^^!.V!^. IMAGE EVALUATION TEST TARGET (MT.3) 1.0 I.I 11.25 ■iilM 12.5 |50 "^^ lilHM £ L£ 12.0 U 11.6 I V V] ^c^l PhotDgraphic Sciences Corporation 33 WEST MAIN STREET WEBSTER, NY. 14580 (716) 872-4503 4tJ- V CIHM/ICMH Microfiche Series. CIHIVI/iCMH Coilection de microfiches. Canadian Institute for Historical Microreproductions / Institut Canadian de nnicroreproductions historiquas Technical and Bibliographic Notas/Notas tachniquas at bibliograph^quaa Tha Institute has attamptad to obtain tha bast original copy available for filming. Faaturas of this copy which may be bibliographically uniqua, which may altar any of tha images in tha reproduction, or which may significantly change the usual method of filming, are checked below. D Coloured covers/ Couverture de couleur f~~| Covers damaged/ Couverture endommagie □ Covers restored and/or laminated/ Couverture restaurie et/ou pelliculAe □ Cover title missing/ La titre de couverture manque □ Coloured maps/ Cartas gAographiques en couleur □ Coloured ink {i.e. other than blue or black)/ Encre de couleur (i.e. autre que blMue ou noi que blMue ou noire) trations/ Planches et/ou illustrations en couleur Bound with other material/ Ralii avec d'autres ducumants r7] Coloured plates and/or illustrations/ I j Bound with other material/ D D D Tight binding may cause shadows or distortion along interior margir*/ La re liure serr^e peut causer de I'ombre ou de la distorsion le long da la marge intirieum Blank leaves added during restoration may appear within tha taxt. Whenever possible, these have been omitted from filming/ II se peut que certaines pages blanches ajout«es lors dune restauration apparaissant dans le texte, mais, lorsque cela itait possible, ces pages n'ont pss 6ti filmies. Additional comments:/ Commentaires supplin.artsires: L'Institut a microfilm* le mailleur exemplaire qu'il lui a *t« possible de se procurer. Les details de cet exemplaire qui sont peut-^tre uniques du point de vue bibliographique, qui peuvent modifier une image reproduite, ou qui peuvent exiger une modification dans la m«thode normale de fllmage sont indiquAs ci-dessous. D D Coloured pages/ Pages da couleur Pages damaged/ Pages endommagias □ Pages restored and/or laminated/ Pages restaur^es et/ou pelliculies ^ Pages discc'oured. stained or foxed/ Pages d*color*es, tachetAes ou piquies Pages detached/ Pages d*tach*es BShowthrough/ Transparence r~j Quality of print varies/ Qualit* inigala de I'impression Includes supplementary material/ Comprend du materiel suppl^mentaire Only edition available/ Seule Edition disponible Pages wholly or partially obscured by errata slips, tissues, etc., have been refilmed to ensure the best possible image/ Les pages totalement ou partieHement obscurcies par un feuiltet d'errata. une pelure, etc., cnt iti filmies i nouveau de facon d obtenir la meilleure image possible. This item is filmed at the reduction ratio checked below/ Ce document est film* au taux de riduction indiqu* ci-dessous. 10X MX 18X 22X [ 26X J 30X 12X 16X 20X 24X 28X 32X examplaire rar. Las details :re uniques du peuvent modifier /ent exiger une male de filmage ited/ foxed/ }u piquies iai/ nentaire jred by errata 'efilmed to / iCement ata. une peiure. de facon i tible. OX 32X The copy filmed here has been reproduced thanks to the generosity of: National Library of Canada The images appearing here are the best quaiity possible considering the condition and legibility of the original copy and in keeping with the filming contract specifications. Original copies in printed paper covers are filmed beginning with the front cover and ending on the last page with a printed or illustrated impres- sion, or the back cover when appropriate. All other original copies are filmed beginning on the first page with a printed or illustrated impres- sion, and ending on the last page with a printed or iilustrated impression. The last recorded frame on each microfiche shall contain the symbol — ^> (meaning "CON- TINUED"), or the symbol V (meaning "END"), whichever applies. Maps, plates, charts, etc. may be filmed pt different reduction ratios. Those too large to be entirely included in one exposure are filmed beginning in