evo.ved,
26 r
Lead A'itrate Ph •> Mr> :. .u
soluble salts of eaH Ti,.? *""'' important of the
solvmg the oxMe! the clrtnaTPr"'^ is obtained by d,s!
n trio acid j it crysudkes m nA K "l^'^""' ^^'"^ '" 'varn,
eight parts' of cold water and whf'^''^' ='"'!. ^-^olves in
yields red fumes of NO, (^ee ;,!?'•" '>^^"=<1 ^'™"ffy -t
w^htifferribla^i-i'\:iT ^ --^'^ -''-
W'^Z/^Z^^,/, so much used n« 1 ■? ""'•""^ "^ ^'^'-«"''^.
lead carbonate a"d lead hirox.de'^Tt-," " "^""P"" ' '^ "^
IS obtained in the Dure «^?« k ^"".^aine compound
solutiou of the n Frate^wfth iralklnif ''='Pv^'^""S ^ cold
falls down as a white powder Fo «":''•" ""^'■,' ^''^n "
m quantity two plans are ei;Dloved fit'"® "•'"'■? '^^"^
principle to that by I reciDitS Ik ^.°"* ^""''ar in
the second an old'a'nd'^S rSrnr^'oreL'knT ''=' '' ""l^
Dutch method. In this nrn,-»L=Hr 1^ known as the
rolled mto a coil, and each coif n/""^^'' "^ '^^^ ^--e
. conlainingasma llqu,nttvofrn,l "^ '" ^" ^''«''^" V^t
several hundreds orthSar, ?nH "f^""" (^'-"^'''^ ^<=id) ;
floorinabedofsfahUi^ ■" "** coils are packed on a
covered with board 'wbtllta Zr^lS'^"'''''^' '^"^ '^-^
l^rly charged is S above a^H- '^y"'' °^.P°'^ ^''n'-
the building is Led After 'remfin,w''r"r""''' ""'"
weeks, the coils are tak^n rL fu ? "'"^ *""■ several
the lead is found to be convmS?.."'" P^*^^ P«" of
It appears that to beorin ^^fl, ^ J° "''"^ ^^'^on te.
■tnd 'th'at the acet c acTdl ' aduallv H^-'""'" ''/°">'^d,
combination by the cirhonir / J "''?" ?"' ^o™ it*
putrifylng orgau'ic matted anTthSs e.iaMetto , '™" "'.^
another portion of ths lo,^ 1 e"at)lcd to unite with
was first anached Th!?^ 'v'ng underneath tliat which
»mewhat, but iteenl^allv .^P"'""'"/'^ "''^"^ '^^d v.ries
the formula "Pb €0"+ Pb h''o''° ' '"'""^ "^'^^^'^ *'"'
/^^v;^/ Sulbhide, or Galena Vh^c • r j
constitutes the chW ore oflhemetV}?','"'^ "^"^": ^""^
"^"^ metal. It 13 prepared as a
262 ELEMENTARY CHEMISTRY, [Lesson
black precipitate by passing sulphuretted hydrogen gas
through a solution of a lead salt. Galena crystallizes in
cubes and octahedra, and possesses a bright bluish- white
metallic lustre.
Lead Sulphate^ Pb SO4, is a white insoluble salt, which
is Ibund native, and is prepared artificially by adding sul-
phuric acid to a soluble lead salt.
Lead Chloride, Pb Clg, is prepared by adding hydro-
chloric acid to a strong solution of lead nitrate, when a
crystalline precipitate of lead chloride is foimed. It
dissolves in about thirty parts of boiling water, separating
out in shining needles on cooling.
Lead Iodide, Pbig, is precipitated in the form of
splendid yellow spangles, when hot solutions of potassium
iodide and lead nitrate are mixed and allowed to cool.
Lead Ckromate, Pb Cr O4, is a yellow insoluble salt, used
as a pigment under the name of chrome-yellow.
Lead can easily be recognised, — First, by the black
sulphide, soluble in dilute nitric acid ; secondly, by the
white insoluble sulphate; thirdly, by the yellow iodide
and chromate ; and fourthly, by the easy reduction of
the metal in the form of a malleable bead when any
of the salts are heated before the blowpipe with a re-
ducing agent.
w.
W
THALLIUM.
Symbol Tl, Combining Weight 204, Specific Gravity
11-85.
Thallium was discovered in 1861 by Mr. Crookes, by
means of spectrum analysis, in the deposit in the flue of a
pyrites burner (see p. 135). The presence of this new
metal is indicated by the occurrence of a splendid green
line in the spectrum. Metallic thallium closely resembles
lead ir. its physical properties ; the freshly cut surface has
a bluish-white lustre, which rapidly tarnishes ; it is so
5*77? K [Lesson
XXIV.]
becific Gravity
THALLIUM.
263
ealiMraw^^^^^^^^ '^- "-il> and can be
found to o?cur In mLV s^,!^^^^°^. ^ '^^ ^^^'' 't is
appears to take The ^i7ce'KSctrh ^''''^'^ "^^
impurity of this mineral M Jflir ' .u f-^ *^ ^ common
gradual oxidation so that it^s S nr^ef '""'^ ^^^^^^rgo^s
when stronrfv hekteH n ^.l, • preserved in water ;
with a bSKeen fl^ '^^^^ ^''^^ ^^d burns
nitric and fuIpEacidlw.>I^^?^ dissolves easily in
more slowly fnhTdrocte ^^ Mrogen, but
bility of the chloride Twn.^J^' ""T'l^ ^"^ ^^^ insolu-
charLteriseV r"^^^^^^ %^^^ a^nd'^V^"
composition, and somewra? r.^^M "'^- ^°"^«PO"ds in
alkali potash, To as it if. n^K^'" P™P«rties, the
an alkaline caustfc solution ^W/-^'^ i"7^'^''' ^'^Wing
which absorbs carbon "S from hf ^""f ''^'^^. Tl HO,
defined series of salK t^^l^^i? .i''?,?"'' '^O'^ming a well'
morphous with the corr«DonH "^""'"'- '"'^'' ^"^ is iso-
Of these the^«/XC Tl sn^ Potassmm compounds.
Kedral^stals^V" r^^^^^^^^^^^
Tl [4 SO, + 24 H, ; whilst the chloride is only slightly
important. ^"'f'^nae^ a i LI3, is the most
strlSpofsons' 'rheT^t^f ? ^^^ ';°?°"''^==. -"^ »ct as
Jemfor,whenap^ec^of zin^-P'-'lP^f^'*.'" ^ P"!^^^"-
tions. It will be seln ^hV. /u '^ """-oduced into its solu-
wm be seen that the properties of thaUium and
364 ELEMENTARY CHEMISTRY. [Lesson
its compounds are inUrmediate between those of lead
and the alkalies. Th i, Hum is a monad in the thalliuus
compounds, 204 p^its of metal replacing one part oi
hydrogen.
LESSOxN XXV.
Class X.—Copper. Mercury. Silver.
COPPER.
Symbol Cu, Combining Weight 63*5, Specific Gravity
8*93.
Copper is an important metal, largely used in the arts,
and has been known from very early tim< s, as it occurs in
the metallic or natii e state, and is moreover easily reduced
from its ores. Metallic copper is found in considerable
quantity in North America and other localities, crystal-
lizing in cubic and octahedral forms ; but the chief urces
of copper are the following ores : (i) a compound of
copper, sulphur, and iron known as copper pyrites, CugS
+ Fcg S3 ; (2) the cuprous sulphide, Cu^ S ; (3) the car-
bonate or malachite, Cu CO3 + Cu H, Og ; and (4) the
red or cuprous oxide, Cug O. The Cornish mines yield
large quantities of copper, whilst much ore is furnished
by Chili and South Australia. Pure metallic copper can
be obtained by reducing the oxide in a current of
hydrogen gas, or by the electrolytic decomposition of a
salt of copper. The process for obtaining copper on a
large scale from the carbonate or oxide is a ve> ^ simple
one, viz. merely reducing these ores together witft carbon
and some silica in a wind furnace. The reduction of th^,'
metal is more difficult when the commoner ore, coppet
pyrites, is employed. In this case the ore is repeatedly
roasted, in order partially to convert the cuprous sulphidi
into oxide, and the roasted ore melted in a reverberator)
?K. [Lesson
xxv.J
COPPER SMELTING.
»55
the corresponding sufphide whHs^^fh, " ^°"^^,««d '"">
umtes with the silica «*''a1i'bt an°d" Ti^'r' f"''
Ihe impure cup. oussulnhiH.-fL ^j ? , I'.sible slag,
poition of the ITJ^t ft ^" and sinl-. to the loulr
metal, and by repeating rhu'n*^ '^^ '"'" " °' ^°"^-e
sulphide or "fine S-M, obtained r ^ J""' "'P™"^
the maallic copper free froi^f: '» order to prepare
ruasied, and Swardf fus.H f P""""' "»'' '^"^ '"^'al is
Ou.ing the first narfof Ik " *^°"'^" ^'''^ 'he air.
sulphu^r,sbufntofrcuprLox1d?bTT " P."'""" °f 'he
later stages of the oroces? tM -5 '°™^'^ '' ^■"' '" 'he
maining quantity of si.E» f """^^ ?"^ "P"" 'he re-
metalli? cVer Cui"^ cJo '"^'I? 'l^^^ri" '^'"^'^e and
set rid of tf, ast'traces «f^~. *^?.+ '*^"- '""rderto
"poled "or stirred up A'h a t^e^e^^^^^^ molten copper i.
Metallic copper possesses p nt r^'^^" "'°°'^-
which is best seen'^^S a rav*^ f l'Y.'^''P '^'^ <=°'°"'-.
reflected from a bright surface of £. ' ". V"""^ "'"«
malleable and ductilf and nn«!..? "'^"'' ' " '^ ^ery
of two mms. in d X"l'^sun„r-- ^'^''' '''"^''"y' ^"'''^
kilos. ; it melts at a r^d i^.f^P? ■ '"?• ^ '"^'gh' of ,40
white heat, comm^nicatrng'k'^;^:^ 'fnt'lt^^'^ A
hydrogen gas, which is passed o%7^h ■ T^^ L ■ ^""^^ "^ '
best conductors of heat and eCricitv rn " °^^ "'^"'e
oxidize either in pure dry or moTst a /'^t J'P^'' ''"^^ "«
ratures, but if heated t^rednes n fL '^'"''"■^ '""P^'
oxidizes to scales of copper oxide \t "' " '^P''''^
posed by metallic roooer at » ,!h u^'^'"" '? ""' deconi-
copper dissolves in TyTod lor.V ^?'- • u'^'"^'>' '"^'ded
hydrogen ; wheu hea ed w?ih ^""^ "''f^ evoiut.on of
phur dioxide (p. I2g) is ^tnlvl,?"^ ^jMphuric acid, sul-
•ormed; and when act^uptnt^h"'' v^^PP^": ="'"''='«
nitrate is produced anH^t?'^ T '^ mT'c acid, co in, r
Many of the c^Lr aHov"^ ("• 72) liberated. "^
an alloy containinraboutTwoThfi'^P?'''^''^^- ^^^^s is
'h.rd of Zinc; it /s h^aXZ^^'co'^p^'r ^S-^^-
V]
W
/
%
*c*J
%
'> •>
w A
>
/;
IMAGE EVALUATION
TEST TARGET (MT-3)
1.0
12.2
I.I
1^6 1^
M 12.0
us
us
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IL25 i 1.4
14
1.6
Photographic
Gciences
Corporation
23 WEST MAIN STREET
WEBSTER, N.Y. 14580
(716) 872-4503
y.
f/j
i
%
i/.A
266
ELEMENTARY CHEMISTRY. [Lesson
easily worked : the addition of one to two per cent, of
lead improves the quality of brass for most purposes.
The yellow- or muntz-metal, used for the sheathing of
ships, contains sixty per cent, of copper. Bronze, gun-
metal, bell-metal, and speculum-metal are other alloys of
copper and tin in varying quantities. They are all re-
markable for the property of being hard and brittle when
slowly cooled, but of becoming soft and malleable if they
are cooled suddenly when red-hot by dipping into cold
water.
Copper is a dyad element, and forms two sets of com-
pounds, the cuprous and the cupric salts : the molecules of
the cupric salts contain one atom of copper, whilst the
cup|"ous compounds contain two atoms of metal. The
constitution of the two oxides Cu O and Cu2 O and the
corresponding chlorides Cu CI2 and Cug Clg, may be re-
presented as follows ;
Cu
Cupric Oxide, Cu_ O
„ Chloride, Cu
-CI
-CI
Cuprous Oxide | > O
Cu
Cu~Cl
,y Chloride I
Cu— CI
Cupric Compounds.
Copper Monoxide^ Cupric Oxide or Black Oxide^
Cu O. — This oxide is formed when copper is heated in
the air, or when copper nitrate is heated to redness :
it yields the blue and green cupric salts, and it is
largely used in the laboratory as a means of giving
oxygen for the combustion of organic substances (see
p. 299). Hydrated copper oxide, Cu Hg Oj, is obtained as
a light blue precipitate when a caustic alkali is added to
a cupric salt : when this is heated q 100*', it loses its
water, and the anhydrous oxide falls as a black powder.
Cupric oxide is soluble in acids, furnishing a series of well
XXV.]
CUPRIC COMPOUNDS,
267
crystallizing salts. Of these the most important soluble
compounds are : v ^ owuuic
Copper sulphate Cu 39^ + 5 H^ O. This salt is some-
times known as blue vitriol, and fs largely manufactured
by dissolving copper oxide (copper scales) in sulphuric
tww /• ^^y^*f »^es in large blue crystals belonging to
the trzchmc system (Fig. 54) ; when heated to redness, it
loses all Its water of crystallization, and forms a wh te
powder, which again at a higher temperature decomposes
leaving copper oxide. Copper sulphate is empbyed in
cahco-prmting, and m the manufacture of Scheele's green
and Brunswick green, and other copper pigments The
sulphate and the other copper salt" gi?ef with excess
of ammonia, a deep-blue coloured solution, forming a
remarkable compound, capable of crystallizing, having
the composition Cu SO, -f 2 NH3. This compfind maf
^tni^r^V k'!? *° '^e ammonium sulphate in which two
atoms of hydrogen have been replaced by one atom of
dyad copper ; thus : NHg Cu T^ ^ ^
NH4 \ S04- Many similar copper
compounds ar(» known, and the production of this blue
colour may be used as a test of the presence of copper.
Copper nitrate, Cu {^83 + ^ H2O, a very soluble salt,
crystallizing in large blue prisms obtained by dissolving
copper in nitnc aci3. Copper chloride, Cu CL. is formed
when copper is brought into chlorine gks, or when co^er
oxide IS dissolved in hydrochloric ac^^ it forS^sS
needle-shaped crystals, Cu Cl^ + 2 H^ v., soluble in ^ter
and alcohol. The alcoholic solution bums with a ch^ac-
tenstic green flame. ^-iwrac-
rJ^^ ^*?soluble coppor salts are : Copper sulphtVe, Cu S,
Obtained as a black precipitate, when sulphuretted hydro-
f^. ^^1\ P^^^^z^ through an acidified solution of a copper
salt; G7//^rf«r/5^«a/^_which, however, is not known in the
^\?J1^^\ ^^ *^^ ^v^^" precipitate, obtained by adding a
rn„fi° S^f" ^^^l»?f carbonate to a copper salt, always
contams hydrated oxide, Cu CO3 + Cu h; O, (the mineral
mmm
268
ELEMENTARY CHEMISTRY. [Lesson
malachite also pos-^esses a similar composition) ; Copper
arsenite^ or Scheele's green, a bright green powder used
as a pigment, and obtained by mixing solutions of sodium
arseniie with copper sulphate.
V
Cuprous Compounds.
Cuprous Oxide, or Red Oxide^ Cug O, occurs native in
ruby-red octahedral crystals. It is artificially prepared by
heating equivalent quantities of cupric oxide and copper
filings, or by boiling a solution of copper sulphate and
sugar, to which excess of caustic potash has been added :
the sugar reduces the copper salt, and cuprous oxide is
precipitated as a bright red powder^ Cuprous oxide
imp&rts to glass a splendid ruby-red colour ; it forms
colourless salts with acids, which rapidly absorb oxygen
from the air, and pass into the cwrespoi >ding cupric
compounds. The most important of these saks rs cuprous
chloride, Cuj Clg, a white solid substance obtained by dis-
solving a mixture of cupric oxide and metahic copper
in hydrochloric aciid : the solution of cuprous chloride
possesses the remarkable property of absorbing carbonic
oxide gas.
The copper salts act as powerful poisons, and they may
be detected — (i) by the black insoluble sulphide ; (2) by
the blue hydrate turning black on heating ; (3) by the
deep blue colouration with ammonia ; (4) by the depo-
sition of red metallic copper upon a bright surface of iron
placed in the solution.
I
MERCURY.
Symbol Hg {Hydrargyrum), Combining Weight 200,
Specific Gravity at 0° 13*596, Density 100.*
Mercury occurs in the native state, but the chief ore
fif mercury is the sulphide, or cinnabar, which occurs
• The atom of mercury weighing 200 occupies a volumes ; and hence its
vapour density is half its combming weight.
XXV.] MERCURY COMPOUNDS. jfi,
by roasting Ihl o J when tl» ."VT' 'l^*'">' °''""'"ed
dioxide, and thi meul voiata^u« i^^"- ''"'"'' "'^ ^« '^e
densed in earthen pi^s*^"'' "' ^'P"""- '» <:°n-
.he soid p:t ^:-ra%l:^:^l pSs'es^'t"'^ ^r
gravuy of ,4^ It boils at 35o» fm^asur«?ht ^'^''^'^
tliermometer), and gives off :> iwhlT ° /"^ ""^ ^ir
the ordinary 'tempf^tu^ xtl'^ilT"!/- '"P"" ^'
when air =1 is 6-076 fiid iL ^'^ "^ "" ''^pour
heavy as hydrogen Mercurv whJn'"'"' !.* '°° ^'^^^ ^s
in moist or dryilr bm wh^^If",''"^^ '^"^^ "°' '"nish
absorbs o.yg7nfpast'gt:S tt red S -'^d' nt"'^
HyTro^X c^ T-^^d r fn^;t'^ra'".'=' ^^^ "'--p"-
a. id, on heatiugf Ss tlpl^r^di^xlK ?."^'""h=
mercunc sulphate ; and nitri? acid evolves nitrir^l '^'f
and forms mercuric nitra*,. »J evolves nitric oxide,
the process of extract?nll'id ^„H*'"!'^ '^ largely used in
(pp. 27, and 27S)f^d fn^he arts fo^.-f™'? "^^'^ °'^*
and other p^rp'oi'es. Mercury u'depositedTo^ T"T
tions upon metallic iron or coDoer ir fh. ? *^""";'S solu-
powder, which becomes S oil bumfi°™ °1/ ^^^^
and Its salts act as valuable fnedWnes.'"""^- '""^"'^
coSn^V tht ^C^;ii!^d^ -•?«^/--"° - '^^
Mercuru Compounds.
Mercury Monoxide, or Mercurir /Owy. u r^ •
tamed by moderately hen HnJ^t •? '^^ ^^^^' '^ ob-
300°. The oxide thus oren^rprl o ^ temperature of
Ime powder • bv nrpHmf^. •^^P^^''^' ^^ ^ ^^^ crystal-
powder. ^ ^' '^ ^^"^ ^s ^« amorphous yellow
270 ELEMENTARY CHEMISTRY, [Lesson
Mercuric Nitrate, Hg | ^^3, is formed by the action
of excess of nitric acid upon mercury, or the oxide.
Mercuric Chloride, or Corrosive Sublimate, Hg CI2, is
prepared on a large scale by heating an intimate mixture
of equal parts of mercuric sulphate, Hg SO4, and com-
mon salt : it is also formed when mercury burns in chlo-
rine. It acts as a violent poison ; it is soluble in water,
crystallizing in rectangular octahedra, fuses at 265°,
and boils at 295°. When ammonia is added to a solu-
tion of mercuric chloride, the sp-called white precipitate
is thrown down ; — it is a chloride of mercury-ammonium,
NHaHgCl. '
Mercuric Sulphide, HgS, cinnabar or vermilion. It
occurs native, and may be prepared artificially by heating
a mixture of sulphur and mercury. When precipitated
from a solution of a mercuric salt by sulphuretted hydro-
gen, the sulphide falls as a black amorphous powder, but
on sublimation it becomes red and crystalline.
Mercurous Compounds.
The most important of these compounds is
Mercurous Chloride, or Calomel, HggClg. It is generally
prepared by heating a mixture of three partb of finely-
divided metallic mercury with four parts of corrosive
sublimate ; the metal combines with half the chlorine of
the corrosive sublimate, anrJ one atom of calomel is
formed, HgClg + Hg = HggClg. The calomel sublimes,
and is deposited in a solid cake : it must be finely ground
and well washed, in order to free it from any soluble mer-
curic chloride which may remain undecomposed. Calomel
is a white powder, insoluble in water ; it is decomposed by
potash or ammonia. It is used largely in medicine.
Mercurous Oxide, Hg20, is obtained as a black powder
by digesting calomel witi;. excess of caustic potash. On
exposure to light, or when heated to 100°, it decomposes
into mercury and mercuric oxide.
xxvj
SILVER,
271
Mer Citrous Nitrate Wt* I N^O,
sodium carbonate ?n a sZn?,!'' "/^S^ly heated with
metallic ra«cu^ on cZer Thi- ^^^ '''' ""* ''^P"^" °f
detected by ^^^t^^^T.:tr.f-:^t^^:^y^
SILVER. ^
^J^jJ./ Ag, Co,nbining Weight 108, .?/...>. Gravity ,o-c
Silver was known to the ai,r,»„rL r. • . ^'
the native state, as well arrnmil? ^ ' • ? " ^°""d >»
mony, chlorine Ind tomine ^t ^'* '"'P'^H''. anti-
smal! quantities in eaIenW,i^;„^ ' j ?'^° contained in
with Profirfrom thf kadtefcl'm'tv'''' ''^'^""^^^
when the lead contains only two nrtw ""* '"■$' «^«"
to the ton. The methoH ^i,^.! j .^ °''"<=ei of silver
of the silver dSs un„i ,hl f'^Tlt'* '^"l" *•>« extraction
silver can be SntS -nto f *" , *^ '^''=''« "^ *e
bycrystaUization,-Smcl'eadfreefro,LPsr'°" °^ '""'*'
out in crystals, and a rich alloy iffeftWhl^'^i'^P^i*^"
the concentration of 300 oz si Lr t^ ^ ? this reaches
undergoes the ooeratinn nf }T,}°.^^^ .'°°' *<= a"oy
mixture is melted^n a furnil '"^'"<''""'' '" "'^ich the
earth, and a blast of tir hWn ? ^ F™"' bed of bone-
ores of Germany, in which tLcT* ^^ argentiferous
-ation With sui/huj; Ti^e'^JLVllri Sn^VaZ^:;
272
ELEMENTARY CHEMISTRY. [Lesson
The ore is roasted in a furnace with common salt, by
which means the silver sulphide is converted into chloride:
the mixture is then placed in casks made to revolve, and
scrap-iron and water are addr^. Tfae iroa reduces the
silver to the metallic state ; and when this i. fully acconi-
plished, metallic mercury is added: this forms a liquid
amalgam with the silver (and gold, if any be present) ; and
by distilling the mercury off, the silver is obtained in an
impure state. A somewhat difterent method is employed
in South America, where fuel is expensive. .Silver pos-
sesses a bright white colour and a brilliant lustre, which
it does not lose in pure air at any temperature ; but when
melted in the air it possesses the singular power of ab-
sorbing mechanically a Urge volume (twenty-two times its
bulk) of oxygen : this gas it again gives out on sol difying
— a phenomenon technically known as the "spitting" of
silver.
Silver is probably the best conductor of heat and
electridtj known, and is extremely ductile ; one gramme
of metal can be drawn out into a wire of 2,600 metres in
length. Sulphur combines at once with silver, forming a
black sulphides siver articles long exposed to the air
tarnish from this cause. Silver is easily sohihle in nitric
acid, the nitrate being formed and nitric oxide gas being
tvolved.
Alloys of Silver. Silver itself is largely used in the
pure state for various purposes in the arts, but it is usually
alloyed with a small quantity of copper when employed
as coin or for articles of plate. The English coinage
contains 7*5 per cent.- of copper in the standard silver,
whilst the French contains 10 per cent.
Silver forms three coippounds with oxygen. The first of
these is called Silver suboxide^ ^zfi : it is a black powder
which readily undergoes decomposition. The second,
a strong base \.txvciA Silver monoxide^ P^g<f)^\%oh\.zS.vitA
in the form of a brown precipitate, v/hen caus ic potash i?
added to a solution of silver nitrate. From this oxide,
wliich is decomposed into metal and oxygen on heating,
XXV.J
^fLVER SALTS.
the ordinary silver ^aho ^^^
t: oS Jot! ?f « -en^/'r 7
sticks goes bv fh. ^ ^ °" '•«="■•'& aniwhtn '^™''°'-
undergoes decomn^;??™^ °/ '"""r tausHc -n^^ '"'°
in contact with^'^ *"'°" "hen exposed V/'.k ^""^ ^^'t
probab y consttrnf T f ''"^'•' a^d a b,ack\^ ^"""ight
change t,L p'a^em S>CoSiSf -^a^^St^
uLtruT^e^/ at'W^fc Sre?^tr I'
" is easily redu'^d\olVtai;fc ?r^f^'^'"«^^^^^^^
and sulphuric acid ThL ti- ^^^^^^ »n presence ^f^ '
'»-s,--.fe,tis?<^urg„t,L'""V'^
T
'^a
mF
•274 ELEMENTARY CHEMISTRY. [Lesson
Silver bromide^ Ag Br, falls as a white precipitate when
silver nitrate is added to an alkaline bromide ; it is also
acted upon by the light, and is soluble in ammonia and
alkaline hyposulphites. Si/ver iodide, Ag I, is a yellow
powder, insoluble in water and ammonia, but dissolved by
alkaline hyposulphites. Silver sulphide^ Aga S, occurs
native in cubic crystals, as silver glance j it is precipitated
as a black powder by passing sulphuretted hydrogen
through solutions of salts of silver.
Silver can be easily detected when in solution by the
precipitation of the white curdy chloride, insoluble in
water and nitric acid, and soluble in ammonia : the metal
can be easily obtained in malleable globules before the
blowpipe, whilst it is reduced from its solutions by iron,
<:4>per, and mercury. Silver is estimated quantitatively
cither as the chloride or as the metal.
Class XI.—Gold, Platinum, and the rare
Platinum-like Metals.
GOLD,
Symbol Au (Aurum), Combining Weight 197, Specific
Gravity I9"3.
Gold is always found in the metallic state : it occurs in
veins in the older sedimentary or in the plutonic rocks,
and in the detritus of such rocks ; it occurs in traces in
the sand of most rivers, and although found generally in
small quantities, it is a widely diffused metal. Previous
to the discoveries of the gold-fields of California and
Australia, it was obtained from certain iron pyrites. In
order to obtain the gold, the detritus or sand which con-
tains the metal is washed in a "cradle" or other arrange-
ment, by means of which the lighter particles of mud or
mineral are washed away, whilst the heavier grains of gold
sink to the bottom of the vessel. When gold has to be
worked in the solid rock, the mineral is crushed to powder
XXV.]
PROPERTIES OF GOLD.
and then shaken up with m. " *''*
.xgacted by amalgaSiaUon. ''"">' ^"<^ ">« gold thus
films, traSts '|re'e„''%r' if''"" ~'°-''^' «"d, in thin
>t can be drawn out int„ « ' •'* "^^'''^ *» soft as learf"
leable of all the metak ,A^ ""■^' ^"'' '* ">e most mal'
perature, in dry o"m'<^rst air t" T.'^T''' ^' ^"^ "m-
I'ke silver ; t is not act«l ..m^ k " ^^ected by silohur
se enic) but dissotst pSce''of7 ''"«if ^^'d (^^5'
nitro-hydrochloric acid At hi^i, /''^^ '''''°""e knd fn
slightly volatile. Pure i^oIH i. K^^ temperatures gold is
the ordinary metal in afua ».(» ''^^P'i*'^'* ^y ^mZ
Phate, which is oxidfzed ?o fem> ' ^."^ ^^'*'"8 ^^^°^^ sul!
gold as a brown powder Th^7/l v^'i""^ Precipitates the
;ofd^:'nf°^4H■^^^^^^^^^
G./<?lrlS^r''i°^>'f »J°;wo proportions, forming
these oxidesforms s^ts w^^ -rT' A"» O^- Sf
W'th bases to formTompourds ^ 'll^!' """ "'^ 'atteruit.
'Jgzinc oxide or maenesS 1 "'"'f''? '" "'''^■'"ed b-ad
the oxide falls as a bTwn powder" ""°" t S"'" ^''iorirt.
be separated by nitric ac"dGo,H ['?'".»*'?'» 'he zinc cat.
direct sunlight, into metal ,n^"°''"*^ decomposes in
when heated to a tSatul^P^"' ""'^ is also reduced
■njportant compound of ^odTril.t""'.'?"'': ^he most
This substance is obtained bv »-^?^ '^ fulminating gold
wth excess of ammonia -a Ln"S °" ^ =°l"tion of|old
^■Pitated, which, when drt^fTi""*" P°«"ier is Ire-
heated to ioo°, or when sfrYj^u^.u''? very easily when
"vo gold chloridesWvn M rl")^ ^^'"™^'-- Therlare
Obtained as an insoluble wi,.>»- '^"''^ """"ochloride, ..u CI
'I heated to the Sng.poiit "flin ^^^^^^^ trichloridi'
Au.Cs, obtained when ISd ;f i' ' f^^_P''^''''^'''/<»-^i^
^'>'s .= the most ■^-V^r^^.^t^^lf ^.I'^^^^l^^
276 ELEMENTARY CHEMISTRY, [Lesson
pirating the solution, crystals of a compound of gold
t ichloride and hydrochloric acid are deposited. Gold
trichloride also forms cystalline compounds with the
alkaline chlorides. Gold salts can be easily recognised
bv the bn .vn precipitate of metallic gold formed on
addition of ferrous salts, which can be reduced to a globule
before the blowpipe, thus :
2 Au Clj f 6Fe SO4 =. 2 Au -H 2 Fe^a SO4 + FcjCle ;
and also by the formation of a purple colour (purple of
cassius). when gold trichloride is added to a dilute solution
of a mixture of the two tin chlorides.
PLATINUM.
Symbol Pt, Combining Weight 197*4, Specific Gravity
2r5.
Platinum is a comparatively rare metal, which always
occurs in the native state, and generally alloyed with five
othtr metals, viz. palladium, rhodium, indium, osmium,
and ruthenium. This alloy occurs in small grains in de-
tritus and gravel in Siberia and Brazil ; it has not been
found in situ in the original rock, which probably belongs
to the old plutonic series.
Tne original mode of obtaining the metal was to dis-
so^ 'e the ore in aqua regia, and precipitate the platinum
(together with several of the accompanying metals) with
sal-ammoniac, as the insoluble double chloride of ammo-
r.ium and platinum, 2 N H,C1 + Pt C^, This precipi»ate
on heating, >ields metallic platinum m a finely divided
or spongy state ; and this sponge, if forcibly pressed and
hammered when hot, gradually assumes a coherent metallic
mass, the particles of platinum welding together, when hot,
like iron. A new mode of preparing the metal has recen Jy
been proposed, the ore being melted .n a ver/ powerf .1
furnace heated with the oxyhydrogen blowpipe. In th
way a pure alloy of platinum, iridium, and rhodium is
[Lesson
of gold
[. Gold
vith the
cognised
med on
I globule
Cj Clg ;
)urple of
: solution
Gravity
h always
with five
osmium,
ns in de-
not been
y belongs
IS to dis-
platinum
tals) with
3f ammo-
recipi'ate,
iy divided
essed and
it metallic
when hot,
ls recently
' powerf il
. In this
lodium is
^xv.] PLATINUM COMPOUNDS, 277
dth'^'d^^vo^ldS rr^ "^^'^ -' the or.
by the lime'of Xchrh'e cttlerc"ompo::^ V^^^T"
IS m many respects more usef.,1 Ao^ ^ 1 . ^^'^^ ^^^^Y
Platinum possesses a bright white colour an.1 a
tarnish under any circumstanre*; in f nf o • '• - ^°^^ "^^
vessels are much used in rUblraJoAT" S ^Jf,!''}"'"
(.11'"%' ?«"■>»" the metal at high tempeSu?L Wh"'
the efffcfof brinJin/s^nS'^aL* remartable degree'
mixture of oxJenlnA^h^K^T 1" '=°"'=" *'"> a
tioned. pSm and S'un^/ •'^7^'*^ '^'" "'«"-
^/?«?^rt^^, PtOo. The first of twY' ana (2; i"/^/////,;;,
powder; easil^ decomposed L helk^t', "'• " r'""'^''
senes of unstable sah^-th»L^ "eating and yie.dmg a
hydrate, by adding to a solu fon nf '1 °^'?'"=.d^' » brown
equivalent of cauftic Dot^oh ^^k l^T"" ""''^'^ half its
first loses its water foSfh.^''^'*''''"^' "^^^^ ''^^'^d,
^ obt^aln?.}'; a ye7o''isre?fyu't-""T -"P-"" "^t"
metal in aoua re^ii • ^1 solution by dissolving the
pound 2f XnuS tCchTo^TS hTd'f H?' ? '""^
separate out. Platinun, t^tr.nhi 'T ^y^'^ochloric acid
alkaline chlorideslXm ^^^^^^^^^^^^ many
)v'th potassium, rubidium TJshimL^ ! compounds
insohible in water and are ^fn^^ ' i? "^ ammonium are
cubes ; whilst^e i'sait °3^ ^^
iarge prisms. soluble, and crystallizes in
27^
ELEMENTARY CHEMISTRY, [LESSON
Platinum dichloride, when acted upon by ammonia,
gives rise to several very remarkable compounds, contain-
ing platinum, nitrogen, and hydrogen : these substances
act as bases, and foniMi well-defined series of sails. These
salts may be considered as molecules of ammonium, in
which the hydrogen has been partly replaced by either a
diatomic or tetratomic platinum.
[For the properties of the rare metals, palladium, rho-
dium, ruthenium, iridium, and osmium, the larger manuals
must be consulted.]
Grouping of the Elements,
\ The following table (p. 279) contains the names of all
the elements whose atomic weights are well ascertained,
arranged in natural groups or families, placed horizontally
in ascending series as regards their combining weights.
Thus we 'have the carbon group, the nitrogen group, the
chlorine group, that of the alkaline metals, and that of
the metals of the alkaline earths. In each of these groups
the elements in the same vertical line possess nearly the
same atomic weights, thus :
Li 7
Na 23
F 19
N 14
K 39*1
Ca 40
CI 35 5
P 31
Rb 85-4
Sr 87-5
Br 80
As 75
Cs 133
Ba 137
I 127
Sb 125.
It thus appears that matter becomes endowed with the
same or similar properties when the atomic weight has
increased by 16, 45, or 50 units. . . .
The elements of the iron group, on the other hand, are
all placed in a vertical series because they possess nearly
the same atomic weights ; the same holds good for the two
divisions of the gold group. Further examination of the
table shows that other relationships exist between many
of the elements : thus it frequently happens that the ele-
ments of one horizontal series are connected by isomor-
phism or by analogous chemical properties, with those
?<*r-^ f~
XXV.]
H
O
Ah
o
SPECTRUM ANALYSIS.
• 9 o
n
I i I t ( I
27^
t I 1 i I I
6
IS
f3
e
O M
s
S
H
6
1 12^.I"|'§.|35'|§,
^ ►-* o w
.3 ♦•g
jjr
.3 M B N
-a M
6
a u
S O
H
rN2
" o
0<
•is 2 S *«
0|o|h
I I
.2 « B ^
'I
CO M
i 1 1 I
6 i
.2. -2
3 .2 2
.IS c »o g 10
I
fe' I i|.^
28o ELEMENTARY CHEMISTRY. [LESSON
in a neighbouririij horizontal division. Thus Vanadium,
showing its clo^e connection with phosphorus by its
volatile oxychloride and by the isomorphism of the
vanadates with the phosphates, is allied in its chemical
characters with niobium and also with chromium and
molybdenum.
These two last elements are connected with sulphur
by the isomorphism of the chromates, molybdates and
sulphates, just as manganese and chlorine are connected
by the isomorphism of the permanganates and the per-
chlorates. Silver on the one hand exhibits analogies with
copper and mercury, but on the other its, monovalent
character and the isomorphous relations which it exhibits
to Sodium, place it near the metals of the alkalies.
The singular relations which here present themselves
can scarcely be the result of chance, but we are as yet
unable satisfactorily to account for them.
LESSON XXVL
SPECTRUM ANALYSIS.
An entirely new branch of chemical analysi'^, of great
dt-licacy and importance, has recently been developed,
chiefly by the researches of Bunsen and Kirchhoff, the
principles of which may here be shortly stated.
It has long been known that certain chemical substances,
especially the salts of alkalies and alkaline e?^.rths, when
strongly heated in the blowpipe, or other nearly colourless
flame, impart to that flame a peculiar colour, by the occur-
rence of which the pre ^ence of the substance may be de-
tected. If many of these substances are present together,
the detection of each by the naked eye becomes impos-
sible, owing to the colours being blended, and thus inter-
fering with each other. Thus, for insiance, the sodium
compounds colour the flame an intense yellow, whilst the
potassium salts tinge the flame violet : the yellow soda
XXV,.] ^P£CTJiu^ Amtysfs. ,8,
r^)^^^^Vt,Zn.:^tV:^^^'^'^^ .he purple
from detecting the purple even :?? P''"^"'* ">« eye
potash salts are preLr'This d ffli'if S^^^ities of
overcome, and this method of oK " '^ " altogether
tremely sensitive, if, instead ^ft^^'T""" ''enderld ex-
the naked eye, it is examin^^ regarding the flame with
consists of a^r'iangi aS^*! 'fe"*" " P"^™" ™s
which the light is refrlcted or wJ '" P^^*'"g ""rough
each differently coloured rav beincr ^•<?'" °^ "* =°""f ;
so that if a source of white hVh^ differently refracted
candle, is thus regarded a co,ft^'..'"'V' ]•>« "ame of a
CO oured rays is obser'ved • /hf °"' ^^"^ °^ differently
being resolved into al Tts variouslv cnTr""^"^ "^^^ ^ht
This coloured band is temed a ?1°T^ constituents,
source of pure white lighTlives ft ''"'"' ^"<* each
specfrum, stretching from red^fL r f ""^^ '^'"'tinuous
violet (the most refrangSe) coin,,, i^^''. ^e/rangible) to
the colours of the rainbfw ^^Sei n' 1""^'"?' '" <■«» ^i'h
plate at beginning of volume) ' ' °^ "'^ chromolith.
If these coloured flames are examin^j i,
prism, the light being allowed to fel f^ ^^ ^^'"'^ °f a
slit upon the prism, it^is at once sP.i /i??"?'' ^ "arrow
refracted differs essentially frZwhfte htt '•"'«'" "'«
". '?<'"S'sts of only a particular ^efnf^'' '"asmuch as
giving a spectrum containing a few iTf.' ^^""^ "ame
the spectrum of the yellow "Ida a7j.'^^' ^^"'''- Thus
fine bright yellow line, whilst the Cnr'°"'^'"^ °"'y one
hibits a spectrum in which there a^etw^h"-''? ,'^^e ex-
lying at the extreme red, and the o hf '"'l^'l' ""^s, one
violet end. (See Nos. 6 and 2 o^ fh ^' '^^ ««^eme
These peculiar lines a.o alwavs nr^d \ ^^""^ P'ate.)
chemical element, and b^ no otherinf "'"''' ^^ the same
^e position of these Les " ^^^^"^"^"bstance ; and .
When the spectrum of a flame tmt J k^'"' ""altered.
sodium and potassium saltsirexam,„ J^.u'' "'"'"^e of
of sodium is found to be c nfin^-d , !^' ""^ yellow ray
whilst the potassium red'and nuTnl'rjf! ?."" P°^'tion!
. .r- -.«va Ais, aa piainiy
282
ELEMENTARY CHEMISTRY, [Lesson
seen as they would have been had no sodium been
present.
The coloured flames which are exhibited by the salts of
lithium, barium, strontium, and calcium, likewisis each
give rise to a peculiar spectrum, by means of which the
presence or absence of very small quantities of these
substances can be ascertained with certainty when mixed
together, simply by observing the presence or absence of
the peculiar bright bands characteristic of the particular
body. (See chromolith.)
The advantage which this new method of analysis
possesses over the older processes lies in the extreme
delicacy as well as in the great facility with which the
pre^nce of particular elements can be detected with
certainty. Thus a portion of sodium salt less than the
-r — * - th part of a grain can be detected ; and com-
180,000,000 '^ °
pounds are found to be most widely disseminated
throughout the earth, which were supposed to occur very
seldom. The extreme delicacy of the method is seen
when we learn that every substance which has even been
exposed to the air for a moment gives the soda line, every
minute speck of dust containing sodium compounds in
sufficient quantity to produce the characteristic reaction,
when placed in a colourless flame. Thus, too, the lithium
compounds, which were formerly supposed to be con-
tained in only four minerals, by aid of spectrum analysis
are found to be substances of most common occurrence,
being observed in almost all spring waters, in tea, tobacco,
milk, and blood, but existing in such minute quantities as
to have altogether eluded recognition by the older and less
delicate analytical methods. A portion of lithium less
•th part of a grain can thus be detected.
than the 7 — ^
6,000,000
A still more striking proof of the value of spectrum
analysis lies in the fact of the recent discovery of four
new elementary "bodies by its means : two new alkaline
XXVI.J SPECTRUM ANALYSIS. jgj
new metals, thallium and inH^.m T' '^"J"^'. and two
tively detected in iron Svrit« T^ ^-^"""^ ^^""^ '•^^Pec-
alkaline metals, dis^ovc?^" b^ Buns^n in^'ilL ^^ "kT
potassium so clos^Iv m fikl;!:^ ^^unsen m i86o, resemble
nearly impossi«Ctet^^^^ 'l^' '^ ^°"^^ be
analytical methods akhouth fW ^^"^ ^^ '^'^ ordinary
distinct briffht bannrnJ.?^ ^^^^"^ .^P^^'^^ exhibit very
other knowf pec?rum V^^^^^^^ or an^
vered by Mr. CrookS* whn .k ^^^ thallium was disco-
line which did not h/lnrc. . °^'^T^ ^ '^P^^^did green
gas ; and t is alwavs oh«..,;ij ? ' °'!°' ''qo'd, or
heated to the poKt whi^^-^ '''^'" *"'='> «'a»ent is
nous, for then ea?h lleml* l'^ u^P°"'' '^™™« lumi-
off b^ it aJon^^d ttTara^e ?&•=!!"?!■ ''8'« S'ven
apparent when its SDectrum toK*" ''"^'" 'i"'* '^come
••equire a much hiX^ temJr f"^"^^- Most metals
flame, in order tha/^th^irP*""l ">*» ♦'"e common
nous but they miy be easufh.'^/^"'^ '^^'"^ '"'»'-
temperature by means of X !f^f"P '° **■« ''^q^site
passing betwee'^To pofntl of fhl"*' Tf"?' '"'''=''' '»
volatilizes a small mrtfon InH V ^' •""^'^? '" question,
enable it to Sve off ts 'ni^,l./^r I ^ '""'"'^'y as to
metals, amonlothersimt Sf ." '^"^ ''?l"- ^hus all the
each be Sn°sed hi ttf ^''"T' ^i'^^'-. and gold, may
their spectra St ^ ' P''"''" ''"«'»' «"«. '^Wch
whIS^hTa^^"^gl?ht°ed'"ff cha^cteristic spectra
electric spark • thus i/tht !, ' i ^''^ ^^^ Passage of an
atmosph4 Of hSgrgL!^ li^.L'':SfL^-"gLt-!
284 ELEMENTARY CHEMISTRY, [Lesson
red, and. its spectrum consists of one bright red, one
green, and one blue line ; whilst in niirogen gas the spark
has a purple colour, and the peculiar and complicated
spectrum of nitrogen is observed when this spark is
examined with a prism.
The instrument used in these experiments is termed a
spectroscope. It consists of a prism (c/, Fig. 6i), fixed
upon a mm iron stand, and a tube ip) carrying the slit,
seen on an enlarged scale in Fig 62 {d\ through which
Fig. 61.
the rays from the coloured flames {e and i ) fall upon the
prism, being rendered parallel by passing through a
lens. The light, having been
refracted, is received by the
telescope (/), and the image
magnified before reaching the
eye. For exact experiments, the
number of prisms and the magni-
fying power are increased. The rays from each fiame are
made to pass into the ttlescope (/}, one set through the
upper uncovered half of the slit, the other by reflection
Fig. 62.
XX
yL]SOL,f/^ AND STELLAR
CHEMISTRY. 285
from the sides of jh» o»«»ii
'o»er half. Jhu° bringZ'" hr,l™ ^' > ?^> «''~"^h the
v.ew at once, so as to f e ab H" ,?".'^ ""° ""e field of
comparison of the lines. ° '"*''* *"y *'shed for
Jhe small luminous eas flam^ (t,\ :. i j
m'nate a fixed scale in the xlh^ (^^^t^"^^ 1° "^ '° "'"-
the surface of the prism (Ji„to^£V, i '^ "-^fleeted from
as a m^ans of measurement telescope, and serves
and'a1STar1KTe:n°'in'ter "-^ '"'^ '^'^'J-
we 1 represented by the coToured nl«. T T^trument, is
mencement of this volume On tf^fw^^''^^ *' ">« ~m-
solar spectrum; No.Tthe sLct^m V^C'P'''''^"** *e
compounds ; No. \ that nf .1,!*^ ™ °^ '*"« potassium
4 that of the second new alkaiinr ""ft" "'''''''«" ' Na
that of the indium corn^s No S'^i;,^^'^'^' ^o. j
flame of thallium ; No 7 k Jh- ^ j-^^' "'^ the green
yellow line being identkal in J •!• *°^'V'" spectrum, the
line marked D ; No 8 k i- P""""" *'"» the dark i>lar
that of the calcium comyu„'drX"";ol'frK ' ^^ 9
tium compounds ; and No 1, .V. ° f^*' °^the stron-
of barium salts. U will be at nn-.f"'"?;''^''*^'' ''Pe<=t"'m
these lines overHe one In^tK °"«e evident that none of
different substai^Vwere p^^i"- '"^ th^^ K ^H the nine
would be easy to det«-V tj£ L ' together m a flame, it
by the appeal" e'oTa^li l^^CcuHstfc Zl. '"«^^'^"'
Solar and Stellar Chemistry.
troscoSf L'^b^rd' Jha'tlte '"= ^"' °^ *"« ^P-
tained differs essenHallv from tL ^^ fPe<=trum thus ob-
hitherto considered inasmuT,.^*''^"'^* ^^'"'^ «'« have
bright light, passing from red L T"'l' "^ ^ ^and of
by a ve.^ la^e dumber ofUV'*^'- "''" '"tersected
decrees of breadth Tndsha^whfi^h '""f' °^ '''""erent
and always -upy cx^c.^^^ T^te' S^TosS^'
286
ELEMENTARY CHEMISTRY, [Lesson
the solar spectrum. The general appearance of the solar
spectrum, showing the positions of some of the most im-
portant of these dark lines, marked with the letters of the
alphabet, is seen by reference to the chromolithograph
plate above alluded to. These lines indicate the absence
m sunlight of particular rays, and they may be considered
as shadows, or spaces where there is no light ; they are
called ^^ Eraunho/^r^s" lines after a German optician,
who first satisfactorily mapped and described them.
In the last few years the existence of these lines has
become a matter of great importance and interest, as it is
by their help that the determination of the chemical con-
stitution of the sun and far-distant fixed stars has become
possible. The spectra of the moon and planets (reflected
sunlight) are found to exhibit these same lines in unaltered
position, whilst in the spectra of the fixed stars dark
lines also occur : but these stellar lines are different from
those seen in direct and reflected sunlight. Hence the
conclusion has been long drawn that the Fraunhofer's
lines are in some way produced in the body of the sun
itself ; but it is only recently that the cause of their pro-
duction has been discovered by Kirchhoff, and thus the
foundation laid for the science of solar and stellar
chemistry.
