LIBRARY OF THE UNIVERSITY OF CALIFORNIA. GIFT OF ? PROF. W.B. RISING . Class f & I CHEMICAL PRIMER: AN ELEMENTARY WORK FOK USE IN SCHOOLS BY S. P. MEADS. OAKLAND, CAL. : PACIFIC PRESS PUBLISHING HOUSE, TWELFTH AND CASTRO STS. ENTERED ACCORDING TO ACT OF CONGRESS IN THE YEAR 188*2, BY S. P. MEADS, JN THE OFFICE OF THE LIBRARIAN OF CONGRESS, AT WASHINGTON, D. C I'ACIFIC I'RRSS, PRINTERS, bTKREOTYPKKg AND 15INDBH&, OAKLAND, CALIFORNIA. PREFACE. PHIS Primer has been prepared for use in those High Schools that can give to chemistry only one term's work. It has grown out of the needs of the class-room, as I have felt them. Its statements are necessarily somewhat narrow, confining the pupil to general rules. Refined accuracy means a treatise, not a primer. The book is as accurate as pains- taking can make a work of its aim and scope. I have given in its pages as much as I think the average High School class can digest in a single term, and I hope my fellow-teachers will carefully examine the plan throughout before passing judgment. I have freely consulted whatever chemical works were within my reach, especially Attfield, Roscoe and Schorlemmer, Eliot and Storer, Appleton, and Barker. I am greatly indebted to Prof. W. B. Rising for his kindness in helping me down from the fence upon the right side in not a few instances indeed, I might say over the fence, in some cases. My thanks are due my worthy Principal, Mr. J. B. McChesney, for his uniform encouragement. I am under lasting obligation to my esteemed co-laborer in the High School, Mr. C. B. Bradley, for his patient assistance. Many ambiguous and obscure state- ments, that came too carelessly from my pen, have been made clear and intelligible by his scholarly criticism. Natural Science Dept., S. P. MEADS. Oakland High School, May 1, 1882. 237410 Brief Suggestions-Mixed. 1T|O not allow pupils lazily to pronounce the symbol or the U formula instead of the name; i. e. : wherever "H" occurs, see that it is called hydrogen Have the pupils copy the two Reference Tables (pp. 16, 28) upon cardboard, and allow them the free use of these for the entire term. Never compel them to memorize formulas, atomic weights, strength, etc. It is as important to know what not to remember, as to know what should be remembered, since the former comprises by far the larger portion of any text- book Let the pupils perform all experiments (except, perhaps, a few difficult ones, or for the sake of taking your turn with the class) in presence of the class, explaining each experiment as it ^proceeds. It takes time, but it is the only way to teach chemistry where a table for each student cannot be provided. If you haven't time, omit half the experiments to accomplish this result. Assign to separate pupils one experiment each a few days beforehand. The experiments may be performed upon a redwood (plank) table (see FRONTISPIECE), costing not over three dollars Every experiment teaches something, and the sooner you can impress this fact the better. While you should make every experiment as impressive as it can be made, get the pupils through the babyhood which craves noisy or showy experi- ments, as early in the term as possible See that a number of larger works upon chemistry are at your desk for reference. After you have passed the "Reactions," encourage any pupils who may show a special liking for the science to work out a number of solutions (not too complex, and mixed by you) by the Analytical Charts Teach pupils to use small flasks and small quantities of chemicals. It isn't necessary to burn a forest to prove that hydrocarbons are combustible, nor to blow up a continent to prove a substance explosive Don't be afraid to teach anything contrary to the text, if you have good authority for it ; but let disputed points alone Teach any simple principles beyond the text, instead of others more com- plex omitted; but don't teach intricate matter outside of text, else the result will be pupils will know neither the text nor the "intricate matter." Use the metric system throughout; it is the system. Use either thermometer. The OKNTIORAPK is used in this book. INDEX PAGE. ACID ACETIC 121 " Benzole 132 " Boracic 85 ' Carbolic 121,135 " Carbonic (H, 140 " Citric 124 " Gallic 124 ' ' Hydrochloric 73 " Lactic 141 " Malic.. ..124 Muriatic. . . . Nitric Oleic Oxalic Palmitic .... Picric Prussic Salts Stearic Sulphuric. . . Tannic. . 73 58 120 123 .....129 127 . .50, 76 76 .129, 131 . ... 