the upper left hand corner, left to right and top to bottom, as many frames as required. The following diagrams illustrate the method: 1 2 3 L'exemplaire filmd fut reproduit grdce 6 la gdn^rositd de: Bibliothdque nationale du Canada Las images suivantes ont 6t6 reproduites avec le plus grand soin. compte tenu de 'a condition et de la nettet6 de l'exemplaire film6. et en conformity avec les conditions du contrat de filmage. Les exemplaires orlginaux dont la couverture en papier est imprimde sont filmds en commen^ant par le premier plat et en terminant soit par la derni6re page qui comporte une empreinte d'impression ou d'illustration. soit par le second plat, selon le cas. Tous les autres exemplaires orlginaux sont filmis en commenpant par la premidre page qui comporte une empreinte d'impression ou d'illustration et en terminant par la dernidre page qui comporte une telle empreinte. Un des symboles suivanti^ apparattra sur la dernidre image de cheque microfiche, selon le cas: le symbole — ^ signifie "A SUiVRE", le symbole V signifie "FIN". Les cartes, planches, tableaux, etc., peuvent dtre filmds A des taux de reduction diff^rents. Lorsque le document est trop grand pour dtre reproduit en un seul clich6. il est filmd A partir de I'angle supdrieur gauche, de gauche d droite. et de haut en bas. en prenant le nombre d'images rdcessaire. Les diagrammi^s suivants illustrent la m^thode. 1 2 3 4 5 6 mm wmm wmm mm M \\ » % 14^ 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. 1 ! mssssssfst^j" N "'sw'WBTrtr-ft.K: N «* Mt- ^- i • I r\i I CO X H cc < UJ LJ < CO UJ o X X u Ui -J < -J < V) UJ I H u. O I CO c^ < ^ Li I UJ i H u. O < cc H o UJ CL CO "•■ m I :^ S 1*5 ^ '' '^AkYGHEMlSlR ^ 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 " '''^''^•#^l^n-n.',.;f^fc/ fc' f h r,i - 1,^ «1 « *o fs *'; i^ f' -5 4 M K i h i 1 .'i 1 1 i| f ' tHiiMuJi feL fc 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 " ■ 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 . /^^ ,„? ' ''^ ''^«" 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"^}^^" « 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,stm>«^«/; 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 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 , 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'irN ''■■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 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-^^^' f^^. « ^ aqueous vaDour- if " "'\^^^'^^ y»'^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;-''."' '^''' '°?" ^"''^'''^ ^"'^ 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' "'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' °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^/^^«/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'*^'^''<'«' ^". 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. /?-' >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 ""'"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 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 *""*""■ '"°'"''^' '^«'"' - 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-^ 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„ ^' °'^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, 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 ^ ^^

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 ^ 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«,//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^^ ^ ^^.^ ^^^ ^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 ^^ » 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 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 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 -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 "? ^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 «> 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,„^ ? ^ 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 u 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^gCoSiSf -^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./'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 ^•« "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 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<,«^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«« °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 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 © >*< la o *- u u u u-u u u o o 1-1 u o 'I* Ik CO u I I oo "'"'^« >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. • ''''°"' '=' 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'<»«/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 ^' '°'" 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 ^"- -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.