If the position of these dark lines in the solar spectrum
be carefully compared in a powerful spectroscope with
those of the bright lines in the spectra of certain metals,
such as sodium, iron, and magnesium, it is seen that each
of the bright lines of the particular metal coincides not
only in position but also in breadth and intensity, with a
dark solar line ; so that if the apparatus be so arranged
that a solar and metallic spectrum be both allowed to fall,
one below the other, in the field of the telescope, the
bright lines of the metal are all seen to be continued in
dark solar lines. In the case of metallic iron alone, more
than sixty such coincidences have been observed j and the
higher the magnifying power employed, the more striking
and exact does this coincidence appear.
whilst all the lines of cerLnoZ'''""?,"" ^ ""ticed,
representatives in the sun F^nm T'^'' ^ave their dark
that there must be some kinrf «? ""'^'^ f^'^'* '' '' ^'ear
bright <!.-,« of theLnTtals^ndL" ""'"-" ^'^'""' ""'
lines, as such coincidences cannot 1^^"'""'.''''^'' '"'^^f
qhance. Is the coincidence of h1.v '¥ '?"" "^ "ere
tne MV-i/ iron lines caused hvlJ '^"''^ '°^" ""=s with
sun? Xnd if so"how do h'?'/i^LP''"''"« °f i™n in the
m the solar spectrum ? " ''"'"^ '° ^PPear a-^,-^.
whlh%aTghrm°ettc itf •=" "y''" experiment, in
into dark lines Thus he i^fX^'" u"'""^' °' changed
cident with Fraunhofer-s Les^^ ^''T '"^"i ""« ("^o-n
as dark lines, by allowTng ,he r^ls frr m Tl^ '° ^PP-^"'
of white Ight (such ■,■> fhl^l. I J""^ * strong source
through a We c<5oured bv i'ol''''''^ "«'«) '<> P^ss
the sin of the spectroscooe '^In.. ' f 'i 't*" '" <■«" "Pon
usual soda spectrum of a L/i/vln'' °^"'=.^ seeing the
a dark ground, a double £^iv^^^^°7 '^°"'''« ''"e upon
and breldth w th the sodf h1 ^,'t'"""' '" Position
the continuous spectrum of ^he' ^h ""f'^" '" '"'««"'
the yellow flame Ls abTorbed 'hJ « "^ ''f^S ^"^ 'hen
>t emits, a consequent Sudon of ilJJ^ ^ '•?'' "^ i's*" "«
of the spectrum occurred anrf^ i intensity m that part
pearance. In like m Wr^h» "^ '""^ '"^''e its ap-
substances have hlenrZ'T.-,T^u\ °^ ™^°y "'her
of vapour having the power 0^.^^^"'^"^^ '" "^^ «'»'«
uemus orbeinlopaqKsuefc'''"^ the same rays
The explanation of the existenrp ^f a , ,■
solar spectrum, coincident whh brLht m.f u''??' '" *=
becomes evident : these dark K^f "metallic lines, now
passage of white light through thl m ""■- "^"^^"^ ^y "-e
metals in question, IresenT f ,£ ^T^^ """P^"' "^ "-e
these vapours absorVexac Iv^hl = '"" '• ''''"osphere, and
they are able to emit^'^i^e suU'rJ:!"'',''^ "s|]'^hich
contains these metals in the condifio^ ? ''■^'•"'^"='"°'e'
lilt condition of glowing eases
288
ELEMENTARY CHEMISTRY, [Lesson
the white light proceeding from the solid or liquid strongly-
heated mass of the sun ^hich lies in the interior.
By observiiig the coincidences of these dark lines with
the bright lines of terrestrial metals, we arrive at a know-
ledge of the occurrence of such metals in the solar atmo-
sphere with as gre.1t a degree of certainty as we are able
to attain to in any que-tion of physical science. The
metals hitherto detected in the sun's atmosphere are fifteen
in number, viz. iron, socium, magnesium, calcium, chro-
mium, r.ickel, barium, copper, zinc, strontium, cadmium,
cobalt, manganese, aluminium, titanium. Hydrogen is
also known to exist in the sun ; indeed this element is
found to exist in large quant ty surrounding the luminous
portions of the sun*s body as a zone of incandescent ^as,
temved the solar chromosphere^ whilst masses of ignited
hydrogen thrown still higher form the red protuberances
seen durin^r a total eclipse. The rapidity with which the
ignited hydrogen moves on the sun*s surface is enormous ;
solar cyclones or circular storms have been shown by
Lockyer to blow with a velocity compared with which our
most violent terrestrial tornadoes are mere summer breezes.
Stellar Chemistry,- The same methods of observation
and reasoning apply to the determination of the chemical
constitution c f the atmosphc res of the fixed stars, as these
ere self-luminous suns : but the experimental difficulties
are greater, and the results, therefore, are as yet less
complete, though not le?s conclusive than is the case
with our sun.
The spectra of the stars all contain dark lines, but
these are for the most -part dififerent from the solar lines,
and differ from one another ; hence we conclude that the
chemical constitution of the solar and stel ar atmospheres
is different. Many of the substances known on this
earth have been detected in the atmosphere of the stars
by Mr. Huggins and Professor W. A. Miller, to whom we
owe this most important discovery. Thus the star called
Aldebaran contains hydrogen, sodium, magnesium, cal-
cium, iron, tellurium, antimony, bismuth, and mercury;
''^vii.j ORGANIC CHEMISTRY. ,«
be remembered, resemhir ti?r ' ^ ^'^"'"' spectra, it will
much as each conS^Mn J/'!:"™ ,°-^ ''''^ ^""' ^"^
:r^ I'nes ; the spectra of ce«2n^n? ?k'' '"'?«f "^d with
other hand, consist simply ofZ^hfli}^, vu^"^' "" '^e
of hydrogen, nitrogen or^LJl '""' ''■'^ 'he spectra
conclude that these nebute are m,.^ "'?",''• "^"ce we
do not consist, like the sun and^tarfof^'^T/S^.^nd
"¥h'eX,rsXcL^f ^t'""^^^^^^^^^ " "^"''
jn its ea^l^ifcy i°\%h\"'ret^^^^^^^ ^T'^" " «"»
lead to the belief that our knowvil^'?*^'' °ht^aei
composition of those far-disLmK ;f- ^^ ?S "^^ chemica"
mtirnkte as the methSls of exnerimf„.^'" J'='l°'»« ""ore
are gradually perfected ^^P^'ment and observation
in Elementary Astronon^."f ' ^""^ ^ockyer's "Lessons
CHEMISTRY OF THE CARBON COMPOITMnc
OR ORGANIC CHEMISTRY ^"'"''^
LESSON xxvir.
teo:^p«S'^'^^,i;«-d
already formed in the bodies'^of n l^f ^ compounds exist
hence the name of Org^k che^t"/' ^°'' ^"'"a's ; aid
Wl"'-'^'
290 ELEMENTARY CHEMISTRY. [Lesson
of compounds which have to be studied under organic
ch/»mistry is so larj^e, and their constitution frequently
so complicated, that they are at present best considered
after the more simple inorganic compounds have been
Certain organic substances do, indeed, differ funda-
mentally in constitution and mode of formation from any
inorganic compound, inasmuch as these exhibit what is
termed an organized structure, being the sole and direct
product of animal or vegetable Ufe. Such an organized
structure is seen in the simple cell, the germ of hving
oro-anisms. It cannot be artificially prepared from its
elementary constituents, whereas any crystalline or liquid
organic body may possibly be thus built up from its
elements. , , . , ,
The first striking pecuhanty which che caiDon com-
pounds exhibit is their extraordinary number, those already
known far exceeding all the compounds of the other ele-
ments taken together, and new ones being daily brought
to light. A second peculiarity of these compounds is, that
they are almost all of them formed by the union of carbon
in different proportions with one or more of three other
elements, viz. hydrogen, oxygen, and nitrogen ; whilst the
number of atoms of these elements contained in the mole-
cule of many organic bodies is extremely large • thus sugar
contains 45, and stearine no less than 173 atoms of their
constituent elements.
The cause of the multiplicity of the carbon compounds
is to be sought in a fundamental and distinctive property
of carbon itself. This con^i .ts m the power which this
element possesses, in a mv.cK 'jg: er deg? ee than any of
the others, of uniting wi^ii iiselj to lorm complicated
compounds, containing an aggregation of carbon atoms
united with either hydrogen, oxygen, nitrogen, or several
of these, bound together to form a distinct chemical
whole. , . , J
Carbon is a tetratomic element ; the simplest compound
of carbon is marsh gas, CH4.
»'J
sxvn.] ORGANIC CHEMISTRY.
of .any other monad woufd how;^^''''"'^-. /°"^ "'"ms
dition; and we find, in feci tC „n' '^"'*^^ '•"■' <^°»-
four atoms of hydrogen /r.n K u ?*= °'' ""o^ of the
for chlorine, 3o tha^^Z 1,.^ substituted, step by step
are obtained; "*^ following substUution pJodu^is
Th ''"'' ^"'^'' ^"'^'^- ^"^''- ^(^'4-
be saturateVnTonly by'^thrunil ''J? u'"*'^^^ """^ «n
monad atoms, bat also by its uTon t"^^ T^^"" '° ^"-'^
one triad and one monad orT^ ° l^° i^"^ ^'oms, or
m carbon dioxide CO »nH u"^ '.<="''''' atom. Thus
have a carbon atoS sa^^Cted w'fc ^'^"JP'^'J^^- ^S. we
cyan.de (prussic acid), CHN 1 \° ''^■''''' •' '" Mrogen
saturated with a triad /N)^d^™„''T,t?^ '^'''■''°" atom
When two atoms of titrTvakn^ . k ^"- ^l"'"^"'-
a new radical or eroun ^JZ- J"^" """e together
mode of this 4a°i 'of Th\"cIX^'^ V''^ ^™P'-'
place by a combination of one of tW «'«,■"«"« takes
of one atom with one of the four ,nl "J "?'"'''"'"« """s
so that two of the eTJioriZT^^°i-^^°^^"^t°^-
saturated or disposed of and o'lv '^"""^ """^ ^^e
combine. Hence, whilst CH;«1'' ""^ ''^'"a'" free to
carbon series, QHlis that „/ V^^ ^T °^ ^^ mono-
S'milarly, C3H, tVt of the tkartnn"'''™ '="^= ' ^^d,
impound of any of these tLl =5- ° T'^^ ' ^"^ no
■ng KspectivelyLore thS, fo^^ '^"^ '^''"°«'n contain-
monad. -^ '"^ '^°'"^' =«, or eight atoms of a
pow:!?s%Fre^e?rL'n°t= S?? "'''*.^' *^ --^-ng
!?■• instance, as carbon monoxide To"" \ T^ ''°^''^'
O-recUy with oXreVmtrrn"''^::.,P-Pe«Lof uniting
U 2
292
ELEMENTARY CHEMISTRY, [Lesson
up the vacant combining powers. Thus carbon mon-
oxide and olefiant gas both combine directly with Clg to
form saturated compounds, which conform to the law
above stated ; whilst, on the other hand, we find it impos-
sible to obtain a combination of chlorine with COg, or
with CgHg
The following graphical representation of these three
typical compounds may help to render their mode of
formation more evident —
Rlonocarbon Senes.
Tricarbon Series.
Dicarbon Series.
From these figures it is seen that an addition of CHg
is necessary to pass up the series. This addition can
actually be experimentally made, and the higher and more
complicated carbon groups thus obtained by synthesis
from the lowest and simplest one, whilst this, in its turn,
can be prepared from its constituent elements. We are
well acquainted with no less than fifteen artificially pre-
pared members of. this series, containi^^J from one to
fifteen atoms of carbon, combined witn a saturating
quantity of hydrogen ; and each member of the series
forms a starting-point for a number of peculiar deriva-
tives, all containing a common constituent, and exhibiting
a family likeness.
The compounds obtained from each of these homologous
series of mono-, di-, tri-, and higher carbon groups, may
indeed be compared with those of the inorganic metals.'
xxvn.] PJ^OPEnriES OF CARBON. ,,3
Sn T^r^^T^^^lr^^^y "^^ -PP°-<1 to con-
plays the same part in AeecomnonnH ^^^1°^^^' ^hich
m the metallic salts, and to wSfh^ ^^ **= ""'^I does
radical has been given Thl r,H- , "^"^ "'^ compound
the three typical fubsLcIs luTt meiH°"'!i'"^^, '" ^^* °f
a hydrocarbon, containing one aSf"l"/°"''d «» be
he ongmal type; and each "f ?hZ ^ !4'''"'-™^^" *an
termed the hydride of a radical S '''?! '" ''^^'-^^r'^
'luicai, and considered to be a
molecule of hvdmirpn H ) • , . ,
Hydrogen, ^ | ,,„ which one atomof the hydro-
gen is replaced by a radical. Thus we have •
MonocarboiT Series Dicarhnn «: •
^M«.c„„^ -MU-;t|j ,„-;--|j
^a:^^o^5SnXtttrd^--^^^^
Monocarbon Series n- v . ^^^^^^^^J"^ Viz. ;
cries. Dicarbon Series t • ,
Methyl-chloride ^Ha) ^ . ^, ^, ., r H . "'^ °" ^"'■^"^•
CI / ^tnyl-chloride *^2 ^s\ t, , , . r- t- ,
And by replacing the s-^me h /^ '"•°^>"-'"-«= ^=3'
radical hydroxylf O H fn eart fTlJ ^^ *^ monatomic
portant class o? bodies' tere^th^.^^r."'^'^'" ^^ '-
Monoc b„„ sen>s Dicarbon Series n ' ,
Med>y,.a,coho. CH, ^ E.hy,.a,coho, C, H.l^ p^^^"™ «"■«.
a?d7rop7'c °h"'' ^^i-^-'^. methyl, CH3 ethvl PR
indivl^iRSuJh'ou? illTh/T'^"' ^-^PO"nd^ 're^.a"j;
peculiar characters to each seriet"'''"'^^' ^^"^ 8-e 'hg
so^rorwS'je'rSs Vd^^^ -''■-'^ (see p. ,76)
Sr;hrh°Se£r^" ^^^^^^^^
294
ELEMENTARY CHEMISTRY. [Lesson
n
thus methylene, CHg, ethylene, C2H4, and propylene, CgHj,
are dyads, each containing two atoms of hydrogen less
th£kn the corresponding saturated hydrocarbon ; whilst
glyceryl, C3 Hg, is a triad, containing three atoms of
hydrogen less than propyl-hydride.
These bodies give rise to a large class of derivatives,
each containing the radical or group of carbon and hydro-
gen atoms. Thus we have from the dyad radicals :
Ethylene chloride, ClaH^f^ ; Ethylene alcohol, Cj H4|§g.
{PI fOH
^j ; Propylene alcohol, C, ^«\0H*
\
Whilst the triad radical glyceryl yields the following :
rci r.,..-„- rOH
CI
Cl
iOH
oh'
All the substances analogous to the foregoing, or derived
from them, are classed as the fatty or paraffin group of
organic bodies. Other carbon compounds are, however^
known, which are saturated, but contain the carbon atoms
more intimately united together than the members of the
alcohol group ; the principal group of these substances is
termed the aromatic group of organic bodies. Thus the
formula of benzol is C,, Hg, and in this body eighteen of
the twenty-four combining powers of the six atoms of
the tetratomic carbon are saturated by combination of
carbon with carbon.
It is found that, however the carbon atoms may be
united together, the combining powers which remain un-
saturated are an even number : from this and from the
tetravalent character of carbon it follows that the sum of
the atoms of monad or triad elements united with the
carbon must be an even number, whilst the number of
dyad elements is not thus restricted.
We shall first study the, properties and mode of forma-
XXVII.] ^ EMPIRICAL FORMULA. ,„
?;:>" P^'^TtL-n^ *r^^^^^^^^^^^^ the faux
series of organic bodies. Pi^operties of the aromatic
Empirical and Ratimial Formula.
The simplest mode of exDres<iino- n,«
an organic compound is to'^write ^own T'S'^'T °f
the constituent atoms side by side, thusT "*"'' "'^
^'^'' • Ethyl-hydride,
'yi Ethyl-Alcohol,
cJr, Ethylamme,
^^ ^""'"^ Acetic Aci4.
chemical composition fthafTsthi P?'"= *^ «^"n=
number of the same eWn ^ uk ''T^'" *e same
their chemical anrphysfcTo,L"*°"^T """y ^'^'^^ i"
tinguish between these '><,«^P'>Ph'i^^^ • ^? "'''l^'- to dis-
cmploy rational formuTJiL,^^^^'''^'^ necessary to
'dea of the chemicrrnafure of til ^"^P?'^ °' ^'^'"S »"
senting the decompositions which thef""';'' ""^ ^^P^^"
foregoing compounds can be reDrP,if»J k "i^"'?'- ^he
rational formul^ : represented by the following
C H )
^H*^ I ' Ethyl-alcohol, ^^^^ \ q
H > N ; Acetic Acid, ^^HgO ) ^
Ethyl-hydride,
Ethylamine,
. ^"^^ denotes that the monad radir;il r w •
in the first three comnnimHc .u . J ^Hg is contained
296
ELEMENT A R V CHEMISTS V. [LESSON
{
that it may be considered to be alcohol in which two
atoms of hydrogen are replaced by one atom of oxygen,
and that a monobasic acid is thus formed. A single
formula cannot possibly represent all the relations of a
compound, hence one body may possess several rational
formulse ; thus, for instance, it is frequently useful to
represent acetic acid by the formula :
CHg
CO. OH.
This signifies that acetic acid contains two atoms of car-
bon attached together (this is shown by the bracket |), of
which one is connected with three atoms of hydrogen, and
the other with dyad oxygen O, and the monad hydroxyl
O W. It is therefore important also to remember that the
formula never pretends to point out the actual position
of the atoms in the molecule, but simply to show the
deportment of the compound. We shall in the future
have frequent occasion to employ both empirical and
rational formulas of different kinds for the same sub-
stance, according to the nature of the reaction or peculiar
property which we desire to explain.
Isomerism.
Carbon compounds having the same percentage com-
position, which differ in their chemical and physical pro-
perties, are said to be isomeric. The isomerism of such
bodies may be due to several causes :
(i) Isojnerism in the restricted sense refers to compounds
which contain the same number of carbon atoms in the
molecule. In the series of hydrocarbons, having the
general formula, Cn H2n Hgn -1-2 cases of isomerism can only
arise from a different mode of arrangement of the carbon
atoms. The first three terms of this series do not possess
any isomers :
CH4 {
CH.
ch:
CH3
CH2
CH3
XXVIlJ
ISOMERISM,
297
central atom, and we thus obtain the isomers / ^
^S: andCHJcS:
.CH3 (CH3
Of the next term three isomers can exist •
CHo
CHa
CHo
CH3
;:
CHj
o 3 •»
beJ-ofto!;:!?-^^^^^^^^ -'- the possible nu.-
froI?Ver&Vthe^^;S"ceS o?" "^ ''''^''
atoms of hvdroeen bv nth^r »iZ f ^°' °*^ °"« <"■ "»ore
tion with one or other of tv,?? v ^^^ P'''<'^ '" connec-
of isomerism arise The fnnnw?'^? ^'T"' ^° »''" <=^5es
of the more simpfe caLs f ° "^ ^°"""'* '"'^'^^'^ ^°">«
Propyliodide.
'CH3
CH„
vCHgl
Normal Butyl Secondary Butyl
Alcohol. Ai t-i ■'
Alcohol.
I CH,
) CHOH
CH3
Iso-propyliodide
' CH3
CH I
.CH3
Fermentation
Butyl Alcohol
ICH3
Tertiary Butyl
Alcohol.
Ethylene Chloride,
' CH2CI
CH
CHgOH
ch;
, CHg
OH
I
CHoCl
Ethylidepe Chloride,
'CHCI2
i
CH,
298 ELEMENTARY CHEMISTRY, [Lesson
With non-saturated compounds a still large number
of isomers is possible, inasmuch as the hydrogen atoms
may be wanting in different positions. Isomerism in the
aromatic series is produced by the same causes as in the
paraffin group of bodies.
(2) Polymerism, — Compounds possessing the same per-
centage composition, but having a different molecular
weight, are termed polymeric ; thus a series of polymeric
hydrocarbons is known which contains double as many
atoms of hydrogen as of carbon :
Ethylene QH^
Propylene CgHg
Butylene Q^s
\ Amylene Q^io
The following compounds are also polymers :
Aldehyde Cj
Acraldehyde C4
Paraldehyde C^
(3) Metamerism, — Bodies possessing the same percent-
age composition and the same molecular weight may also
be formed by the occurrence of different radicals making
up the same total number of atoms, but giving rise to
different compounds. Out of the large number of such
metameric bodies, the following may serve as examples :
Propylamine. Methyl - cthylamine. Trimethylamine.
( CoH. ( C H3 ( CH3
N j H N j CjHfi N \ CH3
Dipropyl Ether. Methyl-amyl Ether. Ethyl-but: 1 Ether.
CgHy J CfiHiiJ C4H9J
Butyric Acid. Methyl propionate. Ethyl acetate. Propyl formate.
Hj^ CaHgOJ^ CgHaOJ^ CHOj^'
LESSON XXVIII,
DETEKMINATION OF THE COMPOSITION OF CARBON
COMPOUNDS.
drogZ:^""^ '""'''""■ ^^''"-"'on of Carbon and Hy.
It is founded upon thffact th^? -t. °''^^"'' substances,
carbon is heateS to redness' with ^'"'^0°'"^°"?'^ °^
dergoes complete combusHorT tL u ^', "^Xgen, it un-
to carbon dioxide (orboncar^^ carbon being oxidized
water, so that by weieUn^ rt5 ^"^."^'^ hydrogen to
products obtainedVbS' 'vf„^"'".y °f j^ese two
stance we can ascertakthl wS nf'^'"u°^ "'^ ^""^
hydrogen which the substance contained ""■^°-' '"" °^
.a^elnTct^-^^^te-^n^^^^^^^^^
^«x-: toTK1-££f hte -
either method the products of com h,?.- u ^^"^ ^eat-in
collected and weighed A L?a?!^'^'^'' ^-^'"^ ^^^^^""x
about 0-3 gram) of the soHH^^k T^""^'^"^ (generally
analysed by Ineansff copper ol ^^ be
bustion tube made of ^^^i'^'^^l^'^t^^^^^^^^
300
ELEMENTARY CHEMISTRY, [Lksson
about 50 to 60 centimetres in length, and drawn out at
one end to a fine point, and open at the other. Before
the introduction of the substance, a quantity of pure and
Eerfectly dry, freshly-ignited, granulated, copper oxide is
rought into the tube sufficient to fill about one auarter of
its length, and the substance is well mixed with tnis oxide
by means of a brass wire (B, Fig. 63) ; fresh oxide is then
added, the brass wire being well cleaned from every pos-
sible trace of the adhering substance, until the tube is
nearly filled.
Fin. 63
The apparatus intended to collect the water produced
is now attached to the open end of the tube by means of
a well-fitting dry cork : it consists of a tube (c), filled
with porous pieces of calcium chloride, and accurately
weighed (this substance effectually absorbs all the water
and aqueous vapour formed in the' combustion): the car-
bon dioxide passes through the tube unabsorbed, and
bubbles into a solution of strong caustic potash contained
in the bulb apparatus. (d), attached to the drying tube by
a well-fitting caoutchouc joining (e). The increase in
weight of the drying tube and potash bulbs gives respec-
tively the weight of water and carbon dioxide produced.
The combustion tube is placed in a long furnace, so
that it can be gradually heated to redness : this is most
readily effected by a number of gas burners arranged in
line, so that each part of the tube can be gradually and
separately heated (f). A larger numb.2r of small burners
xxv..,.] OliCANIC AUALVSIS. 3,,,
rately regulated. After th^wh^t" "'■''>' ''= "«"•<= "ecu-
shown to be proneriv air L^. .'u ''"■'■'inKement has been
the cork, conSi ol »u 'c -n""' °^'l^^ '"''<= "<=»
and when a length of H-sor^fnrPf "'';''<=• '^ Seated ;
the part of the tube con afninTir'"!"*^'' '= '•<=d-hot
heated, until bubbles of carhnnl '"Z"'""'"*^'^ '= Sently
enter the potash bulbs -and ^h^ f"^.''.''^ =<-■<•'" «'<"vly to
this slow .Jisengagernen; of carhnn^^''' '•", ='PP""' ^^ '^at
the whole of thf s1.b"ta„ceis burn" """ "^"""""^^ ""*"
the'tu\^^^^^f^„y;r- ^2 ;?o°'^Lf - *= "''°>«= 'ongth of
as the potash solutbnbegins toTaLTl^t' ■' f"''^^' '''°'-"
nearest the combustion tube fowPntfi^^K '"'° ""« ''""'
carbonic acid), the drawn nnf.ri^r'°u ^''^"fPtion of the
the gas flames extinguTshta' f^ the tube is broken,
and air drawn for sorne minutl. »k end of the furnace
paratus by sucking ^Tt?l^i?!v."!{;°"S\"'« *hole ap-
on the eid of '"L potash"u"bs * Th^'' ^ '"'''= P'^"''
necessary, in ordei fo collert in .k , operation is
acid which still remains in th„^ \ P'^'^'"' "^e carbonic
as this is finishedTthe anaivsisr^.!!,'''","-'"*'^- ^s soon
ception of weighing thr&tubeT^d' '''\''L« ^''-
Many precautions must be taken ^nH J"'', P°fash-bulbs.
details must be oaid in orLf V^ .' """='' attention to
organic analysis : for Lenum°^"^"« ?<=="'-ate results in
manuals must be consumed '" °^ """" ""= '^"-ger
^^'^^^vttZ^xl'^^.l^^X^^ a 'Wuid,it .s
point ; this is again weiehed tht^?- I u ""T" °"' "> a fine
bulb dropped into "h^cf mhistt P?,"'!' ''^'^^n "ff. and the
conducted*^as above described w^' ''"?' "'^ operation
tamed in the body about to b; Z^^" j"?'*^^^" '« -^on-
to place some turnings of metalLf^''^'^-' " '" "ecessary
of the tube to decompos^anv n.^PP^'-/" "'^ fr°"' P^rt
formed and would be absorbed hv°Z ^"T'l *''-<='' are
impair the result. aosoroed by the potash, and thus
303 ELEMENTARY CHEMISTRY, [Lesson
1. Determination of Nitrogen, — Nitrogenous organic
bodies, when heated with caustic soda, or potash, yield
the whole of the nitrogen whi'h they contain in the form
of ammonia. This evolution of ammonia is easily ren-
dered evident by heating a small piece of cheese with
solid caustic soda. Upon this reaction a method is based
for determining the quantity of nitrogen in organic bodies :
it consists simply in heating a given weight of substance
with a mixture of crustic soda and quicklime in a tube,
and collecting the ammonia formed, in hydrochloric acid,
and estimating the weight of ammonium-chloride pro-
duced by weighing as double platinum salt. For every
I GO parts by weight of this salt obtained the substance
contains 6*35 parts of nitrogen.
In certain cases, viz. when the nitrogen is contained as
an oxide in the organic substance, the foregoing method
cannot be employed, inasmuch as these oxides are not
completely converted into ammonia : it is then necessary
to obtain the nitrogen gas in the free state by heating
the substance with a mixture of copper and mercury
oxides, and passing the gases produced over metallic
copper. All the nitrogen comes ofif in the gaseous form,
and may be easily purified by caustic soda from the car-
bonic acid also evolved ; and thus the volume of nitrogen
obtained can be accurately measured. From this volume,
measured under ^iven circumstances of temperature and
pressure, the weight of the nitrogen can, of course, be
calculated.
3. Chlorine^ sulphur^ and phosphorus exist not unfre-
quently in organic bodies, and have to be determined: the
first is estimated by heating the substance to redness in a
tube containing pure quicklime ; the chlorine forms calcium
chloride, in which, on solution in nitric acid, the chlorine
is weighed as silver salt. Sulphur and phosphorus are
determined by heating the organic body with a mixture of
pure nitre ard sodium carbonate, placed in a tube ; sul-
phuric and phosphoric acids are formed and estimated in
the usual manner.
xxviii.] MOLECULAR WEIGHT.
mation of oxyiren hiv^ w« ^ ^^ methods for the esti-
oftcn used. ^^ ^ ^'"'^ Proposed, but these arc not
coS^tt%7^tiut ;^^. P-entage
the number of atoms of carhnnK ^ '^'^''^'^'' h^iy^^^vi
contained in the coi^ouLbu^^^^^^ ?"y^^"» &^-
determination in oX to '^et tn i, '''* '? '"^'^^ ^ ^"^'her
of glacial acetic afid, V^^^rA ^.fc ^" '-^^ ^"?>ysis
to yield 0-580 gram of clrh^nt of substance was found
water; hence ^^a?ts of fepi^^^ ^'^^"^ ^^
pans 01 glacial acetic acid consist of
Carbon . .
Hydrogen .
Oxygen . .
40'o
53'4 (by difference)
lOO'O
ir we divide these numbers respectively by the com-
bm,„g weights of carbon, hydrogen, and oxygen, 1°- v.
6;6_ 53.^ '^ 'i2~"3 3.
-(,■(,, and ^ = 3.3, ^e obtain the relation between
t rt^hirtL'^ttf fer r ^"'^ p--'- Thus
co«tior ^'. *a^c^tS5iJ7---^^^^^^
-:./'^ of the substat;:'wl^t??„'5eUt Tt"/-
304 ELEMENTARY CHEMISTRY, [Lesson
compound of it with some well-known element (such as
silver), in which one atom of hydrogen in acetic acid is
replaced by one atom of silver ; that is, we must find the
weight of C, H, and O, in the ascertained relative pro-
portion, which forms a compound with one atom of silver.
On examination we find that only one such compound
of silver and acetic acid exists ; and we find by experi-
ment that loo parts of silver acetate contam 64'68 parts
by weight of silver; hence, the weight of the carbon,
hydrogen, and oxygen, united with silver (Ag = io8),
. 3S'32 X io8
»s — ^ ^^» — = 58-98. In this silver acetate, however,
one atom of hydrogen of the glacial acid was replaced by
ojie of silver, so that the molecular weight of the glacial
acetic acid is found to be 58*98 + 1« 59*08, or its for-
mula is :
2C
4H
2O
24
4
32
60
The slight difference oLoervcd between the found (59*98)
and the calculated (60) molecular weight arises from un-
avoidable errors of experiment ; the more analyses of
the substance are made, the nearer will the mean result
approach the calculated numbers.
In a similar manner the molecular weights of organic
bases are determined by ascertaining the weight of the
substance whi'-h unites with a known weight of hydro-
chloric acid to form a salt. In the case of certain organic
acids and bases, two or more compounds containing
different proportions of silver (or other metal) and hydro-
chloric (or other acid) are known, and it becomes a matter
for consideration which of these is to be taken as contain-
ing one molecule of the organic compound to one atom
of metal or acid : the choice in these cases is determined
xxvni.] MOLECC/LAR WEIGHT.
enter into combinft 'onZh fm'efaV'.''''*'^'' ^^ ""'"-eadify
There is one mn^t i~ . ^'^'''' ""^ an ac d.
molecular weight^ vo auL° or«Lri?'=H"^ "^ -"'-^O ">e
amed, vrz. the density or" X«tff ^ ^■?'^''^ '^^n be ascer-
VVe have already seen that thil,'^'""'-*'.^^'''*"'- ■""pours.
the molecule of ^almost al voIaX !::'""";'= °""P'^d 4
IS twice that occupied by the a om nf l^^""= '^""'pounds
are a very few exceptions to thU^ hydrogen. There
exceptions can frequently be ini ^^"f"^^ '^»'' ^d these
substances decom^se "hen he^leH"* by the fact that thl
isnotsimplythati^ftheTrSn^?!:'!^'^"'' 'bat the rapour
of water, H,0, weigh.W^S oc °n/'°"!' • '^""^ '"°'«="'e
volume as the atom m'hydroeenwTv '"'" ""^ '^'•g« a
of water-gas is 9 : so hydrfchW^ "! 'i?"" "'^ ^^"sity
365, occupies two volumes and -K 1"<^'."P- weighing
ammonia, NH3, weighing 17 has a d.n?f"^''o'«'7S' and
This same simnl/ff^iil- '^' f ^ aensity of S'C
chemistry.^^TirtS:; .t "."^it.f^ '" -^-'c
M«</ occui,ies in the sa/eous?tJf "^"','"'S''"'f "»»•
''"''SJ'" thai occupied bZTatlmnfL''A '"'''""'' ''^'" *'
Of ojsrprn'dfSe^in^^^^^ ^^"-^ ''-•««
as serving to control the corrert; "?P°«ant matter,
we.ght ascertained by the fo?e^o?n J" fu '.''^ molecula;
•"Stance, the density of the van^ '"^f'""*?'^^- . Thus, for
by experiment to be3o-orCH ^ "^ ^Tl'i ^"'^ '= found
gives a molecular weieht tnl.Tf^ ' ?"<! 'his accordingly
agree ng with that obSned from T^-^^^'H, a numb«
derations (see ante, p. 30") ^™"' P^^'y chemical consi-
pott^oVsas-^r^cr r^-^^ -«»* ^e im.
3o6
ELEMENTARY CHEMISTRY, [Lesson
represented by the formula C3H7O ;* the determination of
vapour density, however, gives the number 59*8 as the
density of acetal gas : hence the molecular weight of acetal
must be 59 X 2, and its formula not €31170 = 59, but
CeHi4 02 = ii'. It is, of course, possible, when the
molecular weight of a compound has been otherwise as-
certained, to calculate its vapour density ; this calculated
density will always differ slightly from that determined
by experiment, owing to the unavoidable errors which
occur : this, however, does not detract from the value of
this method of controlling the molecular formula of a
substance.
XXVI]
conde
ducte(
cury
obtain
We
tion.
given V
temper
\ DETERMINATION OF VAPOUR DENSITY.
Two methods are employed for determining the vapour
density of a compound, (i) By ascertaining the weight
of a given volume of vapour. (2) By ascertaining the
volume of a given weight of vapour. In the first of these
processes, a thin ^lass globe is employed of about 200 to
300 cubic ceatiui tres in capacity, having a finely drawn-
out neck ; the exact weight of the globe filled at a certain
temperature and under an observed pressure having been
found, a small portion of the substance whose density is
to be determined is brought inside, and the globe then
heated by plunging it into a water- or oil-bath (Fig. 64)
raised to a temperature much above the boiling point of
the substance. As soon as the vapour has ceased to issue
from the end of the neck, this end is hermetically sealed
before a blowpipe, and the exact temperature as well as
barometric pressure observed. The bulb thus filled with
vapour is allowed to cool, and is next accurately weighed,
and the point of the neck broken under mercury ; the
mercury rushes into the globe, owing to the vapour being
* We see thut as this formula contains an uneven number of hydrogen
atoms the existence of this substance is impossible : we know that ..he true
formula must be a multiple of this, which multiple, we decide by the vapour
density^
this with
measured
example (
may serve
with dry
filled with
the globe,
to 760 mm.
fo the end
IS necessai
globe, the 1
the weight
xxvinj VAPOVJi DENSITY
condensed, and, if the pv„« • ^°^
ducted, comple ely fin, ^P^"™^"' has been well con
cu.y which thus emeis tL ^""'.""e volume of „,er.'
fig- 64.
this with the w*si*rrT^f ^r
measured undir the same ;''"^' ^°'"">« °f hydrogen ...
example of thfvapVur deStH?^"'^?;- J^^ ^o^o-mg
°^^ay serve to illustrate the method .V°•'\'''^^y<^'•°='»^boS
wth d.y air at ic-c" 2,.^a „. ^^'gh' of globe filled
filed with vapour at i'^o'*^?,.|;^J»='- weight of globe
he globe, 178 cbc. As the ba'rom.»,^^",' ■ ''^P^i'y of
0760 mm. and underwent no ch^n'^i""/"'""" stood near
the end of the eynpr?r^ . "Change from the beeinnin,r
'^ necessary. In order to 'i "? <=on-ection for Surf
globe, the weigh?of air rn„f ' *5^ "'^'s'^' of the vacuous
fte weight of rfoh; f^^?."'^;?^-^ '""St be deducted fr°™
3o8 ELEMENTARY CHEMISTRY. [Lesson
760 mm. weighs 0*001293 gram, and 178 cbc. of air at
I5.°5 would occupy ^^T^ = 168-4 ato°, and the weight
of this air is o'2i8 gram : hence the weight of the
vacuous bulb is 23-231, and the weight of vapour 23720-
2,. 23 1 =0*489 gram. We must now find what 178 cbc. of
hydrogen at 110° will weigh: 1000 cbc. of hydrogen at o"
weigh 0*8936 gram; 178 cbc. will contract to 126*9 cbc.
ato°. 126*9 cbc, of hydrogen at 0° weigh 0*01134 gram;
and this is therefore the weight of 178 cbc. of hydrogen
at 110°. Hence ^^77|^ = 43'i3 is the density of the
, vapour, as found by experiment. The formula of the
substance is Cg H,4, or its molecular weight is 86. In
this example many n "rior corrections, such as the expan-
sion of the glass globe, the error of the mercurial thermo-
meter &c., are not considered ; the above method gives
results which are sufficiently accurate when the object is
to control the molecular weight of a compound.
The sec<ifid method of vapour density determination
consists in ascertaining the volume occupied by a given
weight of substance when heated up to a temperature con-
siderably above its boiling point. The mode of calcula-
tion is in princip-e the same as that of the former method.
For the details of menipulation the reader must refer to
the larger manuals.
Boiiing Point *nd Fractienal Distillation.
Another important physical property of organic com-
pounds is the boiling point. Every volatile ch mical com-
pound has, under given circumstances of pressure, a hxed
and constant boiling point; and this property is useful in
ascertaining the purity of an organic hquid, as well a
enabling us to separate the constituents of a mixture by
means of fractional or continued distillation. The boiling
point of the homologous series of hydrides, alcohols,
[Lesson
of air at
the weight
ht of the
ir 23720 -
[78 cbc. of
ogen at 0°
126*9 cbc.
[34 gram ;
hydrogen
iity of the
ila of the
is 86. In
the expan-
ial thermo-
thod gives
le object is
•
emiination
by a given
rature con-
of calcula-
ler method,
ist refer to
ton.
^anic com-
inical com-
lure, a fixed
is useful in
as well as
mixture by
The boiling
3, alcohols,
xxvni.] FRACTIONAL DISTILLATION 309
Reparation of uS^olfin J^^diSfST/^Te *|
Fig, 65.
Of fractional distillation is represented in Fie 65 Th^
large surface presented by the wide tube in whih the bn m
of the thermometer is placed aUows the yapour of th^
ess volatile constituents to condense and flow back imo
the flask contaming the mixture; the temperature of "h°
3IO ELEMENTARY CHEMISTRY. [Lesson
vapour is indicated by the t'lermometer, and when the
temperature rises beyond a given point the liquid already
distilled over is removed and an empty flask substituted
to collect the portion of liquid next coming over. Each of
these portions is next separately submitted to the same
operation, and the process repeated until a pure substance
with a constant boiling point is obtained.
LESSON XXIX.
MONATOMIC ALCOHOL GROUP.
' General Characteristics. — The primary monatomic
alcohols and their derivatives form a very large and im-
portant group of organic compounds. As an example of
these alcohols we may take ethyl alcohol, CaHgO, known
as spirits of wine : this substance, in common with all the
other alcohols of this series, may be considered as water
in which one atom of hydrogen is replaced by a radical,
having in this case the formula CgH^; hence ethyl alcohol
is ^H^ [ ^" ^^^yl alcohol is in constitution analogous
K )
to caustic potash, jj > O : and as, by adding hydrochloric
acid to the latter, we get KCl (potassium chloride) and
Tj I O ; so the chlorides, iodides, and bromides of all the
alcohol radicals can be obtained by treating the alcohol
with the hydracid. The analogy of the ethyl with the
potassium compounds is still further seen in the fact that
an ethyl compound exist- vhich stands to alcohol in the
same relation as pota u..^ monoxide to caustic potash:
this compound is c ion or ethyl ether, p^u*[0.
We also have analogous compounds to the potassium
salts ; thus we have :
XXIX.J MON ATOMIC ALCOHOLS.
3ir
NO2 j O '
QHg
NO2
Potassium nitrate .
Ethyl nitrate ... ^gHg ) ^
Hydrogen-potassium-sulphate ^ | SO4;
Hydrogen-ethyl-sulphate
Potassium sulphate
Ethyl sulphate . . .
Potassium acetate
Ethyl acetate .
C2H5
C2H3O
K
C2H3O
CnHr
SO,;
jo.
\o..
oxidizmg action continues lone-er ;inntw ' a ' ^^^
acedc Jid is formed, whicffiTe"coX?sSorcTo'
Both these suL. ances may be regarded iVJl^^,-^- * ^2-
oxidized radical, or ethyl in which 2 ttntc ? u'"!"^ ""^
arereplaced by .' atom o'f oxygt^'kfdeTyr tSLttS
the hydride of this radical (called Acetyl) QH3O )
whilst acetic acid is water in which i atom of hydrogfn'is
replaced by acetyl; thus, C.H3O ^ ^^^^^^^ .^ ^ ^^^_
reduced to alcohol. "owever, cannot be directly
3i»
ELEMENTARY CHEMISTRY, [Lesson
Every primary alcohol can thus be oxidized, and yields
an aldehyde and an acid, which stand in the same relation
to one another as the above-mentioned bodi^^s. • All these
acids are monobasic; that is, they contain only i atom of
hydrogen replaceable by a metal. This hydrogen can also
be replaced, not only by the ethyl and the other alcohol
radicals, givir*^ rise to bodies called the compound ethers,
of which ^-.'-^ J O, acetic ether or ethyl acetate, may
be taken as an example, but also by acetyl itself or the
C T-T O )
other oxidized radicals : thus we obtain r^ H^O ( ^» ^ ^"^"
Stance which we shall term acetyl acetate, but which is
f^-equently called acetic anhydride, or even anhydrous
acetic acid.
Each alcohol also forms a series of compound ammonias :
that, is ammonia, H > N, in which one or more atoms of
H)
hydrogen are replaced by a radical : thus, for the ethyl
H
H
!
N ; diethyl-
QH5
series we have ethylamine, or ethylia,
amme, Cg Hg > N ; and triethylamine, Co H5 > N. We
H ) C2H5.
can, indeed, go one step further in the addition of ethyl,
and obtain a caustic substance resembling potash in its
properties, and analogous to the ammonium hydrate,
pj* I O, but containing 4 of ethyl in place of the 4 of
hydrogen; thus, ^ ^h
O : to this substance the
name of tetra-ethyl-ammonium hydrate is given.
Compound ammonias are also knowiT'in which one or
more atoms of the hydrogen of ammonia are replaced by
the oxygenized radical of the acids, and these compounds
are termed Amides : thus we have with acetyl,
We
XXIX.] ALCOHOL DERIVATIVES,
ftcetamide,
313
N; diacetamide,C2H3
H
N;
and ethyl diacetamide, §58 L.
Compounds of the almfir^i ^^a- t^'^ *
nic an. .^os^^^tX^-^''^. ^^^^l^. -"
rorinstance.CH:|A,tH.ethyIa.i„e,a„a§g:Jp,
bodies which in their tu;n.l.t? """^J *'"' &=•. »<> form
and have, therefor, been te™ 'd"'^^* ='''°"°^> &<="
bodies: such substances are ''ncthv? °T °°-™«allic'
These may be considerpH ^c »k ^^ ^<1 stannethyl.
in which the chlorine has Lin'' "^"T-^^Prding chlorides
radical; thus: ''^^° ''^P'^'^^d by the organic
Zinc chloride, Znj a. Zinc ethyl, Zn | Sg, .
Tin chloride
/CI
•ide,SnjCl^.
I CI
Stannethyl,
alc^hdfiJTdtlli^o^Sr ?■=' 1^" *« p'-ary
boiling and melting p^i„"ri„^snm^»*""' ''"'"i""''^' ^^^
corresponding to a known acid has n^f^'fu" *^ ^'^°hol
a blank is then left in the 4ohol series'^" ''" °'''^'»«»'
3M
ELEMENTARY CHEMISTRY. [Lesson
«
CO
+
g
O
ffi
o
o
u*^
<
^
3
>;
^
}_,
<
^
s
r— <
1— <
fTl
1^
}J
Ph
"a
o
PC4
s
c "
22
o
o O (S
++I
o o o
u^ . T^oo rN. CO CO M
i-i ^ CS tJ- invO
+ '++
o
• o o_ o o o
On u->vo f^OO CO
p_oq^oooooo
8 ^ §v3 ^ 8^ 2^^v8 I I I I I I I I I I I
oooooooocooooooooooo
uuuuuuuuuuuuuuuuuuuu
u
o o o o o o o .
so 00 \0 0^ M O "^
VO t^ On O fO i-nvo
\
ONLO
tN.00
2 I I I I 1 I I I M
w
13
6
coooooo
© <M 'It to
»!» O <» 1-" i-l rH rH
p"P^ 'T^ ^T^ T^ f*^^ ^^ ^T^
|X| KH h^ HH HH t-H l-H
M CO >>*< la o *-
u u u u-u u u
o
o
1-1
u
o
'I*
Ik
CO
u
I I
oo
<o e*
I iKffi
l^ o
C<l CO
-M
;5i p p_; c!: 1^; w 51
o
r \
uu
Cerotic . .
Melissic
ONLO
t
1
/-^ /— \
<0 IM
UJ CO
SECONDARY ALCOHOLS,
XX! X.J
In fl, r ^'^'''''^^^y Alcohols.
OH h^X'x^^^^^^^^^^^ the group
the chain. (See the figures on n ,^ n^^??", ^^ ^^^ end of
alcohols are, howeverf known ?;^^ :^ ^^^^^ classes of
termed the class ois^^on^l^l^''^^ °«e of these is
hydroxyl is attached toT?arb7n nl^^^^^ these the
the centre of the chain nr i? . ^^""^ "^^^^^ is placed in
?toms. Aglancearthe^res^r'''^" othe? carbon
in the mono- and di-carhmf /^ ^* P* ^92 will show that
can occur The first series in'which '^^f^^^ ^^^ohok
exists IS that containin/the ^ cTrh. '"^^ ^ compound
The primary and secondar. aiSn^"" '''' F^Pyl radical,
number of carbon atoms aTet^^^^^^ '^^ «ame
of their properties and in the m n^f ^ ' ^5 .^'^^^ ^^ many
decomposition. '^^ "^^^^ ^^ which they undergo
form'uV "'^^ P-Py^ alcohol is represented by the
( CH3 ( CH,
JCHOH or cK^a
(CH, ^) H'
.OH
- I called r,i..HyUa.bi„o,:ca.bi„ontse,fbe.„,
C ^^„ , or n^ethyl alcohol; and .ethyl carbinol, C j ""f
'atrs*'?htdrS„ °° -'if on these substancis€
termed a KetC^'^hus : ''"''' "° ^'^^'^y^e, but a body
Dimethyl
carbinol.
<CHOH
(CH3
- Ho=:
Dimethyl
ketone.
(CH3
<co.
(CH3
3i6
ELEMENTARY CHEMISTRY. [LESSON
The ketones take up hydrogen, forming the secondary
alcohol, but on oxidation they do not yield the corre-
sponding acid, forming acids containing a smaller number
of carbon atoms.
The following is a list of the secondary alcohols at
present known. They all contain the group CH3, and on
oxidation this is liberated in combination with one atom
of carbon as acetic acid, whilst the remaining alcohol
radical forms its corresponding acid. Thus frohi methyl-
hexyl-carbinol we obtain acetic and caproic acids.
List of Secondary Alcohols,
CH.
Dimethyl carbinol
C3H8 O
Boiling point
. 84°
Methyl-ethyl-carbinol C4H10O =: C
9/*
Methyl-propyl-carbinol CgHjgO = C
108°
Methyl-butyl-carbinol
QHi^O = C
136"
Methyl-hexyl-carbinol CgHigO = C
Q"13
i8i'
Tertiary Alcohols.
A third class of alcohols exists in which the hydroxyl
(OH) is attached to a carbon atom which is placed
XXIX.] MONOCARBON SERIES. 3,;
c^lo'rides'^^^^^ ^nd'n '"'^S^ ?*°"^^- These alcohols yield
first term of this class k ?W \ fu ''^°" ^*°"^»- The
tertiary butyl aM^ % f^Sy^^^^^^^^^^
lowing are the members of the Sarv^i'-^^^^^^ ^^^ ^°^-
far as at present known : tertiary alcohol group as
Trimethyl carbinol C,H,oO = C j ^l^\'!^t^'
Dimethyl-ethyl-carbinol QH^.O = C I cPh"^'
( oh'
Dimethyl.propyl-carbinolCflHi^O = cl QU^'^
(OH
100"
I2o'
Methyl-diethyl-carbinol QH^O = C j (C%,
OH
115^
HieO = cjg|jH5)3
Triethyl carbinol
Diethyl-propyl-carbinol C,H,,0 = c| (?i?
( OH '
MONOCARBON OR METHYL SERIES
^.%/«^.M ^«3 ( o, commonly called wood-spirit.
ayi^:^.„i 4ffi3f ^P^"^^^-"
theticaSy built uTfromtt^mn^S?",''''^'''^^ "^ =yn-
31 » ELEMENTARY CHEMISTRY, [LtssoN
organic compounds, by forming a crystalline methyl
oxalate, CH^[^2 04' *^is, on treatment with water, is
decomposed, and yields the alcohol in the pure state.
Methyl alcohol is a colourless, mobile liquid, possessing a
pure spirituous smell ; the specific gravity of i\ liquid is
0-8142 at 0°, and its boiling point is 66°. It burns with a
non-luminous flame, and is soluble in and miscible with
water. Potassium dissolves in methyl alcohol with evo-
lution of hvdrogen and formation of potassium methy-
late, j^3 ( o. Methyl alcohol when acted on by
oxidizing agents -lelds methyl aldehyde and formic acid.
By^ the action ui bleaching powder on methyl alcohol,
chloroform is obtained ; acted upon by hydrochloric acid,
the alcohol yields methyl chloride.
The action of strong sulphuric acid on methyl alcohol
is remarkable, and is the type of a general reaction.
These two substances must be mixed with care, as great
heat is evolved when they come in contact. The first sub-
stances formed are hydrogen-methyl-sulphate, S^ [ S O4
<by exchange of hydrogen for methyl), and water, ^ \ 0.