82 ..124 " Tartaric 124 Acids 24, 134 Aconite 126, 135 Air 32, 40, 56, 65 Albumen 122, 133, 138-9 Alcohol 120, 121 Alkalies 24, 134 Alkaloids 124, 135 Alloys 90, 112 Aluminum 105, 128 Amalgam 90 Amber 182 Ammonium 60, 1 1 1 Ammonia 00 " Type 125 Anaesthetic 57, 120, 121 Analytical Charts 142, 143 Aniline 125-6-7 Antidotes 132 Antimony 90 Antiseptic.. 109, 110, 120, 121, 131 Aqua-f ortis 58 Aqua-regia 59 Arsenicum 87, 133, 134 Atomic Theory 10 etc. Atmosphere 32, 46, 56, 65 Atoms 10, 13 BALSAMS 132 Barium 1 07 Bases , 24, 124 Beer 120 Basic Salts 78 Benzol 67, 122 Bessemer's Process 101 Binary Compounds 11, 17 Bismuth.. ..103 ; . ' . / ,V I) K X. Bleaching PAGK. I'l 81 Combustion Copper Corrosive Sublimate. . Cotton J'AOE. 32, 47 99 97 117 Blowpipe Borax 51,68 85 Boroii. . 85 Brass 112 Cream of Tartar 1 23 1 24 Bread-Making Brimstone Bromine 122 80 74 Creosote. . . . . . 121 Cupellation. 95 Cyanogen . 76 Bronze 112 DAVY'S SAFETY LAMP. Deliquescence. . . 69 54 117 118 61 1 19 Bunsen's Burner 68 CALCIUM -Light Calomel 106 138 . <)6 132 . . .07, 131 132 92 118 Dextrine Dextrose Diamond Diastase Camphor Candles Caoutchouc Carat Caramel Diffusion of Gases. . . 51 56 Disinfectant Distillation .02, 71, 121 54 127 54 16 Carbon 61 . .01, 140 128 . .101, 102 117 106 EFFLORESCENCE Elements Essences Carbonic Oxide Carmine Cast-iron ...121, 131 59, 75 120 120 120 129 Cellulose Chalk Etchings Ether Ethyl Hydrate " Oxide FATS Charcoal 61 67 Chemistry of Candle. . . Chlorine Chloroform Chloral 121 121 . . . . 65 Choke-damp. . Fermentation Fireworks Flame Fluorine . . .119, 131 . . .107, 109 67 75 Chromium Cinnabar Clav 1)0 % inr: Coal gas .... 67 Formula, Empirical . . " Rational. . . . Fusil oil 116 116 121 Cobalt 104 1 ")R Coin 112 68 Fusible metal 103 <>7 102 67 Coke. . . . (lAJ.KNA Galvanized Iron (Jas Illuminating Collodion 117 121 Compound Ethers. . " Radical. IS INDEX. PAGB. Gelatin 122, 1'24 German Silver 11 Glass 86 Gluten 122 Glue 122 Glycerin 131 Gold 1)1 Graphite 61 Gum 132 Gun Cotton 117 Gunpowder 109 Gutta-percha 132 Gypsum 106 HALOGENS 26, 70 Hematite 100 Hydrocarbons 4? Hydrogen 49 Hydrogen Sulphide .83 INDIA-RUBBER 132 Indigo 127 Ink 71, 123, 124 " Printers' 71 Iodine 74 Iron 100 Tsomerism 116 LAUDANUM 126 Laughing-gas 57 Lead 97 Leather 124 Lime 106 Lime-Light 138 Linen 117 Litmus 24 Litharge 63 Logwood 128 Lunar Caustic 95 Lye 130 MADDEK 128 Magnesium 32 PAGK. Malt 120 Manganese 104 Marble 106 Marsh -gas .67 Matches 84 Mercury 96 Metals 91 Methyl Alcohol 1*20 Milk 118, 122 Miscellaneous Questions, 44, 79, 135 Molasses 118 Mordant 128 Morphine 126, 135 Mortar 106 NAPTHA 108, 109 Nascent State 61 Nickel 104 Nicotine 126 Nitre 109 Nitrous oxide 57 Nitrogen 55 Nomenclature 17, 23 OILS 129 Olein 129 Opium 126 Organic Acids 123 " Bases 124 " Chemistry 116 Oxides 33 Oxygen 45 Ozone 49 PAPER 117 Paregoric 126 Pearlash 108 Pencils 62 Petrifaction 86 Pewter 112 Phosphorescence 85 Phosphorus 84 INDEX. PAGE. Photography 95 Plants, Office of 65 Plaster of Paris 106 Platinum 93 Plumbago 61 Potash 108 Potassium 108 QUARTZ 86, 91 Quicksilver 96 Quinine 126 REACTIONS 32 Ref. Table 1 16 Ref. Table 2 28 Ref. Table 2 (con) 141 Resin 132 RochelleSalt 77 Rosin 132 SAGO 117 Sal-ammoniac 59 Saleratus 108, 123 Salt, Common 1 10 Salts 24 Salts, acid, etc 76, 78 Salts, Epsom 105 Salts, Glauber's 110 " Rochelle 124 Saltpetre 109 Sand 86 Selen-salts 78 Shellac 107, 132 Shot 112 Silicon 86 Silver 94 Soap 129 Sodium 10S Solder 112 Solution. . . 36 Spectrum Analysis. .112 Stalactites.. 106 Starch 117 Stearin 129 Steel 101 Strontium 107 Strychnine 126, 135 Sublimation 81 Sugar, Cane 118 " Grape 118, 139 " of Lead 98 Sulphur ; 80 Sulph-Salts 78 TAPIOCA 117 Tar / 67 Tartar Emetic 90 Tin 102 Turpentine 131 Type-metal 98 VERDIGRIS 100 Vermilion 96 Ventilation 65, 66 Vinegar 121, 134 Vitriol, Blue 100 Green 102 Oil of 82 WATKR 13,36, 52 " -type 24, 125 White-lead 98 Wines 120 Woody Fibre 117 YEAST ZINC . .123 .102 THEORETICAL CHEMISTRY. CHAPTER I. MATTER exists in three states: 1. Solid: Ex., iron, lead, ice. 2. Liquid: Ex., mercury, bromine, water. 