^ \^^^ ^ ) 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' "'^ «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/^ 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"''''=^ "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■■<* 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 ^ 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 '^""« + ( 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 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 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 *^. " ^^^ ^^'^»"" ^ 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 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/;/'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, •I ^^ CO tj 2 ^ a -5 < •J u :<; u d P >• PQ CO W en < O o u W H w 1^ II w W H o ^ o u H W o a» W en < ■yi W2' ■♦00 « •♦ ■* M fOOO N ■4- N M rooo N N M moo <) N M ro Q Vb N M O 0>O N b b b MD J3 OONVO>niOOOQ vooo Mvo mvoO Q tJ-vo 00 M vo lo in m ■«^\o oc - vO lo m §io ■<*-vo oo M vo >n O >o ■♦"O eg M \o O >n -"t-MD 00 M bbbb*'oV0 O o b b '• 0» rovo O 5n "1 H O CTv M O O (A .2 o ^11 00 O ' C4 CO ro w 8? 0\ N O Q Q Q 00 O On N O Q 00 0\0\fi O 00 O 00 On ON N N 00 O 00 0\ O^ ro N 00 p 00 p\ CO « 00 b 00 ro N 00 o CONOO ro « ro «5 u H »■* H 00 On O ro t>. O t». On I ON ro tx o t^ c _ ro On ro t>% O f* On i O ro 0\ ro t^ p t>. I b b ro ON ro V«. b CO On ro f^ CO ON ro ro On CO S?*3" o o o t. 2 £ u « 4J "^i? ^^ 00 Z On o •„ u t3 u e ^ •a. 5 g^ UQ -^ o^ •♦ '* •<• Th Ov On On h> ro T^ JO o C) ro II II U Pi cn O C/3 & CO < C llfa <5 o\ ^00 . bo a> T) C CJ OCO _^ ^« . boet.D t3-sc/3 »S^II ro O 0> 00 On m ro N On lOOO 00 Ov ro N ro looo p _ONrO b CO •o ON ro ro Q rovo ro " . PI b O roNO vfi ro p» On O ro M v» ro M On'o M VQ M ON ro N ro On ■♦OO On ro M vS 0\ ■«^ Tl- On ro O NO •< M t>. ■* O VO M t> o O > (n< H H Ii •rf-S c3q o"o" coco ^« ro On H On lOOO ;*.« lb C3> "^1 JSSK ^|8^' — CO N' "'I Ik «. ■* 2 o 00 C *i ro'' O C i< ^S.^H ooo f: cil!'^ H J < 'J fa w c/) <^ W fO 4> •M On o HH I, rO "c3 4-> (J O^ « •coo J3 "S N O IS "5 -»mi»f> «•»'=' ro 00 ■♦ b b N CO -J-OO 1 cr, M 1 On ■* On m 1 8^ ■n '"I t>. ■* OVO 1 HI t> o M • • • . M U b ^ u a m V cr u in 4J s § s* M 8 S M 4J it H o 13 c3q CO" H On lb C3> »:s(>=< WEIGHTS AND MEASURES, "'Ilia P p p p « t^ y> _M o o o b b M Vxio .2.5 «^y JSII O O C4 t^ INI/) 8 8^% 8 fN 4) ^.9 ^^ J* CO Tt-H ij. H «nn5 O t^ tx S 5- P P M JtNVp p JN tN O H VvNb b tN M tvVO " a^8. ^oo ■>♦• N lo o o •1 tx .% M rx 4-> (J o^ « •coo J3 a tNC ^11 N tNVO 00 H IS. ^ I «n f) M vo >ooo o §ro lo fo M VD inoo ro lO ro IS vo ir> Q ro «rt m w vn . P p roiomn O b b Vo in Vf) fO IT) o ro U2jg p txoo -^ M c< 00 N 0\VO 00 I*- S M Q H o^vo 00 ■♦ M g o w o>vo — ■ vVO oo ■♦ 8 - o o o o b o b b tfi ^ JxH lf)N ION 0\-* S 5^2 !?" "^H ON o N rx o «o M lo M O N tN O m H - \P ." P N tN o »o o o NO M b "pj Vn b VO M O N tN *0 M O N NO M O VO H u N O ^, O T(-vc N M N N N O •'fVO N H M (N o o ■*vo n O ■♦VO N O ■♦ N N O b M N c II t— I " NN lOM tN(Y)(x(^ CO N H lo o r*. rp N M in o P ro N M lo 8 O o b b H O 5; 2 Ji f^ ->-TO JO 8 >0 ■<<- fO C) .-O ^00 CO p ... IT, ^ ro N rn ■* O H 0 ro rON ■♦00 ^2 b H IMl ra O O - SUQOQSS:?' 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 // ^ .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 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°" 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- 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?"'°" °' ''^^^' ^^ 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 hydriiamond, 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 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. u t i M It