When the hydrogen-methyl-sulphate comes in contact
with another molecule of alcohol, we have another ex-
change of hydrogen and methyl occurring ; but as this
exchange can occur in two directions, we get either
CH3 I O ^^d S i SO4, or g j O and ^ga j go, : in the
first case dimethyl eth-^r and sulphuric acid ; and in the
second, water and methyl sulphate, according as the excess
of sulphuric acid present is small or large.
Methyl Hydride, or Marsh Gas, ^3 ( ^^^g ^g j^^^^
seen, this gas occurs in nature as fire-damp and the gas of
marshes. It can be obtained easily by heating sodium
acetate with caustic alkali ; the acetic acid spUtting up
319
xxjx.] METHYL COMPOUNDS.
into carbon dioxid** —a
CH,. Methyl h;d?rd;ca„'"a?ro\^"\ f^.H 0,=C0,+
the vapour V carbon disSohid." °^^'"u'^ ^^ P^^^'ng
phuretted hydrogen eas tW *."**' '°e«'her xvith sul.
th.s way it may fe bSt up froTi.t '''''■''?' '"''«'• ''"d^n
It may likewise be obtained bvL 'J""""*'" ^iom^nts.
together with zinc and water^ M^^^ T^^^^ '"^ide
colourless, inflammable Rarwhirh ^^^^^^ ^>"'"'^« >s a
'ummous flame, and wfien m ; v^ ^"T ^'^^ ^ sligh. y
dangerously explosive sas Mncf '^'i^-^''- P>-oducls a
not actAipon this hydride mf ch n^^"'"'"^ ^^^««n'« do
presence of sunlight witf i cWonne attacks it in the
explosion By th^e sW a .ion Tf chlo "' '° P'°<^"^« »
tMui ton Products are formed L„ "^^'or'ne, several f»^
are methyl chloride, CH Ci T.Fr"'^ "'"'^^ "^ *hich
=^^°Vetrachloride,Ccr ' ='''°™f°™, CHCI3, and
eas, condensing at -20^ hvL°^'"^** ^= a colourless
with hydrochlofic acid o^ phosphZ,"''"".'"^','^^' '"'=°ho
also formed along with othi^r !^k 5"^ Pentachloride : it is
chlorine upon mfrrh gas Wh. "^''^'^y ">« action of
closed tulTes to i(x?> f? n„^ *"?" ''^^'^d with potash in
alcohol are formedrthu^-:^"'^"'"'" ='''°"de an^d meX"
CH3a + KHO = CH3Jo^^^,
pres|nce of phosphorus ^ '''°'"'"^ ^^d iodilie in
mar* pjTut^t^'is^^'riUTbv 1^^'' ^'"°""^ ^^'^ on •
Mhyl alcohols with SeachW ' ^}'"^ "P°" methyl or
heavy liquid, possessing a power^J'^'^J ^' '= ^ «obile'
as specific gravity is ^r.fc at o ^^.^--fable smell
Chloroform is much uspH in 5' •''"'' " ''O'ls at 62°
and ■>''"V^''' ^ tempor^^l,;? St ir', "'"'''k",^'"^' "^'n
and is therefore much val,,?rt f "^?^''"'"y '» Pain,
Many other organic"tlatar1,od"ies'"lct1„°P^^'^''°f-
WUU1C& act in a similar
320
ELEMENTARY CHEMISTRY. [Lesson
manner, but none so effectually and so harmlessly as
chloroform. An iodine compound, analogous to the pre-
ceding, has been prepared ; it is termed Iodoform, CH I3,
and is a yellow solid body.
Carbon Tetrachloride^ C CI4, is a colourless liquid, boil-
ing at 77°, obtained as the last product of the action of
chlorine on marsh gas. When this substance is brought
into contact with an amalgam of sodium and water, an
opposite substitution of hydrogen for chlorine occurs,
marsh gas and all the intermediate products being
formed.
Dimethyl Ether, pJJ^ | O, a colourless and sweet smell-
ing gas at the ordinary temperature of the air ; but con-
densing at— 21° to a colourless Hquid. It is prepared
by heating the alcohol with sulphuric acid, as already
described.
Methyl Cyanide,^^^ \ .—When methyl iodide is heated
with silver cyanide, two isomeric compounds of the above
composition are forr d. They are both colourless liquids :
one, which boils at ^ j°, is characterised by possessing an
extremely disagreeable smell. This cyanide is easily de-
composed by acids into formic acid and methylamine ;
thus :
Methyl and Water yield Methylamine and Formic
Cyanide , Acid.
^^3|^2H20 = n| h'+ch^o^.
From this decomposition we see that the cyanogen
is connected with the methyl by the atom of nitrogen,
and this body is therefore called methyl cyanide. The
other isomer has been called Acetonitril, and is best
prepared by distilling a mixture of potassium cyanide and
potassmm-methyl-sulphate. It boils at 77', and is not
acted upon by acids. In presence of potash it splits up
into ammonia and acetic acid.
'T*''
XXX. J
^^ CARBON SERIES.
.. and
Acetonitril and Wafpr ,„-^m a
^^ Water y.eld Ammonia and Acetic A^.d
CN'h-2H20 = NH3 + iCH3
321
hydrogen to form ethy amine Hen.'"'"'' '"'"' "^=««
two atoms of carbon are combined ,.1, "^^ =^^ '^»' 'he
compound really belongs to the"'ethyfferiera"nH"''' *''^
to It the rational formula C } ^ ^ ''' '"'* *^ S'^*
LESSON XXX.
DICARBON OR ETHVL SERIES.
JfoLtor'IpS'o?' *:!: ■■^PS-'^'^' f ™=. is common
hydrate, and, like its numerous ."„^ ' 'n f '^ "'^ "hyi
tives, contains the radical eSwCH ^^"-''n°«'n deriva-
mentation of sugar a"dico ' '" "" """"^ ''-
sugar solutionlTp'r^sen roF°ye'srin""^?\^ ? ^^-o-
carbonic acid are chiefly formeri" A '^ll"''' ^'"^o^ol and
Alcohol aud alcoholic h'miiH^ = ^ " P' 398)-
quantities by the fermentSn nf ^ P^'^P^''^'^ « brge
various sources. The femeZn 1 '•F'' '''^"^^d from
'he d, ute aqueous spirit tCsseDii'?"l''r " '''^'"'^d, and
mpunties: it is obtained in". Sf^'' '^°™ non-volatile
repeated r.ctifica.ionsras U Ms at ';"1''^'"''"'^^ f°™ by
than water. Alcohol cannot hni '°*f '<:mperature
•separated from water by sh^nl fT-7^'' ^"^ completely
spirit which can thus be preDan>H V f '• °''' "'^ ^tro.-igest
water. To withdrav ?n ,1 "^ containing to per .-^nt
distilled with s!^". "K..f .'.''^^^^'.'^.^ 'he spirit must h^
■"""'"- '--f awc of comtining with
322 ELEMENTARY CHEMISTRY. [Lesson
water, such as potassium carbonate or quicklime. The
pure liquid thus obtained is termed absolute alcohol; it is
a colourless, mobile liquid, possessing a pleasant, spi-
rituous smell and burning taste ; its specific gravity at o"
is 0809 5, and at IS^'S, 07939 ; and it boils at 78^-4
when the baroaiietcr stands at 760 mms. It has not
been solidified, becoming only viscid at a temperature of
- 100°. Alcohol is very inflammable, burning with a
slightly luminous blue flame. It absorbs moisture with
great avidity, and mixes with water in all proportions, the
mixture evolving heat and undergoing contraction.
Alcohol can also be prepared from its elements by syn-
thesis. This is done by obtaining acetylene, CgHj, by the
'direct union of carbon and hydrogen (page 95), and com-
bining this directly with hydrogen to form defiant gas,
CoH.; this substance combines directly with strong sul-
pihuric acid, forming hydrogen-ethyl-sulphate, ^ ^6 J SO4;
and this, when boiled with water, forms sulphuric acid
and alcohol by exchange of ethyl for hydrogen, thus :
defiant gas also combines with hydriodic acid to form
ethyl iodide, which forms alcohol when heated with
caustic potash. , 1 , , .
Many salts, as well as gases, dissolve m alcohol ; it
likewise acts as a. solvent for resins, organic bases, and
essential oils, many of which do not dissolve in water.
The determination of the strength of spirit, when free
from sugar or other soluble matters, is ascertained by
determinin;? the specific gravity by means of delicate
hydrometers, and reference to accurate tables, showing
the percentage of water. In these estimations the tem-
perature must be accurately observed, and corrections for
deviations must be made, as alcohol expands considerably
with increase of temperature, and the specific gravity is
XXX.;
there
tains
posse
the h
sale <
ten pi
purpo
and \\
chemi
less a]
extrac
from
(Made
cent., ■
cent.
Alec
a red-1:
line, b<
dation
into ac
atmosp
or mon
(see Ac
cohol H
sium- o
forms, \
respond
Strong «
gen-eth]
forms s^
ethyl-su
Ether
substanc
pounds.
prepared
XXX.J DECOMPOSITION OF ALCOHOL 3,3
possessesj speciL l^avity^ofoS Vtlf''^"'^' '"'
the high duty on Dure snirit Xl^n ^ *• Owing to
sale of a mixture of nin?ty ^^^ „f°.?"""'".' ^""'^ «>=
ten parts of wood-spirit for Sf,f°^f":°"S H'=°hoI with
purposes: this substance is 4T/H<""i^"^ "^'^^""fi-:
and is most useful to the sc^nfll '"^""y'^ted spirit,"
chemist. Spirits win and w , ^^ manufacturing
less alcohol,'flavoun\,^trcmafn%S%'^°r'^^ «°^« »
extracts. Brandy, whiskev f ^H ?., essential oils, sugar, or
from 40 to 50 percent of l/rl""'"" "?'"'= -^o^'^in
(Madeira and portUo 7 or 8 n,Vh? f '■ '"'"^^ ^^°™ «7
cent.. Whilst sty a?eln°J ^ f c'o^^^ f^^.^ 5^°f ^ ^
Alcohol is decomposed when if « vor,«„ •
a red-hot tube ; hydro/en mar.u I P^*^^ P^"'^"^ ^^^°"&h
line, benzole, andffi Kcts^S^ ^f'' "^P'hV
dation alcohol is transformed fc ^^ «^i-
into acetic acid. This oxidation m!? t^^^^J^e and then
atmospheric oxygen in oresenri nr^^? ^I- ^^^^^^^ by the
or mo/e slowly Xen ceEerme^^^^^^^^ P^^^^^^^i!
(see Acetic Acid, p. ^ c i ) Th^^Vr^v ^°^*^? ^""e Present
coholwithrapidit?,I^Lj|<^SSS1ot^^^^^^^^
Slum- or sodium-ethylate, ^^H^ ^ngpotas-
forms salts called the et^TsSes S^f "iff *^''=''
ethyl-sulphate is ^^^»jsO,. Potass.um-
substance is formed in , „ -^'^'J ^- ^'^ 'mportant
pounds. The mosf sTmnK/.^l T^^fr""' «hyl com-
prepared is that of acX^!, "'°" P^ "'''''^l* ether can be
acting upon potassium ethylate witlv
V 2
324 ELEMENTARY CHEMISTRY. [Lesson
ethyl iodide, an exchange of ethyl and potassium taking
place, thus :
and
Ethyl
Iodide
C2H5
Potassium
Ethylate
give Potassium and Ether.
Iodide
I -h ^2
K'JO
KI + V^2
":!°-
Another reaction by which ether is prepared on the large
scale consists in heating a mixture of alcohol and sulphuric
acid to 140°, when ether and water are given off. The de-
compositions which here take place are as follow : in the
first place, alcohol and sulphuric acid form hydrogen -ethyl-
sulphate (sulphovinic acid) and water, by an exchange of
hydrogen and ethyl, thus :
Alcohol and Sulphuric yield Water and Hydrogen-Ethyl-
Acid Sulphate.
This hydrogen-ethyl-sulphate next comes in contact
with a second molecule of alcohol, another exchange of
hydrogen for ethyl occurs, and ether and sulphuric acid
are formed.
Alcohol.
Hydrogen-Ethyl-
Sulphate.
Ether.
Sulphuric
Acid.
The water formed by the first decomposition, and the
ether produced by the second, are given off as vapour,
whilst the sulphuric acid remains behind, ready again to
go through the same series of changes on meeting with
two other molecules of alcohol. This process is called the
continuous etherification process^ as a current of alcohol
may be passed continuously through the sulphuric acid
heated to 140°, and a regular supply of ether and water
thus obtained.
Ether is a colourless, very mobile liquid, possessing a
strong and peculiar etherial smell It is lighter than
XXX.]
ETHYL COMPOUNDS,
325
lieavierthanhydroten and ^an 1 ^''P?/ '^ 37 times
vessel like carbonic acid 4 V h ^""''^'^ ['■°'" ^^^='^' '<>
flame, and explodes Xf mixed wri^'F '^ '""^'T"^
boihng pomt great care must be taken ^L ^"^ ,"^ '°»'
vvlien working with this suh^anl. • ''''°"' '='<Plosion3
becoming mixed with air Fth"'- °'^'"?, '° "'^ ^''PO"r
oxidizing agents vie din^ f), '^ ^^^''y attacked by
and it is%lf: ac^'d' uSVy\\l^?„\7„^;«f - -'coho.^
of substitution products formed ' '^^ ""™'''^''
tainX^X^rSnr ^^^"1^^^!^ ^ °'>
potassium meth^ate, thus; ' "''^^ '°'''''« "Po"
C2H5I +
CH,
!°-
KI -f-
C
C2
51^'
or b> acting on hydrogen-methyl-sulphate, ^Ha \ cq
witli ethyl alcohol. The following is a list of ^ ^ . **
more important simple and i-x^^tL^r^of fhLTeri^s ^
Table of Simple and Mixed Ethers.
Dimethyl ether . . Cg Hg O
Methyl-ethyl-ether . Cg Hg O
Diethyl ether . . . q H,,0
Methyl-amyl-ether . Cg H,^ O
Ethyl-butyl-ether . C^ H^,0
C H
C
C H
C
O
:H!io
Boiling
Point.
-fl2'
So"
ELEMENTARY CHEMISTRY. [Lesson
Ethyl-amyl-ether
Di butyl ether. ,
Ethyl-hexyl-ether
Diamyl ether . .
Cs HigO
Cj^HajO
ai° • •
Boiling Point.
112"
-6
'5
QH
11 Jo
11 )
C H )
Ethyl Hydride, ^Y^\ * — '^^^'^ hydrocarbon is obtained
by heating zinc and methyl iodide in a closed tube to
150°:
2CH3I -f Zn = CaHg-f-Znlg.
It may be obtained from ethyl iodide by heating it with
zinc and water in closed tubes to 1 50° :
2^2H5 1 4. 2Zn -f- H I O = zCgHe + Znl2 4- Zn 0.
Ethyl hydride is a colourless, tasteless gas. It is rapidly
acted on by chlorine, in diffuse daylight yielding . ethyl
chloride, Cg Hg CI. If excess of chlorine has been em-
ployed, a series of further chlorine substitution products
is obtained, the last of which is carbon trichloride,
C2 Clg.
Ethyl Chloride^ CgHgCl, is obtained as a mobile liquid,
having an etherial, penetrating smell, by saturating alcohol
with hydrochloric . acid gas, or by acting with the phos-
phorus chlorides upon alcohol, thus:
5 H
I O + PClfi = 5 C2H5 Q + H3PO4 + H2O.
On heating the mixture, volatile ethyl chloride is given off,
which must be condensed in a freezing mixture. Ethyl
chloride boils at 12" '5.
Ethyl Iodide, CjHJ, and Ethyl Brmnide, CaHfiBr,
'^ '^-J ETHYL COMPOUNDS. 3^7
in double decompositTonri^ '°t'°'' "" ^^ exchanged
^f'0'<»«/</.,C»CN»j.-This substance is formed
Se wirsi.'^l'^c^Tn^^f 1"'' .''^ r '"^ - ""W -
EU,yIan.in. and Chloroform yield EU,yl Cyadde and Hydrochloric '
CjH,N + CHa — r- tr XT . •*'"'•
a 7 -r v-rn.ij _ C3H5N -f- 3HCI
The boiling point of cyanide of ethvl is icf ,„^ •.
possesses a very unpleasant, penetrating smeu' r^ '
the ne^t higher carbon series wfovir."^^ ^j"'"') "'
potash it yields propionic acid, thuj'^' ""'"^ ^''*
P«>p^„itri. ^d Wa.„ yield Propionic Acid and Ammonia.
Prop,omtnl, when acted upon by hydrogen; yields
propylamine, C,H,CN +.H,= C3H, | ^ This reac
smdHni ^t''^A'l C,H-,NO„ is obtained as a sweet-
328 ELEAfENTARY CHEMISTRY, [Lesson
Ethyl Nitrate, ^«^6 1 O, is formed by the action of
nitric acid on alcohol when urea is present, as this body
immediately destroys any nitrous acid which may be
formed, which would prevent the production of nitrate.
Ethyl Hydrosuiphidc, ^'^|]* | S. — This compound,
known as Mercaptaa, is sulphur alcohol, i.e. alcohol in
which the oxygen is replaced by sulphur. It is obtained
by acting on potassium hydrosulphide, u j S, with ethyl
chloride, ethyl and potassium changing places. Mer-
captan, like alcohol, can exchange its typical atom of
hydrogen for metals : it forms with mercury an insoluble
dompound. This body boils at 36°, and possesses the
nauseous, garlic-like smell characteristic of all the organic
sulphur compounds.
Ethyl Sulphide, ^^ | S.— This compound in the
sulphur series is analogous to ether in the oxyg6n series :
it is obtained by acting on potassium sulphide, KgS, with
ethyl chloride. It is a colourless liquid, boil:' g at qi'',
and possessing a strong disagreeable odour.
Hydt'ogen- Ethyl -Sulphate, or Sulphovinic Acid,
^yC \ ^^*» ^^ formed when alcohol and strong sulphuric
acid are mixed. It acts as an acid, and forms salts in
which the typical hydrogen is replaced by a metal. The
ethyl sulphates of the alkalies and alkaline earths are
soluble salts, and crystallize well.
C H )
Ethyl Sulphate, ^^ \ S04,is obtained by acting upon
ether with sulphur trioxide : it is a body which decomposes
on distillation and on addition of water.
Ethyl Phosphates are known:. they correspond to the
tribasic alkaline phosphates in containing either i, 2,
or 3 molecules of ethyl, replacing hydrogen in tribasic
phosphoric acid. Thus we have :
xxjc.] TRrcAiinoN series.
^ *^»osphatc.
329
Triethyl
Phospfiatc
V-n H,
CjjH^
PO^.
Ethyl Ca^„„,,^ C,H,j CO,, corresponding to sodium
carbonate, ,,;- CO,, is prepared by acting upon silver
carbonate wuh ethy, iooide. U is an aromatic a^uid boL
J%/C>««^, C N j 0.-Aco,our.ess!i,uid,boilinga.
fmmcS bv dS"^ ^ P'""'^^''"' ""'^ '^"'a«'>g smell J, i,
.iuri'aLl''"rn^rn;^,T'rtlfcf ';'>'''''' -''"P'''-
ethylamine, thus : '' ''^"""= P°"'^'> '« forms
Ethyl Borate, %^, j bo„ is a colourless liquid which
arf^t{a[n;tbfirA^cr„'"?^'r"f'°^
alcohol. The^mp^unr/CQH 's'lo'"':"''''°"''l"P°"
normal silicic acid H Sin if , "' ? .m<' '^°"'«sponding to
"hich burns evlfnf ;\^,^rwhi e%m 'r'''T 'T''*'
dioxide. ^ ^""*^ smoke of silicon
TRICARBON SERIES.
/^^•m^O'/'^.>j/^/..M C3H; I o,hasbeenfoundinthe
330 ELEMENTARY CHEMISTRY, [Lessom
in all proportions. Propyl alcohol unites with sulphuric
acid to form hydrogcn-propyl- sulphate, ^^J^r | 3O4. The
pt :>yi compourids have not been much studied ; they
closely rescmMc the foregoing ethyl series of bodies.
Primary propyl alcohol, when oxidized, yields propionic
acid (see p. 314).
This acid is likewise formed from propionitril (see p.
327). The secondary propyl alcohol or dimethyl carbinolj
C < H , boils at 84°, and is best prepared from isopropyl
iodide, which is obtained by the auction of hydriodic acid
upon glycerin (see p. 385). From this isopropyl iodide
We can prepare propyl hydride by acting on it with zinc
and dilute hydrochloric acid (i) ; this again on treatment
with chlorine yields the primary propyl chloride (2) ; and
this last, heated with acetate of sodium, gives propyl
acetate, from which primary propyl alcohol can be ob-
tained by the action of caustic potash. It is thus possible
to obtain a primary from a secondary alcohol :
Isopropyl Iodide and Hydrogen yield Propyl Hydride and Hydiiodic Acid.
' CH, ( CH3
(I)
+ HI;
Ch! + Ha = -jCH-
CH3 ( CH3
Propyl Hydride and Chlorine yield Normal Propyl and Hydrochloric
Chloride Acid.
iCH
CHa + CI, == -iCHj -f HCL
CH3
CH3
CH,
(CHjCl
TETRACARBON SERIES.
By acting on ethyl iodide with zinc in closed tubes at
150°, zinc iodide and a hydrocarbon, C^Hjo, called diethyl
or butyl hydride, are formed.
Butyl hydride is a colourless liquid, boiling at 0°, and
is the lightest of all known liquids, having a specific
XXX.] • PENTACARDON SERIES. «,
Exists 'In" he°ght°o^-JJ?'r°'=?'"'= hy-^^carbon also
M in coal OS By the ac1bn"n?" Pf ™'«"'". ". >vo»
hydride butyl chloride ca^ be X.,°„ J''''":i"/ "P°" '^is
afcohol itself has been weD;r.H"'"^t.^"!^ '^^P™ 'f"' 'he
alcohol, as it yields on nff/:fr' J""'. " ">= P"n>a>-y
butyric acid. No less ?hanf?°" \"tyl. «Wehy^e and
ficajjons of butyUlcohd'are knownf" "'""•="'= '"<«"■
B.F.
:09'
fCH,
c ch;
lOH
(.) Secondary butyl alcohol, or methyl-cthyl-carblnol, C ^^\* . . ,,,
I. OH
(a) Fermentation butyl alcohol C /^H^^"*^'
(oh'
(3) Tertiary butyl alcohol, or trimethyl carbinol .
of the ethyl seSSDos^^^^^^ members
yi series, and possess an analogous composition.
PENTACARBON SERIES.
No less than three isomeric hvdriH^c /-^^f^- •
yit^^^;» -^ '-'^"^^^'^ atr^f ^n-iT:;!!
(')-^CPi,; (2)
CH,
.CH3
rcHj
CH,
CH,
CH.
;(3)c
^'"■^^ ^/^^^'Z, *^»g« } 0, occurs commonly as th-
fa^ttr„"f i^m ±^!:°"Ji^L°" ?!''.--d in the manu-
^....,,,^.^. „,_„.^^.^ Muin -^nicn it is obtained by
33a
ruiCMfLiVrARy cueaii^tkv, llesson
washing with water and subsequent rectification. It is a
colourless liquid, possessing a disagreeable, penetrating
smell ; it dissolves in alcohol and eiher, but is not niiscibie
with water. Amyl alcohol boils at C32", and solidihcs
at — ao**. Two modifications of this aLohol are known:
one deviates the plane of polarized light to the left ; the
other is inactive, and boils two degrees lower than the
first. In composition and chemical properties they are,
identical. Hence this is a case of physical isomerism,
Amyl alcohol, like the foregoing alcohols, forms, with
sulphuric acid, hydrogen -amyl -sulphate, which yields
double salts, called the amyl sulphates ; it is also attacked
by hydrochloric acid, amyl chloride, QHjiCl, being
for|ned. Amyl alcohol, in presence of oxygen and fimly
divided platinum, undergoes oxidation to valeric acid,
thus :
Amyl Alcohol.
Valeric Acid.
Potassium and sodium can replace the typical hydrogen
of this alcohol, forming potassium or sodium amylate. The
iodide and bromide are prepared in the same way as the
corresponding ethyl compounds, with the substitution of
amyl- for ethyl-alcohol.
C H )
Amyl Ethery p* j^" > O. is a colourless liquid, boiling
at 176°, obtained by the action of amyl iodide upon
potassium or sodium amylate, thus :
Amyl IodM« and
QH
11
I +
Sodium
Amylate
C5
give
Amyl
Ether
and
Sodium
Iodide.
Naf '^
li;i!°
■f Nal.
Amyl Hydride^ CgHnH. — This substance is a volatile
liquid, boiling at 3>°, obtained by heating amyl iodide
with zinc and wat»-r; it occurs, together u'ith all the
hydrides of this series of alcohol radicals, in American
xxx.]
niG/ncK Ar.coifoLs,
331
ethers, the acelatt, J;«;!ii \ n ;. „
scale -,, if no '^•''^" ^ ' "^ P'"'"-''' "^ " '"'■e*
•l-his 'compound is ob ai, ed 7:'"^ ""^^^^ con/cct?onery.
with potaAium acetate and ,,,1,^ d/stillmg amyl alcohol
prepared by h«afnTthe chlnr "f. """ ' '^ '^''"' »''" be
If this amyl ac ' a"? be h, m , "•' rL"'' P"'""'"!" acetate.
and potassium a'cuue are ?ormeT'' ""'""''' "'"y' '"'-•°''"'
Amyl
Acetate
and Potash give
Arnvl
Alcohol
and
PotassiHfn
Acetate.
C W \ ir » «ic.,noi Acetate
Dia,nyl §[{;,> j -Thi^-.bstance is obtained by acting
on amy oc ide with enri;,,.,, t. • «^i'iij{
boilin/at .S^'from which none'of'th: ^tr*"'^" "^"''f'
can be obtained, but wh?ch yiclis d cllTirr","'
C,„H,,C1, on treatment with ch o ne w .u T*"^'
consider this body as decatyl hyd d" C ^^^ ^^'^^^^'
not belongmg to the amyl group. ' " " "' ""'' '**
HIGHER ArcOHOLS.
^^^Vl^^it^tl! ^: Zr^^^ I-'"'" re.
Hexyl and heptyl alcohoTs are fo.mH ^^"'''■'?' Properties.
licjuors , octyfalcoho? is obtained bvdistm?'" ^"''^"''''^
with potash. The hydride, nfThi.7 d'stjl mg castor oil
a mixtu^re of th'^. ;Lt^f S^f^ "^f^
\..
334
ELEMENTARY CHEMISTRY. FLesson
gas), or even Hg (hydrogen), up to hydrides which are
solid, and contain a very large number of atoms of
carbon, and to which the name of Paraffin has been
given. The hydrides, to which the generic name of Paraf-
fins has aptly been applied, can be separated from each
other by repeated rectifications, and obtained in the pure
state. From these hydrides the corresponding chlorides
can be prepared by the action of chlorine, and from the
chlorides we can form the acetates and the alcohols
themselves (see Amyl Acetate).
Cetyl Alcohol, ^'^^^Ao, is found combined with
palmitic Acid in spermaceti. It formr a white solid crys-
talline mass, but acts in its chemical properties like an
alcohol : thus it forms a chloride; Qe H33 CI ; also a bromide
^"16^33
!".
Ob-
and iodide : it likewise yields an ether,
tained by the action of cetyl iodide upon potassium ccty
late; and a compound with sulphuric acid,
Qft^33
SO.
H
0,
Cetyl alcohol undergoes oxidation when heated with
caustic potash, yielding an acid in which one of oxygen
replaces two of hydrogen of the alcohol, thus ;
Cety! Alcohol
H \^
and Potash yield
+ h|^ = ^"^siOjo ^
Potassium
Palmitate
16 ^31
and Hydrogen.
IL.
This palmitic acid bears the same relation to cetyl
alcohol as acetic acid does to common or ethyl alcohol.
Cerotyl Alcohol, ^^^\ O, is contained in Chinese
wajf; if is a white, solid, crystalline substance. When
heated with potash it undergoes oxidation, and furnishes
an acid called cerotic acid, ^^7 ^53 O | q
of
'^xxij COMPOUND AMMONIAS. ,„
uccbwax. when fused with nntacVi ;*. /u
an acid termed melissic acid, C3.H..O J""'"* " ^°™'
LESSON XXXI.
1. NITROGEN BASES.
Compound Alcoholic Ammonias. ~ The r..n.f- .•
onhepH.a,.ona.i„es.a3C.H.jJ-^-J--
seconda,. ~i„es, as §|| n, nielHylanUne ; and
tertiar, „o„ami„es. as TrielHylamin., §5 j n, have
already been mentioned fp. ■,i,\ Th».A* ^^^- '
We; they all have a strong a kilinJ-f.^"'^'^' ?■■« ^"'a-
macal smell, and they coilbine wUh ?fa"lc^^T°-
salts. These compound ammnnJoe V" ' *^- ^° ^orm
ways, of which thermos? i^Srar^'"™^'' '" '»='")'
thJ;i|oVot:at4TrJ^^^^^^^ - *^ ^yanates of
C3H5N + 2H,=
C3H,
H [n.
H )
3. By the action of the iodides of ,!,»». „
33^
ELEMENTARY CHEMISTRY. [LESSON
ammonia, we obtain the iodide of the compound ammo-
nium, which, when treated by potash, yields the compound
ammonia, thus :
Ethyl Iodide and Ammonia give
QHgl
N =
Ethylamine
and Hydriodic
>cid.
H
H
N + HI.
Ethyl iodide acts similarly on ethylamine, giving rise to
diethylamine and hydriodic acid, thus :
QH.I -fQHfi H2N = (C2H6)2H N +HI :
^nd also acts upon diethylamine in the same way, giving
rise to triethylamine, thus :
QHJ +(C2H6)2HxN = (C2H5)3N -f HI.
Ethyl iodide also combines with triethylamine to form
tetra- ethyl- amrrionium iodide, N(C2H6)4l. In practice
all these compounds are formed together when ethyl
iodide acts on ammonia. The compounds of mono-, di-,
and tri-ethylamine with hydriodic acid pre decomposed
by caustic potash, and the volatile compc nd ammonias
liberated. The case of the tetra-ethyl-ammonium iodide is
diffeient,as it is not decomposed by potash, but yields, when
treated with silver hydroxide, a hydrated oxide, wnich is
non-volatile without decomposition, and is analogous in
constitution and similar in properties to caustic potash ;
Tetra-ethyl-aminoniuin
H yarale.
Potassium Hydroxide.
H^.N j o
hJo-
By acting on ethylamine with other iodides, such as
methyl iodide, mixed amines can be prepared. Tiie
compound ammonias form double salts with pjatinic
chloride ; th^ larger the number of orj^anic radicals con-
tained, the more soluble is the platinum salt. The fol-
^''X..] PHIj^^j^y MONAMINES.
lowing table g-iVes th*. ^^^
points of the Siost i4porTam of^r^"'^*'^'""^> ^^^ boiling
in Jeisit^'^" l^^^ '^e boi i^' '^^.^^^P^^nd ammonias^
increasing number of carhnn ? ^ increases with the
compound. °' ''^^'^°n atoms contained in the
Prt7nary Monamines,
Methylamine .
Ethylamine
Propylamine
Butylamine .
Amylamine . .
Caproylamine, or
"exylamine .
Heptylamine .
C H,
H
H
QH
N
• • . .
• ». •
• • « .
• » •
H )
C3H, )
H f N
H )
H \ N
H )
H )
H )
H > N
H )
H } N
H
• •
• •
• •
Octylamine . . ^
Secondary Monamines,
Wmethylar^ine ' • • c|:|n _
Boiling Point
below 0°
1 8^7
49°7
69°
126*
146^
170^
8°-S
338
ELEMENTARY CHEMISTRY, [Lesson
BoUing Point
C H,
Methyl-ethylamine ', . CjHg f N
H
C2H5
Diethylamine . . . . C-Hg ^ N . . Sf'S
H
Diamylamme ► , . . CgHn f N . , 170"
H
TertiiurY Monamines.
C H,
Trimethylamine
Triethylamine .
D iethylamylamine
Triamylamine .
CH3 ;
C H3
CgHg
CjHg
CgHg
c H3
Methyl-ethyl-amylamine C2H5
C5H,
N
N
N
N
N
4'-5*
91^
154^
257"
135'
A comparison of these compounds shows that it is pos-
sible to have two or more bases of the same composition,
but of different constitution: thusC3H0N stands for methyl-
ethylamine and trimethylamine. In order to determine
the constitution of a body having this composition, it is
necessary to ascertain how many atoms of the replaceable
hydrogen of the original ammonia it contains.
QHg
tion
XXXI.]
^^^^^^ORUS BASES,
Jn addition to the<;^ T.. ' ^ • ^y^
"• PHOSPHORUS BASES.
*"V.^..X^...^,,,,^ g* ) ;"''^;-'^- prepared:
r-inc ethyl with J4 ^ "^ '^ *«'"^
C.H. I P have lately been obtained by a diff.
tion, vi bv ^M- different reac-
«'ith ethy/iodidelnTi' P''°=Phonium iodide PH r
"bove compounds a ° t^'^'f^- °^ ^'"= oxide %n^?* J'
'■on with hMiS™t-«_"'tan.ous?;in c^o^nl'bit
2 2
34P
ELEMENTARY CHEMISTRY. [Lesson
. (2) ZnO + 2C,H6l-f PH4I =
p IT \
C2H5 i P.H I. + Zn I2 + H2 0.
H )
The mixture is sealed up in glass tubes and heated for
several hours to 1 50°, when a crystalline mass is formed.
By the action of water upon the crystalHne mass the
moncethyl phosphine is liberated as a volatile colourless
liquid boiling at 25° and possessing a most powerful and
nauseous odour ; the further action of alkalies liberates
the diethyl phosphine. This is also a colourless liquid
boiling at 85°, possessing a strong smell, different from
that of the preceding compound. Both these phosphines
^combine with the greatest avidity with acids, also with
oxygen and sulphur, to form definite compounds.
Mono-methyl phosphine, CH3 HgP, has also been pre-
pared ; at the ordinary temperatures it is a colourless gas,
in this respect resemblirg phosphuretted hydrogen, H3P.
The following table shows the similarity between
amines and phosphines :
. /'Ammonium Iodide
S 1 Primary Amine Iodide ....
•| < Secondary „ „ . . . .
J \ Tertiary „ „
V Tetraethyl Ammonium Iodide .
a> ( Phosphonium Iodide ....
•S I Primary phosphine Iodide , .
&.< Secondary „ „ . . .
o \ Tertiary . „ „ . . .
£ V Tetra Ethyl phosphonium Iodide
NH4I.
N C2 Hg H3 1.
N (QHs)^ H2 1.
N (CgHs^ H I.
N (CaHs)^ I.
PH4I.
PC2 H5 H3 1.
P(C2H5)2 H2 I.
P(C2H5)3HI.
P (CaHs)^ I.
III. ARSENIC BASES.
The compounds of arsenic with the alcohol radicals
differ somewhat in constitution from the foregoing, in-
asmuch as we are acquainted in the methyl series
with (i) triinethyl arsine^ (CH3)3As ; (2) arsendimethyl,
XXXI.] ANTIMONY BASES.
these ,s constructed on the t^Z ^*^"3)As. The first of
latter cp.nbine directly with one anH^f"""'^' ""'' ">« '^o
respectively, nnd then form ?„ ^ 'T° ^'^ms of chlorine
geneml typ% NH3 We™hus iS""^ ^ "^'""^'"^ '» he
pounds known: ^"^ '•'""e the following com!
AsCI^CHCH ^'■''"'u '"''y^"'^^
AsCHCH M Tnmethyl arsine.
AsCHf c? C ^;:r^™^'h3" chloride.
sodium and ..enic; it Vo7re3 S"'^'^ "" ^» aH'^y of
and trimrthyl phospMne. -°''^'^°"ds to trimethy'amine
■•s 1^:S:i^\Z^^^^^^,^^ substance
bines „.ith chlorine, SLnZ"'' S^f =»', care. ^ It com-
an organo-metallic radi^fl ' One' rffh ^'^^^ *^ P^"^f
compounds is cacodylic acid As(CH3), ( ""'' ™PO«ant
in water, and is nr.t „„■ ' H f C>2 ! it is soluble
and its oxide „ °he^ moT"^'- ^^ '""^^ion of cacodvl
delicate test for the presence of"' ^''''■"^y "^^ "=ed as a
and characteristic odCof this b^od^""' ^'■°™ '^^ '^^^^
Rv ,.»• '^" ^''"MONV BASES.
Byactmgonethynodidewithanalloyofantimonyand
Potassium,acompound caned .^,.^,.,,,^^CH,)
has been prepared; it is a c„..,„,„.. .. ..c:H | '"''
"~'""^" "quia, boiling at
342
ELEMENTARY CHEMISTRY, [Lesson
J58^'5, which takes fire and burns in contact with the air.
It forms compounds with oxygen, sulphur, and chlorine.
Bistmdh forms an analogous compound, Triethbismu-
CgHg
CoHs
ttne^
CgHg
Bi.
COMPOUNDS OF THE ALCOHOL RADICALS WITH BORON
AND SILICON.
The ethyl compounds in this series are the only ones
which are well investigated.
C2H5 )
\ Bor ethyl, Z^^ > B, is a colourless liquid,boiling at 95'',
Qf^s )
possesses a very powerful acrid smell, and takes fire on
exposure to the air, burning with a green flame. It is
obtained by acting on ethyl borate, (3 (C2H5)B03), with
zinc ethyl.
C H
Silicon ethyly j-^u^
C2H5
Si, is obtained by the action of
zinc ethyl on silicon tetrachloride : it is a colourless liquid
which boils at 150°, and is not attacked by nitric acid.
It is acted on by chlorine, monochlorinated silicon ethyl,
SiCgHiaCl, being the first product. This substance acts
as the chloride of a monad radical : thus when heated
with acetate of potash, it yields an acetic ether, and this on
treatment with potash forms a colourless liquid smelling
like camphor, and acting as an alcohol, and having the
formula SiC8H2oO- Hence silicon ethyl may be regarded
as nonyl hydride, C9H20, in which one atom of (tetrad)
carbon has been replaced by one of (tetrad) sihcon. h
substance having the composition Si H CI3 has also been
prepared. This body, it will be seen, is chloroform,CH CI3,
in which silicon replaces carbon.
»>
XXXI.] OJ!GAm.M£TAZZfC SODIES.
B.P. I
343
Silico-nonyl hydride SiC«H„
>)
)>
B.P.
150-
Chloride SiC3V;ci ,,5
Nonyl hydride C,n,, jo.
», cfiloridecjH^Jci Ml
„ acetate r^S^Joaio"
„ alcohol CflHi, I Si?H' )^
^ r I »' alcohol ^^^8H,9 I Q ^^,
COMPOUNDS OF THE ALCORnr t> .
ALCOHOL RADICALS WITH METALS.
Obtained by h';'^cCo7 "'°"'"' ^"'^'^"^ ^
colourless liquld/boaL lt''??8"P"'J f ^' '°'"<J« ■• *' is a
with a greenish flame if con art ^i'th'Sr or '^ ""'^ """'^
forms zinc ethylate, ^ (& H,) ) ' '"f ^'^ ""^ ""yg^n, and
on .Slowly. zL e4l fs\ va uabr °"''"°" ^°^^
which many other compounds ca'^hf^K/'^' \ '"^''"s of
we act with this substan^^TT -v °^ obtamed : thus if
zinc chloride andS^f'^ '"'•^'^'"oride, we^ t
obtam mercury ethyl j on S ^M ?5''''<=""'^ =^1°"^^ W
^inc methyl and zi^c amyl a« a^ n"i?^' ^^ «« l^^d ethyl
of tin lead, mercury, ^^ a l*^.^"'^"- Compounds
alcohol radicals, can be preDarrH I "^ '"^•'^''' "'"^ the
somewhat analogous to the 3tn^'/''i'"='"«^ properties
ethyl,Hg|QH, . ^ '"^ ^"r^gomg substances. Mercury
y^^X QH,' 's a most deadly poison.
jS-<'«4«« ^%/combLs d"rectlv wh^^\"''''l."'"'= ^*yl.
fonns sodium Propionate (^3%X37'^°" ''i°'<ide, and
Sodium Ethyl and Carbon Dioxide yield <!™<- »
344 ELEMENTARY CHEMISTRY. [Lesson
LESSON xxxn.
COMPOUNDS DERIVED BY OXIDATION FROM THE
ALCOHOLS.
Group of Filiy Acids, and their Derivaiives.—Tht
mode m which the aldehydes and acids are connected with
the corresponding alcohols- has been alreadv described
(p. 311). These oxidized • products contain a radical in
which one atom of oxygen is substituted for two of hy-
drogen in the alcoholic radical, thus :
Ethyl alcohol, ^2^5 | O, gives acetic acid, ^a^jaO | ^
Amyl alcohol, ^s^n | O, gives valeric acid, ^^^^ \ O.
These oxidized radicals form the starting point of a
large number of compounds which in their properties
resemble the alcoholic comoounds, but differ by con-
taming an atom of oxygen for iwo of hydrogen. Thus, by
substituting the hydroxyl of an acid, by an atom of chlorine,
Ti ^^i % ^^^°"^^ of the series ; for instance, acetyl
cnioride, Cg H3 O CI : by replacing the hydrogen of the
hydroxyl by metals or by alcohol radicals, we get :
Hydrogen Acetate. Potassipm Acetate. Ethyl Acetate. Acetyl Acetate.
H3OJ, C.H30j^ C.H30j^
C2H3O ) Q
C2H3O ] ^'
Each fatty acid can te again reduced to aldehyde by
distilling a salt of the acid with a formate ; thus : •
CgHgOgNa + CHO^Na =
Sodium Acetate. Sodium Formate.
C2H4O + NagCOg.
Aldehyde. Sodium
Carbonate.
-xx„.] POmaL.^ OF THE ACIDS
1C ^\ '
jnhe oxygen of the hydroxy, be^rep.IeTby sulph^
^"h'°Js
Ky
i5"j«-
^Jie monad acetvl r-o^ i
'nonia, and we then get ; "'P^'"'" Mrogen in am-
Acetamide, H ( iv,
w|th%raTa.roror„e*^^ -es decompose
Thus If we <iecompose a solMfl^ °"'/^ "•'bon dioxide'
.a.va„.c c™, it .^,, „^plt"c°a"rb:^ dToxl^^ '^^
2 <^2 ^3 O
H
hydrogen and methyl, which ]Ih ^ ^ ^^' ^ '
Sir ^'- - --^' -o^nts;,°s^^^^^^^^
butytt^t^f hyfe' =-«"»'• Valeric add yields di.
Likewise sodium methvl =,nH ' '^a ( »
d.rectiy to form sodfuracetate'r''"" '""^'<'« <^°mbi„e
' Na / ^*
3^r^
.ELEMENTARY CHEMISTRY. [Lessom
Many other illustrations of this mode of decomposition
might be given : the above will suffice to show that the
formulae already given for the acids do not explain or
exhibit these reactions. In order to point out these rela-
tions we must write acetic acid, for instance, thus :
CH3CO
H J^'
C H + CO )
and the general formula for the series is " " ^ H ( ^'
That is, the acid
with the monad
is
a compound of an alcohol radical
CO )
group, H ( O, to which the name of
Cd!/-^^ary/ has been given. This substance we thuR regard
contained in all the fatty acids : that it is formed by the
oxidation of methyl we see from the following :
Ethyl Hydride. Ethyl Alcohol. Acetic Acid.
CH,
CH,
CHoOH'
CO OH
iCH3.
The hydrogen of the alcohol radical contained in the
acid can be replaced by monad elements or radicals.
Thus, when chlorine acts on acetic acid, the following
chlorinated acics are formed :
*!!'
•^1^
Monochloracetic Acid.
j CH2 CI
{ CO OH '
Dichloracetic Acid.
CHCI2
CO OH'
t
Trichloracetic Acid.
JCCI3
(COOH-
If the ether of a fatty acid be acted on with sodium,
hydrogen is evolved and sodium takes it" place : thus
CHgNa
CO . C2 Hfi
Wh^n this new body is acted upon by the iodide of an
alcohol radical, sodium iodide is formed, and the radical
replaces the metal. Ethyl iodide gives with the foregoing
from ethyl acetate, ^q^ ^ „ q J , we get
M O J
o!.
( CHgCgHf^
body ethyl-acetic-ether, < CO ) p. ,
which contains an
XXXlt.J
MONOC ARSON SERIES.
A .-..•.1
•demical wit». the h,.t • ' ^^^
" butync acid cf butter, viz.
\
C0)0
methvi *^^*^^^ one atom of hvArT^^ - .' ^^ we onlv
( O ' and (2) { CO r
1
QH.
"•™ or .jfcf ,,,• *^.«»/ l«|»rt„, „aio„ b,
MONOCARBON SERIES
Methyl Aldehyde CU n • .
^edTo* sp,S' f <^?''°1 together with all^t .^^" "^^
ahQnrK ^ ^* ^^ Platinum wim -ru ^'^ ^s 'ed over a
absorbs oxygen, and passS iXf^il^^ll^Vde rapidly
m-
348
ELEMENTARY CHEMISTRY. [LESSON
Formic Acid, ri
> O. — This acid occurs ready formed
in the bodies of red ants, whence its name ; it in likewise
found in stinging-nettles. Formic acid is obtained by the
oxidation of methyl alcohol, as well as of sugar, starch,
and other organic bodies. It is formed synthetically by
acting upon potash with carbonic Oxide gas at 100°,
thus :
Carbon Monoxide and
CO +
Potash
yield Potassiuni Formate.
CHO )
K \
O.
Also when carbon dioxide and aqueous vapour are acted
\ on by potassium ; thus :
2 CO2 + K2 + H2O = ^^^ I O + K HCO3.
Formic acid, diluted with water, can be best prepared
by deromposmg oxalic acid, in presence of glycerin and
water, into formic acid and ca'-bon dioxide, thus :
Oxalic Acid yields Formic Acid and Carbon Dioxide.
Co Ho Oi
- CH2 O
-t- CO,
In order to obtain formic acid in the pure glacial state,
free from water, the leaf!! formate is decomposed by a
current of sulphuretted hydrogen gas, lead sulphide and
formic acid b^ing produced. Formic acid is a colourless
liquid, possessing a peculiarly sharp smell and strong acid
taste. It boils at ipo°,.and below 1° it sohdifies to awhile
crystaUine mass ; its specific gravity at 0° is r235, and it
is m^scible in all proportions with water. Heated with
sulphuric acid, it forms water and pure carbonic oxide
gas, and oxidizing agents convert it easily into carbonic
acid and water. A formate, heated with excess of baryta,
yields oxalate, thus :
Formic Acid yields Oxalic Acid and Hydrogen.
2(CH2 02)
Co Ho O* 4- H5
J49
XxxiiO DICARBON SERIES
IT • * i^^
li-bl^^ts'cL'l ed A^'r.";,! ^Hf /°™^ well.crys.al-
m water. When ammonium' form^f/"'™^'?, "^ =°'"ble
decompose3 into hydrocyare Idd td wlt'r'^'^^^'^'' ''
an.dhydrocya*;&f;iJf4:s'u?'"^''^°- "
acid so that hydr"cyi„?c i3 ?he*n?^''-''™/li''"^ '■°™''=
^ his last may be distinmi,v,y u "'"■'' "'^ '°'''ni<: acid
metallic mercury and "five, t'' '" P°^^^ °' ^^duciig
nitrates on boiling ^^^' ^ ^rey po vders, from thf
H j ^-Ob'amed by acting on ethyl
formate with ammonia rf •
at 1940. """"""'a- It is a colourless liquid, boiling
DICARBON SERIES.
Acetyl Compounds.
Aldehyde, ^2 H3 O ;
formate, thus : ** "^'xture of an alkaline acetate and
,,, Ko:k + |co.k=Jc^h + I|co, .
- '• it h^TS^ifi-f-^^^^^^^^^^^^ at
350
ELEMENTARY CHEMISTRY, [Lesson
with chlorine, and acetic acid when acted upon by oxi-
dizing agents. Aldehyde is capable of existing in three
other peculiar states, or of undergoing polymeric modifica-
tions. If it is preserved In contact with excess of acid, it
remains unchanged ; but if it be pure, it soon deposits a
solid substance having the same composition as aldehyde,
and termed Meto.ldehyde. This substance sublimes un-
changed at 120°, but when heated to 200° in a closed
tube, it forms aldehyde again. Paraldehyde is another
modification, and is a liquid boiling at 124° ; and a third
modification, termed Acraldehyde, boils at 110°. " he
molecular formula of paraldehyde appears to be, CgHigOa,
or 3(C2H40) ; that of acraldehyde, CHgOgjOr 2(C2H40).
Aldehyde is also isomeric with ethylene oxide (p. 360).
Aldehyde forms a crystalline compound with ammonia,
termed Aldehyde-ammonia, ^2^ ^^ | ; and it also unites
with hydrogen-sodium-sulphite to form a solid compound.
In many reactions aldehyde comports itself as the oxide
of a dyad radical, Cg H4, called ethylidene. .
ii"S,\(o-
-This substance is a derivative
Q
Acetalj ((J
of aldehyde, in which the dyad radical aldehydene,
C2"h4, occurs. It is obtained by heating aldehyde and
alcohol together, and is formed together with aldehyde
when alcohol is oxidized with sulphuric acid and manga-
nese dioxide. A compound of a similar constitution, viz.