3. Gaseous: Ex., hydrogen, air, steam. Nearly all substances ordinarily in the solid state may, by applying heat (and removing pressure), be made first liquid and then gaseous. Nearly all gases, by cold and pressure, may be made first liquid and then solid. A change which merely converts a solid to a liquid, or a liquid to a gas, or vice versa, however wonderful such change may be, is not a chemical, but a physical change. Ex., Ice may be heated and con- verted into water, a liquid, and then into steam, a gas. All such changes are studied in Physics, not in Chemistry. Chemistry deals with such changes only incidentally. The molecules (small, invisible particles) of a solid move with diffi- culty upon each other. The molecules of a liquid move readily upon each other, so that the liquid assumes the shape of the vessel holding it. The molecules of gas have an apparent repulsion for each other, so that a gas, regardless of its specific gravity (i. e. whether light or heavy), escapes from an open vessel and diffuses itself throughout the surrounding space. 10 CHEMICAL PRIMER. CHAPTER II. The Atomic Theory divides matter into: 1. Mass. Any portion of matter appreciable by the senses. 2. Molecule. The smallest particle of matter that can take part in a mere physical change. It may exist alone. 3. Atom. The smallest particle of matter that can take part in a chemical change. An atom does not exist alone. Atoms compose molecules; i. e., two or more atoms make a molecule. Chemistry treats of the atomic condition of matter and especially of atomic changes. It will be inferred from the definitions that a mass may be very large or exceedingly small, also, that the molecule and the atom are not visible even with the aid of the most powerful microscope, otherwise they would be "appreciable by the senses." Chemistry treats of more subtle changes than physics. If the mole- cule is not broken up and the atoms' set free to form new combinations, it matters not how violent, or how wonderful the change may be, it is purely physical and in no sense chemical. Of course, atoms "exist alone" during the instant of chemical change. One atom may rarely make a molecule. At this stage the pupil should fix the great rules, and not trouble himself with exceptions. THEORETICAL CHEMISTRY. 11 CHAPTER III. An Element is a substance whose molecules contain atoms of one kind only ; therefore it cannot be separated into two or more different kinds of substances. Ex., gold, lead, hydrogen. A binary compound is a substance which has two dif- ferent kinds of atoms in its molecule, and therefore, can be separated into two different kinds of substances. Ex., water, common salt. A molecule of hydrogen may be represented thus | H H j in which each H represents an atom and the boundary line simply the fact that the two atoms of hydrogen are bound together by chemical bonds into one molecule. A molecule of water may be represented thus | HOH | or more briefly, thus | H. 2 O | or still more briefly by omitting the boundary line, thus H 2 O. This means that in a molecule of watpr there are two atoms of hydrogen and one atom of oxygen. Practically it means that two parts by volume of hydrogen unite M'ith one part by volume of oxygen to form the binary compound which we call water. (Take this for granted now: we'll prove it by and by. See WATER, index). Thus, two gases unite to form a liquid. But this is a chemical change, because the atoms of the molecules of hydrogen and of oxygen are disturbed, their molecules being broken up to form new molecules of a different substance, water. The change may be repre- sented thus: | HH | I HH | -f | 00 j = | H,0 I | H 2 This means that two molecules of hydrogen and one molecule of oxygen break up into separate atoms and then instantaneously re-unite into two molecules of water. 12 CHEMICAL PRIMER. The atomic reaction (beginning at the instant when the molecules are broken up) may be written thus: H, + O H,O Two atoms | One atom One molecule of hydrogen. of oxygen of water, Chemical changes are called Reactions. For all practical purposes the atomic reaction is correct. As it is not nearly so difficult as the molecular reaction (first above) it alone will be used in this book. There are about sixty-seven elements known, and these may be considered the alphabet of chemistry. From these all chemical compounds are formed, as words from letters. A binary compound might be compared to a word of two letters. THEORETICAL CHEMISTRY. 13 CHAPTER IV. Atoms of different elements differ in three essential respects : 1. In weight. 2. In quality. 