II
dimethyl acetal, ^^^ \ Og, occurs in crude wood-spirit.
Acetal is isomeric with diethyl glycol (see p. 361).
Chloral, ^2 CI3 O I ._This substance may be considerec*
as aldehyde, in which 3 of chlorine take the place of 3 of
hydrogen. It is the aldehyde of trichloracetic acid, ana
this body is formed on its oxidation. It resembles alde-
hyde in many properties, such as formmg a crystalline
XXXII.]
ACETIC ACID,
I
C CI HO R n T^^*^ chloral forms a solid hydrate
.2 ^h/^O, H2 O ; a substance now laryelv n^^H ,'^1 i^'
CCl,
I
COH
+Hlo = ca3H + coHjo
formafe. '"^ '""'='' ^ive chloroform and potassium
^«AV Ada, Cj H, O2.
CH,Na + C0j=CjH30>„
Na J " ;
and 2d, by the action of potash on aceion-tril, fhu= •
commonly called Pyrol^n^us acW "* *"' °'''"'"^'* '
wmc) yield acetic acid^ o^d'aS^^Ste^^;
e
IS
352
ELEMENTARY CHEMISTRY, [Lesson
(^
398) : the liquids are exposed to the
Fermentation ,„,^ ^. ^^.,
air at a temperature of about 25° for a fortnight, when the
alcohol is changed to vinegar. This change appears to
be brought about by the presence of a peculiar vegetable
growth {mycodenna aceti), which floats on the surface of
the liquid, first absorbing the oxygen, and then giving it
up to the alcohol. , , , .
% Acetic acid in the pure state is obtained by^ heating
sodium acetate with strong sulphuric acid : it is a colour-
less liquid, boiling at 118° and solidifying to an icelike
mass at 17'' ; and hence the name of Glacial Acetic Acid
has been given to it. It possesses a peculiar sharp smell,
and has a strong acid taste ; it mixes in all proportions
with water, but when distilled the mixture has no definite
, J# \ boiling point ; the residue becomes stronger until glacial
^^ acid remains. Acetic acid may be recognised by its smell,
and by the formation of ethyl acetate ; also by the produc-
tion of cacodyl when an acetate is heated with arsenic
trioxide. Acetic acid is monobasic, and forms a series of
well-defined salts termed Acetates, The acetates of the
alkalies are soluble crystallizable salts. Aluminium and
ferric acetates are soluble compounds used in large quan-
tities as mordants by d- s and calico-printers under the
commercial names of .iquor and Iron Liquor. Lead
acetate, or sugar of h .nd copper acetate, or verdigris,
are the most important compounds of acetic acid and
the heavy metals. The radicals methyl and ethyl, &c.,
can be substituted for the atom of typical hydrogen in
acetic acid, forming the compound ethers (see ante^
page 311). , . r
Acetyl Chloride,, Cg H3 O CI, is obtained by the action of
phosphorus trichloride upon acetic acid, thus :
PCl3 + 3^^H^^|0 = H3P03 4-3^^Cl'^l-
It is a colourless liquid, fuming strongly in the air, and
boiling at 55°. The corresponding bromide and iodide
are known.
m
"i ----wijW '^ '■
XXXII.] ACETYL COMPOUNDS.
Acetyl Acetate, § H3 O j ^^ ^^ ^^^^^ Anhyclride, is a
4C2H3 02Na + POCl3=.2(^2H30)Q\ + 3NaCl
VC2H3OJ /4-PO, Na
It forms with water two molecules of acetic acid
Chloracehc ^^/V/j^.—Chlorine art^ nr^T^TT ^•
replacing one, two, or threeTtLs of t^^^^^ T^'"" ^^^^ ^"
radical acetyl' by chlor ne weThlf ni^f f^y^ro^en of the
//.^..^, ^ ^^2 CI I Q. ^.^;^^^^^^^^^ .^ ^^ .^^ CO CH CI, I J.
and trichloracetic acid, ^^ ^^3 j q Th^ .u ,
H i '^^ -^^ese three bodies
?r6:rs^- Sal*^;,^^^^^^^^^^^^^ boas .
200°. They form salts analosroul to h ''"''' ^' ^''""^
acet.c acid maybe regenerated ^^otL theL bvh'' = ''"'*
of nascent hydrogen. " "^ "^^ action
7-W/^V««V, C.H3O I s_T,,.^ ^^^^^^^^^ ^^^^^^ ^^
(TsVrit iiv^Sbyihittfo^or''"" '? ^'-'-'
phosphorus on acetic acid . Pentasulphide of
IMS a colourless liquid, possessing a peculiarly nauseous
smell, and boilmg at 93°. The anhydride ^2 H^O ( „ .
also known. 'CaH^op-'s
Acetyl Peroxiu •, ^2 H3 O )
pound obtained b ?^e"l^l„ tf I ^ """'^"^'^ -""'"-
-t>. acetate. It ^s a '^^1^^^:^^^^^
^m^^"--
354
ELEMENTARY CHEMISTS. V, [Lesson
ind on heating it decomposes with
oxidizing properties, and
explosive violence.
C, H3
Acetamide. H
H
N, is the acetyl ammonia ; it is
obtained by the action of ammonia upon ethyl acetate by
an exchange of acetyl for hydrogen, thus :
0+H>N=i H
H H
C2H3O
CaHg
C, H., O
N + CH,
O.
It is also formed by the a tion of ammonia on acetyl
chloride, and by the dry distillation of ammonium acetate.
Acetamide is a colourless solid, fusing at 78'' and boiling
* at 222°.
C2 H3 O )
Di acetamide, Cg H3 O V N, and Ethyldiacetamide^
H )
C2H3O)
C2 H3 O > N, are also known. Corresponding compounds
CgH' )
are likewise formed from the chloracetic acids.
Acetone, r H^ i •"'^^^^^ ^°'^r "^i^^> which may be
regarded as methyl acetyl, is formed by replacing the
chlorine in acetyl chloride by methyl, thus :
CH3|,„H.,(C.H30|)^,(C.H,Oj)^,,,„.
It is also obtained by ^he distillation of calcium acetate,
or by passing the vapour of c cetic acid through a red-
hot tube. Acetone is a colourless liquid, boiling at 56°,
forming, like aldehyde, a crystallizable compound with
hydrogen-sodium-sulphite. By the action of soduim
amalgam on a UMxture of water and acetone, two atoms ot
hydrogen are taken up, and secondary propyl alcohol is
formed, thus (p. 330) : C3 Hg O -f Fj = Q ^^8 ^•
XXX
Th
acids
chara
series,
natun
nitric
'S"-*" -^-r"-'^
XXXii.] mG//£Ji FA TTY ACIDS.
355
HIGHER FATTY ACIDS.
characteristics they doservrV.Z"N?^^u I" "leir general
series formic acid LdacetiSrh^ '^"' '*° "^ "^«
natural fats, and thev in. =.n V ^''7 "ccur m many
nitric acid upon mS :;\:^f f^e ('p^ %, ^«'°" °^
potash on the cyanide of /if; ^'^^V,^^^ ''>' "'<= ^«'on of
(p. 290); and (3) b^y repladL!^^ "'''' '°""^'' ''''<^°''ol radical
ni the radicals of XfatltlVT ^'r^°^ hydrogen
They are most of them n f" ' ' "^y, .^t°hol radictls.
water, easily solul^le rakohnl ''""^.' '''!'"> '"'"^'e in
defined series of saUs The h.A,''"'' ''''f' ^°™^ ^ «'«"-
especially palmitic TnH i . • ^ '"' '"'^'"bers of the series
they areLffs2st;nces :t atn^cnr i" ^" ''""^ '''"'i-' '
made from palm-oil ^ beef suerw.,^*,''*"-"°"'P°''"g ^^^Ps
or potassium palmitSrand sSe*- f^."'/' °^ ^^'*'"«
These acids fo™ anhydl-Mes comnn L u^'""*' P- 387).
aldehydes, amides, and aceWnes "^^ '""!r'' "Chlorides,
stitution and in general chem1%lK'^'P°'"^'"S '" <^»n-
same compounds fn the acety er es F """^ ^j'"* '""^
tion of the prooerties r.f nT™ ^°'' 'lie descrip.
on Organic ^he^r^^^l?^ mufbl^ruC ^ ^ '^^^"^^ ""'^
numb r'ofror/ricTomoor i'" '^'^"'^""'^^ *^t a large
well as amo ■^sr'^th^To^'rslHe^Th?' '''l''"^^ -
acids are derived either frnJ.i ^^"'^^- ^"ese abnormal
alcohol or from some comVo;nr''''Pr^'"S abnorma
The isomeric alcoho s adds anH ^'^''''''y.'^onstituted.
4-carbon series are as folWs I ''V^^'-arbons of the
A A 2
356
ELEMENTARY CHEMISTRY. [Lesson
Normal Butyl
Hydride.
Normal Butyl
Alcohol.
CH3
CH,
CH,
Isobhtyl
Hydride
(Trimethyl formcne),
C H o C H o
\>
CH
CH,
CH2
CH2OH
Fermentation
Butyl Alcohol.
CHo CHo
\'/
CH
Normal Butyric
Acid.
CH3
CH,
Secondary Butyl
Alcohol.
CH3
CH,
CH.OH
CH,
CO OH
Tertiary Butyl
Alcohol.
CHo CHo
</
COH
I
CH,
CH,
OH
(I
H,
Isobutyric
Acid.
CHo CHo
</
CH
COOH
The general reactions of the group of monatomic
alcohols and acids which offer the greatest theoretical
interest are certainly those by which it is possible, in the
first place, to prepare the most simple terms of the series
synthetically from their elements, and, secondly, to pass
directly by addition of carbon and hydrogen from these
lower terms to the higher ones, and thus to mount up
the series. Suppose that we begin with methyl alcohol
obtained from inorganic sources ; viz. (i) Marsh gas
prepared from sulphuretted hydrogen and carbon disul-
phide, thus : '
3 SH, -H- CS, + Cug = CH4 4- 4 (Cu, S).
(2) Methyl chloride, from this by the action of chlorine,
thus
CH4 + CI2 = CH3 CI + H CI.
(3) Methyl alcohol, from this by the action of potash,
thus :
CH, CI -f KHO = Cn^ O -f K CI.
XXX
Thei
thee
(I)
on d
p. 35
(
It ha
the ac
upon
obtair
(P- 34<
(2):
and b)
(p. 295
xxxn.l ■ METHYL ALCOHOL. 35,
theXa\''bor;:r47--' '"°<^^^ "y -^-h -e can pass to
on^ifJm'^oSn\th%7h''"f r; ^^«°"""'- This,
p. 351) thus: P ^^''' y'^'<ls acetic acid (see
CNCH3 + KHO + H,0 = C,H3KO, + NH,.
u'el^cM!^^^^^^^^^^^ - - direct., .ed.ce
(P- 349), thus : "'^ ''^ *« ^«ion of hydrogen
Cj H, O + H, = Q H„ O.
andfenn?o^\S|ri;°LLV"P^^^ ""'•y' cyanide,
(p. 29s), thus • ^ ' ^'"^ hydrogen we get ethylamine
CN CH, + H, =
y'XTyf n&wtcTon^r' '"''°" > ^"- -trite
yields the alcohol%hus : ' ''^'^°«P°5"'on with potash,
nitinoTde?t''U'Tre1'he'^f ? .^'^i'- "^ -- ""
stance forms ethyl chlorfl t "''>'' ''ydride: this sub-
from this we can pa s fhroT^" eThl "" '^'"^ "^'"°""« =
alcohol. The repetition of anfnf ^' ^1"'''^ '° «hyl
would enable us t^o PasTtolhrt^ri^Lit-^: aE^^^
358
ELEMENTARY CHEMISTRY. [Lesson
LESSON XXXIII
DIATOMIC ALCOHOLS AND THEIR DERIVATIVES.
As we have seen (p. 294), the hydrocarbons of the
ger\eral formula Cn H2n, of which we may take ethylene,
Cg H4, as an example, are non-saturated compounds, in
which two of the combining powers of the carbon are not
satisfied : hence these bodies combine directly with two
atoms of chlorine, bromine, &c. to form saturated com-
pounds. The lowest term of the series, CHg, to which the
name of methylene has been given, is not known in the
free state, although its iodide, C Hg l2» has been isolated.
The corresponding diatomic alcohol also has not been
prepared, but the diacetate is known.
Ethylene^ C2H4. — This substance, known as olefiant
gas, has already been mentioned (p. 95). It is formed in
the dry distillation of coal and various organic bodies. It
is, however, best prepared by the action of hot sulphuric
acid on alcohol; a mixture of i part of alcohol and 4 parts
of sulphuric acid is heated in a flask with enough sand to
form a pasty mass. The decomposition is a very simple
one ; alcohol loses i molecule of water, HgO, and ethy-
lene is formed. The chief physical properties of ethylene
have already been mentioned (p. 95). It combines directly
with 2 atoms of chlorine, also with hydrochloric and
hydriodic acids: with chlorine it forms ethylene dichlo-
ride ; with the hydraoids it forms ethyl chloride, bromide,
or iodide. It is absorbed by concentrated sulphuric acid,
forming hydrogen-ethyl-sulphate '(p. 324).
n
Ethylene Dichloride, Cg H4 Clg.— Olefiant gas derives
this name from its power of forming an oil when brought
into contact with chlorme. On mixing these gases, drops
are formed ; and when collected, washed, and distilled,
they yield the pure dichloride. This body boils at 82°-5,
xxxnr.] ETHYLENE ALCOHOL. 35,
products areXmed n whl^ '''''°""^' ''"^ substitution
<^U. .0.3 :/K- - tST; 'cte„-^' S
Boiling Point
. 82-5°.
. 115°.
• 137°
. 154°.
182°.
C, H, CI ' I, .
CjHgClgCIg .
C2H CI3CI,.
C CI
sti^n^^ol^ed^'it^^^^^^
whilst those from ethylene 'fn^f^^"' temperatures
potash, those from ethvT rhL^^ """P"'?^ ''^ alcoholic
The la^t term, C^°cX f iLti'can'lors'ries""'^''^"^^''
Glycol, or £;^^/^«^ W/f<,/5(,/, QH, | ^H __^j^.^
uXrr'^^c'JJi^>;,t\r°^^^^^^^^^
bemg formed, thus : ""uue ana glycol diacetate
Ditee """ S»- Acetate yield^SUve^r a„d Glycol Dlaceut.
••'25, it boils a?^97»-5,Td1t'i soffi5'= ^f''^ ^t °° is
m alcohol and water^ ' When exoosed I ' ProP""'""'
with water and platinum black ft ?h!„ k *"■ '" ~°t^'^'
and is converted^nto gUuic 'acid,^Zs • °'^^'" '^P'''"^'
IMAGE EVA).UATION
TEST TARGET {MT-3)
O
U
£^
d
f.^
<?
1.0
I.I
11.25
^1^ U^
^ i£ mil 2.0
m
LA. 11.6
Photographic
Sciences
Corporation
23 WEST MAIN STMiET
WEBSTER, N.Y. 14580
(716) 872-4503
V
qv
<p
^
- - -•■ ^
'i>\^^^
^
)
f/.
H
360 ELEMENTARY CHEMISTRY. [Lesvon
CH.OHj^O^^^^^^^jCH
2OH
OH-
CH2OH
On treatment with hot nitric acid glycol oxidizes further
to oxalic acid, thus :
CHgOH
CHoOH
j+20,= {^00H^^jj^0^
From these reactions it appears that glycollic and
oxalic acids stand to glycol as acetic acid does to ethyl
alcohol. A substance having the composition CgHgOg.
and called Glyoxal, stands in the relation oif an aldehyde
to Glycol. Glycol acts like alcohol in other respects;
the typical hydrogen can be replaced by sodium, forming
compounds analogous to sodium ethylate : it also forms
a compound with sulphuric acid, called glycol-sulphuric
acid; and when heated with hydriodic acid, it forms
ethylene iodide and water.
Glycol differs, however, from alcohol, inasmuch as it
forms two acids, two chlorides, &c. Thus, by the action
of hydrochloric acid on glycol, the first product obtained
is glycol chlorhydrine — that is, glycol in which i atom of
CI takes the place of the monad group, O H ; whilst by
the further action of chlorine a second replacement of
the same kind occurs, and ethylene chloride is formed.
(2) Glycol Chlorhydiine. (3) Ethylene Chloride.
(CH2CI . jCHnCl
JCHgOH' ICHaCr
There are also two acetates of glycol known, mono-acetate
and diacetate
IOC2H3O , p„ {OC2H3O
TvAO ethyl compounds exist, mono-ethyl glycol and di-
ethyl glycol: this latter body is isomeric with acetal
(P- 350).
(i) Glycol
J CH2OH
) CHoOH'
C2H4
II
Ethylene Oxide, Cg II4 O. — This substance is prepared
\
■'riiiri>iTil'"'"--'Tr"-"
a niin m'jJBMU'.tviBir«?'irr'— !
xxxm.] ETHYLENE ALCOHOL. 36,
bs« t^r^^iw °y Kl^\ on ethylene chlorhydrine, which
oxlrf/ T'?<="'^ °\ hydrochloric acid and forms ethylene
oxide. It IS a volatile colourless liquid, boiling at n°-q
soluble in all proportions in water!* I does not form
i'mn^nn'Tf'"''"''?!^"' ^ ^Tstalline compound wkh
amm.onm, but it combines readily with hydrogen, ch o-
rine, acids, &c. Alcohol, Q H, O, is formed by !he direct
cora°c^dt&::f "'"> ""^-'^-^ °» -'•-'- 2^-
c^^J^J'% '"''•'^^ ^!° ","''^^ '^''■^"ly ^i* one molecule
polSen:XL^"'=°'' ^""^ ^'^^ -'"^ S'y-' "> f^-
Diethylene Glycol
OH
(0C,H,O + C,H,{OH^^.
Triethylene Glycol.
OH
OH CoH.
OH
It WH ^'^^^^ mentioned (p. 350) that a dyad radical,
ethylidene, IS supposed to exist in aldehyde, which is
isomeric with ethylene. The difference between these
two series is that m ethylene two atoms of hydrogen are
united to each atom of carbon, whereas in ethylidene the
one carbon has one atom of hydrogen attached to it, whilst
the second carbon is connected with the other .ree atoms
of hydrogen. Thus :
Aldehyde,
Ethylidene Series.
CH3
CHO'
Ethylene Series.
Ethylene Oxide,
Ethylidene Chloride, | ^^^^
CHa
CH,
O;
Acetal,
CH,
CH
/OC,H,
tocjv
; Ethylene Chloride, {ch'cI »
Diethyl Glycol, Y^^\
.OC,H,
,OCaH, •
i
362 ELEMENTARY CHEMISTRY. [Lesson
Many compounds of ethylene with the elements of the
nitrogen group are known. The dyad ethylene replaces
2 atoms of hydrogen in 2 molecules of ammonia ; and thus
primary, secondary, and tertiary diamines and ammonium
compounds are formed closely analogous to the com-
pounds of ethyl. The ethylene diamines are volatile bases
obtained by acting with ammonia on ethylene dibromide.
Similar compounds in the phosphorus and arsenic series
are also known.
HIGHER DIATOMIC ALCOHOLS AND DERIVATIVES.
The higher carbon series yield olefines correspondins
to ethylene.
\ The following is a complete list of the olefine'j and
glycols, as far as they have been prepared :
Ethylene .
Propylene .
Butylene .
Amylene .
Hexylene .
Heptylene .
Octylene .
Decatylene
(Diamylene)
Cetene . .
Cerotene .
Melene . .
Olefines,
, C2 H4
Boiling Point
C27H54
■f-
+
3^*
35^
69°
95^*
+ 125*'
+ 160^
+ 275'
Glycols.
Boiling Point
Ethylene Alcohol . CgHgOj I97'5°
Propylene Alcohol . CsHrO, 1 8b*
XXXIV.] DIATOMIC ACIDS,
Butylene Alcohol
Amylene Alcohol
Hexylene Alcohol
Octylene Alcohol
Boiling Point
O2 183°
C6H12O3 177°*
CgHj^Og
207*
QHjgOg 237=
363
acids can be obS i^y'S^^^^ an aldehyde and t.oo
ethylene yield secondarv ^Ia I .'- ^^^ olefines above
hydrochloric and hXodic ^rln ' l^^^^^ compounds .with
the primary chlorfdl^ anV ^^^^^^^^^^^ are .W^, with
radicals. ^uuiaes ot the monatomic
LES ON XXXIV.
-..CM. --. -so™ ..CM XH. OX..™.
spondi!;^ diatomic alcohol by f afo^In'nf " '" *''" '=°^^-
second by the replacement of 4 armsofTlf^,; ''a^ '^^
by 2 atoms of oxygen. The fiU/nf T *''^ hydrogen
may be termed tlttacii! Arlfi^^^^ ^^"""^^ °f ^cids
the Oxalic Acid Series ta^'!t'''l"' ^""^ 'he second
in each. The rektfnn'^f^ f substance best known
acid, servinuas a tv^!" f°l#'>''°' '», glycoUic and oxalic
the folloviirg ■ ^^ °^ *^ «^»^«1 relations, is seen in
!
Glycol.
CHgOH
CH2OH'
Glycollic Acid
CH2 OH
CO OH 5
I
Oxalic Acid.
CO OH
CO OH
I
\
364 ELEMENTARY CHEMISTRY. [Lesson
In like manner we have the following series of acids :
General formula, Cn Han Oj,
Name of Acid. Lactic Acid Series
(Monobasic). ^
Carbonic Acid ) /- tt /-^
(Hydrate) ^ • • ^ «, O,.
GlycoUic QH^ O,.
Lactic CgHg O3.
Butylactic .... QHg O^
Valero-lactic . , . QH^^Oj.
Leucic QH12O3.
Oxalic Series of Acids {Dibasic),
General formula, Cn Han— 2 O4.
Name of Acid. Formula.
Oxalic ...... Cg Hg O4.
Malonic . . . . . C3 H4 O4.
Succinic C4 Hg O4.
Pyrotartaric .... C5 Hg O4.
Adipic ...... Cg H10O4.
Pimelic Cy Hig04.
Suberic Cg H O4.
Azelaic C^ H16O4.
Sebacic C10H18O4.
Brassylic C11H20O4.
Rocellic C17H32O4.
Carbonic Acid, CHg O3.-— This substance is only
known in its salts, the hydrate not having been pre-
pared. These salts may be supposed to contain the
II
radical carbonyl (see p. 381), CO. Carbonic acid differs
xxxiv.J OLYCOLLTC ANV OXALIC ACIDS. 365
from the higher members of the seHf^c ;„ ^ ...
atoms of replaceable hvdroeen Thfc ^ ^^"^^'''•ng two
by the fact that both the^^'^o^^^^^^^ of w"^'"? ^°^
connected with the group CO,^hus : ^^ydroxyl aBe
(OH
Hence two sets of carbonates exist :
Normal Sodium Carbonate, CO | ^ ^^ .
( O Na*
Hydrogen Sodium Carbonate CO \ ^^
' / O Na*
are diiasic, or contain fwr!7,f i j °' '"'^ second series
both series^re diatomic ^'''■°«^" '''"^ replaceable;
-^s by the action of potaTh o'n^ToScetrctiSf
Potassium Monochlor- and Pnfoei, •
acetate. ^'^ ^°^^«^ S've Potassium and Potassium
01 c'lr^''""^ ^ '"" = ShI'ko, +-^Sr
andfo^s sartscal^rGlvwUa!?,"''',f"l ^'■y^'a'line mass,
atom of metal. An amSe caUe^ which contain only one
- well as a substance isoS^SKS^cfer
^66 ELEMENTARY CHEMISTRY, [Lesson
great variety of ways, chiefly by the oxidation of different
organic bodies. Oxalic acid can be prepared synthetically
by heating carbon dioxide an 4 sodium together to the
boiling point of mercury :
2 COj, -I- 2Na = CaOiNaa. ^
The best way of preparing pure oxalic acid on a small
scale, is by acting upon sugar with nitric acid • it has gene-
rally been manufactured in this way, but at present it is
prepared in very large quantities by the action of cau3tic
potash on sawdust. Crude potassium oxalate is thus
formed, and from this a pure oxalic acid is obtained by
precipitating the insoluble calcium oxalate, and decom-
posing this by sulphuric acid. Oxalic acid can also be
' prepared by the direct oxidation of glycollic acid.
Oxalic acid crystallizes in prisms which possess the
composition C.H2O4 -f 2 H2O : these crystals lose their
wattrof crystallization at 100°, or in vacuo over sulphuric
acid. When heated to about 160° oxalic acid rapidly
decomposes, forming carbon dioxide, carbon oxide, and
formic acid, whilst a small quantity of oxalic acid sub-
linries undecomposed. Heated with sulphuric acid, oxalic
acid is decomposed into water and equal volumes of
carbon monoxide and carbon dioxide gases (p. 91).
Oxalic acid is a dibasic acid, and forms two classes of
salts called Normal Oxalates and Acid Oxalates. The
alkaline oxalates are all soluble in water ; the oxalates of
the other metals are generally insoluble. The potassium
oxalates are :
C2K2O4 + HgO,- Potassium oxalate (normal oxalate).
C2HKU4 + H2O, Hydrogen potassium oxalate (binox-
alate).
C2HKO4C2H2O4 -f- 2 HgO, Potassium quadroxalate.
Calcium oxalate is a very insoluble salt, and is the form
in which this metal is obtained for quantitative estima-
tion. Methyl and ethyl oxalates are obtained by distilling
the respective alcohols with oxalic acid : the first boils
XXXIV.] LACTIC ACID, .
307-
at 161°, and has the formula ^2^2 I r^ .u
lormuia (cJi JJ Og; the second boils
at iSe'^, and has the composition' ',^^2 \ q
Oxalic Amides — Rv h«o.- ^^2^6)2 i ^
a white powder calleffi^i^.^stft r^'""^ °"^^^'^'
Ammonium Oxalate.
!c8:nh:-^h.o={co.nh,
Oxamidj.
CONf
CO NH*-
0>:amide, ^' H^ | N, may be considered as being two
oxalate, a sub^sta^ce^ail^d'^^-a^/^Xg"; -™~
having the fonnula ^H ^ | ^' belonging to a mixed type]
Lactic Acid, C3 H, O3.
An acid of the same com do. S- ^*'"*= 'fermentation,
of animals : this Ts^ however nn/ir"/-^"!^*"" ">« "^^h
tamed by the fermentatl^n^f « 'dentical with that ob-
termed para-lactic add ?t .L"f ,! ''/"'^^ '^e former is
g) By the direcroxlda^^ro" X';/°[-? -'«-% =
by^^UU'^ deccmposuion of nfo„o^c\l!7p?opion.c acid
C.H,0 + HCN + Ha+aH.0 = KH.a;c:H,03.
}68
ELEMENTARY CHEMISTRY, [Lesson
Lactic acid is a syrupy liquid of specific gravity 1*215,
which cannot be distilled without decomposition, but, when
heated, forms lactide (the anhydride), C, H4 Og, and di-
lactic acidy Q Hjo O5. When it is heatea with hydriodic
acid, lactic acid forms propionic acid. The lactates foim
a well-defined class of salts, containing as a rule one atom
of metal — the other atom of hydrogen being replaceable
only by an organic radical : thus we have ethyl-lactic acid,
forming also a definite series of salts. All
jHfi > O2,
the lactates are soluble in water and alcohol : the zinc
lactate is the most characteriscic of the salts ; it crystal-
) lizes in shining needles.
Lactyl Chloride^ Cg H4 O Clg, is formed by the action of
phosphorus pentachloride on calcium lactate.
Lactamide, C3 H^ Og N. — Lactic monamide is obtained
by the action of ammonia on lactide. It is isomeric with
alanine^ a substance formed by the union of aldehyde,
hydrocyanic acid, and water. Alanine is decomposed by
nitrous acid, and lactic acid formed ; thus :
C3 H7 NO2 -I- H NO2 = CgHeOg + H2O -f Ng.
Para-lactic or Sar co-lactic Acid exists in muscular
tissue : it is isomeric with and closely resembles lactic
acid. The two lactic acids are distinguished by the dif-
ference in the solubility and crystalline form of their salts.
Sarco-lactic acid can be artificially prepared from the
ethylene compounds, wiiereas ordinary lactic acid is
derived from aldehyde. Hence the rational formulae of
the two acids are :
Ordinary Lactic Acid.
CH3
CHOH;
COo H
Sarco-lactic Acid.
CH2OH
CHg
COoH
The higher acids of the lactic series do not possess
sufficient general interest to entitle them to consideration
XXX
in ar
acids
is obt
likewi
upon
1
Q H2
This
occurs
small <
duced
artifici*
(0 E
tartaric
(2) B
(
(3) B
Succii
at 180°,
j)osing i
chloride
phorus p
also kno^
dibrom-si
treated w
verted inl
two class
alkaline 1
brown pre
xxxiv.]
SC/CCimc ACID,
acidToKhTSc'^erl'es. ^^ '^^'^^^'^ ^^"^ ^^ ^^e higher
Maionic Acid C H O
upon ethyl cyanacetate, thus f ^ ^' **''"'" °'" P^^sh
Ethyl Cyanacetate. w,
Q H, (CN) O,. C, H, + 3 H O - C ■ H n ^ /'""''"'•
occu^^•rfXr't™Vo'od''1n''^'''"^'^°" of amber ; it
small quantities n vSs p'ni^ i"^"-^'" ''^^i"'. and in
artifidair "'^ ^^""-t^r oT 'S^L^'^n' |."<1 'J - P™-
artihcially prepared : ^ ^P" 39o). It can be
ta«inc LLV37O °' ''''"°''" ^"^'"l "P- ™a«c and
'^^ ? n'^r J: !"*" '"^^^"'''^ ''^ "-="' «•>- ••
QH,(CN), + ,H,0 = C,H,0,+ .NH,
(3) By the action of nitric acid on butyric acid, thus •
at 'l^Xr^i^,,^^, '^af ."l"\r '^H Which a-se
Posmg into succinic anhvdrid/»^A ''^P"""' ^^ecom-
chloride as well as anhydride wh.n T'f :, ^' ''"^^ a
phorus pentachloride. Bromine luh^.v?'^'' '^''* P''"^- '
also known, viz. '«<»«<.<5r.;J,°Z"l,,fi^v '^°V''S^"«s a™
treated with water ai^d silver oxid^, '^ ^"^^' ^^en
verted into malic and tartaric addt' <t ''^^P^'^^ely con-
two classes of salts and u H h!" ■ '^'"^P'"": arid forms
alkaline metals are soluble and^w' > "'^ «alts of the
brown precipitate with ferric sail ™ ^" insoluble
BB '
se
370 ELEMENTARY CHEMISTRY. [Lesson
Succinic Afihydride^ C4 H^ O3, is also known.
The amnionia derivatives of this acid are ;
C4H4 O2 ) C H )
Succinamide, H2 > Ng, and 5«<;a«/w/^<?, *j^* '' > N.
Hg )
Iso-succinic Acid. — This substance, which is isomeric
with succinic acid, is obtained by the action of potash on
cyano-propionic acid, thus :
C3 H5 (CN) 0„ -f 2 H2 O = Q He O4 + N H3,
Iso-succinic acid melts at 130°, and is readily distin-
guished by its reactions from its isomer. It is derived
from ethylidene, as succinic acid is from cthyleni
Cyano-propionic Acid.
(CH3
) CH CN ;
( CO2H
Iso-succinic Acid.
(CH3
\ CH CO2H.
(CO2H
For the special properties of the higher carbon acids
of this series the reader must consult a larger work on
the subject.
Connected with succinic acid very intimately are two
acids of much importance, viz. malic and tartaric acids.
Malic Acid, C4 Hg Og.
This acid occurs in the juice of most fruits, especially
in that of garden rhubarb and mountain ash berries,
from which it can be readily obtained. It can also be
prepared by the substitution of O H for Br in monobrom-
succinic acid :
Monobrom-succinic Acid.
COijH
Ag)n =
Malic Add.
COoH
Ag)
8bX+HlO=jC.^HjOH + -|
-wmf^
Lesson
^^' j N.
isomevic
3tash on
f distin-
derived
on acids
work on
are two
acids.
specially
berries,
also be
nobrom-
XXXIV.] \ TARTARIC ACID.
It is dibasic. The malates ar. c^i kV ^ '^^^^^ * ^^-nce
acd Itself crystallizes fn needles Wh'^ ^^'^V' "^^^'^
js heated to about i8o° it loses h n *"!,". ""^^'^ ^^id
into a nev/ acid C H n u -^ 2 P, and is converted
.states, fonning%,V^^* ^^t;jt^^ ^^^^^«. ^^ two isomeric
stances both uliite dTectw "^^^ -^'^'' ^hese suli?
succinic acid, C, H^ O^f ^ "^ hydrogen, and yield
Tartaric ac d exist«5 in fK« • • ^
tamarind, &.) ; it 'f dep^*^fte{}"^: lr"">' '™'''' fe'-^P^.
the fermentation of wine, ar^d this sa^^if t""" '^'' ^"""S
Several interesting isomeric conHlf' '^°''" ^^ '''^''''"^
ex.s : thus the ordinaTacid no''°°' "^ "»«^ric acid
turnmg the plane of poUr.Ved iP.v..'''"''^'^^ Po^e-" of
and therefore is termed «!w^?' '■°"°<' '» «he right
another form obtaiS from ««:/r''''''f ^"^'^ ^hiU
does not affect the ray orno^r.^^T?'"^^ of tartar
and .s said to be inactive ^tv "?^ H^'*- in any way
termed Raccmic ^.2^ can ' be divideT'r 'C^*^"' ^'^d
or dextro-tartaric, and a new aci 1 1 '" ° ^^^ common
power of deviating the plane rfnPf'?^'"?^ ''"^ °PPosite
be a fourth modificatfon ofltf' ^^^-^^ ^=o appears
tmguished by being inactivf lit ^"''' *'•'<='» 's di^.
capable of being spHt up fito fh^ """"=' ^ut not
The mactive variety of m«' • ^ -1*° ^<=*'ve varieties
arfficially by the Action "r^.r"* "^J" ^ Prepared
succm.cacid,C,H,Br^" eachiffK"'''''^ "" '"brom
."-.replaced by OH;anr,^^''din^g ;^^S4 ^-^^^
Bibrom^uocinic Add.
I CO,H
(c5
bfl?^^+Af|
B B 2
CO H ^"*^"''-^*''^'
^5^|.^^H), + 2 Ag Br.
372 ELEMENTARY CHEMISTRY, [LESSON
f'
Tartaric acid is also formed by the action of nitric acid
on sugar of milk.
Tartaric acid (dextro) crystallizes in large oblique
rhombic prisms belonging to the monoclinic system, which
dissolve easily in water. When heated to i8o° it fuses
and undergoes decomposition, evolving a peculiar odour
of caramel. In presence of oxidizing agents tartaric acid
is converted into carbonic, formic, and oxalic acids ; and
when fused with caustic potash it forms acetic and oxahc
acids. When tartaric acid is heated with hydriodic acid
for several hours, it is first reduced to mahc, and after-
wards to succinic: acid, by losing hrst one and then another
aton of oxygen. Tartaric acid is a bibasic acid, con-
taining two aloms of typical hydrogen which can be re-
placed by metals : hence there are two classes of alkaline
tartrates ; thus we have —
Hydrogen Potassium Tartrate K ) ,-, tt .^
(Cream of Tartar), H \ ^4^4^ 'o''
Potassium Tartrate, ^ > C^fi^.
Tartaric acid forms with antimony a remarkable com-
pound termed Tartar Emetic This compound may be
considered as potassium tartrate, in which one atom of
potassium is replaced by a monatomic radical, Sb O. We
then have tartar emetic :
(s
^SbO S ^4^400) 4- HjjO.
This body is obtained by boiling a solution of cream of
tartar with antimony trioxide ; the oxide dissolves, and,
on cooling, tartar emetic is deposited in crystals. This
salt is much used in medicine, but acts as a violent poison
when taken in quantity. Tartaric acid and citric acid are
largely used by the calico-printer to act as a discharge
or solvent for the mordant, thus giving white spots on a
coloured ground.
xxxv.j CYANOGEN COMPOUNDS,
Citric Acid C\^ n tu • , .
found in the j,^iceVfH;eTen>on anW " '"''^'''=' ^"^ *' '^
ffu.ts, together with maUc a^' ^nd occurs m many other
these sources crystalSesTn T.r^, ,''"' f "* obtained from
dissolve very eas^^^y in wl ter '?hre. °"'''' f y^'^'=' "hich
m which one, two/or tifree atom, nf f i''' °^ "="•=''« ^^^i^t,
by metal. The c trates of the^ll°[-'''"^™8^" "« --eplaccd
jhose of the alkaline-eanh metals '^l'"^'^'^"'^ ^°'"bie,
insoluble in water. "petals, of lead, and silver, are
LESSON XXXV,
pounds : i^^^taat oi tlie cyanogen corn-
Hydrocyanic H )
Acid, Cn|-
Cyanogen
Gas,
Cyanogen
Chlox-ide
Cyanic Acid,
O.
CN)
cn| •
CN )
ci|.
CN
H ^
Sulphocyanic CN )
Acid, H p.
Cyanamide, H >N
H )
It ^ *
cases as if it were ^^ i \t ^ j .t. •
A^ere | N, and this group becomes
connected M'ith the nvr^l.v -i • '^^conies
anogen fompounds are ?ema ,'ablf f°^ ^'^''^^• ^''^ "-
/^/vm-nV modifications hus tj I r™'-"° ^'^"'^'^ «^
cMoride. CNCWnd s^-iidXroUTh, ^e ^^"^^
cyanic acid, ^?^ ( n o«.i . . . r m' ^^^''^Ug .
' 11 4 ■^» ""« ^yaijunc acid, .^'
ri
^"il»"i"lH«P"'"TlP
374 ELEMENTARY CHEMISTRY, [Lesson
Cyanogen Gas, or Dkyanogen, ^^ | .—This substance
is obtained by heating the mercury, gold, or silver
cyanides ; it is found in small quantities in the gases of
the iron blast furnace. I«^ properties have already been
mentioned (p. loi). It is formed by the action of heat on
oxamide, and ammonium oxalate, and is thus connected
with the ox'xM.: group, as cyanogen is oxamide, minus
two molecules of water. Cyanogen forms with potash a
mixture oi potassium cyanide and cyanate.
Hydrocyanic Acid, oxPrussicacid, HCN.— Hydrocyanic
acid has quite recently been obtained by the direct union
(without condensation) of nitrogen and acetylene, when a
series of electric sparks is passed through a mixture of
these gases ; thus :
N2 4"C2H„ = 2HCN.
The mode of preparation and chief properties of this sub-
stance have already been mentioned. This acid easily
undergoes decomposition, and cannot therefore be kept
for a length of time e-ther in the pure state or in aqueous
solution. It yields ammonium formate, thus :
HCN-f-2H,0 = ™0|Q.
as aceto-nitril yields acetic acid (p. 351). With chlorine
and bromine it yields cyanogen chloride and bromide.
Th^*>est method of detecting hydrocyanic acid is founded
on '|he formation of Prussian blue. To the liquid con-
tainmg the acid a few drops of a ferrous and a ferric salt
are added ; then excess of caustic soda ; and lastly, an ex-
cess of hydrochloric acid : the formation of a deep blue
liquid, from which a deep blue precipitate separates either
at once or after a little time, indicates the presence of
hydrocyanic acid. The prer-ence of this substance may
also be recognised by evaporating some of the solution on
a watch-glass with ammonium sulphide to dryness on a
water-bath : on adding a drop of ferric chloride, a deep
red colouration of ferric sulphocyanide is produced, if
hydrocvanic acid be present.
XXXV.] CYANOGEN COMPOUNDS.
■xlt 'Il'fi '""""^' CyamWes are formed by the direct
Tion to ?h^ ?'=''""" ^^l^ "Pon a metallic oxide: fnaddl
burnt in rvan->^nn ^' ^<"^, IS formed when potassium s
cyanides are Ss^nhii '''^'"''' ^"^ ammonium
amnmr.f fK ^P- ^ cyanides are insoluble in water •
lormuicfi ot these compounds, it is useful f/^ J
cyanogen by the svmhr^ rv a , ^° express
376 ELEMENTARY CHEMISTRY. [Lesson
porating the solution, large yellow quadratic crystals of
potassium ferrocyanide, containing three atoms of water of
crystallization, are deposited. It is not poisonous, acting
as a mild purgative. When heated strongly, it yields
u^i^f !Jm"I ''^^"'u^ .^"^ ??" '^'^^^^' ^"d ^^hen treated
^ith dilute sulphuric acid, hydrocyanic acid is formed.
By the action of strong and hot sulphuric acid, the salt
is decomposed, and carbonic oxide gas evolved ; thus ;
6 CO + Fe SO4 + 2 K2 SO, + 3 (NH J, SO,.
Solutions of this salt produce with ferrous salts a white
precipitate which quickly becomes blue on exposure to
air. !< erne salts produce a deep blue precipitate of the
ferrocyanide of iron and potassium, Fcn > Cfy, • * this
K I
substance is insoluble in saline solution!, but dissolves
m pure water with a deep blue colour. From this
aqueous solution of a ferrous salt produces a deep blue
Cfyg. This
precipitate of insoluble Prussian Blue ^^ (
Fe )
valuable pigment is manufactured on the large scale
by precipitating yellow prussiate of potash with proto-
sulphate, of iron (green vitriol) which has been exposed
to tx.e air, and then washing the precipitate with chlorine
water. Potassium ferrocyanide gives with solutions of
copper salts a chocolate-coloured precipitate of coDoer
ferrocyanide Cug Fe Cyg. ^^
Hydrogen Ferrocyanide, or Ferrocyanic Acid, H. Fe Cy
—This acid is formed by adding hydrochloric acid to a
strong solution of the foregoing salt. It acts as a strong
acid, and is tetrabasic, forming a series of salts in which
the four typical atoms of hydrogen of the acid are replaced
by an equivalent of metal.
* Where Cfy stands for Ferrocyanogen Fe Cy,.
■ V-IPW
XXXV.] CYANOGEN COAfPOUNDS. ^„
redtusZe T/ZZ't ^^I' %-'''''' -'^ -lied
gas through a^soludon of the '^ ^^' ^'''''"S chlorine
loses one Itom of po assium ^the ^'"^"' P™^^'?'^. which
tion ; with ferrous salt "deeoW-"' °"^^'''°*"^°'°^^-
£^ue is formed. In th?s laL, ,!.P''^?P"»'« ^^ ^'-"^^'««
reduced to a ferroc "an^en coLounH *t'^l™cyanide is
of the two oxides of iron\;™ .f p ' •"''"f ^ '" presence
2 K IT. r- , ' ^"^^^ Prussian blue ; thus ■_
aK,FeCy, + 3Fea, + H,0 = .HK3KeCy;+
Fe^ a„ + FeO = f1 ) ,^
ji'^ J (^« ^=^6)2 + H, O + 6 K CI.
b. ti^rs^^nSc^^K^o^^- ^^^
a|pTotSstK^3S!^0-pPi:^;^^^^^^^^^
phide a deep purple colouf ^'' °^ ^^ ^^^^^^^^e sul-
c^^^^^i^^L^ ^or.s with chlorine a
are both obtained ty the ac&Thr^'^'^'"^'^"^ ' ^^^^^^
cyanic acid ; ^ ^"^^ °^ chlorine upon hydro-
Gaseous Cyanogen Chloride, Cy CI
Cy3Cl3
Boiling Meltine
Pomt. Point
-12° -15
Cyanic Acid, ^^ o.-The salts of this acid t .
cyanates, are readily formed bv th. H ' '^
cyan-des, and by thJactioT^of ^l-VnlS lll^^.l?^
378
ELEMENTARY CHEMISTRY. [Lesson
Cyanic acid itself cannot be prepared in the free state
from its salts, as on liberation it at once changes into
polymeric modifications called cyanuric acid and cyame-
lide^ or decomposes by combination with water into
carbon dioxide and urea. It can, however, be obtained
by heating cyanuric acid in a retort, and collecting the
volatile cyanic acid in a freezing mixture ; it forms a
colourless mobile liquid, but it immediately changes
into solid cyamelide when taken out of the freezing
mixture. Cyanic acid in aqueous solution combines at
once with water to form ammonium carbonate,
^jo + H^Oa^NH^HCO.,,
and with ammonia to form urea,
™|o-|-NH3 = CON2H4.
Cyanic acid is a monobasic acid.
Ammonium Cyanate^ ^^^ | O, is formed by bringing
together dry ammonia and cyanic acid ; but this salt
undergoes gradually at ordinary temperatures, and at once
at 1 00°, a remarkable molecular change, becoming urea^
CN
NH
II
CO
5 O = H
4) H
N2.
Cyanuric Acid, ^ > O3. — This polymer of cyanic acid
is a solid crystalline substance formed on heating urea,
or by acting with water on the solid cyanogen chloride.
It is a tribasic acid, and is formed on the type of three
molecules of water.
Sulphocyanic Acid, ^ i S. — The potassium salt of this
acid is easily prepared by heating potassium ferrocyanide
with sulphur : on dissolving and crystallizing potassium
sulphocyanide, j^ i S, is deposited. The acid may be
''XXV.] CVANOGE^ COMPOUNDS.
obtained bv arfmo- .
sulphurettc/hydrolen ■"''"'"" '"'Phocyai.ide with
CNSH + H,0 = cos + NH,
wir/r^/rirstl tPX"^e is brought into contact
-Iphocyanide i formed Th: "'' c1 '"'"'"'
i^ a white insoiuble pot-er wh rr™ ""' ^ ^«
^eMing up to a large mass !^'nd ''rv ''r\^^'"^" ^eited,
of the so-called Pharaoh's se"pents ' ""' P'-'^P^^^io"
Cyanamide. H ( M . n • ^N )
Hi' ^'^-^''»««^'i''^, CN N ; and
CN i ^ )
CN i ' "^"^ "^y *= action of
ammonia on cyanogen chloride c
compounds of cyano|enexis°ibr',h!/"'^ other amidic
the latter manuals m^st be consulted '"'''"°" °^ ^^'"^
^-, or a.WV.,SnN,.-This important sub.
";^''in smTf ru^„T1n^";il'" *^ -J""^ "^^ '-,
tamed artificial,y-(o'?>rrm~ti~,e!^ is ob-'
CNNH,o=5°
(^) By the action Of ammo"„i ethyl carbonate, thus :
CO \ ^ H3 J cc
Ethyl Carbonate, ^ ^^'
2
2 .
Urea,
N2 + 2^2g
A I- I •
rticonoi.
38o ELEMENTARY CHEMISTRY. [Lesson
(3) By the action of mercuric oxide on oxamide :
II
C2O2
Oxamide.
II
CO
H2 ^ N2 4- COjj + Hg.
Carbamide.
The first of these methods is that by which urea is
best prepared. For this purpose yellow nrussLfe of
K "c/"':^' • "" T"^^""' c.ioxide.Tnd'thr^Uture
iicattd on an iron plate ; potassium cyanate is thus
formed ; and tins salt is dissolved in water and mixed wi h
ammonmm sulphate. On evaporating to dryness the
urea can be extracted with alcohol. Urea thus prepa ed
crystallizes in lous striated needles, which dissolve !n
hJTt'^kd'JoT'^lv,"' t^ ^r'^ ''^f '° *<^ same extent n
lot alcohol. \yh,n heated to 120°, urea fuses and beeins
L^-'/ Xbt T:1^ .substances termed ««,«.//;S
oima, whilst at a higher temperature cvanuric arid i^
produced. When heated with Vater inclosed tubes o
Zf'i/T''' '^""'; •="J''°"''= '-''^'^ »"d ammonia, showin"
that It IS an amide of carbonic acid. Nitrous acid decom^
poses urea instantly into carbonic acid, nitrogen and
water. Urea ,s the product of the oxidation of °he ni?ro
genous constituents of the body, and the quantity of ur™t
on nl!f ? "'"''"'■'' "f '\ '-'"'"'y °f *? changes go ng
U.-ea^kraten"nH"T™"^' "1"^ ^^'''^ ^"'l ^"^ b^ases^
U ea nitiate and oxalate are the most important salts
With mercuric o.-cde urea fonns an important ii oluble
tinuaml^nf''-'" " •""P'°r'^'! •'•^ ^ ™^ '- of estlm^i^
tne quantity of urea in a solution ' ^
Compound <7m^i«.-These compounds are formed bv
acting on cyanic acid with a compound ammon™^hey
may be considered as urea, in which one or more atoms
of hydrogen are replaced by methyl, ethyl, &c Com-
outyryl, &c., are also known. ' ^ '
XXXV.]
CARBONYL COAfPoUNDS.
38i
CARBONVX. A.O SU.PHOCAKB0.V. COMPOU^OS
The radical carbonvl CO W^ a ^
free state as carbon r^onox do n^'''^' u""^ known in the
from it the following common nH« ' ^f bonic oxide gas
^.Carbonyl Chloridl CO cT 'r^T ^^^^^^^ •- '
dioxide, CO . O. ' ^^ ^^2- ^^'■J^onyl oxide or carbon
Potassium carbonate, CO I ^^-r- u ,
' ^ ( OK. Carbonyl sulphide, COS.