3. In strength. The First Difference needs no explanation. When we say that atoms differ in weight, we mean that they differ in weight. (Atoms of the same element have always the same weight). The Second Difference needs explanation. The quality of meat may be determined by eating it, and the quality is said to be good or bad. The quality of. cloth may be told by wearing it, and the quality of cloth is also said to be good or bad, as the case may be. The quality of an atom is determined by electricity, and the atom is said to be, not good or bad, but positive or negative. If a current of electricity from two or more of Bunsen's quart cups be passed through the binary compound water, the water will be decomposed and bubbles of gas will appear at each pole. If the gas from the positive pole be collected (see Fig. No. 1 ) and tested, it will prove to be oxygen. If the gas from the negative pole be collected and tested, it will prove to be hydrogen and will have twice the volume of the oxygen. NOTE. The water should be acidulated slightly with sulphuric acid. The hydrogen will always have a little more than twice the volume of the oxygen, because the liberated oxygen is more soluble in (the remaining) water than the hydrogen. The pupil may learn right here, that a gas can be dissolved in water just as well as a solid. The nature of a mere solution will be explained hereafter. 14 CHEMICAL PRIMER. Fig. 1. A A Platinum Ends (poles, or electrodes). The law of electricity being that "like electricities repel each other and unlike attract," as oxygen goes to the positive pole, it is negative to. hydrogen, and as hydrogen goes to the negative pole, it is positive to oxygen. Thus, by means of a battery acting upon their compounds, the ele- ments may be arranged with reference to their "quality," but an atom of an element is always positive or negative, not absolutely, but relatively. For example, if we arrange in line sixty-seven boys from north to south, the first boy would be a north boy to any other. The second boy would be a south boy compared with the first, but a north boy compared with the third. The tenth boy would be a south boy com- pared with the fourth, but a north boy compared with the fifteenth. Any boy would be a south boy to all boys north of himself, but a north boy to all boys south of himself. Thus, the elements are arranged inline according to their ' 'quality," oxygen standing first, being most negative. (See Reference Table No. 1). This difference in "quality" is of the utmost importance in chemistry. The Third Difference may be explained by an illustration. If one man can hold a 100 Ib. weight, we may call his strength one. Then, if another man can hold two 100 Ib. weights, his strength would be two, and it would take two of the first kind of men to match one of the second kind. If a third man can hold three 100 Ib. weights, his THEORETICAL CHEMISTRY 15 strength would be three, and it would take three of the first kind of men to match one of the third. But how shall we match the second kind of men and the third kind? Evidently, three of the second kind would match two of the third kind. If a fourth man can hold four 100 Ib, weights, his strength will be four; etc. The strength of atoms is measured, not by 100 Ib. weights, but by the strength of hydrogen atoms. The strength of the hydrogen atom is taken as one. The strength of those elements whose atoms each require one atom of hydrogen to match them is one; of those elements whose atoms each require two atoms of hydrogen to match them, the strength is two; of those whose atoms require three atoms of hydro- gen, the strength is three, etc. These elements are called respectively monads (1), dyads (2), triads (3), tetrads (4), pentads (5), hexads (6), and heptads (7). This strength of the atoms is often expressed adjectively by the terms, univalent (1), bivalent (2), trivalent (3), quadrivalent (4), pentivalent (5), etc. CHAPTER V. The names of the elements are abbreviated in chemical language. O is the symbol for oxygen, S for sulphur, Sb for antimony (Latin, stibium), etc. The dictionary will give the Latin name from which a number of the symbols are derived. The following Reference Table exhibits the symbols of the elements and the three essential differences of their atoms : REFERENCE TABLE No. 1, SYMBOL. QUALITY. Shown by order of iiaiues. ATOMIC WEIGHT. STRENGTH. Negative End. Oxygen 16 2 s Sulphur 32 2 N Nitrogen 14 3 fF Fluorine 19 1 |ci Chlorine 35.5 1 Bromine 80 1 1 / Iodine 127 1 LCK Cyanogen* 26 1 Se Selenium 79 2 P Phosphorus 31 5 As Arsenicum 75 3 Cr Chromium 52.5 2 B Boron 11 3 rfi> C Carbon 12 4 1 Sb Antimony 122 3 Si Silicon 28 4 H HYDROGEN 1 1 Au Gold 196.6 3 Platinum 197 4 * r Hg Mercury 200 2 (and Hg 2 a dyad) i ; Ag Silver 108 1 T Cu Copper 63.5 2 (and Cu 2 a dyad) Bi Bismuth 210 3 Sn Tin 118 4 Pb Lead 207 2 Co Cobalt 59 2 Ni Nickel 59 2 Fe Iron 56 2 (and Fe 2 a hex ad) Zn Zinc 65 2 Mn Manganese 55 2 Al Aluminum 27.5 (A1 2 a hexad) Mg Magnesium . 