Carbamide, CO | ^^2-
^.yaySfsXtcXr^^^^^^^^^^ existence of .he
•s not known in the free stat^ ' m ^=^""ied, although it
compounds are mentioned under ^T ""^ *= ^^^or.)'
portion of this work. '"'^ '=^''*'°n '" the inorganic
chIo1^t"to'f^rm\a)borvrchrH" l!-""^^ directly with
koovvn as phosgene gas) ' w^r"*^! F° ^'^ (sometimes
carbonyl sulphid\ C(fs ^nd with" a'us"tic n P,""!; '° ^°™
potassium formate, *^<^"}o """^ P°'''^'> '° form
Carbonyl Chloride m r-i ■ r
and dry chlorine gas'es ar? S." '°u™ed when dry carbonvl
At the ordinarySempe;atu''™"l' '°^''^^ in sunlighl
when cooled it condpn^of . , '^ ^ colourless aas h if
+ 8", and possessing lV°unnlf"''''=^ "<!""*' ^olSg""
In contact SJi.h watef it quickfv .If "'' '"locating sm^eU
dioxide and hydrochloriclcfd : ''e<=°™Po^«s into carbon
/OC., + H,0 = CO, + aHCl.
heated porcelain tube or beHeX'"" "^^ether through a
fulphocyanide with dilute suTnh^' ^^ ^*?i'"^ °" potassiu,,^
less gas, which burns w^h n il? a" '"'"^- '' 's a colour-
-ell -mewhatresSi^Kr^hTrtt'je^ ? P-ul?a^
hydro
row»>ii
38a ELEMENTARY CHEMISTRY. [Lesson
Jt is absorbed by caustic potash with formation of iiot.-is.
Slum sulpliidc and carbuii'uc. """auon oi potas-
Carbamic Acid, CO | •^,'/., is not known in the free
state but the ammonium salt is formed when drv
with watci It forms ammonium carbonate ; thus ;
•^■olSX + ^'^-coj^;
NH.
NH,.
W en ui-ea is hea cd to 100° with water it takes up water
and is converted into ammonium carbonate, men
heated alone cjanuric acid is formed, but in presence of
, nitrous ac,d It IS completely decomposed, as follows •-
^^ 1 NH,' + 2 HNO, - a N. + CO, + 3 H.O.
SulphocarboHicAcid, C S J ^H j^^^ ^^ ^^^^^^ ^.^^.^^
unites with metallic oxides to form carbonates, so carbon
carKfcV'"Tf "'"' ."^-'"'"f =""phicles to form su%ho"
caibonates. Ihus sodium sulphocarbonate is formed by
fS^H^'n"'''^:;-?"'"''^'^'''"^ ■" " '"'»«i°" of sodium
su nho r-, P" •^^''f""'" of hydrochloric acid to an alkalin^
hZl h *°"'''""' V''P^°'^-'"'''o"ic acid separates out as a
heavy, brown, peculiarly smcliin- oil.
Siilphocarbamideox Sulphur Urea, C S I ^H, j^ ^^^^^
by heating ammonium sulphocyanide to i7o« It crv,.-,!
withaci!i:'t;?o";:;!:^s "^"^^'^'-"''' '"^e'^S'rea,'c'oS:';
uH^r^f^^lj^sf's^AXT^^'cot:^^^^^^^^
going compounds. Uric ac d is bibisir nnH oil •. u"
Th^ mtttt^rtrL^ • ti'Hl^S r~^-;
derivatives have been Za^ilJd^^l^girK'-J^T bt
^«8H
«xv.] CAIWONVL COMPOUNDS. 3^3
, yielding „' s^.1JniM\n;r,leS;:;^;'.S"'>(NH;; n;"',;
can be gene ally 7c.; nl.d" ♦'•"r;«ivc, of uno acid
C^^tl' "" "'^"""l'^ ''<^i<l. '"' """'""■'"« 'he
in,m"3ad;ir^,^s"suc'^;"ltinV^:nd',-,T '" TA" 'I"'^""""
uric acid, by the oxidation n?ll ""'' '''''-' "'■<^" and
tissue. It crystallizes in bi«htc^o,,H;'"*'-'"''"' ""'"«"
contact with baryta water ttdmnmL'' P"""'- <''"<1 i"
sarcosine. '^ " decomposes into urea and
C.H,N.O, + H,0 „ CH,N,0 + C„H,NO,.
molTcMtacer add^wifh" meV''T'"''"'' ''^ -""^ "P""
methyl glycocoll. "^ '""hylamine : it is therefore
Monochlonicetic mid Mclhvlainini. »;™ c
.Acid «inyraniure give Sarcosine and Hydrochloric
!CO,H+ H
Acid.
N
(cSi +Ha
fromr«:^b5^!?^^i;?--;f„''- ■■ V ^V""^ •'-^. di«--ing
is also found i^ muscular'^tis^.r'""^'^"''^."': ^'■'^' '"» = i^
in colourless pr'smritrsolS . "''^^""'"e crystallizes
reaction, and ft foras with acids ^^ "■ '"T^'y ^"'"""c
lized salts. ^''"'^ * *«"cs of well-crystal-
Hi
384 ELEMENTARY CHEMISTRY. [Lesson
LESSON XXXVJ.
TRIVALENT ALCOHOLS AND THEIR DERIVATIVES.
The hydrocarbon groups having the general fomr^la
CnHau-i act, in accordance with the views already ex-
pressed (p. 362), as triaiomic radicals, to which the geneiic
name of Glycerins has been given, from the special name
(OH
of one of the series, viz. C3 Hj ] OH .
(OH
Froni this formula it is clear that the possible number of
derivatives of the triatomic alcohols is much larger than
that of either of the preceding classes. Tlic relation ex-
isting between the composition of the mono , di-, and
triatomic alcohols of the same carbon series is a very
simple one, as is seen by the following comparison of the
three carbon series :
Propyl hydride.
Monovalent propyl alcohol,
Divalent propyl glycol,
Trivalent propyl glycerin,
C3 Hg.
C3 Hy OH.
p TT ^OH
^3 "6 \ OH-
( OH
\ OH .
(OH
'- :i
The glycerins of the mono- and dicarbon series have
not been prepared ; that of the tricarbon series is best
known, and may be vaken as the type : amyl glycerine has
alsio been prepared.
XXXV,.] TXiyALj^.vr ALCOHOLS.
(OH
385
^'^-■«.C.H.OH.-T.i. substance is confined in
most oils and fat«j K/m-k
^ist of triatomTc ';,':* 'ofSfwl"'' ''"'■"^'' -•>■■<* con-
acid series : thus beef suet or ^?. •'™' "^ '^'^ *■«'/
stearate, or glycerin in whkh ?L '"''"'' '" f 'y^erin trf.
drogen have t4en reolac^H hi 3 atoms of typical hv-
C:, H„ O, of stearic Sfp^(3,"°'f"'es of thTradica'^^,
n small quantities in the ir^lZ' .^^^^"'^ 's also found
's formed from fat^bv the nrn. V'^'"^'*''- Glycerin
reatment of the oil with caus^^. .It' ,°^ f A«f)?«/4, or
he compound, formTn^ an a l=.r ^'' "''*'='' decomposes
.berating the WcSKch ret" Jn','f'^'", (*°^P). and
the soap ,s separated C hro^T,f f " solution, when
order to obtain pure ewZZ ,Z ? .'"■ c°""non salt. In
by lead oxide ; fheUS - ™*'' ^ <^'=c°'"Posed
^-ad-soap or plasterfrpredp S"' a" '°^"°"' ''■"' 'he
method IS to decompose the fee^'t1;K ^T^" """"^ ''«'«■•
free stearic acid an/ elvcerfn h • *"! "^ P^ssure steam,
Oiycerin is a ooloufless thi-^'"^ P-'oduced.
gravity 1-28; it posseS 1 '^'"P^ ''1"'d, of specific
name), and is soullT^' ^ZT/'JVt'^ whence hs
distilled in presence nf Jl, *"'' alcohol. It can b*
it nndergoes'^decom'pos t12n wheVh?r. ^""u '" ^"'"^ ^ut
mixed with dilute ni'r c ac^ ^. '?'' '" "'«''''•■ When
^on and forms ^/^..^^.fj^^^^g'ycerir. undergoes oxida-
hydriodic acid to sUda^r?Vo?y&de,'?h;sf "^^'^ "^
( CH„OH Sccoudary Pr„py, x<,jy,
JCH0H+5HI - IrH? j_ ,
alcohols to the'^monat^ ictrt'; oTilolZhl^ ^^"^^ °^
c c
\
386 ELEMENTARY CHEMISTRY, [LESSON
If the nitric acid employed to act on glycerin be
concentrated, a new compound called Trinitrin or Tri-
nitro-glycerm, is formed : this is glycerin in which the
three atoms of typical hydrogen are replaced by NOg ;
thus, 3(No^, I ^3- This substance explodes violently on
percussion, and has been used for blasting and other
purposes under the name of Nobel's Blasting Oil, oi-
Glonoin Oil. It is, however, extremely dangerous, and
has caused many fatal accidents.
Heated with hydrochloric acid, glycerin forms com-
pounds termed Chlorhydrins, of which *here are three
formed by the replacement of i, 2, or 3 molecules of
hydroxyl (OH) by chlorine, thus :
• Glycerin. Chlorhydrin. Dichlorhydrin. Trichlorhydrin.
(OH (CI ( d r CI
C3H.{0H; C3H.J0H, ^^^^J g•H^ ^^"^ {g"
Glycerin Ethers of the Fatty Aa'ds.— The acetins are
prepared by the action o<' strong acetic acid upon glycerin ;
they are three in number :
Mono-acetin.
C3H5
H2 ioa;
C2H3O )
Di-acetin.
H
C2H3O
C2H3O
Tri-acedn.
O
3 »
rzHsO
(
C
C2H3O I
C2H3O )
o.
These substances/which resemble the fats in constitution,
are obtained by acting upon glycerin with glacial acetic
acid. They are thick oily liquids, only sparingly soluble
in water, boiling at a high temperature.
The Stearic Palmitic and Oleic Ethers of Glycerin^
or Stearins^ Palmitins^ and Oleins, are of great import
aiice, as forming the natural fats. The stearins may be
prepared artificially by heating glycerin with stearic acid.
XXXV..] ST£AI!/ArAJVz>J..4rs: 8
Monostearin. n- ,^ . . '
crystallizing the stearin frnm i ^•"^'' > titration and
forms brigh^t whle sr,^rn/'prt/3°';i''°" ■" '"".^'t^^- ''
water, but readily soluble in etheVTK^ "] ?''^°''°' ^^^
stearin appears to undereo ch1nt« ^''!. ^'^"'"g Point of
bab e that this substan?e^fs 3 J J"** '''■"^^.'' '^ P'°-
distinct modifications '^ °^ existmg in several
of &^rtrbet:; ttiel^:roS"^^.H-* --^
action of the mono- di- and^nVM /^"^ ^'''^^' ^V the
ethylate, the. three ethvi-^lyc^ ^^^^""^
been prepared ; these aref '' ""' ^^thylins, have
a.omt|iSCrp.'3".)'"Th"us"«!I1^^^^^ '" '"-Po'X-
. °'-"'™'^3H.|0,; Tri-glyceri„,c:H;/ ^
Natural Fats and Oih tk, . ,
all compounds orgty?erin~cIiflv "S' °",' ?"'' <■«= "e
stearic acids; and thev are rnnf{"'''J'P'' "''"'^' o'eic, or
of plants and anima?s The 1,'"^'' '" "'^ ^°^'<'^ both
without decomposition and whfn. 'f^' >^ distilled
powerfully smelling su'bstonZtn 5''^''' «'><= rise to a
tleV"^ -■■« separfte^fntoThe dr^n/a'^d'"' ^P,' ?«9).
the former become dry and re<iim T.^ ^ non-drymg ;
from oxidation, whilst^hrlh r^,?",-P?f-? ^^ -r
Y\ «4 *-k '^
C C 2
uiiailCrCU, i
ne
388
ELEMENTARY CHEMISTRY. [Lesson
drying oils are generally glycerides of acids not belonging,
but nearly related, to the fatty acid series : such, for in-
stance, is the acid of linseed oil, called linoleic acid
Cjg H28 Oa. Oleic acid, C^g H24 Og, is found in almost all
oils and fats, the compound of this acid with glycerin
constituting the liquid portions of the fats.
When the oils or fats are acted upon by nitric acid,
they are decomp ised, and amongst other products the
series of fatty acids is formed. Fatty bodies when boiled
with alkali undergo the remarkable change termed Sapo-
nijication (p. 385) ; the fat is decomposed into a fatty
acid, which combines wiih the alkali, and glycerin, which
is liberated, passes into solution. Fats may also be sapo-
nified or separated into acid and glycerin by distillation
with steam alone.
■
I
Ally I Compounds.
Intimately connected with glycerin are the compounds
of a non-saturated monovalent radical, C3 Hg, called allyl.
By the aciion of phosphorus iodide upon glycerin, a mono-
valent iodide, C3 H5 I, is obtained, from which a number
of bodies have been derived whilst the acrid substance
acrolein, formed in the destructive distillation of glycerin,
is the aldehyde of this series.
Allyl Alcoholy ^ 5 ( o^ obtained by acting with am-
monia on allyl oxalate :
C2O2 ]
C2O2
2(C3H,) S
02 + 2NH3=. 'hM N2+ 2(^^55 I o).
Allyl oxalate and ammonia yield oxamide and allyl
alcohol.
It is a colourless liquid, boiling at 105°, possessing a pun-
gent smell. It is oxidized in presence of air and platinum
to acrolein and acrylic acid, which stand to this alcohol
m the same relation as aldehyde and acetic acid stand to
4'-*"
[Lesson
jlonging,
I, for in-
eic acid
ImosC all
glycerin
ric acid,
ucts the
in boiled
;d Sapo-
a fatty
n, which
be sapo-
stilldtion
389
npounds
led allyl.
a mono-
number
ibstance
jlycerin,
'ith am-
nd allyl
gapun-
ilatinum
alcohol
itand to
XXXVI.] ALLVL COMPOUNDS.
ethyl alcohol : thus acrolein is ^3 H3 ) . ,.
CaHjO) H \'^^^ acrylic acid
sodfum .V; . ^°'"'"" '"""'^'^ *" ^"yl ^'<=°''°'. forming
rofbeT„ffe7l-« "^typical ^rogen in'the alj
place, ^..//^, .^,., C3 H, j ^_ ^^.^^ ^^^^^ ^^^ s
pre^trbTlct/or^^^^^ -^,.'''e sulphide artificially
solution of potassium sulnh^H J °"^5 *"•*.''" alcoholic
with the natural essence '^I„?it' "^'"*"^' '" Properties
cyanide ^:< "^ ) « " "'^""^'■' '''^^^'^ •'«'^'^''-
Oanule ^ ^^ | s, ,s found as tho essential oil of black
t~ng^ir^^U^|-itS'^s°iv^? sS^"^ -'/^r' ^y
at .48°. Allyl sulphide bofls at ,y°'^^"''''=- J' ^oils
is 1o™:?'wa?e l/c'olof ^"''o'^/ f ^' ^'-'^°'. and
hydrogen bein</removpH 1 °?"^;^ed, two atoms of
theabftractionVro°i^:^^?-,re.tZ^^^^
Q Hg O3 - 2 H2 O = C3 H^ O.
Acrolein is a colourless liquid, boiling- af c^-.o a
sessmg a most pupcrent odour/ wWchL.rll f h' ^""^ P^''
membrane of the nose and ^Is It ran, Hi '^^?"^«"s
acrylic acid, C3H3O ) '/!' ^^ '^^^^^y «-dizes to
^ ^°» U]0> ^ substance possessing close
'St^;:^i^^l^'' ^"'"^'^ -'"'^'"- -'" Mrogen
ac,^s:'who:ei<;r^So" dInfaloloT ""^.^ °/ '"''"°'^--
of allyl alcohoU«"rnty?tt:n tap" eV'ThT'^'i?"
?;^"!I'^! f-'^^ of fatty a'cids in"coSin'-t J'/.^±'^!^
390 ELEMENTARY CHEMISTRY, [Lesson
Acrylic Acid.
Crotonic Acid
Angelic Acid
C3 H4 O2
O.
C. H« O.
Pyroterebic Acid Cg Yi^^O\
Hypogasic Acid C^^'H^^O^
Oleic Acid
Erucic Acid
Q2 ^42 ^2
Crotonic acid occurs in croton oil, and angelic acid
in the archangel-root, whilst angelic aldehyde CH O i c
contained in the essential oil of chamor^ir^ ffleTc' ?^id
exists as has been said, in many oils esoeciallv n
almond oil, olive oil, and lard : this add wLn S uoon
by nitrous acid forms a new solid acid isomeric ^d?h
' Ilydrocarbons of the Acetylene Series.
A series of non-saturated hydrocarbons isomerJr wUT,
acetylene (pQs) exist ; they combine directly wiMwo^^^^^
four atoms ot chlorine or bromine, ar d in thriatter r.^
form saturated compounds Thete hvHr^^o 1 ^^^^
closely related to tlLe of%heXlen^t^^^^^^^^^
Thus, by acting upon the iodides or bromides of th^ ethv
lene series w,th alcoholic potash, we get the hydrocarb^^^^^
of flie acetylene series, thus : ^yarocarbon
Ethylene dibromide. Acetylene
Q H, Br, + 2 KHO = Q H,+ 2 KBr + 2 H,0
carbtns°"°"'"^ " " "'' °^ "'^ ^"^^'^'^"^ =^"es of hydro-
Acetylene .
Allyiene. .
CYotonylene
Valerylcne .
Hexoylenc .
C2H2
C3H4
^6 "10
B. p.
18°
45°
80°
(EnanthylideneCyH,, I'J^
Caprylidene . CH/ 1^^°
Rutylene . . q H 3* J ^o
Benylene . . Q^H.^ 225°
ca^'boflTd \UTo^e1 utdTr^s V^^^T^ ^^^^^^
(P.95). ThecoLpoLdsofa^^yTne^a^^^^^^
XXXVI.] ACETYLENE SERIES. 39,
acetyl oxide, ^.' C«. H | ^ .^ ^^^^^ _ ^^.^^^ .^ ^^ ^^^^_
C, Ag H T'°" °^ "^ '"^"' '''•' ''" "'''^' ^ '''""^' compound
CaAga H \ ^' '« Precipitated as a white powder. Both
these substances explode when heated or struck with a
hammer; and both when heated with hydrochloriracid
evolve acetylene gas. . /"i^i-iuonc acia
If acetylene be led over fused potassium, the metal
C^ni'jtc K-^'L'ZtT' T"""S the'compordi-
v,2 ri is. and Lg Kg : these bodies decompose violentiv in
contact with water, forming potash and acetylene "^'^^ ''"
A/fy/me CoU, IS formed by the action of potash uoc-i
propylene dicfiloride. The other members of this se^fes
are powerfully smelling liquids which combine with two
^.nd four atoms of bromine. ^ °
TETRAVALENT ALCOHOLS AND THEIR DERIVATIVES.
n 1!!rA'''\-^^'^''u^''^ ^^''^i''^^ ^^ y^t known is ermn/e
a solid white substance found in certain lichens and
fungi ; Its composition is C, H.^ O,. When disso?ved^n
cold concentrated nitric acid, erythrite forms the nitric
ether of this alcohol, ^^^^^^ | 0„ a body crystallizing in
large white prisms, and decomposing with explosion on
percussion Treated with hydriodiclcid, erytCe forms
secondary buiyl iodide, thus : ^ ^
Q 1^10
O4 + 7HI = C,H»I + 4H20 + 3l2.
HEXAVALENT ALCOHOLS AND THEIR DERIVATIVES.
The best-defined member of this series is mannite[
»-fl Wu Ofi, which is the alrniml of a ^-- '— - i- ,»
392 ELEMENTARY CHEMISTRY. [Lesson
& mannt'Ti*'.v?,H ^f^ f g^'Uke substance contained
in manna, the exudation from several species of ash
M^nite can be artificially prepared from cE varieties
sodiramSLf ^ "" "' ^''- '-'^<1 -"^ wateS
CaH,jO, + Hj = CeH„0,.
By oxidation of mannite, the reverse change occurs anH
canX"'be'tff"f li' ^•""°'" '^ P™d3'th cha^
re«nnt f ^^^^^^ ^^ ^ peculiar ferment. The chfef
Ire " That^Xf, 1.''^^"'^"' character to mann te
are. ,i; i hat when this substance is acted on bv nifr-V
acd, a compound, called mtro-mannite^Tio^^I ^^,^
IS mannite containing the 6 typical atoms orhydmS
vr
o
6)
replaced by NO^ : thus its composition is QH3
s^^oni^to^et^^^^^^^^^ "f^ \^^'^^^^ radicaUhiS?^' J
sponds to ethyl nitrate m the monatomic series h\ T^at
mannite is attacked by hvdriodic ar M f« o c- t ^^ ^^^
to elvcerin /'n -jR^^ 3 I Vu 1 , »n a similar manner
tu glycerin (p. 380; and erythnte (p. ^oi). the mnnatnm.v
Iodide.
compound mannite hexastearate, C H ( n
.The substances having the compoliUmPof the iodides
^^o;^^g,yc='=38r*^^^^^^^
ISO- or secondary, and «^/ i^rXry iodides th^' ^
xxxvn.] SACCHARINE BODIES. 393
the iso-hexyl iodide yields the secondary hexyl alcohol.
as It
( CH
boiling at 137°, whose rational formula is c\ ^A ■
• ij . ^ OH
yelds on oxidation first a ketone, CH,C,H,
butyric and acetic acids. ' < CO . and then
LESSON XXXVII.
SACCHARINE BODIES.
inasmuch" asX' coma^^S '^""«<l/-bo-hydrates,
proportion to for"-.^ wat^runi^'d'^^}; carhon^'^hrf''^
?u" ^motifs °o^f x^r "A^--^^^^^^^^ ^^^/r
three classes :(,Sucroses or th. '^ '"'''' ^^ ^'"''^'^^ '"'"
coses, or the grie stars'- 7,1 I^"f"' ^'°^'' ('^ ^lu-
woody fibre. ^ ' ^^^ ^myloses, or starch and
sub^st^LI. "'''' "''■'' ^''-''^^^ '^''^ains several distinct
I. Su erases.
^12 ^22 On.
Sucrose +
for cane sugar).
Lactose -f-
(or milk sugar).
( Melitose )
< Melezitose > +
( Mycose ;
2. Glucoses,
Dextrose +
(or grape sugar).
Levulose - -
(or fruit sugar).
Galactose —
3. Amylases.
Starch -f-
Glycogene.
Dextrine -\-
Inuline —
Gums.
Cellulose.
Tunicine.
The most imnortpnt ri;e<-ir.r«,.-^t,; \-^ • .
^ . -.-wx.5«,siiiiijj pxiysicai property of
394 ELEMENTARY CHEMISTRY. [Lesson
Jlwr^^M 'r '^ "\*''' ^i"°" °° polarised light. Like tar-
taric acid (p. 371), and many other substances, these sac-
charine bodies possess the power of turning the plane of
p0Iar.2at.0n, some to the right hand and some to the lefr'
thus dextoose, or grape sugar, turns it to the right; lev.:
lose, or fruit sugar, to the left. The right-handed sub
Ki^dTlwThl^'" '•'^ ''^^^'-^ '^ -th-a^.te
i4=u\stir:-s"-^^^^^^ "^^^^^
especally the sugar-cane, beetroot, mallow, and suear^
maple; also, ... smaller quantity, in honey and vaS
levulo,"/ '^?"' '°^""'''' *'!?.^ ""'"'"^^ of dextrose and
levulose. Sugar is prepared from the sugar-cane, which
contams about 18 per cent, of sugar, by crushing 'out the
ju.ce by passing the cane between rollers ; the juice is at
once heated to about 60°, and a small quantity V .Silk of
lime added for the purpose of precipitating the albumtaous
matter denved from the cane, the presence of whkh ren!
ders the ju.ce l.able to quick fermentation. The Tuice is
then ra.sed to the bo.ling point, the scum which rises 'to
the surface removed, and the clear liquid remaining is
bo led down m copper pans until it attafns a certain con-
sistence when .t .s filtered through linen bags, and agafn
evaporated to a syrup, which, on cooling, deposits crS
of mo.st or brown sugar. The mothS liquor is^gain
evaporated, and again allowed to cool and deposit another
crop of crystals ; the dark-coloured, uncrystafiizable sugar
IS termed molasses, or treacle. The refining of sugar is
a process conducted chiefly in England. TSe raw fugar
TK Iff '™A- ^""^ ?S?'" ''°"^<^ ^'* •■■ne and filtered
^if-'^i'Tf •'.1"°!' '= '•'^" decolourized by flowing thrS
a th.ck bed of an.mal charcoal, and the colourlefs fiUrale
evaporated down to the point of crystalL.ation, under
dimmished pressure, m vacuum pans. The object of this
IS to enable the syrup to boil at a lower temperitme than
It would do under the ordinary pressure, and thus 4 pre"
vent formrtion of uncrystallizable sugar, and to avoid the
Lesson
ike tar-
ise sac-
>lane of
he left :
'; levu-
^d sub-
4-, the
—This
plants,
sugar-
v^arious
se and
, which
Dut the
e is at
nilk of
ninous
h ren-
Liice is
ises 'to
ling is
1 con-
again
rystals
again
lother
sugar
gar is
sugar
:tered.
rough
Urate
under
>f this
than
> pre-
dthe
*xxvii.j PROPERTIES OF SUGAR 3^5
pi^acTV^^^^^^ ,7-P wh^h then takes
crystallize in moulds, giving ^loafsu"' ^1 ""'"^ '°
crystals are freed from fdheWn^ m J^^ Y °'' ^^^ ^"^^11
drying in a hydro-eSractor n? T^^I^ ^^^"°^ ^^ l^i^k
Much saving i^ aUaTned Ly 'th'e usTof ^th^'""^ ^^^"^•
and If its employment were universaln th^'""^
where the sugar is first nrpn^rJ^ .k r ^ • ^ colonies,
treacle, or uifcrys all ^abTe S woulH T'^"^^^."^"^^
the profit to the nlanw ^^ ' .^°"^^ ^^ avoided, and
method of treating t?r. P'^P^^^^opately increased. A
posed which Mfffirt r?^^^^^^^^^ ^^n pro-
raw sugar. It depends upon tKct ^^^i; "V^«"^^<^ture of
res'XheKke" ""^^f^' ^'^-'^ Phospho-
more of hot, water, and s nearivLL w**' -^""^ '" '"^^'er
ether. Its k^ci&c. X^' 1!"^^^^^^'^^}^^^^, .^"hol and
Sugar melts at i6o° to a colourles, ifn .il^ »to the right,
on cooling to a colourIe« tr,n /i 5""'' "''"='» solidifies
and, on sfand^g^""™^,";^^^ (barley-sugar),
more strongly iated,'":atT^"'5rvToff ^^d'a Y't"
coloured mass, called caram^^l fc iJr. u V^ ? ^ ^^^^-
acted on by nitric acid eftW tlv I ^^ ^^^'"^- ^^en
formed, ac^cSng to 'thf str.n^^^^^ °^^"" ^^^^ ^^
heat employed'"^StV'onJ%^fpl^^^^ fcifcont^ ^^ ^'^
into .a black mass, with evolutiVm nf J^^Tu ^^""^^ ^"^ar
mixture of these two acids n.K f^^^^'"'' ^''''''^^' A
form a nitro comXrC 3 fNO^^o^"'' ^'^ ^"^^^ ^^
mass, liable to explode on' peV^i^s^^^^^^^.^i^l.^^^^P?^
crose easily reduce the noble mSLnf?h°"',°^. '"'
on warming whilst cnnWr ctiJ? , ^^^^^ solutions
posed in alilLe olS ,f fu^^^^^^^ T'^ ^^^^^^ ^V^^^"^-
''•■— tlv fermPn.oKiJ k! . :_°__^"^'^^'^'- Cane-sugar is not
' "'"-^ ""^ "^ presence ot yeast it takes up
di
?96 ELEMENTARY CHEMISTRY. [Lesson
a molecule of water and forms a mixture of dextrose a ad
levulose, both capable of undergoing fermentation :
ClaHagOii-f H20 = CeHi20e4-CeH,20e. .
Sucrose. • Dextrose. Levulose.
^ By the action of dilute sulphuric acid, the same change
IS produced; and also by long-continued boiling of a
solution of sugar. Sucrose combines with certain metallic
oxides to form definite compounds ; thus we have
CjgHggOu CaO : whilst other metals replace some of the
hydrogen of the sugar; thus lead forms a compound
havmg the formula CigHigPbgOn.
Lactose, or milk sugar, occurs only in the milk of mam-
malia, from which it is obtained in the crystalline state
' by evaporation. The crystals, which are rhombic, con-
tain an atom of water of crystallization, given off at 140*
Lactose dissolves in 6 parts of cold and 2 parts of boiling
water ; it does not possess nearly so sweet a taste as
sucrose, and feels gritty in the mouth, and its specific
povver of rotation is -f 59° 3'. Lactose does not ferment
Itself; but when much yeast is added, fermentation occurs
after some time, mannite being formed. In presence of
: cheese, &c. the lactic fermentation sets in. Dilute acids
convert lactose into a peculiar glucose, called galactose,
which is directly fermentable, and yields mucic acid
when treated with nitric acid. Lactose reduces an alka-
hne copper solution in the cold, precipitating cuprous
oxide ; but the quantity of this substance formed is not
so great as when the same weight of glucose is employed
Lactose, when oxidized, yields mucic, saccharic, tartaric,
and oxalic acids.
Glucoses, C6Hi20e. Dextrose, or right-handed glu-
cose, grape- or starch-sugar, is found in many kinds of
fruit, m manna and honey mixed with levulose, or left-
handed glucose. It forms a normal constituent of blood
white of Qgg, and exists '1 small quantity in healthy urine,
whilst it is excreted in large quantities in that liquid in
the disease termed diabetes.
xxxvu.]
DEXTROSE.
m
Dextrose is formed in many ways.
(2\ ll ^hi'l"!""'"'? "■•, dextrine with diluted acids.
,^ rV -K "!"" °C"]i'" "P"" s""-':h (see Dextrine)
. (3) »y the action of dilute acids upon sucrose fwhen it
IS formed together with levulose). sucrose (.wften it
(4) By the action of acids upon many glucosides
Dextrose is prepared by boiling starch wUh dilut-
sulphuric acd adding chalk to neutralle thracid a^,d
evaporating the liquid to a syrup when the sugar cr;stal
•?N- A"- ™^': ^'=° ^ ^''^"y prepared by washi,^. ho'ev
with dilute alcohol : the levulose being^nTore soluble Is
hus removed. Dextrose turns the plane of polarization
the right : its permanent rotation-power s+ 56° l"
n dtte';irn).l=1°""H^"^'" "f ^^^t^r^M dissoh^ef easily
in dilute alcohol, and is not nearly so sweet as sucrow •
It'^"?"' Devrror"""" '!3°'^?'^ °' water.w'hich theyTse
^TnlTrf in a solution can be ascertain^eS by e^^
ploying a standard solution of alkaline copper salt Fro^
silver salts the metal is deposited by dextrose in the form
ox ali^rd":- ''"™ '''" ""•''^^^ ''''"™^^ to sacchari:™
cr^^JmZL°l M'>"<1«'' &lucose.-This forms an in-
anH lli^h^i tif "'"y''^" ^y™P ' " '^ "'°'-« soluble in water
and alcohol than dextrose, and is therefore sweeter Its
action on polarized light changes remarkabTv with the
temperature : thus at a temperature of ia" C. itsTotatorv
power IS io6», whereas at 90° C. it is reduced to 5,° Le
vulose reduces cupric salts like dextrose; it is obiained
by neutrahzmgwith lime the mixture of glucoses obta ned
by thf. action of sulphuric acid on sucrofe The°evXse
ime-compound is a solid, whilst dextrose forms a ^"quid
o^afi^^HH ^y <J<=<=rP?s'"g this lime-compound wih
oxalic acid pure levulose is obtained.
1 he isomeric acids h-.ving the composition C H n
C^».«. and ..../l«r/.), obtained by the'^ac ton of dilme'
nunc acd on the different sugars,' must be regarded Is
3CS ELEMENTARY CHEMISTRY. [Lesson
products of oxidation of mannitc, the hexatomic alcohol :
levulose yields mannite when acted on bv nascent hydro-
ffcohol '^''"'^' ^° ^^'' substance^ as aldehyde to
Mannite, ^o^a | q,. v
se. Mannitic Acid. Mucic and Saccharic Acids.
Alcohol, ^2^6 1 o.
He
Levulose.
Aldehyde.
Acetic Acid.
FERMENTATION.
r]3'%"5"'^ ^^^ ^•^•'' ^^^^"^ ^° ^ peculiar and interesting
ciasG of decompositions, which have long been known
but differ altogether from the ordinary chemical actions'
Many organic bodies are capable of undergoing fermen-'
te^ed'? P'''^'" ^^ "."^^^^ complicated substances
termed ferments, giving rise tc severa^ products differing
tr^tf^^r ^h.^'l^t^^^o^the fermented body and hf
ferment Careful investigation has shown that the pro-
cess of fermentation entirely depends upon the presence
arid growth of certain livin/ organisms fori^ng the
ferment. Different kinds of Termelits give rise "f dif!
ferent products Thus we have one ferment (yeast) wh^h
effec s the alcoholic fermentation, another which iels up
the lactic fermentation, a .nird producing the acetous
fermentation, &c. Most of these ferments^are vegeSe
growths of a low kind, but one at least, viz. that causing
the butyric fermentation, is an animal ; and this, Strang!
to say cannot live m contact with free oxygen, but
flourishes in an atmosphere of hydrogen. In order tha
the ferment should grow, it must be supplied with proper
xxxvn.] FERMENTATION. 399
food especially with ammoniacal salts and alkaline phos-
phates : these are contained in the albuminous nfat?er
generally present in the Uquid about to be ferm^nleH
In order that the fermentation should go on w^f the
temperature should be from. 20" to 40°; ft much^hth«-
f/des^o";ed ""■■ ^^"'P-^'--. the vitality ofThe'fe^^'e^^
nnJ",.,"^'' "'^^^^ spontaneous fermentation sets in with-
beer mirk''E*l'''^"r "-^r^ '■^™^"' = '^us wne,
nn^f'w^A "',?''•' *'"'" *"°*^<J simply to stand ex-
Th.i I *^ ^"■' ''1''°'"^ ^°"'" o-- othenlise decompose
These changes are, however, not effected without the pre
sence of vegetable or animal life, and are tn.e fermen"
tations: the sporuUs, or seeds if these liWng boZs
always float abon in the air, and on dropprg^into he
hquid begm to propagate themselves, an<f^n^he a tor
growmg evolve the products of the ferJnentation iVlhi
above liquids be left only in contact™ a r which has
been passed throu^^h a red-hot platinum tube, and thus
filt^r^d'?? 'P"'"'^" destroyed ; or if the air 'te simply
filtered by passmg through cotton wool, and the sporXs
prevented from coming into the liquid, it is found that
these fermentable liquids maybe preler^'ed for any lenetl
Th'!l%'^'/''°"' ""''^■•g°i"g the slightest change ^ ^ ''
and cI?bonkac1d '^™^°'««°"' ^'^--'-^ -chiefly alcohol
2. The acetous fermentation, producing acetic acid,
3. The lactic fermentation, yielding chiefly lactic acid,
acfd. '^'■"' *^^""«'"^tio°. yielding chiefly butyric
mannltef """"""^ '■^™^"'^''°". giving rise to gum and
6:^i!^\tf' ^"■"•""^<i'>n.--V^t glucoses are able, when
dissolved m presence of the yeast-plant {Myciderma
400 ELEMENTARY CHEMISTRY. [Lesson
QHigOg = 2C2HeO + 2 CO2.
• About 6 per cent, of the g'ucose undergoes a different
change, part being used as nourishment for the yeast
ftr^T^^' part forming glycerin and succinic acid!
Prom 100 parts of glucose about 3-5 parts of elvcerin
are Produced, and o-6 to 07 of succinic acid, whilft^ra "S
I 5 parts of cellulose and fatty matter are formed by the
growth of the yeast. The alcoholic fermentation occuK
best at a temperature of between 25° and 30°.
LESSON XXXVIII.
AMYLACEOUS BODIES AND GUMS.
Dextrine, QH
10 ^s*
^ : » -6**10 ^6- — This substance, called British
Gum is prepared by heating starch to about ko° • if a
small quantity of nitric or hyu ochloric acid is added to
ranidlv ' iSivt^- ^^^P^^^.^^^^ion takes place much more
^T^hJ^ f^ '? ^^^° ^^^"'^^ together with dextrose
^V\^ ^^T f "^^^^^ ^^^"^^^ "P«" starch. It deviates
the plane of polarization strongly to the right, its rotatorv
power being -f 138° f. Dextrine is very soluble in watS^
and inso uble in alcohol, and on boiling with dilute ac^s
dextrine is converted into dextrose,
.n^"""^ ^^^^^V.-The natural exudation from several
species of acacias ; it consists chiefly of the potassium
and calcium salts of arabic acid, C,, H,, 0,„ P°'^"'^""^
W/;. -A substance contained in the roots of many
plants ; It IS intermediate between gums and starch : it
yields levulose when boiled with dilute acids. '
Glyco,S[en or Animal Starch, is an insoluble powder
'rgfucose "" '"^ P'"''"^" ' '' '' '^'''y ^° '-^^'^"
[Lesson
mainly
different
e yeast,
ic acid,
glycerin
St 1*2 to
1 by the
1 occurs
British
>° : if a
Ided to
ti more
extrose
leviates
otatory
1 water
e acids
several
assium
' many
ch ; it
)owder
iverted
xxxvnij STAJiCIi OJiAWi.£S.
Starchy C«H n /^ * ^^^
DowH?^''"' the vegetable world itTn' ^'^'^>' ^'«""s^d
powder composed of P;ra;,Jj;^-^J^ consists of a whiUf
S»tarch and Fig. 67 the srrannC^* c\ ^^P^^senting potato
^^^^^^r organued structure, and are
Fig. 66.
Of various sizes. Thp f^n^ •
Potato. 0185 mm.
isago . o 070 „
Wheat . . .0050mm.
indian corn . 0-030
|^»'« • . o-oio mm.
Beetroot. 0004 „
Starch erani.W • ' ^^""^*- °o°4..
^ass called starch paste*^ jf'*i?'" °P^". ^ming a S
'"■•ger quantity of wat- ,., '"^ P''*'« ^e boiled with^
•o finely diWd'ed thTtTh..!?'L?^':^'='« of «arch1.e"cl^
- ^ .^„. uirouyi, a niter; and if
402 ELEMENTARY CHEMISTRY. [Lesson
boiled for a length of time, the solution becomes clear
and the starch is rendered soluble ; and from this solution
alcohol precipitates a white amorphous powder of soluble
starch. When heated to i6o° starch is converted into
dextrine. Starch, in its insoluble and soluble modifica-
tions, forms with free iodine a deep blue compound, the
Fig. 67.
colour of which is destroyed a little below loo", but
appears again on cooling. This colour is characteristic
of starch, and is not produced with dextrine or the other
isomers of starch. When the soluble azotized matter
contained in malt, called diastase, acts upon starch, it
forms dextrine and dextrose ; and by a longer action the
dextrine is also converted into dextrose.
Starch. Dextrine. Dextrore.
3(C6HioO,)4-H2 = 2(CeHio05)-f CeHigO^.
The action of dilute sulphuric acid upon starch is similar
to that of diastase. Strong sulphuric acid in the cold
th^
XXXVIII.]
GUN COTTON.
403
f o°dTsso&t''°Z"^ '^ '=.°r°""<' ^^^ Nitric acid
J;""''r\^^^^''^- -This^is tSI co^S.riSfr„^iSi3- (
111. pure state trom cotton or Imen fibre bv boilino- r.n^ ti,^
mpunties with alkali, alcohol, ether, &a CeUufose is f
white substance insoluble in water, icohol, or ether but
Rv t?,r"^.'" ^"J ammoniacal solution of cupric oiide
veVed eltheHnfo'Lr^ =l'P,!?""*= u^"'*' celluCis conJ
Hue w;?h ;!.h' ^i'. '"soluble substance which colours
f tLs^'l^idtK TdiUerj^th'"^!^^^^^^^^^
A uS iublr "^- byfi-'i- of ^^ Sukof S'
A useful substance is obtained under the name of p^ch-
"u^huSS''' "PP'"^ "^'^'^ °' P^P- - °o "'-4
Ca« C<7//<7«.— The action of strong nitric acid ,.nnn
cellulose is interesting. If cotton woofbe hrown in smaU
portions at a time into a mixture of equal volimerof
strong sulphuric and nitric acids, it does not undergo any
fCmlw^^T'- ^'" °u" ^^>""S '' 's found to bive?^
ta wwSi tiree .V ^ ^''ttit"""" P^duct, being cellulS
-tl^n, r H /m'^"?^^"*^ hydrogen are replaced by NO,
kJIZ' ?•"' (N02)3 05-and is called trinitro-cellulose
mtTXSeTr'^^'^'*^^ •'-" propofSJafroffLt
(i) The explosive force of ^un cotton is, weight for
weight greater than that of gunpowder. (2) The pro-
dioxfd. .nr -."'''^^ °^ ^^ ^°"°"' tjeing chiifly carbon
dioxide and nitrogen, are not so apt to foul the Ln M
When moistened t becomes inexplosive, and onh^equ-'res
drying to render it again explosive. ^ requires
Ihe reasons which render the general adoption of this
D D 2
404 ELEMENTARY CHEMISTRY, [Lesson
substance doubtful are : (i) its liability to explode on per-
cussion ; (2) the possibility of its spontaneous decom-
position when kept for a length of time.
Gun cotton, or certain forms of this substance, dissolves
readily in admixture of ether and alcohol, and yields
a solution which is termed Collodion, and is largely used
for the purpose of forming a thin coating on glass t®
receive silver salts, upon which the photographic image
j GROUP OF GLUCOSIDES.
• "{J^e ^u^erous substances constituting this class occur
in the bodies of many plants, and yield a glucose on
decomposition together with other bodies ; they may be
considered as kinds of compound ethers of glucose The
most important are amygdalin, salicin, and tannin.*
Amygdahn, QoH^^NOn + S H^O.-^Found in bitter
almonds, and obtained by dissolving out by alcohol, and
precipitating the amygdalin with ether ; it forms small
white crystals which are soluble in water. The most
remarkable decomposition which amygdalin undergoes
IS that which is brought about in the bruised almond bv
the presence of an albuminous substance called Synap-
tase, by which bitter almond oil, hydrocyanic acid, and
glucose are produced : '
Amygdalin. Hydride of Hydrocyanic ^-i
^ Tj XTr^ . TT ^ Benzoyl. Acid. Glucose.
C,oHarNOa + 2H,0 = QHe0.fHCN+2QHijOe.
Salicin, CisHigOy, contained in the pith of the willow
and poplar, and also found in the castoreum contained in
a gland of the beaver. Salicin crystallizes in bright white
needles; it is soluble m water and alcohol, but insoluble
m ether, and its solution possesses - .... jngly bitter taste
follow?^"^^ of certain ferments t decomposed as
Salicin. Saliffenin. Glucose.
XXXIX.] GROUP OF GLUCOSIDES. 405
is c^nSd'w^^^^^^ .Q,H23 0,,.~This substance
lb contained widely diffused in certa n parts of nlantc • ;T
^dadf fnf h ^ '^'^^"^"^ ^'^ insolubrc^mp Pund Vith
?^^ ' ?^ by producing a black colour (ink) with ferric
compounds. Tannic acid occurs in largesrqulntities^n
gaU-nuts (an excrescence formed on the ofk b^a^Wt
nut ' T?''- ^ ^I ^^"^^"^ ^'^'^' fr«»^ the powdered S
.^1 Ki^""'" ^^"' prepared is an incrystallizable mass
rinn n "f ^^^^^^^d alcohol, but insoluble in pure S
Tannin forms glucose and gallic acid when it is exoosed
to the air, or when treated by dilute acids ^
Gallic Acid. Glucose.
Tannin
(1 -L .. U n ^aiuc Add. Glucose.
Tannin heated to 2 1 5° yields pyrogallic acid
Ubummous ferment found in the seeds, thus
Potassium Myronate. OilofMusUrd. GIucos.
LESSOM XXXIX.
THE GROUP OF AROMATIC COMPOUNDS.
It has already been stated that in these bodies ^\^^
i:te\teln^^eT' '''''''' -mbinedTog^hrtht
th.t th? ! ?^ foregoing group, or, in other words
that the aromatic hydrocarbons contain relatively less
hydrogen than those which we have hithertrstyied
Another peculiarity of these substances is tS thev con
tarn at least 6 atoms of carbon, and that the more com
SVors'T'a 'P"^ "P>^^ those coralninH
t4iDon atoms. It appears in fart f^of 0I1 ^.u^ _„._^..
4o6 ELEMENTARY CHEMISTRY. [LESSON
bodies contain a group of 6 carbon atoms, in which i8 of
the combining powers of the carbon are taken up by
union of carbon with carbon (p.292), whilst 6 remain open
to saturation.
The simplest combination amongst the aromatic series
is that of benzol, CgHg; and from this body a large
number of other substances can be derived by substitu-
tion of one or more atonr ^ f hydrogen by more or less
complicated molecules. 'V- -y^ for instance, we are ac-
quainted with four hydrocarbons homologous with benzol,
but differing by CHg : these substances are in fact benzol
in which i, 2, or 3 atoms of hydrogen have been replaced
by methyl, CHg. We thus have :
» (i) Benzol, CgHg
(2) Toluol, or )
Methyl Benzol )
(3) Xylol, or Di-
methyl Benzol J
(4)
QH8,orC6H,(CH3).
Boiling Point
. 82°
CoHift, or C
'8^^10>
Cumol, or Tri- j /- tt
methyl Benzol ) '^s^is'
or C<
(Hgj
CH,
CH3
CH.
ch:
ch:
III'
139°
168=
Each of these methylated benzols yields an important
series of derivatives, corresponding to those obtained
from benzol itself. Thus in each, one or more atoms of
hydrogen can be replaced (i) by chlorine, giving chlorine
substitution products; (2) by the monad NOg, yielding
nitro substitution products ; (3) by the monad N Hg, yield-
ing amido compounds ; or (4) by the monad O H, yielding
a peculiar set of alcohol-liice bodies, termed Phenols,
as well as a series of true alcohols, isomeric with the
phenols. The following table gives the names and formulae
of some of the derivatives of benzol, and methyl benzol,
or toluol :
Benzol . . . ... CgHe.
Monochlor-benzol . Cg H5 CI.
[Lesson
Ich 1 8 of
1 up by
ain open
ic series
a large
Jubstitu-
; or less
are ac-
i benzol,
t benzol
•eplaced
ling Point
III'*
139°
168°
portant
btained
toms of
hlorine
ielding
J, yield-
ielding
henols,
ith the
)rmul£e
benzol,
XXXIX.] AROMATIC COMPOUNDS.
. CoH,(NHa).
407
Nitro-benzol . .
Aniido-benzol, or )
Aniline \
Phenol, or )
Carbolic Acid (
CoH5(HO).
"^o^^ol QH8,orCeH5(CH3).
Monochlor-toluol . . Q H7 CI, or Cg H4 CI (CHJ.
Nitro-toluol . . . C7H7N02,orCoH4(N02)(CH3).
^"toS"! • C,H,N,orC,H,(NH,)(CH3).
■Cressol ...... C; H^O, or C6H4(HO)(CH3).
A series of bodies, isomeric with these toluol compounds,
exists, in which the substitution takes place with the
hydrogen of the methyl. This is termed the Be/izy/
series.
Toluol. Benzyl Chloride.
QHg, or CeHfiCCHg). C7H7CI, or CcHjCCH.Cl).
Benzylamine.
CeH,(CH2)
N, or H
H
N.
C.
SI0,
Benzyl Alcohol
C(5H5(CH2)
or
H2)J
H \
O.
By oxidation benzyl alcohol yields an aldehyde, C7 H. O
oil of bitter almonds, and an acid, C^HgOg, benzoic aczd,
both derived from this alcohol, as ethyl aldehyde and
acetic acid are derived from ethyl alcohol.
The di- and trimethyl benzols -Iso furnish similar
double series of isomeric derivatives. In like manner
all the higher alcohol radicals, ethyl, propyl, butyl, &c.,
can be substituted for one or more atoms of hydrogen in
benzol ; and thus an almost unlimited* number of isomeric
4o8 ELEMENT A R Y CHEMISTR Y. ' [Lesson
billies may be prepared: thus ethyl benzol, Q He (CoH«)
IS isomeric, but not identical, with dimethyl benzol or
( CV\ ( CH
xylol, CqH^ ^ ^j^3; cumol or trimethyl benzol, CqUJ Ch!
^ ( CH3'
is isomeric with ethyl toluol, C^H^ j^aHg^ ^^^ ^.^^^
propyl-benzol, QHfiCgHy. ^
It is important to be able to distinguish between these
classes of isomers; this can be easily done by sub-
mittmg them to the action of oxidizing agents, such as
dilute nitric or chromic acids. Thus, toluol or methyl
benzol, CCH5CH3 ethyl benzol QH^QH,, amyl benzol,
C«H,C6Hii,all yield benzoic acid,C6H,C02H,on oxidation.