24 2 Ca Calcium 40 2 Sr Strontium 87.5 2 Ba Barium 137 2 f Na Sodium 23 1 1 K Potassium 39 1 (H^ Ammonium* 18 1 Positive End. (See Chap. VI). THEORETICAL CHEMIST R Y. CHAPTER VI. A binary compound is named by placing the positive element first and changing the ending of the negative into ide. EXAMPLE. Formula. Name. Na Cl = = sodium chloride. K 2 O = potassium oxide. It will be noticed that sodium and chlorine are both monads (see strength in Reference Table No. 1), and therefore it requires one atom of each to match the other in the molecule, as in the first example. In the second example, potassium is a monad (see TABLE), but oxygen is a dyad, therefore it takes two atoms of potassium to match one of oxygen in the molecule. Again, in putting dyads and triads together, we must take three dyads to match two triads in the molecule, a strength of two times three equaling a strength of three times two. EXAMPLE. As, S 3 Arsenicum sulphide. Again, two dyads must be taken to match one tetrad. EXAMPLE. C O 2 Carbon oxide. Five dyads must be taken to match two pentads. EXAMPLE. P.j O,-, phosphorus oxide. P 2 S 5 phosphorus sulphide. NOTE. Just as we sometimes say "the father of Mary," instead of "Mary's father," the older chemists say "sulphide of phosphorus," instead of "phosphorus sulphide. " (They also expressed the same by "sulphwretf of phosphorus, " or "sulphuretted phosphorus. ") 18 CHEMICAL PRIMER. Atoms of two or more elements bound together by chemical bonds so closely, as to act as one atom in the formation of compounds, form a Compound Radical. Two very important compound radicals are inserted in the Reference Table and linked with the elements with which they are closely allied. Their compounds with a single element are considered and named as binaries, though they contain three different kinds of atoms. EXAMPLE. K CN = potassium cyanide. (H 4 N) 2 S = ammonium sulphide. H 4 N CN ammonium cyanide. NOTE. The pupil should write the formulas and names of a great many binary compounds, putting the atoms together according to the strength in the Reference Table. Be careful that the multiplications make the positives match in strength the negatives, as in the examples. It does not matter if many of the compounds are merely theoretical. It is, however, a great gain at this point, to have as many binaries as combine according to the strength given in Fig 2. the Table, shown to the scholars. For instance, a substance might be shown and the class told that it was a compound of sulphur and sodium. They should then all write labels for the bottle containing it, giving formula and name, as in Fig 2. CHAPTER VII. Ic and Ous Binaries. These may be introduced by an illustration. In one of our eastern townships lived a man, who was afflicted with periodic insanity. When in his right mind (ordinarily), he had the strength of his brother. He could be called a monad. In one of his insane fits he carried three men upon his back over a gate five boards high. He became a very decided triad, you see. THEORETICAL CHEMISTRY. 19 Now, the Reference Table No. 1 gives the "strength" of chlorine one', i. e. as a monad, but sometimes it acts with a strength of three. i. e., as a triad (sometimes as a pentad, or even as a heptad). Carbon is given a strength of four, and this it ordinarily has, but sometimes it acts with a strength of only two. Thus, it forms two binary compounds with oxygen, CO 2 and CO. Evidently, if we say carbon oxide, we shall not know which is meant, because the name may apply to either. As a rule, an atom with an even strength never has an odd strength, also, an atom with an odd strength never has an even strength. The strength increases or decreases by twos. This will be noticed as we proceed. We must invent some way to distinguish the different compounds, when an element acts with different strengths. When the positive takes more of the negative, it has the ending ic, when it takes less of the negative, it has the ending OUS. EXAMPLE. C O 2 = carbonic oxide. C O = carbonous oxide. When the positive takes more of the negative, than in the ic com- pound, it has the prefix per (from hyper = more); when it takes less of the negative, than in the ous compound, it takes the prefix hypo (unden). EXAMPLE. (SO hypo-sulphurous oxide). S O. 2 sulphurous oxide. S O 3 sulphuric oxide. S 2 O 7 per-sulphuric oxide. NOTE. Per and hypo are sometimes prefixed to the negative instead of to the positive. The first example above is theoretical, there being no such free compound. Few elements form hypo- and per-binaries, and the pupil will be troubled very little with them. They are given here, so that if, in the larger text-books, he sees hypo- and per- binaries men- tioned, he may have some idea of what is meant. The scholar should here solve many problems, such as the follow- ing: 20 CHEMICAL PRIMER. 1. Put together sulphur and antimony to form two compounds giving antimony a strength in the first compound as in the Table, and in the second compound a strength of five (which it sometimes has). Name one ic, the other ous. Am. Sb. 2 S 3 antimonous sulphide. Sb 2 S5 = antimomc sulphide. 2. Put together iodine and mercury, giving mercury a strength, first, as in Table; second, as in the parenthesis of Table. Name. Ans. HgI 2 = mercuric iodide. Hg 2 I* mercurows iodide. NOTE. In this last compound, mercury seems to be a monad, *. e., it seems to change from the even to the odd strength. A few of the other elements do the same thing, as you will see. For practical purposes, this last formula has sometimes been written Hg I = mercurows iodide, but it is better to write as above. The ic and ous compounds of the same elements often differ very much in physical and chemical properties. You will see, by looking at the samples from the laboratory, that mercuric iodide is red, while mer- curous iodide is green. Again, carbom'c oxide is not poisonous, while carbonows oxide is poisonous. A binary may be named by prefixing the Greek numer- als (mon, di, tri, tetra, etc). In all cases where a mistake would be likely to occur, this very exact method is used. EXAMPLE. C O = = carbon monoxide, (ous.) C O 2 = = carbon di-oxide. (ic.) Fe 3 O 4 : = tri-ferric tetroxide. Fe 2 O 3 = = di-ferric trioxide. (ic.) NOTE. The older chemists used, as a rule, per and proto for ic and ous respectively, as: Fe O = protoxide of iron, instead of ferrous oxide. Fe 2 O 3 = peroxide of iron, instead of ferric oxide. Instead of ous, the prefix sub was also used, as: Hg, C1 2 = sub- chloride of mercury. Compounds, in which there were two of the positive to three of the negative, often took the prefix sesqui (one and one-half), as: Fe 2 O 3 = sesquioxide of iron. THEORETICAL CHEMISTRY. 21 CHAPTER VIII. Inspection of the following questions and the methods of solution will reveal the great value of the Atomic Theory to the chemist, and indeed, to the world of industry. 1. In 116 kilograms* of mercuric sulphide (Hg S) how much mercury? Hg = 200 atomic weight (see Table). S = 32 " HgS = 232 molecular weight. 232 kgs. of HgST= d 200 kgs. of Hg. 1 = ^2 of 200 kgs. of Hg. 116 " = of 200 " " of 200 = = 100 kgs. of Hg. Ans. - 2. How much lead chloride (Pb C1 2 ) could be made from 50 grams of lead ? Pb = 207 at. wt. C1 2 = 71 " Pb 01, == 278 mol. wt. 207 Pb = 278PbCl 2 1 " = T^T of 278 Pb 01, 50 = ^ T of 278 " 278 50 207) 13900 (67^ grams. Ans. 1242 1480 1449 31 "See metric system. 22 CHEMICAL PRIMER. It will be noticed that there are two distinct kinds of questions. The first gives the weight of the binary and requires the weight of the element. The second gives the weight of the element and requires the weight of the binary. In the first class of questions, of course, the answer is less than the given weight. In the second class the answer is more than the given weight. After obtaining the molecular weight by the addition of the atomic weights, decide whether your answer is to be greater or less than the given weight, aud arrange the first equa- tion below the molecular weight accordingly. 3. From one metric ton of the iron ore hematite (Fe 2 O 3 , ferric oxide), how many kilograms of iron could be obtained, provided the hematite contained 25 per cent, of earthy impurities, or waste? 1 M. T. = 1000 kgs. 25 per cent, waste leaves 75 per cent. 750 kgs. of pure ore. Fe 2 = 1!2 at. wt. O 3 = 48 " Fe 2 O 3 = 160 mol. wt. 160Fe 2 O 3 = 112Fe 1 " = T J TF ofll2Fe 750 " = ^f-g of 112 Fe = 55~ kgs. iron. Ann. NOTE. The pupil should perform very many problems similar to the above. To show one common process of getting the element from the ore, heat some lead oxide (litharge) on charcoal (carbon) in the blow- pipe flame. The carbon takes the oxygen from the lead, forming car- bonic oxide (C O 2 ) and leaves the lead free, i. e., not combined with any other element (See Exp. 50). 