:^ylol, or dimethyl benzol, CgH^ | ^^3, isomeric with
ethyl benzol, yields, however, on oxidation, first toluic
acid, C6H4I ^p^2 (monobasi ,, and afterwards tereph-
thalic acid, CeH4|^^2H (dibasic). In like manner
methyl toluol and diethyl benzol yield these two acids on
oxidation.
Benzo/ (or Benzene), CeHg.—This body can be prepared
from Its elements by synthesis, by heating acetylene, ob-
tained by the direct union of carbon and hydrogen, nearly
to a red heat ; triacetylene or benzol being formed:
3 Cg H2 = Cg Hg.
Benzol is likewise found in the light oils obtained by the
destructive distillation of coal. It is a colourless liquid
refracting light powerfully, boiling at 82°, and freezing at
45 . It is also obtained by distiUing benzoic acid with
slacked lime. Benzol is attacked by chlorine, and several
chlorides formed; when treated with nitric acid, an in-
teresting substance calle4 nitro-benzol, CeHg(N02), is
produced, a substitution product in which one of hydro-
gen of benzol is repla ed by NOj,; and wc also know
XXXIX.]
3»
BENZOL SERIES.
409
a solid substance C2i\\eei di-nitro-denzol CH 2 CNO ^
thus: '^ »s Replaced by the monad group (NH,),
Nitro-benzol. " Aniline
C,H,(NO,) +3H3 = C,H,(NH,) + 2H2O.
^ftenol^ or Carbolic Acid C H /'OH^ tu- • 1.
round in the heavy coal o Is. It dissolvf^Q in <Ko ^ii r '
mfectant both alone and when combined with lime
a bright yellow crystalline ^odv verv soliih£ in „,o^ '
IS obtained by th/action ot r^It'dc^aTir^n Lny "U
P^rril '"'•^^ •*'^''^^' "^'•^°^^^ ^^i^i and its ?er?vatives
Pcric acid IS employed in the arts as a yellow dvefo;
silk and woollen goods. yeiiow aye tor
pofl&^s b1:;tf [^X^'H ^Se^ltiS^o^Tyll^^ei'?;
Sen K Tn>Tdlb^Zl.^"hi't:l4S"-
aniline from benzol has just bten descrTbed, the?edS?
of nitro-benrol being generally effected by a mtaure of
Tact'iof of"n„?'f "^ "'^'■''- • ^'"^y ^^ be ob^Sd b?
me action of potash on isatine (p. 419) : ^
C,HrNC),+4(KH0) = QHrN + ;^TcoJ+X
di^ilia.^:r o?cofr °"^'' "'^ P™''""^ °f *^. <J-t"'="ve
/
/
410
ELEMENTAR Y CHEMISTR V. [LESSON
Aniline is a colourless liquid, possessing a peculiar
smell; its specific gravity at o° is i'036, and it boils at
182**. It is nearly insoluble in water, but dissolves in
alcohol and ether; it unites with acids to form definite
salts, but it does not turn red litmus paper blue. Crude
aniline is manufactured now en a very large scale for the
preparation of the so-called aniline colours, so generally
used in calico-printing and woollen and silk dyeing. The
smallest trace of aniline may be easily detected by adding
to an aqueous aniline solution an aqueous solution of an
alkaline hypochlorite, when a splendid red colouration is
formed : this is prepared in quantity by adding to aniline
sulphate a dilute solution of potassium bichromate. This
substance forms one of the important aniline colours,
femd is called mauve; it contains a base of complicated
constitution, termed mauveine, C27 H24 N4. The colour
mauve can be prepared by many other methods : the best
of these is by heating anihne with a double chloride of
sodium and copper. The other colouring matters derived
from aniline are noticed on the next page. AniMne gives
rise to a very large number of derivatives ; thus we have
a series of compounds in whieh one or two atoms of
hydrogen in the NH2 are replaced by ethyl andother
radicals. Thus we have ethyl aniline, CgHgN |
We are also acquainted with di-amido-benzol, thus :
Aniline or Amido-benzol. Di-amido-benzol.
CeHfiCNHg). C6H42(NH2).
Aniline has also been called Phenylamine, H
H ,
in certain respects it resembles the compound ammonias :
thus, for instance, it is capable of forming a hydroxide
analogous to h* [ ^» ^ body which is a non-volatile
strongly alkaline base, ^ ^eHfiCCaHg^ ) ^^ ^^^^^ Triethyl-
phenyl-ammonium-hydroxide. If one atom of hydrogen
CgHg
H*
N; and
[Lesson
peculiar
boils at
lolves in
. definite
Crude
i for the
generally
ig. The
y adding
3n of an
ration is
3 aniline
te. This
colours,
iplicated
e colour
the best
loride of
; derived
ne gives
we have
itoms of
nd other
5C2H5
H
IS
N; and
imonias :
ydroxide
i-volatile
Triethyl-
?ydrogen
XXXIX.] ANILINE COMPOUNDS. 4,,
CeHlNHfnU^ ^^ °^^^^^^ ^^^^'-^^ - -etyl, .e get
CaHgOr' aniline acetate; and this on heating loses
a molecule^of water, yielding an amide called acetanilide,
® * ( CjHgO' J"^^ ^s ammonium acetate yields ace-
tamide (p. 354).
C,H.(NH,) + NO,H = C,H,(OH) + H,0 + N,.
If, however, an aqueous solution of aniline nitrat,. K.
crystallizes in colour esl needles aTdtheTh5 ^'7^°""'^
percussion it decomposes Xex^e violence n' °"
percussion. Diazo-amido-benzoTfs ako obtafn?H h " °"
group N, acts, therefore, as a dyl^ 'two of .h^'f^'*'^
0^to«/, „ Py„^,u,^ C.H,f gg.-Thi, „b.
.^■^^
412 ELEMENTARY CHEMISTRY, [Lfssoj
nhpn?!' r^^ u'w^^li'J^'^ ^>" ^^^ ^^'^»"" ^ potash on iodo-
p enal, C,H,I(OH), and is produced by the dry dis^
lillation of catechu, many resins, and wood.
formpH i>^^"'''- t""^^ tr;^\>so"icrs of l>yro.catechin are
fnrm^H' » -^f ""T ^5^ fp^^r<i^nmHe. The latter is also
formed by the dry distillation of quinic acid, and by the
ac .on of potash on iodophenol. The isomerism of these
nn.^ T'P^''" u"*' '' ^^ ^"^ explained by the different posi-
tions which the two groups of hydroxy! take up iAihe
benzol molecule In hydroquinone the hydroxvl^is con!
^toms ;^nd'Z k"5*'°" ^''^ ^^° neighbouring carbon
^LS. n 1 A ^""^^ \s easily converted by oxidation into
sTeirrstSiyX^fe ^^^'^" ^^'^"^' "-^^--^
Hydroquinone and oxygon ^kv^ quinone and water.
. Tetra-chlorqumone or Chloranil, C„CJ,0,, is obtained
in golden scales by the action of hydrachloric acid ard
^^m^ZZt^T^ ^'^ quinone phenol, and other aromadc
compounds. It is a very stable body, not being acted
u^^n by concentrated sulphuric or nitric acids lx%7a
BENZYLIC OR TOLUIC SERIES.
Toluol.iQX Methyl Benzol, Q H^ = Q H, (CH J -This
at III , and does not solidify at - 20"^ • it i«i aUn fr^r«,o^
by the distillation of toluic add with Excess of l°me l1
can be prepared from benzol by rep'LinTonVatom of
hydrogen by methyl (p. 406). By the action of ox dSina
agents it is converted into benzoic acid, thus : ° ""'"^
C,H.+ G3-C,H,0,+ H,0.
Nitro-toluol, C,H, (NO^), is obtained by the action o)
nunc acid upon toluol ; and by reduction a basic substance
xxxix.j ANILINE COMPOUNDS. 4,3
solid substance wSich exists ilw»il'ir'^- ' '^". " ?
line and in fact'is a tce^sarVi'nTr^^i "„t7o"Z p2 p''o"e
TouWlT£a?;o=''' r? ".^^^ violet anilin'e ?oZrs
isomirirwhhbenlyiirmine"' '""^ ^' '^^ ° ■^°'"''"- ^
wiftTt'r'' S'*^' (f 1.0).-A crystallizable solid, homoloirous
with phenol, contamed in the crude carbolic acwXh
JS a mixture of phenol and cressol ; it bcils at 201°
J^osamlwe, C^ H,. N3 -The compounds of ?his sub
«S« Th^co?'^'"'''' 'Z^ T''^'^ ^lour known as
f!3 J ^"^..'^o'o"'' maybe obtaine 1 various wavs
thrcrude' sXan;;"' ''^ ""'''' co.sisis 7n heSg
temperate of from ,2o^o'?Io»' ^^'"^ '°^''^" '° ^
beino^ 15 nnrt^ „> J '.° '40 : the quantitres taken
rTOmed: ' ^°™""°" "^ '°=^"'""« ""^y "e thus
|i!j4si;^i;s:::a';^?ri:^:i^'.ir^^
^^tp^r^^iiuTrn'"^-:^^^^^^^^^^^
B^the tifio'n" of "a':'- ^t't ^ =^""^ ^^^^^^^^^^^^^^
= l^f:S'n^.ra-^S;^^^^^^^^^^
«andmg ,„ the same relation as blue and whUe Mgo
414
ELEMENTARY CHEMISTRY. [Lesson
An aniline blue is obtained by the replacement of
three atoms of hydrogen in rosaniline by phenyl, C, Hg,
on heating rosaniline with aniline, thus :
C20H19N3 + 3 CeHfiNHg^ C2oHi«(QH6)3N3 + 3 NH3 ;
whilst a violet is obtained by substituting three of methyl,
ethyl, or any of the alcohol radicals : thus triethylros-
anihne, Qzq^iq (C2H5)3N3, is manufactured for its splendid
colour, and is known as Hofmann's violet.
BENZYL GROUP.
!<>.
Benzyl Alcohol,^^^'''^^^ 5 O, obtained by the action
of alcoholic potash, or nascent hydrogen, on oil of bitter
almonds (which is the aldehyde of the series). It is an
oily colourless liquid, boiling at 20''°. Oxidizing agents
convert it first into the aldehyde, ' HgO, and lastly into
the acid of the series, QHgOg, ben^. ic acid.
Benzoic Aldehyde^ oil of bitter almonds, CeHgCOH. —
This oil does not exist already formed in bitter almonds,
but is the result of a decomposition of the amygdaUne
contained in the almond (p. 404).
It can likewise be obtained by distilling a benzoate
and a formate — in this respect resembling the aldehyde
of the alcohol group; it also forms a crystalline com-
pound with hydrogen-sodium-sulphite. Bitter almond oil is
a colourless strongly-smelling liquid, boiling at 180°; the
commercial substance (used in cookery) is very poisonous,
as it invariably contains an admixture of hydrocyanic
acid. On exposure to air or oxygen, or when acted upon
by oxidizing agents, it is converted into benzoic acid.
Benzoic aldehyde may be regarded as toluol or methyl
benzol, in which two atoms of hydrogen of the methyl are
— (COH); whilst
renlaced bv one atom of oxvsren.
CgH«
XXXIX.]
BENZYL GROUP.
41S
Benzoyl Chloride, QH^ CO CI, the last substance in
which the one remaining atom of hydrogen in the methyl
IS replaced by chlorine. vapour of bitter almond oil
decomposes into benzol and carbon monoxide when passed
through a red-hot tube ; and benzoyl chloride is formed
by the direct action of carbonyl chloride on benzol, the
monad group (CO CI) changing places with one atom of
hydrogen, thus :
Carbonyl Chloride. Benzol. Benzoyl Chloride.
CO CI2 + CgHg = CeH«(CO CI) -f H CI.
Benzoyl chloride can also be formed by the action of
phosphorus pentachloride upon benzoic acid ; it is a colour-
less liquid, boihng at 199^
' Benzoic Acid, C^Hp^, or CgHg CO2H.— Found in
many resms, especially in gum benzoin ; it also occurs in
the urine of cows, and in the putrefied urine of man and
other animals ; it can be obtained by the oxidation of
benzyl alcohol and bitter almond oil. Benzoic acid may
be easily prepared by heating gum benzoin, when the acid
sublimes in pearly white plates ; it fuses at 121° and boils
at 250°. Benzoic acid forms a series of salts, most of
which are soluble : the ferric benzoate falls as an in-
soluble red precipitate when sodium benzoate is added
to ferric chloride.
Benzoic Peroxide,^^^^ \ Og.— A well- crystallized
substance, obtained by the action of barium peroxide on
benzoyl chloride ; it explodes when heated, and resembles
acetyl peroxide (p. 353).
, Benzoic Benzoate, or Benzoic Anhydride, &2« ^ \ O,
obtained by acting upon potassium benzoate with benzoyl
chloride, thus : ^
CtH.O I o 4. c, H,0 CI = grH^O ^ q ^ ^€1.
4*6
ELEMENTARY CHEMISTRY. [Lesson
It is a solid substance, fusing at 24°, and boiling at
about 310°; it is soluble in alcohol and ether. Several
mixed anhydrides are also known : thus we have acetyl
Denzoate, CyH^O ) ^•
Bensylamine. H > N, a colourless liquid, isomeric
H )
with toluidine, boilinjr at 182°, obtained by the action of
ammonia upon benzyl chloride. It is a true amine, and
gives rise to corresponding secondary and tertiary amines.
Hippmic Addy CgH^NOa, is contained in the urine
of horses and herbivorous animals. It can also be arti-
tkially prepared from zinc glycocine and benzoyl chloride.
h is in fact glycocine in which one atom of hydrogen is
replaced by the radical Cy Hg O of benzoic acia, thus :
Glycocine. Glycocine Hentoic Acid, or Hippuric Acid.
C,H3(NH,)08. C,Ha(C7H60)(NHjj)Ps,.
Benzoic acid is converted by passing through the animal
body into nippuric acid.
SALICYLIC GROUP.
The members of this group are closely connected with
the benzyl and benzoyl series, differing from the former
of. these by the substitution of an atom of hydrogen by
hydroxyl (OH).
Salicyl AUehyde^ Q H^ 0,^ - Cg H4 OH C O H.—The
volatile essential oil of the flowers of the meadow-sweet
iSpircea uimana) consists mainly of this aldehyde. It
is also formed by the oxidation of Saligeninc^ Cj Hg O4,
the alcohol of the series, a body derived from salicin, a
XXXIX.J
SALICYLIC GROUP,
417
bitter principle found in willo^r bark. The close relations
of sahgenine, cresaol, and benzyl alcohol are seen in the
following formulae :
Saligenine. Cre»sol. Benzyl Alcohol.
CeH,(OH)CH, j ^ . c,H,(OH)CH«; C.H.Ch/j ^
Salicyl aldehyde forms salicylic acid on oxidation.
,v''{'1^u'a^'''^'S^ ^^ 9^ ^^^ "' ' ^°""d together with
the aldehyde m the oil of Spircea, and it is formed by the
oxidation of salicin, &c. It can be obtained synthetically
from phenol by acting upon it with sodium and carbon
dioxide, thus :
Sodium Phenylate. Sodium Salicylate.
CoHjONa + COjj-CeH.OH.COaNa.
On heating salicylic acid again decomposes into phenol
and carbon dioxide. It crystallizes in large four-sided
prisms, and is monobasic but diatomic. It occurs in the
oil of winter-green {Gaultheria procumbens) as the methyl
compound CeH.j^H^^^^
Gallic Acid, Q He O, - C, H, j ^^^\ , is obtained
from tannin (p. 405). It can also be prepared by the
acid°^ °r^^"stic potash on di-bromo- or di-iodo-salicylic
QH,l203 + 2KHO«2KI + C7He06.
twn"'nmmc nf k'^1 ^^ '^^^'^^^ ?s salicylic acid in which
two atoms of hydrogen are replaced by two of hydroxyl
^ a\ ^" 'Jf.^'*"?» Salhc acid splits up into carbon dioxide
dna pyrogalhc actd ox trihydroxyl oenzol, CeH3(0H) .
Coumarin, CsHeOa-CeHa | ^^^^ -This
is the
odoriferous principle of the tonlca 'beln and other sweet-
smeUing plants. It can be artfncially prepared by acdng
u. K
4ia ElEMEMAKV CllEMtSTHW LLesson
with rtcctic^ nnhydi'idc on llic potrtsslum or iotllum vam*
pound of Brtlicyl Aldohyilo \
Sodium SnUtUol. Acfttc Anhyi^Hde. Siulium Acetrtle.
CouttirtHit.
CO
^«^^M ctl.o"*"^^"^'
INDIOO.
This substunco is Ihc blue colouring rnaltcr derived
^from several species of inHpifem. The Icrtvcs arc
mAcerated in water, when they undergo ovidaiion, fonii-
itig a yellow solution, which, on exposure to air, deposits
indigo in the form of a dark blue powder. Thi , when
evaporated to dryness and cut into small cakes, con-
stitutes the indigo of commerce. The pure colouring
matter termed Indigotinc is obtained from commercial
indigo in crystals by sublimation ; its composition is
C|^ H.ft N| Of Indigo is insoluble in water and in cold
alcohol and ether ; strong or fuming sulphuric acid dis-
solves indigo, forming a deep blue solution. Indigo
occurs sometimes in healthy urine in small c|uantitics.
When indigo is exposed in contact with alkalies to re-
ducing agents, it passes into a soluble and colourless
substance by absorption of hydrogen. The substance
thus produced is called white indigo; its formula is
Ci* Hj, Nj O,. This property is largely employed in
indigo dyemg. An indigo vat being prcparcti, containing
I part ot indigo, a parts of ferrous sulphate, and 3 parts
of slaked lime, to about 200 parts of water, these arc
allowed to stand for some time in a closed vessel. The
cloth is then dipped into the liquid, and on exposure to
air becomes permanently dyed by the deposition of
insoluble bhie indigo in the fibre of the tissue.
XXXIX.] aNNAMVL Gnotn\
MclrtVf ''" healed With caustic potash yields »nllc7llu
/^f///>/^ C,If.NO,.--My the careful oxidation of indigo
It B substance Is fSmied ; it crystallizes in large defo
tunllne, C«ii«llc Ptilasli. Aniline.
<■'. Ho NO, + 4 KHO - C„ H, N + J (K, to,) + H,.
When I.I11C intliBo is trcHtctt wilh tin and hydrodiloric
ncijl, It m first reduced to white indlpo, and then o a
yoll.,w body, which on hcatinB with z nc oowder and
water fonn, MM, C,II,N. Inll i, a crysunhTe sub
5 ancc which forms the startinB-point of the ind ko »e?"es
I l,c production of salicylic acid from indigo and of
m-iline from isatine, show that these bod es contain tit.
urthl^pTs^^d^r'' " """"• ''"'" -«tiSn"„5S
I'lfioi . . . CnU,c,ii,s.
Isatine. . . CflH3(OH)C301IN.
Blue Indigo. ^>H.C,HN|,,^
White Indigo r«J]\9S^2"^^ I O.
v-fl ill v-j rlji N j
CINNAMVL GROUP.
S/yro/, or Cinnamol, C- H..— This hvdrorarhnn ;«
"ubi ct'Xo ATir; " '""'° fc-I=d w&Xe
uDjectcd to a high temperature :
IS s
E£2
430 ELEMENTARY CHEMISTRY. [Lesson
Styrol is a colourless powerfully-reft-acting liquid, which
smells like beniol, and boils at \^(i\ It is converted into
bcnioic acid by oxidation with aqueous chromic acid,
and may be considered as benzol in which one atom of
hydrogen is replaced by the monad group Cg Hg.
Cmmmyl Alcohol, ^»jj« \ O.-Storax and Balsam of
Peru contain a crystalline substance called styracin ; this
is the cinnamate of cinnamyl, ^»^Jq | O (analogous to
acetic ether, ^ ^^«q | O). The alcohol can be obtained
by boilinvc the clhc^r with alkalies : it then separates out in
, white shining needles meltincf at 33*, boiling at 250 , and
possessing a pleasant hyacinth-like smell. It oxidizec
first to cinnamyl aldehyde and then to cinnamic acid.
CinnamU Aldehyde, C^ Hg O.^This substance con-
stitutes the chief part of the essential oil of cinnamon. It
is a colourless oil smelling strongly of cinnamon. On
exposure to the air it passes into cinnamic acid.
Cmnamic Acid^^""^^ \ O.-This acid, which closely
resembles benzoic acid, occurs in storax and balsam of
Peru. In addition to the previously mentioned methods,
it can be prepared by heating oil of bitter almonds with
acetyl chloride ;
Oil of Bitter
Almonds.
Acetyl
Chloride.
Cinnamic AcLd.
Cinnamic acid is a monobasic acid, and it crystallizes
in colourless prisms, which sublime when gently heated.
On distillation with caustic baryta, cinnamic acid iicids
styrol, CjHaOjj « CgHa + €0^.
ESSON
which
:d into
: acid,
;om of
sam of
1 ; this
{OUS tu
stained
5 out in
o'*, and
>xidizec
:id.
:e con-
ion. It
n. On
closely
isam of
lethods,
ds with
HCl.
stallizes
heated.
i ^icids
XXXIX.] NAPHTHAUN GROUP. 431
NAPHTHALIN GROUP.
n^^J.t'^^^'''^'?^ Sl« "-•-This hydrocarbon occurs In larjre
quantity in the fieavy coal oils, and is formed when tfe
T^^Zl^l ^'T^ "T !?^\"y ^^^^^ substancl^ evcralcohd
I'n crvs allt'.i^n'1 ^^^ '^T^^ "" ^^.^"^^^ ^"^^- Naphtha-
792, and boils at 218", but sublimes at a lower tcm-
\ZX^; •^^' '.^''^r" ^'^"^^ '" naphthalin are rnnectTd
S^SlTii'''-"''^^' ^^y^? ^^««^' '" benzol,a» U seen
from the following graphical representation :
HC-
w
HC-
CH
w
CH
/
C
//
CH
H
ces^sWefyterd t ""it"^"" '" "aphAalin can be suc-
combine dlrectlv wffh Jw '"? ' ''"' ""Phthalin can also
tomoine atrectlv with chlorine, and series of furtk...
Sri» Ha' "Z."^ oi-tained'Toth Im^fhe
matters, which have however as yet not bi'en nrermr ' «5
o?nitdc^Sa^^^^^^^^^^ Byth:fu?th?r"^:;io'^
m nitric acid naphthalin is converted into Phthalic Acid
C, He O4. This substance is conn#»rtP^ «.-.i, *C uff:??
M
422
ELEMENTARY CHEMISTRY, [Lesson
series, as when heated with excess of lime or baryta it
is converted into benzol, thus :
Phthalic Acid. Benzol.
C, Ho O4 - Ce H« + 2 CO^.
!CO H
CO* H '
When a solution of naphthylamine hydrochlorate is
mixed with solution of potassium nitrite, the hydro-
chlorate of diaso-naphthol is formed, Cj© Hg No H CI (cor-
responding to the formation of diazo-benzol from aniline,
p. 41 1). On heating the aqueous solution of this body, a
substance called naphthoic C^o Hg O, analogous to phenol,
is formed. This yields nitro substitution-products, one of
, ( NO, •
which, dinitro naphthoic Cjo H^, < NO-j, forms the beautiful
(oh
yellow die known as naphthalin yellow,
ANTHRACENE GROUP.
Anthracene^ C,4 H,o. — The constitution of this hydro-
carbon is rendered evident by the following graphical
formula :
HC-CH
/ \
HC— C C— CH
// W // w
HC C — C CH
\ / \ /.
HC=CH HC=CH
Anthracene is contained in the least volatile portion of
the coal oils ; crystallizes in white silky scales melting at
213°, and boils above 300'' C.
It can also be artifically prepared together with the
hydrocarbon, C14H14, by heating benzyl-chloride with
water in closed vessels at 190° ; thus :
4C7H7C14-2H20 = CuHio + Ci4Hi4-h4HClH-2H30.
C,
yxxix.]
ALIZARINE.
4*3
By the action of nitric acid nitro-substitution products are
formed, and oxyanthraceneoranthraquinone.CiiH, | °>.
Dicric ''add* ''Z^T^' "\l""'"y °""=^ hydrocarbons, with
Pkt^^ i^"*' ^""^ '<"™' ">e compound C. H 4- r H
iv ei£< F^'^'Oifing i'^ fine scarfet crysta Cand\S,ei
by dissolving anthracene and picric acid \k hot bemS^
and allowing the solution to cool. '
Alizarine, C„H.0, = c„H. (HO), (g
>.
Alizarine, the colouring principle of madder, is containpH
in the root as a glucoside (calleJr«*,««), which undereoes
decomposition on boiling with acids or alkal es or fv I
process of fermentation which goes on in the mii!t rL
It can be artificially obtained by heating anthT^uinnn^
with concentrated sulphuric .d, when"&" Zf
S^frii^Tusr"'^ ^"^^ °» ^"-" ^^
C„H„o,(SO,K),+ 2KHO=C„H.O,(OH), + 2K,SO.,
Disulpho-anthraquinic acid and potash yield alizarine
and potassium sulphite. The above mode'^of formZn
of alizarine ,s interesting, not only for its technicaUmDOrt-
ance, but also as being the first instance of the ar™?ck
mTtt a "d l^'drsr'n"'""^ T"""^^^ vegetable colouring
matter, ana the discovery of artificia alizarine marks an
era in the history of applied chemistry. A secoXeUot
coloured body (not found in the natural maddert has ^^^0'
observed in the artificial product, and this turns out ^n
h^ methyl alizarine, or afearine in which one atom of
hydrogen IS replaced by methyl, CH, "* "^
Alizar.ne u deposited in long, red, needle-shaped crystals
It s but very slightly soluble in cold, but monoluble in
hot water, and easily dissolves in alcohol. AHzarine nro
duces insoluble red-coloured compounds w h XiSn-i
or hS"" """J^' *''>'='> ^'e termed lake., and a pZ"e
or black compound with ferric oxide. Hence in ^cXk
4H ELEMENTARY CHEMISTRY, [lko^o.,
printing solutions of these oxides are used as mordants^
and are printed in pattern on the cotton cloth, which,
after undergoing certain preparatory processes, is then
.boiled in the "dye-beck," containing the ground madder-
root mixed with water. The alizarine of the madder forms
with the mordanted cloth an insoluble compound, which
is coloured pink, purple, black, or chocolate, according as
the mcrdant has been pure alumina, or pure iron, or a
mixture of the two. Animal fabrics, such as silk or
wool "o not require the application of mordants ; th^
are ac^r alone to fix and render insoluble the colouring
ma »^e^.
• 1*.« madder-root yields another red colouring matter
called purpurine, Q^^ Hg O5. Both of these substances
ire hydroxyl derivatives of anthraquinone and they can
both be reduced to anthracene by the action of zinc
dust. An IsoHAcr with Alizarine is contained in Rhubarb
called Chrysophanic Acid, and this is also a derivative ol
Anthracene.
XL.] TURPENTINES AND CAMPHORS. 425
LESSON XL.
TURPENTINES AND CAMPHOR GROUP.
This series of bodies appears to contain a common
group of ten carbon atoms, affording a large number
of isomeric derivatives. It is particularly difficult to dis-
tinguish between many of these bodies, which appear
Identical m their chemical relations but differ in their
physical properties ; and hence are said to be i>hy steal
tsomers. The foUowmg are the hydrocarbons from which
these substances are derived :
Diamylene
Camphene
or
Menthene.
^10 ^18*
Terebene
and its
Isomers.
^10 ^16*
CymoK
'-to "14*
These hydrocarbons yield oxidized products termed
Camphors ; we thus have :
Menthene Camphor. Borneo Camphor. Uurel Camphor. Thymol and
Ca
Cio Hjjo O. do H,. O.
Qo Hig O.
-arvol.
O.
The camphors stand in the same relation to the abov*
hydrocarbons as benzyl alcohol stands to toluol. By a
further process of oxidation acids are formed ; thus we
have:
^10 S^«*r^T'°^''i" ' . ^10 Hie O2, camphinic acid ;
^10 Hie O, laurel camphor ; Cio Hie O4, camphoric acid.
Turpentines and Isomers, Qo Hie.~Oil of turpentine
of commerce generally consists of a mixture of several
isomeric modifications of this hydrocarbon. It is ob-
tained from several species of pine : that from Pinus
nigra, abies, and sylvestris constitutes common turpen-
tine; that from the larch is known as Venice turpentine.
On distillation with water a volatile aromatic liquid comes
over, and rosin or colophony remains in the retort
4^6
ELEMENTARY CHEMISTRY. [Lesson
Tlie best-known natural varieties are terebenthene^ from
the Pinus maritimay boiling at 161'^, and possessing a
power oi' left-handed polarization of —42 3': austra-
teretentheney from the Pinus AustraiiSy boiling also at
161*, but possessing a right-handed polarizing power of
•\- 2'^°5'. These turpentines, when heated, or when acted
on by sulphuric acids and other reagents, form isomers
differing in their action on the ray of polarized light, some
being right- and some left-handed, whilst others are in-
active. Terebenthene combines with hydrochloric acid,
and forms isomeric compounds ; it also combines with
water to form a solid hydrate. On oxidation, the turpen-
tines pass into resins.
Many essential oils are isomers of turpentine : of these
m^y be mentioned essential oil of lemons, of bergamot,
neroli, lavei. Jer, pepper, camomile, caraway^ ploves, &c.
These often contain other oxidized oils in addition to the
terebenes. Of these bodies, laurel or common camphor,
Cio Hjg O, is the most important ; it is yielded chiefly by
the Laurus camphora of China and Japan, although it
can be obtained from other plants. Cainphor is a white,
crystalline, semi-transparent mass; it fuses at 175**, and
boils at 204** ; it is soluble in alcohol, and its solution
deviates the plane of polarization to the right -f 47° 4'.
Camphor dissolves in alcoholic potash unaltered, but, on
heating, is first converted into Borneo camphor, CjoHigO,
and afterwards into camphinic acid, Cjo Hjg Og, and cam-
pholic acid, CioHis02. On boiling with nitric acid, it is oxi-
dized to camphoric acid, CioHie04. Like the turpentines
camphor also exist' in several physical isomeric modifi-
cations, which chiefly oilier in iheir action on polarised
light. The camphoric acids obtained from these different
camphors alsj exhibit differciices in their properties.
Resins and Ba/sams.— Resin, or colophony, is obtained
in the distillation of crude turpentine ; the other resins,
such as lac, mastic, copal, &c., have a similar composition.
They are oxidation products of the terebenes.
Caoutchouc^ or India Rubbery and Gutta Percha.—
XL.]
VEGETO-ALKALOWS,
437
^.-?n,..f . f ""'"Pt?""^' °^ hydrogen and carbon, and
\h. ^It":^^' '."^^^^"^^« *°, ^he chemist. Caoutchouc is
the hardened juice of several tropical trees (Ficus elastica
Jatropha elastica Siphoma caLchu\ and in the pu?e
s.ate IS white. Caoutchouc combines with sulphur in
various proportions, formincr the vulcanized caoutchouc of
commerce, which contains from 2 to 3 per cent, of sulphur.
rll^T'^K^'^/" '^'■^"^^y ^^^^ ''"^P^"^^ ^ black, horny mass
called ebonite, or vulcanite, is formed. Gutta percha is
fnt .t^^ejiardened ;uice of a species of a sapotacea, grow-
w'?;f!" :?'"^°', ?i"?^Pore, &c. The pure substince is
wjite, and insoluble in alcohol, but soluble in ether.
VEGETO-ALKALOIDS.
Under this name a series of bodies containing carbon,
hydrogen, oxygen, and nitrogen is grouped, which act as
bases, and are found in certain plants. These bodies
have not been artificially prepared, and although it is
believed that they belong to the class of compound
ammonias, yet their constitution is at present unknown.
Some few of the alkaloids are liquid and volatile, and
contain only carbon, hydrogen, and nitrogen : these have
a more simple constitution. The alkaloids exert a powerful
influei :e on the ray of polarized light, some deviating ihe
plane to the right and some to the left; they also com-
bine with acids to form salts, in this respect resembling
anmionia, thus ; ^
NH3 + HCI == NH.Ci or NH3HCI.
Ci,Hj,N03-f HCl r= CirH^oNOjCl or CiyHi^NOjHCL
Morphine. Morphine Hydrochlorate
They also form double crystallizable salts with platinum
tetrachloride, m this respect again resembling ammonia.
1 he aL^aloids act most powerfully on the animal economy
some, such as strychnine, nicotine, &c., form the most
violent poisonr with whiVh wa or-/* ^^^..»:~i.^j ...i--i_^
428
ELEMENTARY CHEMISTRY, [Lesson
others, such as quinine and morphine, act as most valuable
medicines.
Alkaloids containing Carbon^ Hydrogen^ and Nitrogen.
Piperidine, CgHnN.— This alkaloid is obtained bv dis-
tilling piperin, C17H19NO3, the base contained in black
pepper, with an alkali. Piperidine contains one atom of
hydrogen, which can be replaced by an alcoholic group :
hence its formula is ^s^^o \ n. it is a colourless liquid,
boiling at 106°, and possessing a strong ammoniacal odour
of pepper.
C H )
Conine, 8 ^u ( n, contained in the hemlock, Conium
macidatum. It is a colourless liquid, boiling at 212°, and
has a strong alkalitie reaction, forming salts with acids.
Conine acts as a narcotic poison. Under certain cir-
cumstances, Conine yields butyric acid by oxidation.
Nicotine, C10H14N2, is the chief alkaloid contained in
tobacco, which contains varying quantities, from 2 to
8 per cent, of this substance. Nicotine boils about 240°,
undergoing partial decomposition, but it may be distilled
in an atmosphere of hydrogen without loss.
Nicotine is soluble in water, alcohol, and ether, and it
acts as one of the most violent poisons with which we are
acquainted ; a small quantity acting on the motor nerves,
and producing convulsions and afterwards paralysis.
Nicotine does net ontain any hydrogen replaceable by
an alcohol rad'xai, and, when treated with iodide of ethyl,
a salt corresponding to ammonium iodide is produced :
Nicotine.
Ethyl-nicotine-iodide.
Ill
C5H7
III
2 (Cj H^
N,I,
XL.]
ALKALOIDS OF OPIUM,
429
Alkaloids containing Carbon^ Hydrogen^ Oxygen^ and
Nitrogen.
Alkaloids of Opium.—O^ivim. is the dried juice of the
head of the poppy {Papaver somniferum) ; it is prepared
largely m Asia Minor, Turkey, Egypt, and India. The
bmyrna opium is most esteemed, and contains from 10 to
15 per cent, of morphine. There are no less than six
ditterent alkaloids contained in opium ; ^ these morphine
and narcotine are found in largest quantity :
Morphine . CiyHieNOg. Papaverine . CaoH^iNO^.
Codeine. . QgHgiNOg. Narcotine, . C22H23NO7.
Thebaine . QgHgiNOa. Narceine . . C23H29NO9.
In addition to these substances, opium contains a neu-
tral crystallizable substance cal'ed Meconine, C,« H,^ O^
and an acid called Meconic Acid, QH^Oy, with which the
alkaloids are chiefly combined, as well as many oth-r
substances in small quantities, besides extractive matter
&c. These alkaloids, although possessing a very closely
analogous composition, have not yet been converted one
into the other. Opium acts as a most valuable medicine
in small doses acting as a sedative, although heightening
the pulse and the action of the heart. Taken in larger
doses It acts as a narcotic poison, a stupor and prostration
soon ensuing, resulting in loss of all voluntary power of
motion, complete coma, and death. It appears that
thebaine is the most powerful of tho alkaloids, then papa-
verine, narcotine, codeine, and morphine.
Morphine, C,j H,^ NO3 + H^ O.— In order to prepare
morphia, the opium .s extracted with water, and the me-
conic acid precipitated by calcium chloride ; on evaporating
the filtrate, crystals of morphine hydrochlorate separate
out. Morphine dissolves in 1,000 parts of cold and 400 of
boiling water ; hot alcohol dissolves it easily, whilst it is
insoluble in ether. It forms crystalline salts soluble in
430 ELEMENTARY CHEMISTRY, [Lesson
water, and it appears to contain no replaceable hydrogen,
as an ammonium iodide is obtained when it is acted upon
with ethyl iodide. Small quantities of morphine can easily
be detected by the formation of a deep blue colouration
when this substance comes in contact with ferric chloride.
Codeine, CigHgiNOg-h HgO, is left in the mother
liquors from which the morphine has crystallized. Codeine
is much more soluble in water than morphine, and is
contained in opiam in much smaller quantities ; it has a
strong alkaline reaction, and neutralizes acids.
Thebaine, C19H21NO3, is contained in very small quan-
tities in opium ; its poisonous properties are more violent
than any other of these alkaloids ; it produces tetanus.
/'^;>rt;z/^r/;/<?,C2oH2iN04.--Distinguishpd from the other
opjum bases by giving a deep blue colour with strong
sulphuric acid.
Narcotzne, C22 HggNOy, remains insoluble when opium
is treated with water, and it is obtained by dissolving it
out from the " marc " or insoluble portion of the opium
with hydrochloric acid. It dissolves in 128 parts of boil-
ing alcohol and 19 of boihng ether. Narcotine when
heated with potash furnishes ammonia and methylamine,
as well di- and tri-methylamine ; and when treated with
hydriodic acid, it furnishes 3 molecules of methyl iodide,
and a new base called nornarcotine for every molecule of
narcotine, thus :
QoHh (CH3)3N07-r3 HI = Ci9Hir NO7+3 CH3I.
Narcotine yields nornarcotine and methyl iodide.
Alkaloids of the Strychnos.
Two alkaloids possessing most powerful poisonous pro-
perties, and called Strychnine and Brucine, are found ir*
the seeds of the Strychnos nux vomica and in the Sirych-
nos Ignatius, or the St. Ignatius's bean.
Strychnine, Cgj H22 N2 O2, is a base forming crystal-
Uzaljlc salts, of which i\ per cent, is contained in St.
XL.] ALKALOIDS OF THE CHINCHONAS 43,
small doses in medidne Tf, cL* 1!"^' «f'^=" ■" very
and tart. Stry"S can L il, '"^^ ^^emely bitter
the minutest quantufes L vi^n-^'^*^''' J'''^" P''«^«"' i"
and potassiumTchSe L'^^ f '"^ with sulphuric acid
passes rapidly into aTedlnH T^^ P'"'P'^ =°'°"'-. **l>'ch
^^««4 q'^ h' n o' +1 '^^"■°'<'/ yellow colour.
angustura blrk, tnd' toVjht^hh' «""",? •'°"^. '° ''^'^^
vomica: it is more%n^,Kl» • strychmne in nux
strychnine" BSlnd*itVs"aItrare 4",^ "•"^°''°' "'^"
less bitter than the strw-Wn^ ^ 'ess poisonous and
distinguished from stSrnebv°SrK"'^^- ".<=^" •>«
a^cTdtfnlleeSThi^'^S^s""^^^^^^^^
Alkaloids of the Chinchonas.
The alkaloids are combined in the bart w,>T, o r.« r
-d^cfnractras ? tbri?"'"'"^ ' V -- vSt^
possess the\"mfv:iua\lfp^'^SL""'^''°"'°^ ''°^= "°'
may be detected bta"ddin|ctS:r°er''a/f V,^"'"'!!^
an excess of ammo'nia. to'solutT^ns^Tthe' s^'lJlfatX'
4P
ELEMENTARY CHEMISTRY. [Lesson
a green colour is produced. Another characteristic reac-
tion consists in the deep red colour produced when finely
powdered potassium ferrocyanide is thrown into the solu-
tion of quinine in chlorine water. Quinine appears to
possess no replaceable hydrogen, as when treated with
ethyl iodide a salt of an ammonium compound is formed.
Quinine sulphate is the salt used in medicine; it is not
very soluble in water, but dissolves easily when a drop or
two of sulphuric acid is added, its solution possesses
very strongly the property oi fluorescence.
Quinidine and Quinicine. — The first of these isomers
of quinine is found in the bark, and it resembles quinine
in its febrifuge qualities, but it deviates the plane of
polanzation strongly to the right. Quinicine is obtained
by acting upon quinine by heat. IL is a bitter substance,
possessing a semi-solid resmous consistency, and deviating
the pHne of polarization fsebly to the right.
Cinchonine, Q^ H5,4 N^ O. — This body is separated from
the quinine which accompanies it by its less solubility in
alcohol : thus cinchonine requires 30 parts of boiling
alcohol for solution, and iherefove ciystallizes out whilst
the quinine remains in solution. Cinchonine is not nearly
so powerful a febrifuge as quinine ; it is, however, used as
a medicine in some countries. Although it only differs
from quinine by containing one atom less oxygen, it has
not yet been transformed into the latter. It does not pro-
duce a green colour with chlorii^e water and ammonia like
quinine ; it acts as a strong base, and forms salts which
are more soluble in water and alcohol than those of
quinine.
Cinchonidine — Cinchonicine. — The first of these isomers
is found, together with quinidine, in the brown resinous
mass left after the extraction of the two chief alkaloids.
It produces a left handed rotation on a polarized ray,
whilst cinchonine produces a right-handed polarization.
Cinchonicine is obtained by heating a cinchonine sulphate
to 1 20° or J 30° ; it deviates the polarized ray feebly to the
right. Hence we have
XLI."
Qi
Cir
Cir
Cir
QH3
( Theoi
hydro
Cafi
+H,C
found
Ameri
of chc
The qi
per cei
cent. ;
Ade
interest
Under
pounds
the bodi
especial
possess
ledge of
They do
h'ke form
pure Stat
XLI.]
THEOBROMINE,
OuttL '"'"'"^ ^ ^•''^^. '^'-h-ded rotation.
tJ^
Quinidine
Quinicine
Cinchonine
Cinchonidine
Cinchonicine
»
»
»
powerful right-handed
feeble right-handed
powerful right-handed
powerful left-handed
feeble right-handed
Theobromine^
n
»
»
yy
»
F-r/^^^^ ^»» *^^ crystallizable alkaloid ronf ^'^^^ •
[Theobroma cacao) If in th.t c, kI. ^^^^ '" ^°^^a
hydrogen be replaced bv methil ^"^/*^»^%^»e a^om of
Cafeine, or r^^/^. or^Sv/':^^^^^^^ is formed.
+H,0.-The active Z'^^S Ii\^^^^^ S"-N40,
found in the leaves of //^^/^S^L?/ *^^ .^"^..^offee ; also
Americans use in placro^t^^^^^
of chocolate made from the fruft of '"/>^T^"^'^ ^'^^
I he quantity of the alSloid rln. • ^'^^''^''''^ '^^^^^'^^^
LESSON XLI.
ALBUMINOUS SUBSTANCES.
the bodies of ^n,^\^lTotclr?Zt S^^''"^ P^^'o" °f
especially ,he seeds/of veSles^ Th'" "'■""° P^^
possess a very caxxlnWrZlA ■ ■ ^"^^^ compounds
ledge of the.rC^heSS^f""''°"' '""^ ""know!
They do not crystallize and J! «"' '^ ™°" incomplete.
like form ; hen Je rSdiSt" 'If '""f'''*"^ J'^''^"
Pure state : so that ^^^rel'l^S^'Z^TJ'Z,^,^^
434 ELEMENTARY CHEMISTRY. [LESSON
chemical composition. They all contain sulphur, and
most of them phosphorus, in addition to carbon, hydrogen,
oxygen, and nitrogen, and in their difiterent forms possess
nearly the same composition.
Albumin is seen in one of its purest forms in the white
of ^%% ; it is also contained in the serous or liquid portion
of the blood. It may be obtained by adding acetic acid
to white of ^%^ and diluting with water, when a white
flocculent precipitate of albumin is formed. When dried,
it forms a yellovk', transparent, gumlike mass : this, on
addition of cold water, remains as a white insoluble
powder, which, like the precipitated albumin, dissolves
in water containing a small trace of free alkali. One of
the most characteristic properties of albumin is its power
\ of coagulation ; if soluble white of t%g be heated to about
65° C, it becomes solid and opaque; in this state it is
insoluble in waier, but dissolves in dilute alkali.
Fibrin. — This substance exists in solution in the blood,
but immediately becomes solid when ihe blood leaves the
living body ; it can be obtained by washing the clot or
thick part of blood, until the red colour has disappeared,
or it may be obtained by agitating fresh blood with twigs.
It is then obtained in the form of colourless filaments,
which are tasteless and insoluble in water : on drying, it
forms a horny mass like albumin. The fibrin of flesh
appears to differ from that of blood ; and differences have
been obser\'ed between the fibrin from arterial and that
from venous blood.
Casein is the nitrogenous substance contained in milk
and cheese ; it closely resembles albumin in its properties,
being coagulated by acids. Casein is insoluble in pure
water, but dissolves in a very dilute solution of an alkali.
In milk the casein is not coagulated by boiling, but an
acid, or a portion of the inner coating of the calPs
. stomach, called rennet, at once separates out the casein
and butter as curds, and leaves the milk-sugar and salts
in solution as whey.
Vegetable? contain similar substances, which are
and
are
XLI.] ALBCrMmoUS SUBSTANCES. 435
contained with starch in wh I/p" a ^''^^' ^^^^'^^ substance
whilst vegetable albumin ^nd .0 •"'' ^' ^^^etable tibri, ,
and seeds of pCr tI " ^0!^'" °''"J^ ''' ^^^ J"'^^^
percentage composition of the Ir"^- '^^\ ^^^^^ ^he
impossible to iho anv fori, 1 ^^^'"^'"o"s bodies ft ^s
substances): ^''^^"y ^^^"^"Ja^ ^or these complicated
Carbon
Hydrogen
Nitrogen .
Oxygen .
Sulphur .
Phosphorus
Albumin.
53-5
70
15-5
22 'O
1-6
0-4
lOO'O
lOQ-O 1000
anSfltody' rittXared h ''k T'^ """'^'^-^ fr™" 'he
then known as elue f.t^tl^ ^"'''"^ 'he tissues, and is
tion is the same as 'that of ,tT ^'''";" • ''^ ^"'"Po^i-
prepared. "'^ "'^ "«'"e from which it is
nii^j'Sttrone^S 'T"^"' "--•• -^ c^-
slightly advanced ^urJowtd"r^°/'r^'^'y '= "^^ ^^--^
chemical constitution of the l^l^t °^"'^ composition and
animal body is veTincomnl.,^ ^''^^ contained in the
the chemical chants whTh'^f' ""'" "rOn^erning many of
the anima, we aSt'fn^^r/.X^f-"' ^"'' "'
calTli^mXtettL^d'aTry °^ '*-'=
.rts°:^^^d^{Ft"^^^^^^^^^^
the friable and earthy m.» "i' ""''' ' "•>«» ''""'t^
contains- '^ '"*"*'' '^'''''e remains. Bone
F F 2
436 ELEMENTARY CHEMISTRY, [Lesson
Animal matter 33
Calcium triphosphate . . . . . 57
Calcium carbonate 8
Calcium fluoride i
Magnesium phosphate 1
100
The Blood of animals is the channel by means of which
their bodies not only receive all the requisite supply of
materials for their growth and for the repair of waste, but
by means of which they are able to get rid of the worn-
out matters which need immediate removal. In verte-
brate animals the blood has a red colour and a tempera-
ture above the medium in which the animal lives; in
mammalia, and especially in birds, this artificial warmth
is plainly noticed. The temperature of the blood is
singularly constant in different animals under the most
varying conditions of climate ; it is 36"'9 (98° F.) in man,
and 42°'8 (or 109° F.) in birds. The chief peculiarity of
blood is the existence in it of very small round or oblong
discs, differing in size and shape in different animals
(diameter 0*0075 ^i^« ^"^ man, and four times as large in
frogs). These are called the blood globules, or corpuscles ;
they are of a red colour, and float in a colourless liquid ;
when the fibrin coagulates, it carries down wi- j it mechani-
cally the red globules.