4. How much lead in 100 kgs. of lead oxide (Pb O)? Am. 92^f |. 5. One M. T. of lead would make how many kilograms of litharge? Am. 1077/oV- THEORETICAL CHEMISTRY. 23 CHAPTER IX A ternary compound is one having three different kinds of atoms in its molecule. Most ternaries contain oxygen as a connecting ele- ment; it is therefore omitted in the name. It is under- stood to be the connecting element, unless otherwise men- tioned (See Chap. XXIII). It is not omitted in the formula. A ternary is named by placing the positive first and (the O being omitted) the negative last, with the ending changed into ate. EXAMPLE. K 01 O 3 = potassium chlorate. H 2 SO 4 = hydrogen sulphate. As in binaries, we have different compounds of the same three ele- ments, and so must have different names. When the O is less (relatively to the negative) than in the ate com- pound, the negative takes the ending ite. Rarely the O may be less than in the ite compound, when hypo ite is used. Sometimes the O is more than in the ate- compound, when per ate is used. EXAMPLE. K Cl O = potassium hypo-chlorite. K Cl O. 2 = potassium chlorite. K Cl O>7 = potassium chlorate. K Cl O 4 = potassium per-cbloraff. 24 CHEMICAL PRIMER. As in binaries, the hypo- andper- ternaries are very few and will trouble the student very little. The ite compounds are also few in comparison with the ate. This will be a good rule for beginners: "Call every ternary an ate, unless you have reason to call it an ite." Name the following: H 3 PCX = ? Mff S(X ) Which is the ate and ,_ d --* 'Which the ite com- K NO 3 - Mg SO 3 = j pound? Ca2HO- " CHAPTER X. There are three great classes of ternaries, with which the scholar should early become familiar, viz. : acids, bases, and salts. Acids are generally sour, and turn blue vegetable colors (such as litmus) red. Bases (those that are soluble in water are called alka- lies) turn red litmus paper blue. Acids and bases are chemical opposites. They attack and destroy each other, forming salts (and water). This power of forming a salt with its opposites is the true test for an acid or a base. The test with litmus paper is a very good one and usually answers. NOTE. The pupil should here test a number of acids and bases with litmus paper. Of course, acids, bases, and salts may exist in either of the three physical states: solid, liquid, or gaseous. Solid or gaseous acids and bases must be dissolved in water before testing, or the litmus paper wet (which is the same thing). Acids, bases, and salts are said to be formed on the water-type, thus: THEORETICAL CHEMISTRY. 25 | H O H I = a molecule of water. | A negative element OH | = a molecule of an acid. | A positive element OH | = a molecule of a base. PA positive element Q a negative element [ = a molecule of a salt. In the above water type, by a negative element is meant one negative to hydrogen, and by a positive element one positive to hydrogen. In the Reference Table, if the element is above hydrogen, it is nega- tive in forming acids, bases, or salts; if below hydrogen, it is positive. Write the name of the following, and mark as acid, base, or salt. (Consult Table). K Cl O^ potassium chlorate =. salt. H 2 S O 4 hydrogen sulphate = acid. Ca 2 HO calcium hydrate base. Na 2 SO 4 = ? NaHO=: H NO 3 Mg a 2 PO7 = KNO;= NaClO,^ NOTE. The division into positive and negative elements is not always made at hydrogen. Thus, zinc is usually positive in forming by the water type, and Zn 2 HO zinc hydrate base, but rarely, when in pres- ence of a stronger positive element, as potassium: Zn 2 HO zinc hydrate becomes H 2 Zn O 2 = hydrogen zincate = an acid; and we have the salt K 2 Zn O 2 ~=- potassium zincate. So chromium usually by the water 3 CHEMICAL PRIMER. type acts as a negative element, and H 2 CrO 4 = hydrogen chromate an acid, but rarely chromium acts as a positive element, and we + have Cr 2 6 HO = chromium hydrate = a base. The pupil at this stage, however, should not attempt to deal with exceptions, but should treat the rule given as though it were absolute, and should consider all elements above hydrogen as negative and all elements below hydrogen as positive in the formation of