Healthy human blood possesses the following average
composition, and its specific gravity is i'055 :
Coagulum, J Fibrin. ....... 030)
or clot. \ Corpuscles 1270 j ^
/'Water 7900^
) Albumin . 7*00 f o-.^
Serum. j p^^^^ ^^^^^^^^ ^.^ V 87'o
(, Salts 094 )
The colour of the blood discs is due to a substance
called hcematin : this contains about 7 per cent, of iron,
but the iron can be withdrawn by sulphuric acid without
XLiJ ANIMAL CHEMISTRY
437
or arterial blood, Sned ?„ ''the eft ^^e°ofT' A '^"^
and m the arteries anH r^^^^^l\ , , ^^ ^^^ *»eart
in the right sidTol th"ta7[nZ°vli„'^'Vr'""^''
oxylen, nitrogen and ?aZ ±'^"^2'^^'' ^f^^^> especially
of the issues U effected bvX^''"'' ^"''/''^ oxidation
the arterial blood (freshly ^oxMizKo" t '^^ ^''\ «^^ =
tains in ico volumes 14-5 volumes nfnl '""«?)<="":
carbonic acid and 2V2 f^Ly,„ v°; ""."^ogen. 62-3 of
(charged with the pioducS^nf.' «?''=?*" venous blood
the saW gases are runrin°LTo^p"ortlon nf '''^ '^°<^y;
and 15-3 volumes respectively P'^°P°"'°" °^ '3'i, 7r6,
te.S'ed^;;x;;«' ^f'^iToLinT ^ "T^^ - -"='--
constituent, ftc'rystrilizes Fn ^F. ™' '^?™* ^" ^=«e"«ial
very easily decomDosed a1 T'^^P"^ "^^^"=5' ^nd is
comVsitio'L oT°pXg:^n afe gTyferin '.Kn^'T^- °' -^S"
several tatty acids anri Llt.^^^ \ phosphoric ac d,
Neurin^ 1Z -r ^ .! ammonium base called
H \ °- Neurine decomposes on heat-
iKfyClneTa';;'^"?!"^.^"'' ^^^'-^ ^'-hol : and
with a concentrated solnrn^^V'^'^^-y '^"[■"^d by acting
ethylene ox"de: " °^ tnmethylamine upoS
C, H, + (CH3)3 N + H, O = (CH3)3 C» H, O H N | ^
Ethylene oxide and tnmethylamine yield neuri" and
lining membranri ThrstomLh'."thif '^ '''•'"'^'^ "^ "'^
a substance called ieisin^ht^ this secretion contains
effecting the ^^Jt'^l'^^^J-lU^Z^^:^::}^
W^
438
ELEMENTARY CHEMISTRY, [LESSON
parts of the food. It has an acid reaction due to the
presence of free 1- f"-: and hydrochloric acids. The Bile,
a liquid secret d in tbe iiver and poured out into the duo-
denum : thi > substance contains several peculiar nitro-
gcnizcd acids, viz. taurocholic acid, QH^gNSOy, and
^lycochohc acid, C^^H^jNOe. A peculiar substance
termed taurin, C, H7 N S O3, is obtained by the action of
acids on bile : this body, which is isomeric with the com-
pound of aldehyde ammonia with sulphur dioxide, can be
prepared artificially by the action of sulphur trioxide on
ctliylene by heating ammonium isethionate, H4 N C H,
S O4, which parts with H^ O, and forms taurin.
Milk.— T\iQ composition of tiMS important secretion
varies considerably in different animals, but each kind
contains all the materials needed for the formation of the
body of the young animal; thus it. contains casein (a
body having nearly the same composition as flesh), fats
(butter), and milk-sugar, together with those inorganic
salts, especially the alkaline chlorides and calcium phos-
phates, needed for the formation of bone. The follow-
ing gives the average composition of milk of different
auimals :
Woman.
Water
Htitier
M ilk-Sugar and Soluble Salts .
Castin and Insoluble Salts . .
88-6
2-6
40
3 9
Cow.
87-4
4-0
S'o
3-6
Goat.
82*0
4'5
4"S
90
Ass.
90s
i'4
6-4
i'7
Bitch.
66-3
14-8
2-9
i6'o
The specific gravity of milk varies from 1-03 to 1*04.
The Urine.— It is in the urine that a large portion of
the waste nitrogenous portions of the body pass off as
urea and uric acid. The urine is secreted by the kidneys
from the arterial blood. Healthy urine contains, in 1,000
parts, 957 parts of water, 14 of urea, i of uric acid, 15 of
other organic matter, and 13 of inorganic salts.
FUNCTIONS OF ANIMALS AND PLANTS
The general characteristics of animal and vegetable hfe
may be stated as follows : the animal lives upon organized
^ XLi.J RESPIRA TION AND ANIMAL HE A T. 439
rnH^nJ?,lf; taking up oxygen and evolving carbonic acid
and other oxidized products ; the plant lives upon unor^
gamzed materials, especially carbonic acid, water, am-
monia and salts, organizing them and evoMng oxyge^.
tT^ nl^ni^'^'l^ function of the animal is oxidation, that of
he plant reduction. The food of the plant serves merely
to increase its bu k ; that of the animal is employed (after
wornL'"bTa1?t>^'' 'f ^''°"^'). ^° ^^^^^^^ the'marerfal
Z^\T^^ ^^"^ ^^^'''^ operations of life. The animal
obtains the energy necessary for its existence from the
n^r^T"" i ''l^^'" ^^y ' ^^ Pl^"^ obtains the ene gy
necessary for the organization of its food directly from
^*aC dull*
Respiration and Animal Heat.^Tht process of re-
spiration, essential to the life of all animals, consists in
the aerating of the blood, circulating through the lungs ir
TT}^^ ^PP^^tus, by means of the oxygen ol the a^n
The blood does not come iqto actual con act with the air
?hrn ' !f P'"?'^^ ^/ ^ ^^^^^ ^"^^^^^ ^^ ^^ry thin membr me;
through which the exchange of gases takes olare hv
solution and diffusion. Not^only dLs th^bbofe i^
oxygen (see Blood, p. 436), but it loses the products Lf
combustion with which it is charged, and is thus rendered
tL?T '° T^^^f." ^"^ ^^^^y ^^^y »s^^^-"P "material
The volume of air thrown out of the human lungs at each
ordinary expiration amounts to from 350 to 700 cubic
centimetres : this, however, by no means emp^es the
lungs, whose capacity is much greater : the number of
respirations amounts to about fifteen in each minute
1 he expired air diff /s remarkably from the inspired air!
as it contains from 3 to 6 per cent, of carbonic acid, and
will not support the combustion of a candle.
Under different circumstances of health or disease
^^nl r "V' "^'T^^ °^ ^"^^''^^' ^fter a meal o^
W^I'a ^"^'^^"g to the temperature, pressure of the
elh.tn ;IT "^ '''' .7^'y^"& conditions, the quantity of
exhaled carbonic acid varies considerably. The deter-
mination of the quantity of carbon': acid exhaled by an
440 ELEMENTARY CHEMISTRY. [Lesson
animal under the above circumstances is a subject of the
highest miportance, but one which is surrounded bv
numerous experimental difficulties.
The following results of determinations of this kind
give an idea of the variations and the amount of carbonic
acid which occur under change of conditions ; they also
show that the quantities of excreted urea and water like-
wise undergo similar variation. The experiments were
made on a healthy young workman.
I . Day of Rest.
r" J . Absorbed
txcreted in grams. Oxygen
T, J r ^ ""' '^Vater. Urea, in grams.
,By day from 6 A.M. to 6 p.m. 5329 344 217 234-6
„ night „ 6 p.m. „ 6 a.m. 378-6 483-6 15-5 474-3
2. Day of Work.
By day from 6 A.M. to 6 P.M. «S4-6 1094-8 201 204-8
» night, „ 6 P.M. „ 6 a.m. 399-6 947-3 16-9 659-7
clearrSiat-'^ numbers the remarkable facts become
iytll^^TJZf' ""^ ^^^'°" ^'^^^ '' ^--^^^
isllSX^^tih^^^^^^^ -^- carbonic dioxide
duriL^r.'"f J^^K•^^' J^'^"^ °?y^^^ ^^ absorbed than
during the day ; this substance being stored up for use
on subsequent occasions. ^
res^lt^^-^'^''^ suffering from diabetes gave the following
rc\ ^^creted in grams. Absorbed Oxygen
„ , C^»- Water. Urea. in grams.^
By day. . . 559-2 308-6 296 278-0
„ night . . 300-0 302-7 20-2 294-2
Hence it is seen that the patient ;vas unable to absorb
XLI.]
RES P IRA TION.
441
sufficient oxygen '!— >.g the night to serve as a store of
torce for subser. , nt ievelopment o^ '*nergy.
We naay ac ;urae as the result of e best experiments
that a man ^ , ^ j flf 19-8 litres 01 carbonic acid (at o^
and 760 mrr.j cl ^ lour ; this amounts to about 40 grams
ot carbonic .'cid. ->r io-6 grams of carbon, per hour : the
Heat which ir \ ys evolved by the combustion of this
carbon goes to keep up the temperature of the body. It
IS ditticult to determine with accuracy how far the whole
of the animal heat can be accounted for by the ronibus-
tion ot this carbon, as v:he chemical changes which go on
in the body are of a very complicated nature, and as yet
little understood. Considering, however, the subject in a
general point of view, there cannot be much doubt that
the whole of the animal heat is derived from the com-
bustion of the materials of the body ; thus we find that
in birds whose temperature is higher than that of mam-
malia, the quantity of carbonic acid evolved is more than
half as much again as in larger animals ; whilst m cold
climates, where the loss of animal heat is great, men find
It necessary to eat enormous quantities of fat, this doubt-
less serving to maintain the temperature of the body.
The effect of starvation on the quar ities of carbonic
acid and urea, taken as representing the rate of change
going on in the body, is very remarkable : in a dog, the
quantity of carbonic acid was reduced by fasting for ten
days to one-third, and the urea to one twenty-second part
of the amount given off on full diet ; whereas in a man
the carbonic acid was nearly reduced to one-third by
starvation. An interesting fact has been observed, viz.
that hydrogen and marsh gas are evolved in small quanti-
nes from the skin and lungs under certain conditions.
Ihis subject is quite in its infancy, and demands careful
expenmental investigation, as it is by such patient research
alone that we can hope to form any real estimate of the
income and expenditure of the body. The special study
of the chemistry of the body has been made a separate
branch science, termed Physiological Chemistry,
ASK- .mi*iti.-
•
442 ELEMENTARY CHEMISTRY, fLESSON
FOOD OF PLANTS.
Animals, as we have ^een, are unable to produce the
complicated chemical compounds which they need for
their structure ; plants are, however, able to do this, and
fiom the elementary constituents to build up their various
parts. This function of plants is entirely dependent upon
the sunlight ; without sunlight the green colouring matter
of the leaves of plants cannot decompose the atmo-
spheric carbonic acid, and, therefore, without sunlight
the plant cannot grow. In order to separate the atoms
of carbon and oxygen, an expenditure of force is neces
sary : this force is derived from the rapidly vibrating
solar rays ; it is they which tear asunder the carbon and
oxygen atoms, and thus enable the leaves to take up and
assimiidte the carbon, throwing out the oxygen into the
air for the subsequent use of animals. When vegetable
matter is ignited, it bu'-ns to carbonic acid, and generates
exactly the same amount of force as the vibrations of
heat which w^ere needed in the form of vibrations of
light, originally to decompose the atmospheric carbonic
acid. Hence, when coal burns, the light and he^\ evolved
may truly be said to be that of the sun ; and, as animals
depend for their existence upon vegetables, and these in
their turn cannot live without the solar radiations, animals
may with truth be called children of the sun.
The bodies of plants may be considered to be com-
posed of two kinds of substances : organic^ such as starch,
vegetable fibre, &c. ; and inorganic salts, constituting
the ash o^ the plant. The carbon needed for the first
of these materials thu plant obtains niainly from the
atmosphere ; the nitrogen, hydrogen, and oxygen, which
the organic substances contain, the plant takes up both
by its leaves and by its roots ; whilst the whole of the
inorganic salts is absorbed from che earth by the roots,
which act as the mouth of the plant, whilst the leaves
may be coL^.pared to the lungs of animals. Every pknt
-■^ ■*■#!»/#;. ^^ v''-^- )^>.^tj*'-)(aPS%, ^
XLI.]
J^OOZ^ OF PLANTS.
443
plant is dcpenSen %o„Ptty „ft„'"°;f »'-^ ™«?"?Is the
m which it grows PlajVt, ^„c/ .u ^* particular soil
of selection, by the roots of ?h. ? ^''^, P'^'^""" P°«'«'
food, as wel aVthl c„k' '"'^ mineral constitueits of
the i^S Of VcSToV 'th^ l^^^
go on we know notWng?thus we cannot "efnl ^'^■<='|.*"'
acorn turns out alwavs t,. K„ , cannot explain why an
sown in the same S ,n^ " °^> <"■ ""^y o^ t«'0 seeds
at.a..re^X-i---^^^-
fKi-thrrpo^JtinV^suK^^^^^
of the interestincr f^rfc «;i.;oi: u -^ t^^* ^°^ ^" account
specting th;Te1tion?or;ta'rr. ""Zl^^Tl^f T
&c. we must refer the reader to books on ?h A ^°'h
science of Agricultural Chemistry. ""^ '"■^°'='>
444
ELEMENTARY CHEMISTRY,
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446
ELEMENTARY CHEMISTRY,
QUESTIONS AND EXERCISES UPON THE
FOREGOING LESSONS.
In order to enable the pupil to master the principles of
the science, he must conscientiously write out answers to
the Questions, and work out the Exercises given in illus-
tration of each Lesson.
Lesson I. Introduction.
\
\ with all the
lical actions
I. Describe an experiment to prove that when a candle
bums the materials are not annihilated.
/ 2. Distinguish between a chemical element and a com-
pound.
3. What is the construction and use of a chemical
balance ?
4. Name a few important elements.
5. Is it likely that we are now acquai
elements existing on the earth, and wh]
6. Describe some cases in which
occur.
Lesson II. Oxygen and Hydrogen.
I. How did Priestley first prepare oxygen gas ?
JK 2. Describe the process now adopted for obtaining this
gas.
3. Whence is the name oxygen derived ?
w 4. State the action produced (i) by animals, (2) by
plants, on the air.
$. Learn by heart the composition by weight of potas-
sium chlorate.
^
pota
7.
elenr
8.
ozor
9.
ic
II
How
12
yield
must
13"
[It
sever
by a
given
X I-
measi
2. :
cubic
V 3. ]
4. ]
Work
How
5. I
C, to
expant
>w 6. \
occup]
\
f »^*,*».«,p=,,,i6«»#:*»^^^-,,**««#«.
this
r.
QUESTIONS AND EXERCISES.
447
•f el/memsf GivTrfexIS: '^"'"'^'"'"^ ^'^hts of the
s/ ozoneY^^' " *^ composition and what the properties of
9- How can hydrogen be obtained from water '
.?■ ^"V°" i**^ '^••J^'' Pi-operties of hvdrogen. '
Ho;-crthirbe°™hibiredT ''^''-^- ■'^-- in the air?
/ 12. 65-2 parts by weight of zinc in decomposin? water
-r yield 2 parts by weight of hydrogen. HoT m."nc
must be employed to obtain .^ pounds of hydroeen '
13- What .s the derivation of the word hyd^ogfn" '
Lesson III. Chemical Calculatiom, &'c.
[It will generally be found necessary to divide this into
several lessons, and to famiUarize the pupil o the suw"«
gLn.f " ^'^'' ""'"''"' "'■ ^''"^'^^^ *^" those tre
■^meas^res""'" ^^"""^^ *^ """'''' '>'"*="^ °^ ^^'S^^ ="d
cubic m"^"^ '"'''^ centimetres are contained in ,
^ 3- How is a thermometer made and graduated.?
Wtrlfort'h'e^^^o:^;;^: thermometric scales now in use.
How many degrees C. and R. correspond to + 42'' and ~ 32- y ,
•* C. and F. .. _l .Z-o „„j •* o ^' 1
C. and F
F. and R.
»
+ 327" and — 2^ R.?
+ 78"^ and — 172^ C. ?
r ^-J^ 273 volumes of gas be at the temperature of o"
^cc^pTttn^trt^dTo'.i.^^ '"'== °^ •'^'^^"s- ^' - ^'
; J.--
448
ELEMENTARY CHEMISTRY.
i^ 7. State Boyle's Law of Pressures.
8. What volume will 1,000 cbc. of oxygen at o and
y- 760 mm. become at a temperature of 16*5°, and under
a pressure of 735 mm. ? *. ,.
9. Learn by heart the weight in grammes of one litre
of hydrogen at 0° and under 760 mm. pressure.
10. What simple method is used for calculating the
weight of one litre of the elementary gases at the standard
temperature and pressure ?
11. How many cubic centimetres of oxygen gas mea-
sured at lo** and under 745 mm. pressure can be got by
heating 20 grms. of potassium chlorate ?
12. What is the weight in grms. of 516 litres of hydro-
gen gas measured at ~ 20° and under 770 mm. pressure ?
^ 13. State the laws of gaseous diffusion.
Lesson IV. Wafer.
[It may be necessary to divide this into two or more
lessons.]
1. How did Cavendish determine the composition of
water ?
2. Describe the most exact methods of determining the
composition of water (i>by volume, (2) by weight.
3. Wl.at is meant by the latent heat of water ? How
is this determined ?
4. How can you show that when a liquid solidifies heat
is given out ?
5. Describe the changes in bulk which water under-
goes when heated from 0° to 100°.
6. When does water boil ?
7. How is the latent heat of steam determined?
8. Explain with a drawing Carry's apparatus for
freezing water by its own evaporation.
9. Define the term " thermal unit."
la How is the tension of aqueous vapour rneasured?
II. Why must the barometric pressure be noticed when
giaduating a thermometer ?
12.
13.
1. I
2. \
sea's I(
3. V
100° O]
4. V\
mecha]
nitroge
5. D
of the
6. H
by weig
7' D]
quantit'i
8. W
regards
9. He
10. E
f II. \\
Less
1. Giv
nitrogen.
2. Exp
multiple
3. Stat
4- Whj
meats in
5^ Stat(
gases ; gi
dioxide ?
i-*,«*-. t^ mmm»,%m^,t^ -wi*-^
QC/£SrwjVS AND EXERCISES. 445
\\' wt".'? ^l'^ "'^'^'' obtained ?
>3. What .s the con^position of hydrogen dioxide?
Lesson V. The Atmosjihere.
2. WhatTt^!!''" ""'T" e^' be prepared?
sea's K? "^^ ""^^^ ^''Sht of tL Urometer at the
•-°oTa''nt"tart"p'°" '' ^ ^"'^^^ '^"P-^'"- t>'an
m^chS m?xre'r„dTo[°!;''ch""°^,'''^* *^ -^ - a
nitrogen and oxygen ? chemical combination of
of ^the'^aT"'' "^^ •""'^^ "^"'^'^'"S a eudiometric analysis
regards vegetation ? ^ ^°^' """ '="''°ni<: acid play as
9- How is rain formed ?
< ' "^'"' °'^^'- constituents of the atmosphere.
LESSON VI. My.V^.^.„^o.^„.y^,,,_^,„
nitrog^r •'' '^°™P°-'-" by weight of the five oxides of
multiplSip^r^oni' ""''"' ''^ <=bemical combination in g[
l WhaVrdrtt'Sstf b'^rr"'^ r-^'^^ "^eory. -»-
ments in the gaseous statl -.niTf" '^e densities of ele-
S. State thf larrespectin" th '''/'°" ''^ ^''^'^•=-
f?ses; give the densfties of stelm ''^"'"^.0^ compound/
dioxide ? °' '^^am, ammonia, and carbonT ~ ~
G G . ■
W-
4SO
ELEMENTARY CHEMISTkV,
I
6. Calculate the weight of one litre of hydrochloric
acid gas at o° and 760 mm.
*i^ 7. What happens when electric sparks are passed
through the air ?
8. Learn by heart the combining weights of oxygen,
hydrogen, nitrogen, chlorine, potassium, sulphur ; and
the formulae of nitric acid, sulphuric acid, nitre, and
potassium sulphate.
9. Write out in symbols the decomposition occurring*"
in the preparation of nitric acid, and explain the meaning
of these symbols.
io. I want 500 grms. pure nitric acid ; how many grms.
of nitre and sulphuric acid shall I need, and how many
gtms. of hydrogen- potassium-sulphate will remain?
^ J II. Mention ihe tests for nitric acid,
12. How is nitrogen pentoxide prepared?
13. 100 parts by weight of this substance contain 25*93
parts of nitrogen, and 7407 parts of oxygen. Show that
the formula of the substance is N^ O^.
Lesson VII. Oxides of Nitrogen and Ammonia,
1. Name the chief properties of laughing gas.
2. How many grms. of nitrogen monoxide and water
can be obtained from 213 grms. ammonium nitrate?
3. How is the composition by volume of nitrous oxide
gas determined ?
4. I want 100 litres of nitric oxide gas when the Cem-
perature is 0° and the pressure 760 mm. ; what weight in
grms. of copper and nitric acid must I take ?
5. Point out the relation between nitrogen pentoxide
and the nitrates, and nitrogen trioxide and the nitrites.
6. Give the formulae representing three different modes
by which ammonia can be produced.
7. How many litres of ammonia measured at 10° an^
under a pressure of 755 mm. can be obtained from
100 7rms. of sal ammoniac?
8.
macl
9.
ascer
10.
/^ I. :
State
K" '
chano
o
3. i
obtain
use?
4. ^
water i
5. \r.
and in
liquid (
6. E
temper
7. D
determ
8. St
9. H
and un
burning
83)?
10. S
dioxide
Less(
I. Ho
100 litre
monoxid
formed ?
'" ^»»'^-^M.,4mmmiim»,'m,m
from
QC/ESr/Om AND EXERCISES.
fchiie!""'^ ""^ principles of Carrd
mach
451
aminonia freezing
:^s%nZJi ""' '^°™P°^'"°" by volume of ammonia
10. How can ammonia be liquefied? 1
Lesson VIII, Carion ancl Carion nio.,-^e.
Stietch^Suatilr'^ -°'^'««"- o^ -bon.
use? ^'^'" °f materials will you need lo
,4 What law regulates the absorption of. this gas in
&. fctate the results of this determinS
an'd .mrTKr^tnt'-^-'de measured at 300°
burning one ^o^Z 0I ^^TcaS jNo^'tlaS
diJx°df^o°::^a,'^^satVm\7^^^^^^^^^^ ^''^^ -'^-
LESSON IX. C....«^,,,,,^,,„^^^^^^^^^.^^^^;
i~ 1^: 7cLC"dioxid;'°a? :^'" 'h^ "^^1^" '° -"-n
monoxide, and how many Ure^'f th'^c. '^^ *"'° ^'"'^"'^
formed ? ^ ^'^ °^ '"'^ '''"er gas wiU be
G G 2
452
ELEMENT AR V CHEMISTR V.
2. Find the volume in litres at io° and 740 mm. of
carbon monoxide which can be obtained from loo grms.
of oxalic acid and formic acid' respectively.
3. What is formed when caustic potash and carbon
monoxide are heated together ?
4. How is the composition of carbon monoxide ascer-
tained by eudiometric analysis ?
5. What is the composition of marsh gas and fire damp ?
6. How is olefiant gas prepared ?
7. State shortly the properties and composition of coal
gas.
8. How is the illuminating power of coal gas ascer-
tained ?
9. Describe the construction of a Bunsen s burner.
10. Explain the principles of the Davy lamp.
11. How many litres of carbon dioxide are formed by
the combustion of one litre of olefiant gas ?
12. How is cyanogen gas prepared ?
13. I want 50 grms. pure hydrocyanic acid ; how many
grms. of potassium cyanide and sulphuric acid shall I
need to use ?
Lesson X. Chlorine.
1. Write down as an equation the decompositions which
occur in the preparation of chlorine from rock salt.
2. I want 100 litres of chlorine gas at 10°, and under the
pressure of 735 mm. ; how many grms. of the materials,
viz. Na CI, H2 SO4, and Mn Og, shall I require ?
3. Describe experiments proving the power of chlorine
to combine with hydrogen.
4. Explain the bleaching action of chlorine, 2^ A state
what is meant by nascent condition.
5. What is the difference between atoms and molecules
of the elements, and what volume does the molecule
occupy in the gaseous state ?
6. How many kilos, of salt and sulphuric acid must be
*»*'.*'««|r«:'«PJS
QUESTIONS AND EXEXCISES. 453
miLd r " ""' '^°'"P°^iti<>" of hydrochloric acid detcr-
the%o^erpo:.;i*;/°dr'" °^ '"^ "^'"^ °' •^'"o-e and
12. Show from the composition of the «u ti,,* .1
formula of potassium chlorate is K CIO "''
defiiifecom^ounlof this^^cMwith'ateT"''''"'' '° ^"^
Lesson XI. 5^.;«,>,,, j^aine, and Fluori,,,.
I' wvf';"''* l*"^ """^^ "f obtaining pure bromine
^^2. What ,s the composition of bfo'mic a„d"perUmic
5. Show that the aqueous hydriodic arM K„-i-
constant temperature, ind contaTn ng 7 p^r'ee''°t'''"f H r^
does not correspond to a definite hydrate ''
when"p°::erau"tiXfe '^'^°'"'"^' ^"'' ^'^'--
7. How can fluorine be prepared ?
8. Mention the most remarkable property of H F
9. State the general relations which Q Hr T * - ^
exhibit amongst themselves. ' ' ^' ^'^^ ^
Lesson XII. Su/p/iur and Sulphurous Acid,
meVwilhlnttu^^^""^ ^^"^°"^^^ ^^ ^^-^ -Ip^- is
3.
IMAGE EVALUATION
TEST TARGET (MT-S)
1.0
I.I
iM. MIS
"f 110
1^
I
2.2
IL25 i 1.4
2.0
1.8
1.6
Photographic
Sciences
Corporation
23 WEST MAIN STREET
WEBSTER, N.Y. 14590
(716) 872-4503
//
^ .<cV
iV
\
;\
\
'1^^ ^^^
s* ^^
<s
^'^
.%,^
^
6
454
ELEMENTARY CHEMISTRY.
2. Name some of the chief properties of sulphur.
3. Write down the names and symbols of the compounds
of sulphur, oxygen, and hydrogen.
4. How is sulphur dioxide prepared? How can it be
liquefied ?
5. How many cubic centimetres of sulphur dioxide at 0°
and 760 mm. can be got by the use of 12 grms. of copper,
and how many grms. of sulphuric acid will be needed ?
6. How is real sulphurous acid formed from sulphur
dioxide? Explain the constitution of the salts termed
sulphites.
7. How does sulphurous acid act as a bleaching agent?
Lesson XI H.
Sulphuric Acid and Sulphuretted
Hydrogen.
1. How is sulphur trioxide prepared, and what are its
properties ?
2. Describe the decompositions by which sulphuric acid
is prepared in the leaden chamber.
3. How many tons of chamber vitriol, containing 70 per
cent, of real acid (H2SO4), can be prepared from 250 tons
of pyrites, containing 42 per cent, of sulphur ?
4. What is the composition of the crystals of the leaden
chamber ?
5. How many grms. of oxygen can be obtained by the
decomposition of 450 grms. Hg SO4 at a red heat ?
6. Explain what is r.ieant by the terms " monovalent *'
and " divalent."
7. How would you detect the presence of sulphuric acid ?
8. What is the composition of sodium hyposulphite?
9. Give a list of all the known compounds of sulphur,
hydrogen, and oxygen.
JO. How is sulphuretted hydrogen prepared ?
11. Explain how this gas may be used for the separa-
tion of the metals into groups.
12. Point out the relations existing between the oxygen
and sulphur con.pounds.
,.i^,;*u:fj.^ ,
ir.
ipounds
n it be
de at o"
copper,
led?
sulphur
termed
agent ?
etted
are its
ric acid
I 70 per
50 tons
leaden
by the
valent *'
ic acid?
hite ?
lulphur,
separa-
oxygen
QUESTIONS AND EXERCISES. 455
13. Explain the constitution of the crystals of the
leaden chamber.
Lesson XIV. Silicon, Boron, ^c,
1. Mention the chief properties of selenium and tellu-
ri-um.
2. How is silicon prepared ?
3- What names does the substance Si O., o-o by ?
silfca? '"^ ""^^ '^^ ""^^^'^ ^'^ ^''^''^^^ ^^^ ^^ in'soluble
talLu"^^''''' ^^^ ^^'"'''^ "dialysis," "colloid," and « crys-
6. How is silicon tetrafluoride prepared ?
7. Where does boracic acid occur ?
8. What is the composition of borax ?
Lesson XV. Phosphorus Compounds,
.hkh'^h:rneet?'""''' "^'"^^^^^ ^'' ^^^ P^-^P^--
2. How is phosphorus prepared from bone- ash ?
^* WW t\e different modifications of phosphorus.
4. What weight of phosphorus pentoxide can be ob-
tamed by burnmg one kilo, of phosphorus ?
I* ■r;.'^^ IS trihydrogen phosphate prepared?
phospYaJel^^'"" '^' '^'""^^ ^' '' ^"^^-^ ^«d--
o. Jk"?"^ .'^^"^ ^^'^^' ""^ ^^d""^ metaphosphate can be
got by heating 100 grms. of microcosmic salt?
8. \Vrite down the decomposition which occurs when
9. 4 (H3 PO3) = 3 (H3 PO4) + PH3. Describe this
for mT'^'^'"' "'^ ^"' ^^^ P^^P^^^^^^ «f tirsubstances
10. How are the chlorides of phosphorus prepared ?
456
ELEMENTARY CHEMISTRY.
.
Lesson XVI. Arsenic Compounds,
1. How is arsenic separated from its ores ?
2. Name the oxides of arsenic.
3. What are the peculiar charrcteristics of the arsenites
and arsenates ?
4. How does ferric oxide act as an antidote to the
poisonous properties of the arsenites and arsenates ?
5. What is th« composition and mode of preparation of
arseniuretted hydrogen ?
6. Name the tests by which arsenic can be detected
with certainty.
7. Point out the general chemical relations of the
arsenic, phosphorus, and nitrogen compounds.
8. Define "atom" and "molecule,*' "atomic weight"
and " molecular weight."
9. Given the density of any body volatile without
decomposition, to find its molecular weight.
I J. Explain, with examples, the difference between
atomic and molecular formulas.
1 1. Explain fully what is meant when we say that chlo-
rine is a monad, oxygen a dyad, nitrogen a triad, and
carbon a tetrad.
12. Give examples of compound radicals belonging to
the monad, dyad, and triad groups.
13. How is the quantivalence of an element or radical
denoted ?
14. Write down a representation of the possible group-
ings of the atoms in the oxi-acids of chlorine and of
phosphorus.
15. Write down a series of decompositions in which the
radical hydroxyl plays a part.
Lesson XVI L The General Properties of the Metals.
1. Name the metals which are lighter than water.
2. At what temperatures does mercury boil and freeze ?
-^m^-''^^:,,mmJ^^iSmmk'i
QUESTIONS AND EXERCISES. 457
3. Describe the modes in whirh th*. «,^f n-
generally occur. ^ ^^^ metallic ores
4. State some of the peculiar properties of the allovs
5. Give an account of hydrogenium. ^'•
7 Wh f "^^^^ ^^\''^' "'^y ^" 'he oxides be arranged ^
7. What is meant by a metallic salt ? ^rrangea .
«. iLxplam the relations existing betwpf^n tK« of« •
poinds **'" '"^ ""'^"'"'^-S 'l'^ ^'°°>i'^ i^eat of com-
I. Explain the classification of metallic oxfdes
th"r-c"nsrituT,onr^"'= ^^'^ "^ ""^'-^^^ -"what is
I ESSON XVIII. Crystallography.
I. Give the chief characteristics of crystaUine structure
Je ^*^""S"'sh between amorphous a^nd cdlular slru^:
4^s^J^I.^^^^- characterS^'of the
si,f;id''e7py.^mid'"^'"''"'^""°" '^^"-'^ fr°™ '"« double
mipSus bodi*1 "■'^"'"^ °f isomorphous and of di-
Lesson XIX. ^^fe/f ^/^.^^ Alkalies.
m^ufacrur:^?"'""'"" -'"' P'-^P^-'^' ^°<1 how is it now
2. State the sources of the potassium compounds
3. How is caustic potash obtained .? '"P°"""=-
4. Describe what happens when gunpowder is burnt
5. Supposing that the decomposition is a siLpJe one,
I /
458
ELEMENTARY CHEMISTRY,
how many cbc. of (i) carbon dioxide and (2) of nitrogen
gas at 0° and 760 mm. will be given off by burning one
gram of English musketry powder ?
6. Name the characteristic tests for potassium salts.
7. What are the sources of the sodium compounds ?
8. Describe the salt-cake process.
9. How many tons of vitriol containing 72 per cent, of
H2 SO4 will be needed to convert 100 tons of salt into
salt-cake, and how many tons of ihis latter will be formed .?
10. How many tons of aqueous hydrochloric acid con-
tainmg 30 per cent, of HCl will be formed in the pre-
ceding reaction .?
11. Describe the decompositions by which salt-cake is
converted into soda-ash.
' 1 2 Required 500 tons of soda crystals ; what will be the
weight of salt and pure sulphuric acid neecJed }
13. How were the tv.-j new alkaline metals discovered .?
14. Explain the analogy in constitution existing between
the potassium and ammonium salts.
15. How is hydroxylamine prepared, and what are its
properties ?
Lesson XX. Metals of the Alkaline Earths and
Aluminium.
1. What is the composition of slaked lime ?
2. Describe the uses of lime in agriculture.
3. How can temporarily b d water be softened 1
4. Name the commonest minerals containing barium
and strontium.
5. How can oxygen gas be prepared from barium
dioxide, and how can this process be rendered continuous ?
6. Mention the distinguishing reactions of the com-
pounds of calcium, strontium, and barium.
7. How is metaUic aluminium prepared .?
8. What is the meaning of a mordant .?
9. Calculate the percentage composition of common
alum.
^ jfi^-iMiti
'^Jummmntf'
litrogen
ing one
alts,
ds?
cent, of
lit into
Drmed ?
id con-
he prc-
cake is
be the
vered ?
etween
are its
md
)ariuni
)arium
lUOUS?
\ com-
mmon
QUESTIONS AND EXERCISES. 455
\\ h2 f/^/°'°>"-«d glasses obtained ?
12. How IS co-mmon earthenrare glazed f
■ Lesson XXI. Magnesium, Zinc, Manganese.
percentage ctpSn f ^ =^" '^^^'"S '^e following
Magnesium .... g.-g
oit: ; ; • • • J-
^«- • ■ • : ; : J^^
lOO'OO
separ"t:d\ro:;\tse'Xirnrf ^ '^ distinguished and
^3. State the method employed to extract .i„c from its
be^gof?™mTo^o|™lffSrr'^ ^'"= -■P'^- -
oxfdef.""' ''^r ^°'"P''=Wo„ of the several manganese
pretrre°:f";rmrcln^^^r,;- under the
Lesson XXII. iron
peniefo? t" '°™^ °' ^"^^ "-■-' '-l-rt-nt physical pro-
of^crSm": ^^fcty^'",\^-' , Ho- -any tons
^30 tons of pyrites contlf "^^ //^ "^t f^^ -.dation^of
460
ELEMENTARY CHEMISTRY,
3. What is the composition of red haematite and spe-
cular iron ore ?
4. How can the ferrous and ferric salts be distinguished?
5. Describe the manufacture of cast iron from clay
iron-stone.
6. What chemical changes go on in the processes of
" refining " and " puddling "?
7. How do cast iron, steel, and wrought iron differ in
their composition ?
8. Describe (f) the common method for making steel,
and (2) that known as Bessemer's method.
9- 3)285 grms, of pure iron wire are burnt in excess of
. oxygen and chlorine gases ; required the weight (i) of
oxide, and (2) of chloride formed.
' 10. What is the cause of difference in the appearance
and properties of " mottled " and " white " cast iron ?
Lesson XXIJI. Cobalt, Nickel, Chromium, Tin, b'c.
1. Mention some of the chemical characteristics of
cobalt.
2. How can cobalt and nickel be distinguished by the
blowpipe }
3. Give the formulas and names of the chromium oxides.
4. Hov/ can we pass from chromium sesquioxide to the
trioxide, and vice versd ?
5. Write down the formulae of the potassium chromates.
6. What is the constitution and mode of preparation of
chromium oxychloride }
7. In what form does tin occur .?
8. How can tin compounds be distinguished }
9. What weight of crystallized " tin salts " can be pre-
pared from one ton of metallic tin }
Lesson XXIV. Antimony, Bistnutk, Lead, Thallium,
I. Write down the formulae of the corresponding oxides
of arsenic and antimony.
' -^..■SdfyBtn
■^'*m'm>tBi»m-itli<Wk'
QUESTIONS AND EXERCISES. 461
2. How are the two chlorides of antimony prepared ?
3. How much manganese dioxide, salt, and sulphuric
acid will furnish chlorine enough to convert 100 erms of
antimony into the trichloride ?
4. Point out the chief distinguishing properties of the
bismuth compounds.
5. Mention the decompositions which occur in the
process of lead smelting.
6. Describe the action of lead upon water.
7. How is white lead manufactured ?
8. 100 grms. o{ lead oxide when reduced to the metallic
state m a current of hydrogen lost 7-1724 grms. Calcu-
late the combining weight of lead.
9. 4'997S ^rms. of lead chloride needed 3*881 grms ot
metallic silver for complete precipitation. Required the
combining weight of lead, those of silver and chlorine
being given.
Lesson XXV. Copper and the Noble Metals,
1. How is copper obtained from copper pyrites ?
2. Calculate the percentage of water contained in crys-
talhzed copper sulphate.
3- What is the density of mercury vapour .^ Does it
obey the usual law of densities ?
4. What weigut of mercury and corrosive sublimate
must be taken to yield three kilos, of calomel ?
5. How is the silver extracted from argentiferous lead >
6. 100 parts by weight of silver yield 132-84 parts of
silver chloride. Given the combining weight of chlorine
required that of silver. '
7. What decomposition does silver chloride undergo in
the light ? **
8. Describe the method used for the extraction of gold.
9. How can platinum ore be worked into coherent
metal ?
10. Give the distinguishing tests for copper, mercury,
silver and gold. *rir , ^ 1
462
ELEMENTARY CHEMISTRY,
Lesson XXVI. Spectrum Analysis, '*
1. Describe the phenomenon observed when a source
of white hght is examined by means of a prism.
2. What pecuHarity is observed in the spectra of
coloured flames ?
3. How does the spectrum of a glowing solid differ
from that of a glowing gas ?
4. Mention some facts to show the extreme delicacy
of the spectrum analytical methods.
5. How can the spectra of the metals be obtained ?
6. Describe the construction and mode of use of the
spectroscope.
, 7. Draw a rough sketch of the spectra of the following :
—sodium, potassium, rubidium, lithium, and strontium
(see Frontispiece).
8. Explain what is meant by Fraunhofer's lines.
9. Describe shortly an experiment to show the rever-
sion of the bright line of sodium.
10. Why does Kirchhoff conclude that iron exists in
the solar atmosphere .''
11. How do we know that the fixed dark solar lines
are not caused by absorption in the earth's atmosphere ?
12. How can we learn the composition of the atmo-
spheres of the fixed stars, and why are we in ignorance
about the composition of the planets ?
13. State the results of Mr. Huggins' observations upon
the spectra of the nebulas.
Lesson XXVII. Introduction to Organic Chemistry.
1. Name the two chief peculiarities of the carbon com-
pounds.
2. Give examples of monad, dyad, triad, and tetrad
elements.
3. Explain what is meant by saturated and non-saturated
carbon compounds.
^ ^m i m m im mimmmk^-s
■ QUESTIONS AND EXERCISES. 463
^^4. Name the chlorine substitution products of marsh
n.ono^'S':'a"ndttrlo'n3^^Vu?a".ed"'°" "^ "^^
7. What is mlnnf I ^"^^ ^^ ''^■•'■^™ compounds ?
te4 "poI^arotSI^TadicIu^". °'^^""= ^^'''<^'''' -' "y the
pound 'Czofc h' irdml""?/' "'^ '^'-'^^^^ corn-
group of bodies » "' ^'''"' ^™'" «•'« °f 'he alcohol
pirL?i;Vr3i?frut: '"^ '"""^''°" "«'-- -
LESSON XXVIir. 0;s^«/.^„«/,,,-,.&>..
n.a«o?^oTtt%irC\rdr;erc'^^^^^^^ ""^ -'-
compounds. v^iugen contained m or
and o?yl'n^:i:id°/d'on°c' T'"'"'"^ '='^^'^°". "^X*
dioxide,T„"d '0^040 g™ watr" R °'^?°°. ^l"-'- ^^
between the number l/^„mfnf Vk ^''^"'«d «he relav.
3. What is tl mlcuZ wefeht'Tan"'"*,'^"'''-
cM<.acetic) whosesilversalt ^A /sfe'^te
gr^.TLrn1io\Veinn':^r^r''"f'°" °-^^'
grm. of the silver salt rontSned o^fsf^ *"•'," ' °'39l
quired the formula of thTacM rnn/^'^-^""- I''''*''- ^e-
gen, and oxygen. ^ contammg carbm, hydro-
of 'an"°r^n'r/^od; tZT^TZ °' '^^ -P°" <J---ty
moIeculaP weight ? ^ "^^"^ "'^ ascertaining it^
464
ELEMENTARY CHEMISTRY.
6. What is the density of ammonia, marsh gas, olefiant
g^a, methyl alcohol, ethyl alcohol ?
7. Describe the two methods employed for determina-
tion of vapour density.
8. Required from the following numbers the vapour
density of a hydrocarbon of the marsh gas series :
Globe filled with air at i6°'5 7-566 grms.
vapour,, 140° 7783
Capacity of globe, 115*5 cbc.
n
C,H
Lesson XXIX. M anatomic Alcohol Group.
I. Explain the analogy in constitution existing between
the ethyl and potassium compounds.
' 2. Write down the formulae for ethyl alcohol, ether,
acetyl acetate, aldehyde, acetamide.
3. Give the names of the following :
4. What is the chemical change which occurs in the
passage from a primary alcohol to the corresponding
acid?
5. Write down a list of the first eight primary alcohols
with their derived acids.
6. Fow is a secondary alcohol distinguished from the
isomciic primary one ?
7. Explain the construction of dimethyl carbinol and
trimethyl carbinol.
8. Name the properties and mode of preparation of
methyl alcohol
9. What is the action of sulphuric acid upon methyl
alcohol ?
10. By what reactions are we enabled to pass from the
methyl to the ethyl series ?
II. Explain the difference betw en met..yl cyanide and
acetonitriL
'f--^'^^[:A!^0k&i^m»i.
■thikjtm.
|(K^%W#<^ *> V
QUES7/0m AND EXERCISES. 465
Lesson XXX. nkarbon or Ethyl Series.
I. How can alcohol be nremrpH f,.«r^ •* •
materials? prepared from Us inorganic
e.h^i-?:[pVa4td"Jrhen'' '"""'""" «''^'«-. P"'--"-
f w -f "^^ "'^. "."'in"ou^ etberification orocess
.oo'v"eTh..Tr/aC\°L' t|:3« -n be p epared from
carbonate w: 11 be produced ' ^ ^'■'"'- °' P^'^'^^i""
pro^pSi^^r^^^^^
8. How can amyl alcohol be 'prepared from QH„H f
9- What is the action of chlorine upon 9"ii \ ?
AmticX^oVu'tS?''^'^'- ^'"-^^'^ ■'^ P« from
Lesson XXXI. Compound Ammonias.
of 'a Slelll'j.^rri^^rel^^^^^^^ formula
cent, of metallic platinum' '^'^'"'"S °'» ''"""g 29-4 per
t Ct^e iU^mX*ftrrT'Tec'o''nr ^ ^^T'^'' ^
monamines. pnmaiy, secondary, and tertiary
H H ^ 9 •
■uAfe
466
ELEMENTARY CHEMISTRY.
7. Describe the composition, properties, and mode of
preparation of the p^ Dsphorus bases.
8. What is the comoosition of cacodyl and cacodvlic
acid ? ^
9. How is zinc ethyl prepared, and what are its chief
properties ?
10. Na(QHs)+CO,=C3HsNaO,; explain this reac-
tion.
I
Lesson XXXII. Oxidized Derivatives of the Alcohols.
I. Mention the chief reactions by which the fatty acids
can be formed.
\ 2. How many grms. of potassium formate can be got
from 500 litres of carbon monoxide at 15° and 745 mm ?
3. Required 100 kilos, of CH,0, ; how many kilos, of
oxalic acid are needed 1
4. What is the formula of formamide ?
5. How can acet-aldehyde be produced from acetic acid
and how can aldehyde be reduced to alcohol .? '
6. Explain what is meant by the acetous fermentation.
7. What is the composition of red and iron hquors ?
8. How many grms. of glacial acetic acid can be ob-
tained from 25 kilo^ of potassium acetate .?
9. How is acetyl acetate (acetic anhydride) prep .red.?
10. Name some of the chlorine substitution products of
acetic acid.
II. Give the formute and mode of preparation of thi-
acetic acid, acetyl peroxide, acetamide, acetone, acety-
lene. ^
12. Show that by substituting hydrogen in the radical
of acetic acid by methyl and ethyl we obtain (i) propionic
and (2) butyric acids.
13. Describe the constitution of the isomeric alcohols
acids, and hydrocarbons ol the 4-carbon series. '
14. Point out several methods by which we can pass
from the di- to the tricarbon series.
QUESTIONS AND EXERCISES
Lesson XXXIII. Diatomic Alcohols.
467
2 M^5 '^ "l^^"' ^y ^ diatomic alcohol ?
^^2^ Mention -he chlorine substitution products of ethy-
poJndT'^'' '*^'^"^ ''S-rded as a non-saturated com-
4- HoHT is glycol prepared ?
To w :, :: * "" °' "ci-r •»"■•"* '"--.
TO. VVha^ IS the name of ^^n,, I q p
". Write out the formula of loLe «hyle„e diamines.
Lesson XXXIV. Dialogic Aa<is.
of'-theTxahc' s'erie^' der^e^^J"^ '\<='''= -"- and (.)
glycols.? ^^''"^'^ ''°"' the corresponding
the' fifs'S.' ''^''"^''' "'•"""'■^ ^"<1 - the first term of
i Hoit manf^'Sl'sM o^'™^"'^' ^"^ocarbonate.
'oogrms.of'g?^col™^to°oxl'?:^id^' ""l""-^<* '" °-<J-
an^- s" i^mT '"'''" ^""^ "^ °'^'-"^'' ^o™ carhon, oxygen,
^^^ Describe the manufacture of oxah'c acid from saw-
propioSrac'd'' '""" '"''^ =^" ''^ fo^ed from chlor-
8. Xn what important respect, as regards »t.» <„.„_..•_.
H H 3 " " "■■"■ '""""""I
I
468
ELEMENTAR Y CHEMISTR Y.
of salts, do lactic acid and its homologues differ from
oxalic acid and the higher terms of its series ?
9. Distinguish between lactic acid and sarco-lactic acid.
10. Explain the reaction —
QH,(CN), + 4H,0 = C,H,04 + 2NH3.
1 1. How can malic and tartaric acid be obtained from
succinic acid ?
12. Describe the several varieties of tartaric acid.
13. What is the action of hydriodic acid upon tartaric
acid ?
Lesson XXXV. Cyanogen Cofnpounds,
1. Write down the typical formulas for the most
important cyanogen compounds.
2. Describe the tests for hydrocyanic acid.
3. How can hydrocyanic acid be directly obtained from
inorganic sources ?
4. What are the chief points of relationship between
the cyanogen and the oxalic acid groups of compounds .?
5. How much yellow prussiate of potash, manganese
dioxide, and ammonium sulphate can yield 500 grms.
urea ?
6 50 grms. of urine yielded on analysis 475 cbc. of
nitrogen at 1 1'^ and 754 mm. Required the percentage of
urea contained.
7. Write the formulae for cyanuric aCid, diethyl urea,
sulphocyanic acid, and cyanamide.
Lesson XXXVL Triatomic and Hexatomic Alcohols.
1. Show the relation in composition existing between
propyl alcohol, propylene glycol, and glycerin.
2. Explain the process of saponification.
QUESTIONS AND EXERCISES. 463
h/dief ''" ""' '°''™"'* ">- composition of the chlor-
Name the above bodies
8. Explain the following :
QH„0.+ „HI = QH.3l+9H,0 + 5i,.
Lesson XXXVII. ^«^... ««^ c/^,„,,.
rcfinin^i^'o'f ^aSt-^ff^'P""" °^ "'^ preparation and
uponr„?sugar?"'°" °' ''^^^' ^^ <!"«= sulphuric acid
S- How is dextrose prepared?
fermemlfion!''"' ''''°""' °^ '"^ P""<^iP=J phenomena of
LESSON XXXVIII. ^....,, ^«^, ,„^ ^,^^^^^^^_
adLYaSUU''rtoTr''orrun?o^S^,r°"' ^^^ -"^
470
ELEMENTARY CHEMISTRY.
Explain the above equation.
5. What is the composition of ink ?
6. State some of the general characteristics of a gluco-
side.
Lesson XXXIX. Group of Aromatic Compounds,
1. How do we suppose the carbon atoms in benzol are
arranged ?
2. Write down the formulce for benzol, toluol, xylol, and
cumol.
3. What substances are formed by the replacement
of one atom of hydrogen in benzol by N 0„ N H . and
OH?
4. Describe the methods employed for preparing ani-
line.
5. Required the volumes at 0° and 760 mm. of nitrogen
and carbon dioxide obtained by the combustion of
216 grms. of aniline.
6. How is rosaniline prepared }
7. Explain the action of nitrous acid (i) on aniline
nitrate, and (2) on the alcohohc solution of aniline.
8. How can oil of bitter almonds be converted into
benzoic acid, and vice versd ?
9. Explain the constitution of toluidine and benzyl-
amine.
10. Explain the following :
^VWfiO I o ^ c,H,0 Cl^^jjJsO I o + KCl.
1 1. Explain the relation of leucaniline to rosaniline, and
of white to blue indigo,
12. What is the composition of winter green oil ?
13. State the relation of naphthaline and anthr^icene to
benzol.
14. What is the chief colouring matter of madder ?
I.
2.
3.
alkaJ
4.
5.
6.
morp
7. .
nine,
8. J
hydro
1. h
bodies
2. H
, 3. D
blood, ;
4. D
5. W
tion of
the bod
6. Fr
necessa:
energy t
Qi^MSTWm AND EXERCISES.
. Whaf ,V . .
471
,3. Name the ch!^?;rc„Sr''V°V^ ^«^"f''=^' oHs P
alkaloids. peculiarities of the group of ve-eto
4- Mention the name? nf .!,« • "
5. What is the con^tt.,,- '"* °P""m alkaloids
6. What tests mav1»"°? "^ "arcotine?
™o.phine, b™^etra^„'- -d^^^^^^^^ the presence of
"■•ne, and thdrisome'rs."'^ P™P^«''^^ "^ V'inine, cincho-
"y-irochlorate -tains^^itpr/lgi',"^^^^^^^^^^^^^^ -'•-se
bodieJ'di&^„'=d"J=;f^/';^';ac^^^^^ do the albuminous
2- How may fibrin alh?,^ . '^°"'Po«nds ?
3. Describe s!S;th;To",„?<:?r'^'^'" be separated ?
blood milk, and bile.^ ~™Posit.on and properties of
. t WhatTlfe re^ir of^f "f ' ^'"^ -^'^ble life
Jjon^of carbon dio-dl^"^^^^^^^^
''. From what source rfn ,„• ,
necessary for existence and th' -f"^''" '^e rnergv
-ergy needed for the Sit^, ^ Pi-.s draw Si-
APPENDIX.
II
Note.— (9« the Absolute Weights of Hydrogen, Oxygen^ and the
other Gases.
In the foregoing pages we have taken the density of Oxygea to be i6
(Hydrogen = i) and we have chosen as the standard of absolute weight
Kegnault s number 1-429802 as the weight in grammes of i litre of oxycen
gas, weighed in the latitude of Paris at 0° C, and under a pressure of 760 rnm.
ot mercury, this being generally received as the most reliable of this great
expenmenters numbers. Hence we adopt ^ of this, or o-o893626, as the
absolute weight of i litre of Hydrogen measured under thelame circum-
stances.^ Kegnault s experimental number for the weight of x litre of Hy-
drogen IS, however, 0-089578; and if we accept both of these experimental
numbers as correct, the density of Oxygen becomes 15-96 instead of 16.
/*i, recent classical researches on the combining weights of the elements
(tne most reliable and accurate determinations which we now possess), Stas
concludes that the true combining weight, and therefore the true density, of
Oxygen is 15-960 when H = 1, and thus a remarkable confirmation of the
accuracy of Regnault's experimental results is obtained.
If we wish to calculate the weights of the gases with the greatest possible
^mT^wk Vk &"""■'.'."' ■■"^" ««i!>cuus uompounas, we must multiply this
number by the densities of the respective gases, as given in (or obtained from)
b Stas ^^*"^"^ ' ^®"^*^ ^'■°'" ^^^ combining weights, as determined
In the third column the experimental densities of the gases are found as
they have been determined by exact observation : it will be seen that m some
cases these numbers closely agree with those obtained by Stas, whilst in
others (especially those of the older experimenters) the difference becomes
more apparent.
I' Ji. III.
Density Weight of i litre Density
calculated at 0° & 760 mm. experimental,
(Stas).
Hydrogen
Oxygen .
Nitrogen .
Chlorine .
Kromine .
Iodine. .
Steam . .
Ammonia . . ,
Hydrochloric Acid
1*000
15 "960
14-009
55-368
79 '750
126-533
8-980
8-504
18-1&4
0-089586
1-429802
1-255010
3"i68478
7 '144483
"■335586
•804482
0-761839
1 "629071
I 000
15*960
i4"02S
35*343
79*978
125-83
9 '001
8-614
iB-ooS
Regnault.
Bunsen.
Mitscherlich.
Dumas.
Gay Lussac and
Thenard.
Biot and Arago.
»» »»
Abnoj
Absoli
Absor]
Absori
sphe
Acetal,
Acet-al
Acetan
Acetate
Acetate
Acetic i
Acetic a
Acetic a
Acetic a
Acetone
Acetonit
Acetous
Acetyl ai
Acetyl c(
Acetyl p(
Acetylene
Acid, defi
Acid-form
Acids der:
Acids of b
Acids of c
Acids of ic
Acids of p]
Acids of SI
Acraldehyi
Acrolein, 3
Acrylic aci,
Adipic acid
^]^ a mech£
Air, analysi;
Air, physica
I
INDEX.
AcetaJ 350
Acetamide, 35: ^^
fe-d^t"™-™' 33»
JSa'Sd^^-fef^'^^
AS^„?.1ff '"» S"^' "'
Acetonitril, 320
Acety peroiidr'' /-^^
Ac.dsofchlprinl;;;|
Acids of iodine, t2i
Acids' of PVlP^°'^'«. ^58
Acra dehyde, 3SO ^
Acrolein, ^80
Acrylic acid, 389
Adipic acid, 364
Agate. 147 •" *
A»r a mechanical inixh.«
Air. analysis of, 5?"*'"'^'^' 5^
Air, physical Dmn-rf-- -r
Air, sohibiJity in water. 3a
Alabaster, 218 * ^
A bumin, 434
Alcob„|.^-g.co-p^„dsof.3„
Alcohols, tertiary, V16 ^
A kaijne earth metals 21.
Alkaline metals, 197 ' ^'*
A llo rop.c oxyg;n,^^7
Allori!;-V3^^™P'^^'^^^>'36
Alfe?;^'38,
^jt o^opper, 265
A oys of Silver, 272^
Ally alcohol, 388^
|fe?5^-"^2e. 389
A um cake, 323
Alumina, 223
Alunnnium, 222
AU,^'J''l'' !"'Phate. 22,
^^-SiSr^SisTt
il
'474
INDEX,
Amalgams, i86
Amido-benzol, or aniline, 40^
Ammeline, 379
Ammonia, 74
Ammonia, composition of, 79
Ammonia, freezing machine, 78
Ammonia in the air, 57
Ammonias, compound, 289, 312, 335
Ammonium and its salts, 213
Ammonium chloride, 214
Ammonium cyanate, 378
Ammonium sulphate, 214
Amorphous phosphorus, 156
Amygdalir., 404
Amyl acetate, 333
Amyl alcohol, 331
Amyl ether, 332
Amyl hydride, 332
Amylaceous bodies, 400
Amylene, 362
Amylene alcohol, 363
Analogies of the arsenic group, 168
Analogies of sulphur group, 146
Analogy of oxygen and sulphur, 143
Analysis, definition of, 15
Analysis, organic, 299
Angelic acid, 390
Anhydride, definition of, 132
Anhydrite, 218
Anihne azo compounds, 411
Aniline blue, 413
Aniline colours, the so-called, 412
Aniline, properties of, 409
Aniline yellow, 411
Animal chemistry, 435
Animal heat, 439
Animal starch, 400
Animals, functions of, 438
Anthracene, constiti tiou of, 422
Anthracene group, 422.
Anthrachinon, 423
Antichlor, 131
Antidote for arsenic, 165
Antimoniates, 255
Antimoniuretted hydrogen, 256
Antimony bases, 341
Antimony, ore of, 254
Antimony, oxides of, 255
Antimony oxycliloride, 255
Antimony pentachioride, 256
Antimony pentoxide, 255
Antimony, properties of, 254
Antimony sulphides, 256
Antimony trichloride, 256
Antimony trioxide, 255
Appendix on weights of gases, 472
Aqua regia, 110
Aqueous acids, boiling points of, i. 8
Aromatic group, 27, 405
Arragonite, 218
Arrow-pi>ison, 431
Arsenates of Fodium, 165
Arsendimethyl, 341
Arsenic, 163
Arsenic acid, 165
Arsenic and hydrogen, 166
Arsenic and sulphur, 166
Arsenic bases, 340
Arsenic, detection of, 167
Arsenic pentoxide, 165
Arsenic trioxide, 164
Arsenious acid, 164
Arseniies, 164
Arseniuretted hydrogen, 166
Atmosphere, the, 50
Atomic heat of elements, i£o
Atomic theory, 59
Atomicity or iiuantivalencs, x63
Atoms and molecules, 168
Aurates, 277
Azelaic acid, 362
Azo compounds of aniline, 41 1
B.
Balling furnace, 209
Barium and its compounds, 221
Barium chloride, 221
Barium spectrum, 222
Barometer, 30
Baryta, 221
Base, definition of, 67
Basic oxides, 186
Beer, alcohol in, 323
Beetroot starch, 401
Bell-metal, 252
Benyl group, 413
Benylene, 390
Benzoic acid, 414
Benzoic aldehyde, 414
Benzoic anhydride, 415
Benzoic peroxide, 415
Berzol, composition of, 294
Benzol derivatives, 406
Benzol, homologues of, 406
P.
I
,J
B'^nzol properties of, 408
Benzoyl chloride, 41c
genzyl alcohol, 41! ^
«enzylamine, 416
Benzylic or t.;.;.. series. 4x2
Besseu.er steel process, 24^
Bicarbonate of soda. 2^0
Bichromate of potash. 246
Bile, acdsoftfie. 438 ^
Bismuth bases, 341
Bismuth, oxides of, 2^7
Bismuth, properties of, 257
Bjsmuth, salts of, 2S7
Bisulphide of crbon: 142
Bitter almonds, 404 ^
Biuret, 379 ^ ^
Black-ash furnace, 200
Back mustard, 405 ^
5f*=^o-\»deofcopper, 268
Black oxide of manganese. 234
Blancyixe, 221 ' ^*
Bast furnace, use of, 240
Basting oil, 386 ^
Beaching by sulphur. 13 r
B caching character of chlorine 10^
B caching, mode of, m "^' '°^
Bleaching powder. 210
olende. 230
Blood, composition of, 4.6
{, ,^pipe flame, loo
Bohemian glass, 225
Bo, er crust, formation of, 2t8
Boiingpomt. detern.inat 01, of ->o8
Boilingpointofwater, 4-^ '^°^
Bone-ash, 154 ^~
Bones, composition of, 4.6
Boracic acid, 154 ' ^^
Borax, i -is, 211
Bor ethyl, 342
cone acid, 153
Boron, 151
Boroa trichloride, ir.
Boron irifluoride, i^t
Boron trioxidc, 152'"'
Boyle s or Mariotte slaw 20
Brain, substance of the, 437^
Brassyl,c acid, 2U
iJraunite, 233
Breathing, explanation of ia
Britannia metal, 252 ' ^
«romic acid, n8
Bromine, 117
Bromine, oxi-adds of, J15
INDEX.
^7S
Bronze, 252
Brown oil of vitriol, 136 '
Brucne. 430. 43, ^0
Bunsen s gas-lamp. ,00
Bunsen and Kirchhoff's spectr m
discoveries, 280 specti.m
BuS^laSe^tr'-"^^^. '''
Butylene. 362 ^^
Butylene alcohol, 36.5
C.
Cacodyl, 341
Cacodylic acid, 341
<-arimuim, 231
Caesium and rubidium, 212
Cafeine, 4^0 ' "
t-aJamine, 230
Calc-spar, 218
C=i cium carbonate, 218
Ca cium chloride. 210
.V^'^!"'" compounds, 214
Ca cium fluoride, 219 *
Ca cium hypochlorite, 106
Calcium oxide, 217
Caelum phosphate, 2,9
Ca ciuni sulphate, 218
Calculation of analyses. 303
Calculation of vapour den?hv ^r-^
c' cut'-°"' °^hemical dia^gf^'^,
^.acu.ations of volume, 31 ^ •*
Calibration of thermometers og
?atn-enr'^^^ '
Camphene, 425
Camphor, 426
Cane sugar, 394
J^aoutchoiic, 426
Capacity for heat, ,79
Caprylidene, 390
Caramel. 395
C'arbamic acid, o^-y
Carbamide or urea, 379
Carcmols, 238, 315' ^^'
Carbo-hydrates, 393
Carbolic acid, 40^
Carbcn, 80
Cafbc;n a letr^d, 290
Carbon and hydro|cn, 93
1 I 2
476
INDEX,
Carbon and hydrofren, direct com-
bination, 95 .
Carbon and nitrogei;, lox
Carbon and sulphur, 142
Carbon, combining powers of, 294
Carbon compounds, arrangenieiu o*",
293
Carbon compounds, chemLstry of,
289
Carbon dioxide, 84
Carbon disulphide, 142
Carbon, estimation of, 299
Carbon monoxide, 91, 365
Carbon, properties of, 290
Carbon tetrachloride, 320
Carbonate of lime, 27 8
Carbonates, classes of> 363
Carbonic acid, 87, 364
Carbonic acid exhaled from lungs,
441
Carbonic acid in air, 55
Carbonic oxide gas, 91
Carbonyl chloride, 381
Carbonyl radical, 364
Carbonyl sulphide, 381
Carboxyl, 3415
Carry's freezing machine, 44
Casein, 434
Cassius, pui-ple of, 252
Cast iron, 235
Caustic potash, 199
Caustic soda, 205
Cellular structure, 290
Cellulose, 403
Centigrade scale, 27
Cerotene, 362
Cerotic acid, 334
Cerotyl alcohol, 334
Cetene, 362
Cetyl alcohol, 334
Chalcedony, 148 •
Chamomile, oil of, 390
Charcoal, 82
Chemical action, definition of, i
Chemical analysis, explanation of, 15
Chemical balance, 3
Chemical compound, examples of, 1
Chemical equations, explanation of.
Chemical properties of the metals,
185
Chemistry of carbon compounds,
286
Chili saltpetre, 210
Chinchonas, alkaloids of, 431
Chinese wax, ^34
Chloracetic acids, 353
Chloral. 351
Chloranjl, 41a »
Chlorates, 114
Chlor-carbonyl, 365
Chlorhydrins, 386
Chlorhydrosulphurtc acid, 138
Chloric acid, 114
Chloride of lime, 919
Chlorides of phosphorus, 162
Chlorine, 104
Chlorine, acids of, 115
Chlorine and carbon, 117
Chlorine and hycfrogen, 104
Chlorine and nitrogen, 115
Chlorine and oxygen, no
Chlorine and sulpnur, 142
Chlorine from hydrochloric acid, J09
Chlorine group, relations of, 125
Chlorine m organic bodies, 30a
Chlorine monoxide, ni
Chlorine tetroxide, 113
Chlorine trioxide, 113
Chloroform, 319
Choke damp, 85
Chrome alum, 346
Chrome ironstone, 245
Chromic acid and chromates, 246
Chromic compounds, 245
Chromium, oxides of, 245
Chromium oxychloride, 247
Chromium, properties of, 245
Chromium, reactions of, 248
Chromium trioxide, 247
Chromosphere, 288
Chromous compounds, 245
Chromyl chloride, 247
Cinchonidine and cinchonicine, 43-!
Cinchonine, 432
Cinnabar, 269
Cinnamic acid, 419
Cinnamic aldehyde, 419
Cinnamyl alcohol, 419
Cinnarnyl series, 419
Citric acid, 372
Classification of metals, 1S2
Clay. 224
Clay ironstone, 240
Cleavage in crystals, 191
Coal, 83
^^^-^■*^^*f nH^^m .
INDEX,
2S3
Coal gas, 96
Cobalt chloride, 341
Cobait, salts of, 243
Codeine, 429
Coefficient of expansion, 28
Coinage, silver, 272
Coincidence of spectrum line
Collodion, 404
Colloids, 148
Coloured flames, ^c^tra of, 28.
Coloured glass, 226
Combining powers of carlwn 200
Combining volumes of ga^"' ^
Combining weights, e/pla^I'ti^n of.
^>™f;"'"^^eight3, tableof, 7
Comhustion, explanation of /,
Combustion furnace, 3C0 ^
rnml!!!'v " °^ ^^^ diamond, 88
Composition of sun'« ^t^ u
287 atmosphere.
Composition of the air ci
Composition of the earth's crust «
Compound ammonias. 312. 3 f' ^
Compound and simple bod es ,
Compound radicals" lox, 174 ' ^
Compound ureas, 380
Compounds, non-saturated, 29.
Compounds, saturated, 200
Condensing towers, 208
Conine, 427
Constitution of salts, i8q
Continuous spectra, 281
Copper acetate, 351
Copper arsenite, 268
Copptr carbonate, 268
Copper chloride, 271
Copper, metallurgy of, 264
Copper, monoxde, 268
Copper nitrate, 268
Copper, ores of, 263
Copper, properties of, 26s
Copper pyrites, 263
Copper salts, tests of, 268
Copper sulphate, 268
Copper sulphide, 268
Corrosive sublimate, 270
Corundum, 222
Coumarin. 417
Cream of tartar. 372
Creatin, 380
Cjr^tinine, 274
CVessol, 412
Croton oil, 390
Crotonic acid, 390
Crotonylene, 390
Crown glass, 224
Cryolite, J23
crystal glass. 225
Crystals of leaden chnmbcr. ,02
Crysta hzation, water of A
Crystallography, ,9, ' ^^
Cry'^taliofds.^/a ^
cutr:c^~^-«'-.-5
Cupellation, 271
Cupric oxide, 268
Cupnc salts, constitution of -fi.
Cuprous chloride. 268 ^^
Cuprous oxide, 26S
CuS,tr°""'*"^'^'"°^^^7
Curds, 434
Cyamelide, 377
Cyanamide, 378
Cyanates, 377
Cyanic acid. 377
Cyanogen chlorides, o,.
Cyanogen compound? xoi, 37,
Cyanogen gas, 102 "
Cyaniiric acid, 378
CymoJ, 425
D.
l^alton's atomic theory ,0
J^avy lamp, loi ^' ^^
Decatyl hydri<l<., 333
Decatylene, 362
Uecimetre, 25
I)ecomposition of water 26
IWcion of arsenic,*^,
l.'etermina'inn ,.c '
306 "^'*"" "f vapour density,
J^ew, deposition of. S7
J^extrine, 400 ' ^^
jJextrose, 396
iJiacetamide, 354
B.-acetin, 385''^
gf-allyl ether. ,83
^luiunc acid, 380'
477
473
INDEX,
Jiialysis, 148
]>iamond, 81
1 Maiirond, combustion 01", 8
I)iamyl, 313
Diamy! ether, 326
Diamylene, 36a
Diastase, 402
Diatomic acids, 363
Diatomic alcoliofs, 358, 362
Diazo-amido-benz I, 411''
Diazo-benzol nitra'e, 411
Dibrom-succinic acid, 369
Dicarbon series, 321
Dicarfjon series, figure of, 292
Dichloracetic acid, 346
Dicyanamide, 378
Dicyanogen, 102, 373
Diethyl ether, 323
Diethylamine, 335
I Diethyl^ jjjlycol, 361
Diethylin, 387 "
Diffusion of gases, 31
Dilactic acid, 367
Dimethyl aceial, 350
Dimethyl acetic acid, 347
Dimethyl benzol, 406
Dimethyl carbinol, 315, 330
Dimethyl ether, 320
Dimorphism, 197
Discharge in calico-printihg, 372
Disinfecting liquor. Con Jy's, 235
Distearin, 387
Distillation, 47
Distillatic», fractional, 308
Distribution of the elements, 9
Disulpho-anthraquinic acid, 423
Divalent elements, 171
Dolomite, 228
Double cyanides, 375
Double decompositions, 64
Drying and non-drying oils, 387
Dumas' method, 307
Dyad radicals, 175, 294
£.
Earth's crust, composition of, 9
Earths, metals of the, 222
Earthenware, 227
Ebullition, 42
Elastic force of aqueous vapc.ur, 45
Electric spark, action of, on air,
62
Electric spark, spectrum of. 283
Electrolytic decomposition of water
_,37
*;.lftments, distribution of, 9
Elements, grouping of, 279
Elements, fist of, 7
Elements, molecules of, 105
Emery, 223
Empirical and rational formula, 294
Epsom salts, 329
Equation, chemical, explanation of,
19.
Eruc'c acid, 390
Erythrite, ^91
Essential oils, 4' 'i
Etching on glass, 124
Ether, 323
Ethers, mixed and sin ')le, 325
Etherification process ^^24
Ethyl-amyl-ether, 3^. ,
Ethyl aniline, 410
Ethyl borate, 3^9
Ethyl bromiue, 326
Ethyl-butyl-ether, 326
Ethyl carbonate, 328
Ethyl chloride, 326
Ethyl compounds, 311
Ethyl cyanate, 329
Ethyl cyanide, 327
Ethyl diacetarfiide, 354
Ethyl hydride, 326
Ethyl hydrosulphide, 328
Ethyl iodide, 326
Ethyl nitrate, 327, ti^
Ethyl phosphates, 328
Ethyl series, 321
Ethyl siliccttes, 329
Ethyl sulphate, 328
Ethyl sulphide, 328
Eihylamine, 335
■pthvlene, 95, 358
'' V 'ylene alcohol. 359
I ;' vlene dir! ' nde, 358
Eiliylene cxide, 360
Ethylene series, 361
Ethylidene series, 361
Ethylin, 386
Eudiometer, use of, 35
Eudiometric analysis of air, 53
Evaporation of water, 44
Expansion of cases by heat, 28
Expansion of water on freezing, 40
Experimental errors, 69
/
.,_; „#
*-tmmmStt^
283
uf water,
JNDEX,
479
ilx, 294
ition of.
2:
Fahrenheit's scale, 27
rast colours, 223
fats and oils, natural, 187
Jattyacids, group ot 34,
fatty acids, synthesis of, 347
f atty gror.p of bodies, 294
fermentation, 399 ^
fermentations, various, 300
ferric ucid, 239 ^^
ferric compounds, 218
f errocyanic acid, 375
f errous oxide, 237
f errous salts, 2 \%
f errous sulphate, 237
f jbrm, 434 ^'
filtration, 47
Fire damp, 93
Fixing orphotographs, 273
F ame of blowpipe, 100
t* ame, structure of, 07
flint, 147 '^'
Flint glass, 22 e
Flowers of sulphur, 127
f uor spar, 123, 219
rluonne, 123
Food of plants, 44a
rormamide, 348
Formates, 348
r ormic acid, 348
Formic acid, synthesis of, 93
FoS oh.tr '""^•^"^^''^^
Fractional distillation, 308
Fraunhofer's lines, 285
f reezing by evaporation, 44
Freezing machine, by ammonia,
^uel, composition of, 84
f ulminating gold, 275
Fuinanc acid, 370
Fumerolles in Tuscany, 152
Funiic sulphuric acid, 133
Galactose, 396
Galena, 125, 261
Ga he acid, 403, 416
^jall nuts, 405
Galvanized iron. 230
t'arhc, oil of, 389
78
4.58
^ases, diftusion of, 31
rl'!"' *^f P^"**':*" < hy heat. 28
Gases, physical properties of; 2 i
su?e', 2^^"°" "^ ^"'"""^^ ^"^ P--"-
Gases^ spectra of glowing, aSr
Gastric juice. 437 *'
Galatin, 435 ' -^ '' "♦''
(ieneral reactions of radiails, 310
l*errnan silver. 244 ^
G acial acetic acid, 352
Glass, porcelain, and earthenware,
Glass varieties of, 225
Glauber's salts, 211
Glaze for porcelain, 226
G ocosides, group of, 404
vilonoin oil, 385
Glucoses, 396
^lutin, 435
G.ycerin, 384
Jjlycerin ethers, 385
G ycerinic acid, 3S5
G ycogen, .;oo
^ ycol, 359
G yco chlorhydrin^, 360
J^lycol diacetate, 360
(» yco s, boilirig points of, 361
Giycolhc actd, 365 ^
Gold monochloride, 275
^^o d, occurrence of, 274
Gold oxides, 275
Gold, properties of 27 c
Gold, reactions of, 276
<Told trichloride, 275
Graduation of a thermometer, 27
Gramme or gram, definition of ^,
Granules of starch, 401 ' ^
Graphite, 82
Green vitriol, 237
Gum arabic, 400
Gum benzoin, 414
Gun cotton, 403
Gunpowder, 201
Gutta percha, 426
Gypsum, 125
H.
Hail, cause of, 59
Hard water, 218
".^/rIl, apirics 01, 70
■^■■■'^SiSt^--
48o
INDEX,
Heat, atomiCj 180
If eat, expansion of gases by, 28
Heat of solidification, 40
Heat, specific, 179
Heavy carburretted hydrogen, 94
Hemlock, alkaloid of, 427
Heptylene, 362
Hexagonal system of crystals, 194
Hexavalent alcohols, 391
Hexoylene, 390
Hexyl and heptyl compounds, 333
Hexylene, 362
Hexylene alcohol, 363
Hjgher alcohols, 333
Higher fatty acids, 353
Hippuric acid, 415
Hofmann's violet, 414
Homologous series, 308
Homologous series, example of, 292
\ Horn silver, 273
Hydracids, 106
Hydraulic mortars, 189
Hydrides of phosphorus, 161
Hydriodic acid, 120
Hydrobromic acid, 118
Hydrocarbons of acetylene series,
390
Hydrochloric acid, 106
Hydrochloric ac'd, condensation of,
206
Hydrocyanic acid, 102, 373
Hydrofluoboric acid, 153
Hydrofluoric acid, 123
Hydrofluosilicic acid, 150
Hydrogen, 18
Hydrogen bromide, 117
Hydrogen dioxide, 48
Hydrogen disulphide, 141
Hydrogen, preparation of, 21
Hydrogen sulphate, 133
Hydrogen sulphide, 139
Hydrogen sulphite, 131
Hydrogenium, 186
Hydrometers, 57
Hydroquinone, 412
Hydro-sulphurous acid, 138
Hydroxides, definition of, 187
Hydroxyl substituted by chlonne,
*39
Hydroxy lamine, 216
Hvpobromous acid, 119
Hj'pochlorous acid, iii
Hypochlorites, in
Hypogaeic acid, 390
Hypophosphorous acid, i6i
Hyposulphurous acid, 138
I.
Iceland spar, 218
Illuminating powers of coal gas, 97
Indestructibility of maLter, 2
India rubber, 426
Indigo, 418
Indigotine, 418
Indium and its spectrum, 232
Indol, 419
Ink, 405
Introduction to inorganic chemistry,
I
Introduction to organic chemisirN-,
28p
Inulin, 400
Iodic acid, 121
Iodine, iiq
Iodine and nitrogen, 123
Iodine pentoxide, 12a
Iodine, test for, 121
Iron, 235
Iron in the sun, 287
Iron liquor, 352
Iron, manufacture of, 240
Iron, oxides of, 237
Iron pyrites, 238
Iron sesquioxides, 238
Isatine, 418
Isobutyric acid, 347
Isa dimorphism, example of, 25-3
Iso-hexyl iodide, 392
Isomers of 4-carbon series, 356
Isomeric acids, 356
Isomeric derivatives of benzol, 408
Isomeric dyad radicals, 361
Isomeric substit ;tion products, 359
Isomerism, explanation of, 296
Isomerism of amyl alcohol, 332
Isomerism, physical, 425
Isomorphism, 197
Isomorphism of platinum salts, 275
Iso-succinic acid, 369
K.
Kaolin, 224
Kelp, 119
Ketones, 315
KirchhofF s discovery, 286
Kupfernickel, 244
■'^*>t*^',..\.*».„.
^mmM^^^^mm-^kn
Lactamide, 367
Lactic acid, 367
Lactic series of acids, ^64
Lactide, 367 *
Lactose, 396
Lactyl chloride, 367
Lagoons in Tuscany, 152
Lakes, 223 ^
Latent heat of steam, 43
Latent heat of water, 40
Laughing gas, 69
I.aitrus cawphora, 426
Laws of chemical combination
Laws of gaseous diffusion, 32 '
Lead acetate, 260
Lead, action of water on, 259
i-ead carbonate, 260
Lead chromate, 245
Lead ethyl, 343
■Lead glass, 225
Lead nitrate, 260
Lead oxides, 260
Lead, properties of, 259
Lead, reduction of, 258
Lead sulphate, 261
Lead, tests for, 261
Leaden chamber, 135
Leaden chamber, crystals of, i^c
Leucanihne, 413 ' ^^
Leucic acid, 364
Levro-tartaric arid, 371
Levulose, 397
Light carburetted hydrogen 22
Ivight nature of sun, 278
Lime, 217
Lime in agriculture, use of, 217
Limestone, 218
Lime-water, 217
Liquefication, heat of, 40
Liquid carbonic acid, 87
Liquid sulphur dioxide, 130
l^ist of elements, 7.
List of non-metallic elements, u
Litharge, 259
Lithium compounds, 212
Litre, definition of, 25
Loss of matter impossible, 2
Lunar caustic, 273
X, ,^ M.
Madder, colouring matter of, 42,
Magnesia, 221^ ' ^^3
INDEX,
Magnesium, 228
Magnesium sulphate, 220
Magnetic oxide of u-ou, 2jo
Malachite, 265 "'^
Maleic acid, 370
Malic acid, 370
Malonic acid, 368
Manganese alum, 234
Manganese dioxide, 234
Manganese, oxides of, 2:1a
Manganese, properties of; 232
Manganic acid, 234 ^
-^8 Mangaiious compounds, 23,
o^ Mannite, 391 ' ^^
Manufacture of iron, 240
Marking ink, 273 ^
Marsh gas, 93
Massicot, 260
Matter, indestructibility of. a
Mauve, 410 '
Mauveine, 410
Meadow-sweet, oil of, 416
Measurement of temperature. 2?
Measures, tables of, 444 ' ^
Mechanical mixture, 1
Meconine, 429
Melene, 362
Melisic acid, ^35
Mehsyl alcohol, 335
Mercaptan, 328
Mercuric chloride. 270
Mercuric compounds, 269
Mercuric cyanide, 37c
Mercuric nitrate, 26g
Mercuric oxide, 269
Mercurous chloride, 270
Mercurous compounds, 270
Mercurous nitrate, 270
Mtrcurous oxide, 270
Mercury ethyl, 343
Mercury, properties of, 269
Mercury, reactions of, 277
£s;dr3T9'^"^'^^^'=^
Metallic elements, 176
Metallic oxides, 187
Metallic salts, 189
Metallic sulphides, 189
Metals and nnn-!i;*t-'.. ^
Metals, chemical pVoperSes of, 185
481
482
INDEX.
Metals, classification of, 182
Metals, distribution of, 181
Metals of the alkalies, 197
Metals of the alkaline earths, 214
Metals of the earths, 222
Metals, physical properties of, 177
Metals, separation of, 141
Metamerism, 298
Metantimoniates, 255
Metaphosphates, i6o
Metaphosphoric acid, 160
Metastannic acid, 251
Methyl acetyl, 353
Methyl alcohol, 317
Methyl aldehyde, 347
Methyl benzol, 406
Methyl chloride, 319
Methyl compounds, 318
Methyl cyanide, 320
Methyl-ethyl-ether, 325
Methyl-hexyl-carbinol, 316
Methyl hydride, 93, 318
Methyl series, 317
Methylated spirit, 323
Metre, definition of, 24
Metric system of weights. 23
Metrical system, table of, 444
Microcosmic salt, 159
Milk, composition of, 438
Milk sugar, 396
Mineral chamelion, 234
Mirror or plate glass, 227
Mixed ethers, 325
Moisture in the air, 56
Molecular formulae, 170
Molecular weight, determination of,
303
Molecules of elements, 105, 169
Molecules, volumes of, 105, iSg
Molybdenum, 253
Molybdenum trioxide, 253
Molybdic acid, 25.;
Monad radicals, 175, 293
Monamines, primary list of, 337
Monamines, secondary list of, 337
Monamines, tertiary list of, 337
Monatomic alcohol'group, 310
Mono-acetin, 385
Monobasic acids, table of, 314
Monobasic organic acids, 347
Monobrom-succinic acid, 369
Monocarbon or methyl series, 317
Moaocarbon series, figure of, 292
Monochloracetic acid, 346
Monochlor benzol, 409
Monoclinic system of crystals, 195
Monohydrogen phosphate, 160
Monostearin, 386
Monvalent elements, 173
Mordant of alumina, 223
Morphine, 429
Mortar, 217
Mountain limestone, 228
Mucic acid, 397
Multiple proportions, 58
Muntz-metal, 266
Murexide, 383
Mustard, oil of, 388, 405
Mycoderma aceti, 3:52
Myronic acid, 300
N.
Naphthalin derivatives, 421
Naphthalin group, 421
Naphthalin yellow, 422
Naphthol, 422
Narceine, 429
Narcotine, 430
Nascent state, explanation of, 104
Nebulae, constitution of, 288
Neurine, 330
New metals discovered, 282
Nickel, properties of, 244
Nickel, salts of, 244 .
Nicotine, 427
Niobi.im, 252
Nitrates and Nitrites, 74
Nitre, 201
Nitric acid. 63
Nitric oxide, '72
Nitro-ferrocyanides, 377
Nitrogen, 49
Nitrogen and hydrogen, 74
Nitrogen and oxygen, combination
of, 62
Nitrogen and oxygen, compounds of.
Nitrogen bases, 335
Nitrogen, determination of, 302
Nitrogen dioxide, 72
Nitrogen monoxide, 6g
Nitrogen pentoxide, 68
Nitrogen tetroxide, 74
Nitrogen trioxide, 73
'^Mmmmmm
Is, 195
60
104
iination
inds of,
02
Nitro-hydrochloricacid, no
^itro-mannite, 302
Nitro-toluol, 412
Njtroprussides, 377
Nitrous acid, 73
Nitrous oxide, 69
{•"roxyl chlcride, 68
Nobel's blasting oil, ,85
Non-Iuminous gases,^97 '
J-on-mf-taLs and metals 6
^,on--atarated compounds, 2a r
Ijonyl compounds, 342 ' ^^'
Nordhausen acid, i^^
^^ormal and acid salts, 190
^»A- vomica, alkaloid of, 430
O.
Occlusion of gases, 186
Occurrence of the meial-, rSr
Octylene, 362
Octylene alcohol, ,65
Otnanthylidene. ggo"*
Oi of buter almonds, 415
O. of garlic, 389 ^
Oj of mustard, 389
Oil of vitriol, 133
Oils and fats, natural, 387
Oils essential, 426 ^ ^
^lehant gas, 96
Olefines, series of, 362
O eic acid, 390
Olem. 387
Opium alkaloids of, 428
Ores of iron, 240
Ores of the metals, 182
^•"ganic analysis, 299
Organic chemistry, 289
J^rganj compounds, density of -o-.
Organic matter in the air .7 ' "^ "
Organic radicals, 203 '^
Organic synthesis, 356
Organo-metallic bodies, ,4,
Orpiment, i66
Oxalic acid 92, 365
^xahc amides, 366
Oxalic series of acids 364
< 'xamic acid, 366
Oxamide, 366 "
Oxi-acids of sulphur, 129
Oxidation, 13 ^
"• '«rav,iin,, it/4
INDEX,
483
Oxidizing flame, 100
Oxyanthracene, 423
Oxychloride of phosphorus 162
Oxygen, discovery of^ I r
Oxvfen'nr^"'°^P'-^P'^'-''^^'«'iof,
Ov,^P^ necessary to life, 14
Oxyhydrogen blowpipe, 3,/
Ozone, action of, 170
Ozone in the atmo:.phere, 58
P.
Palmitic acid, 314
Palmitin, 387
Papaverine, 429
i'arabanic acid, 38?
Paracyanogen, 356
Paraffins, 334
Para-lactic acid, 368
Paraldehyde, 349-'
parchment paper, 403
Paste for coloured glass. 226
Pentacarbon series; 3 5t
Pepsin, 437 ^^
^erbromic acid, 119
Perchloric acid, 115
Periodic acid, X22
1 ermanently hard water, 218
Permanganic acid, 234
Peroxide of hydrogen! 48
Peroxides, 187 *> "^
Peroxides organic, 3^4
Pers alts of iron, 238
?:w£r52""-^^""^"^-^' 33t-3
Phenylamiiie or aniline, 410
Phocgene gas, 367 *
l^nosphamines, 339
Phosphites, 157' ^
phosphoric acids, 158
phosphoric acids, modification oi' ,r«
Phosphoric anhydnde, 157 ' '^
Phosphorous acid, 156 ^
phosphorous anhydride, 1=6
Phosphorus bases, 339 ^
Phosphorus and chionne. 162
r'nosnhni-iic o,,j 1 1 ' *_
Phosphorus m organic bodie^; 302
12
484
INDEX.
Phosphorus, oxides of, 156
Phosphorus oxychloride, 162
Phosphorus pentachloririe, i6a
Phosphorus pentoxide, 157
Phosphorus, properties of, 156
Phosphorus, sources of, 154
Phosphorus trichloride, 162
Phosphorus trioxidc, 156
Phosphuretted hydrogen, 160
Photographs, fixing of, 273
Photography by magnssiuia wire,
229
Phthalic acid, 422
Physical isomerism, 425
Physical isomerism of amyl alcohol,
332
Physical properties of gases, 23
Physical properties of the metals.
Picric acid, 409
'Pimelic acid, 364
Pipcridine, 427
Pitchblende, 242
Plants, action of, in sunlight, 81
Plants, functions of, 438
Plaster of Paris, 218
Plate glass, 224
Platinum chlorides, 277
Piatinum-lik'^ metals, rare. 278
Platinum, metallurgy of, 276
Platinum, occurrence of, 276
Platinum oxides, 277
Plumbago, 82
Poisoning by arsenic, 164
Polyatomic radicals, 293
Polyethylene glyculs, 361
Polyglycerins, 387
Polymerisni, example of, 298, 345
PopPYi juice of, 428
Porcelain, 227
Porcelain clay, ^24
Potash, 199
Potash alum, 223
Potash-lime-glass, 225
Potassium, 197
Potassium aurate, 275
Potassium bichromate, 246
Potassium borofluoride, 153
Potassium carbonate, 200
Potassium chlorate, 202
Potassium chlorate, composition of,
15
Potassium chloride, 20a
Potassium chloro-chromate, 248
Potassium compounds, sources of,
198
Potassium cyanide, 375
Potassium ferrate, 239
Potassium ferricyanide, 377
Potassium ferrocyanide, 375
Potassium hydroxide, 199
Potassium iodide, 203
Potassium nitrate, 201
Potassium oxides, 199
Potassium perchlorate, 115
Potassium salts, characteristics of,
* 203
Potassium-silico-fluoride, 152
Potassium tartrate, 372
Potato brandy, 331
Potato starch granules, 401
Pressure of the air, 51
I'rimary alcohols, table of, 314
Primary propyl alcohol, 32Q
Prismatic analysis, 278
Proof spirit, 323
Propionitril, 327
Propyl alcohols, 329
Propylamine, production of, 327
Propylene, 362
Protagon, 437
Protosulphate of iron, 237
Prussian blue, 376
Prussic acid, loi, 373
Purpurine from madder, 423
Pyntes, iron, 238
Pyrocatechin, 411
Pyrogallic acid, 418
Pyroligiieous acid, 351
Pyrolusite, 234
Pyrophosphorlc acid, 159
Pyrotartaric acid, 364
Pyroterebic acid, 390
Q.
Quadratic system of crystals, 19a
Quantitative analysis, 15
Quantivalencc of the e.ements, i68,
171
Quartz, 146
Quicklime, 217
Quicksilver, 268
Quinidine and quinicine, 43a
Quinine, 431
Quinone, 412
~I I^ VjU,» ^ •'
INDEX.
R.
485
Racemic acid, 371
Radjcali, compound, loi
KadicaJs, organic, 293
. Kain, cause of fall of, 56
Rapeseed oil, 790
Rational formula:, 20;
Rei^lgar, 166
Reaumur's scale, 27
Red lead, 260
Red liquor, 352
Red oxide of copper, 268
Ked oxide of mercury, 260
Red prussiate of potash, 377
Reducing flame, 100
1-efining of iron, 242
Regular system of crystals, 102
Resins and balsams, 426
Resorcine, 412
Respiration and animal heat, 439
Reversal of bright lines, 287 ^^^
Khombic sodium phosplnte, i=;8
Rhonribic system of crystals, 195
Rocellic acid, 364 ^^
Rock crystal, 146
Kosanilme, 412
Rubiatinctoria, or madder, 42,
Rubidium and caesium, 212
Ruby, 223
Rutile, 252
Rutylene, 390
S.
Saccharic acid, 397
Saccharine bodies, 393
bafety lamp, xox
Sal-ammoniac, 76
Salicin, 404
Salicyl aldehyde, 416
bahcylic acid, 416
Salicylic group, 416
Sahgenine, 296, 416
Salt, definition of, 67
Salt-cake process, 206
halt glaze for earthenware, 226
Saltpetre, 201
Salts, acid and neutral, 132
oalts, formation of, 1S8
Sand, 146
Saponification, 385
Sapphire, 223
Sarco-lactic acid, 368
SaJTOsine, 383
Saturated compounds, 290
Scheele s green, 260
ocheelite, 253
Sea salt, 205
Sebaic acid, 364
Secondary alcohols, 315
Secondary propyl alcohol, 330
Se enic acid, 144
>e enious acid, 144
Selenite, 218
Selenium, 143
Selenium dioxide, 144
belenium trioxide, 143
^elemuretted hydrogen. X45
Silicates of the metals, 147
Sihciuretted hydrogen, 148
b; ico-formic anhydride, 146
Silicon, 146 *
Silicon carbon compounds, :, 12
Si icon chloroform, ISO ^^
Si icon dioxide, 146
Silicon ethyl, 342
bi icon oxychloride 150
Silicon tetrachloride, 149
Silicon tetrafluoride, 150
bi ico-nonyl compounds, 342
Si ver, alloys of, 272 ^"
bilver bromide, 273
Silver chloride, 273
Si ver, extraction of, 269
Si ver from lead, separation of 271
Silver glance, 274 "o'. -«/i
Silver nitrate, 273
Silver oxides, 272
Silver, reactions of, 274
Simple and compound substances ^
Snus composition of, 288 ' ^
olaked hme, 217
Snow, formation of, 56
boap, formation of, 384
boda-ash manufacture, 207
boda bicarbonate, 210
ooda ciustic, 125
Soda crystals, 210
SoJa-lime-g!ass, 224
boda waste, 220
Sodium arsenates, 165
godium arsenite, 164
bodium carbonate, 206
bodium chloride, 2c?
486
INDEX.
Sodium hydrogen carbonate, 210
Sodium hydroxide, 205
Sodium hypochlorite, in
Sodium hyposulphite, 211
Sodium ir the sun, 287
Sodium lines reversed, 287
Sodium metaphosphate, 160
Sodium nitrate, 210
Sodium oxides, 205
Sodium phosphates, 158
Sodium, preparation of, 204
Sodium p\ rophf)sphate, 159
Sodium salts, characteristics of, 21 1
Sodium silicate, 211
Sodium stannate, 251
Sodium sulphate, 211
Sodium sulphide, 21 r
Solar and stellar chemistry, 285
Solar spectrum, 286
^Solder, plumbers', 252
Solubility of gases in water, 86
Solubility of salts in water, 48
Specific gravity of the metals, 177
Specific heat and atomic weight, 179
Spectra of alkalies, 285. See/nmtis-
piece.
Spectroscope, description of, 283
Spectrum anah sis, 280
Spectrum analysis, delicacy of". 282
Spirea nlmaria, oil of, 416
Spirit, methylated, 323
Spirits, alcohol in, 323
Sporules in fermentation, 399
Standard gold, 275
Standard temperature and pressure,
^ 30 .
Stannic acid, 251
Stannic chloride, 252
Stannic oxide, 251
Stannous chloride, 251
Stannous oxide, 251
Starch, 401
Starch granules, 401
Starlight, lines in, 288
Steam, composition of, 35
Steam decomposed. by inm, 20
Steam, latent heat of, 43
Stearin, 387
Steel, 242
Stellar chemistry, 288
Storax, 419
Strontia, 220
Strontium and its salts, 220
Structure, cellular, 191
Structure of flame, 98
Structure, organized, 2S9
Strychnine, 430
Strychnos, alkaloids of the, 430
Styrol or cinnamol, 420
Suberic acid, 364
Subphosphate of sodium, 15S
Substitution products, 291
Succinamidc, 369
Succinic acid, 368
Succinic anhydride, 369
Succinimide, 369
Sucroses, 394
Sugar, 394
Sugar of lead, 260
Sugar of milk, 396
Sugar refining, 394
Sulpharsenates, 107 *
Sulpharsenites, 107
Sulphates, 125, 137
Sulphides, 125
Sulphites, 131
Sulphocarbamidc, 382
Sulphocarbonates, 365
Sulphocarbonic acid, 365
Sulphocarbonyl comfourids, 3S1
Sulphocyanic aci ', 378
Sulphovinic acid, 328
Sulphur, 125
Sulphur and hydrogen, 138
Sulphur and oxygen, 128
Sulphur dioxide, 129
Sulphur in organic bodies. -02
Sulphur, oxi-aclds of, 129 "
Sulphur, purification of, 127
Sulphur trioxide, 132
Sulphuretted hydrogen, 140
Sidphuric a<;id, 133
Sulphuric acid, tests for, 139
Sulphuric anhydride, 132
Sulphurous acid, 129
Sulphury! chloride, i ;o
Fun, storms in the, 288
Sunlight decomposes carbonic acid,
14.
Sunlight, properties of, 285
Superphosphate of lime, 154
Sweet spirits of nitre, 327
Symbols, explanation of, 15
Symbols of the elements, list of, 7
Synaptase, 404
Synthesis, 356
Synthesis, de/initfon of, i.;
Systems of crystallog^raph?. ;/,'
T.
tSI^ ""l ^'''°''°'■'' '-'"^i acids. 3r4
?jSf°ff'^"?entary bodies^''*
J^abJe of tensions, 46
Tannic acid, 405
iannm, 405
•lantalum, 251
Tartar emetic, 372
tartaric acid, 370
i aurin, 438
Tellurates, 145
Telluric acid, 145
lelluriuin, 145
Tellurium dioxide, 145
re lunum trioxide, 145
Jellurous acid, 145
lemporarily hard water, 218
tension «f aqueous vapour, 4 =
Terebene^nd its isomers, 4'4
lertiaryaJcohols,3i6 ' ^ *
lests for hydrocyanic acid, 374
iests for iron, 239 ' "'*
lests for nitric acid, 66
^etra-ethyl-ammomum, hydrate- q,^
Tetravalent alcohols, 3^1 ' ^^^
Tha he salts, 264 ' ^^'
'ru V "■'' -^a'^s, 262
i ha hum alum, 263
J ha hum oxides, 262
1 hallium, properties of, 26^
^ hebauie, 430
ineine, 433
Theobromine, 433
1 heory, atomic, 60
1 hermometers, 25
J piacetic acid, 340 q„
Tin dichloride ^5^ ''^
J^^'^al, 153
im mordant, 251
Tin, ores of, 250
rm, oxfdes of, ^5,
J in plating, 252
Aiii ^..vpajc ijquor, 251
INDEX.
Tin, reduction of, 250
lin sa ts, 251
1 m sulphides, 252
iin tetrachloride, 252
iKanmm, 252
tobacco, alkaloid of, 427
To ujc series, 412 ' * ^
To u.d.ne, 412
■loluol, 406
Toluol or methyl benzol .12
Tri-acetm, 386 ' '''^
inad radicals, 176, 294
1 riatomic radicals, 384
Trlr.'^T P'^o^Phoric acid, ,52
Incarbon series, 329 ' -"^
Tncarbon series, hg„re of, 202
1 rich oracetic acid, 346 ' ^
Trichlorhydrin, 385 ^^
i richnic system of crysta's t, fi
Tncyanimide, 378 ^^ ' '^^
^nethyj phosphine, ^^^c,
Tnethylamine, 335 ^^^
^nethyhn, 387 ''^^
rnmethyl carbinol, 317
T,nmethylamine, 338
Tnnitrin, ^85 "^
Trinitro-cel'ulose, 403
Irinitro-glycei-in, 38s
1 nnitro-phenoi, 409 ^
Tristeann, 3^7 ^
Trivalent elements, 168
lungstates, 253
^ungsten. 253
J iingsten trioxide, 25,
Turnbull's blue, -^jj "
Turpentine and its isomers .,e
Type metal, 254 "'"S 4?5
U.
487
Uranite, 248
Uranium, 248
Uranium, oxides of, 248
Urea, 379 4**
Ureas, compound, 380
it"- ^"'' 380.
•-_nnc, compusition of, 438
Use of symbols, 15 ^"^
483
INDEX,
V.
Valero-lactic acid, 364
Valerylene, 390
Vanadates, 258
Vanadium, 257
Vanadium pentoxide, 258
Vanadyl chloride, 258
Vapour density, 306
Vervacite, 233
Vegeto-alkaloids, group of, 427"
Ventilation of rooms, 85
Verdigris, 352
Vermihon. 370
Vitriol, white, 231
Vola'Jle organic compounds, 305
Voltameter, 26
\
W.
Water, 33
Water, action of, on lead, 259
Water, decompositioc of, 19
Water formed from hydrogen, 22
Water frozen by evaporation, 44
Water, hardness of, 218
Water of crystallization, 48
Water, physical properties of, 39
Water, synthesis of, 34-38
Wax, bees', 335
Wax, Chinese, 334
Weighing, mode of, 4
Weight, molecular, 303
Weights and measures, metric system
of, 23
Weights and measures, ubles of,
„,444{ 445,
Weights of gases, calculation of, 61,
472
Wheaten starch, 402
Whey, 43^
White indigo, 333
White lead, 260
White precipitate, 270
Window glass, 224
Wine, composition of, 438
Wines, alcchol in, 323
Winter green oil, 317
Wolfram, 253
Wood spirit, 317
Wrought iron, 235
Wrought iron, manufacture of, 242
Xyloidlne, 403
Xylol, 406
Yeast plant, 399
Yellow pru!>siate of potash, 375
Zeolites, 224
Zinc ethyl, 343
Zinc, ores of, 230
Zinc, properties of, 230
Zinc salts, 231
LoHdoHi PrinUd by K. Clay, Son.', and Taylor.
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