acids, bases, and salts. After deciding from the formula, test all acids and bases by litmus paper, and thus prove the rule. This water type should be so thoroughly mastered, that, having the Reference Table before you, you can tell at a glance, on seeing the formula, whether the ternary is an acid, base, or salt. CHAPTER XI. It will be noticed that in the Reference Table four nega- tive elements and one compound radical are linked together. These elements are called the haloid elements (or halogens = salt-forming), because they form salts (and acids) with- out oxygen, I. e., they form binary salts and acids. EXAMPLE. H Cl = hydrogen chloride = a binary acid. Mg C1 2 = magnesium chloride = a binary salt. These salts and acids may be referred to the water type by counting in the missing oxygen, thus H Cl = hydrogen, a negf. and the mis- sing O = an acid. THEORETICAL CHEMISTRY. 27 Write the name, and mark as acid, base, or salt, the following: 4-- K 2 SO 4 = potassium sulphate = salt. + i K CN potassium cyanide = binary salt. , j H 4 N NO 3 = ammonium nitrate = salt. H I ? Mg 2 CN = MgS0 4 = CHAPTER XII. The following Reference Table No. 2 will be found a great aid in writing formulas of ternaries. It is to be used in connection with Table No. 1, the negative "groupings" in No. 2 being used with the positive (to H) elements in No. 1, and the positive groupings (all radi- cals) of No. 2 with either the negative elements of No. 1, or the nega- tive groupings of No. 2. The positive groupings in No. 2 being radi- cals, unite with a single element to form a binary, while the negative groupings in No. 2 not being radicals (in the same sense), unite with a single element to form a ternary, EXAMPLE. (C 2 H 5 ) 2 O = ethyl oxide (common ether) = a binary; but Mg CO 3 magnesium carbonate a ternary; and K HO = potassium hydrate = a ternary. NOTE. H, united with the hydrate grouping, gives H HO or H 2 O hydrogen oxide, a binary. The grouping HO is often considered a compound radical (hydroxyl) and its compound with an element is sometimes named as a binary. Ex: K HO = potassium hydroxide, instead of as in third example above. CHEMICAL PRIMER. REFERENCE TABLE, No. 2. Qnadriralent TRIVALENT OR TRIAD. BIVALENT OR DYAD. UNIVALENT OR MONAD. or Tetrad. A A. A GROUPIE NEGATIVE. HO = hydrate ros. POSITIVE. (Radicals. ) NO 8 = nitrate H 4 N == ammonium O 2 H 5 = ethy] 01 3 = chlorate 2 H 3 O 2 = acetate {C, 6 H 31 O 2 =palmitate >. ( ID Cite) s ' SO~ 4 = sulphate SO, = sulphite CO 3 = carbonate C 2 O 4 = oxalate C 4 H 4 O 6 = tartrate C 6 H 5 phenyl CH 3 = methyl GbHiii = amyl Cr O 4 = chromate ^ Se O 4 = selenate PO 4 = phosphate AsO 4 arsenate C 3 H 5 = glyceryl (in fats) AsO 3 = arsenite Sb O 4 = antimonate B O 3 borate C 6 H 5 O 7 = citrate . f \ Si O 4 = silicate P 2 O 7 = pyrophosphate THEORETICAL CHEMISTRY. It has probably been noticed that in the examples given in the previous chapters, all hydrates contain HO, which acts as a monad with reference to the elements that go with it, also, that all sulphates con- tain the dyad grouping SO 4 . To write the formula of any substance, whose name is given, as potassium carbonate, we first find the carbonate grouping in Table No. 2, and write it thus, CO 3 // , indicat- ing for convenience its strength by the two marks above. In Table No. 1 we find K has a strength of one ; placing this before the carbonate grouping, we have K'CCV'. But it takes two monads to match one dyad, therefore we must multiply K by two, and we have K 2 CO 3 for the formula required. Write the formula for magnesium phosphate ; phosphate grouping = PO 4 '" magnesium = Mg"; As it takes three dyads to match two triads, we have Mg 3 2 PO 4 for the required formula. NOTE. The above Table contains only the most common groupings. There are phosphate groupings other than the two mentioned; also other borate, sulphate, and silicate groupings, etc. For rarer groupings see "Table No. 2, continued." The number of radicals, both negative and positive, is countless. 30 CHEMICAL PRIMER. CHAPTER XIII. Write formulas for the following, and mark as acid, base, or salt: potassium arsenate = K As O 4 = salt. calcium acetate = Ca 2 C.jH 3 O. 2 = salt. hydrogen nitrate = H NO 3 = acid. magnesium hydrate = Mg 2 HO = base, hydrogen silicate calcium phosphate calcium oxalate = lead chromate sodium carbonate potassium arsenate calcium phosphate = ethyl hydrate (common ether) hydrogen acetate = ammonium oxalate = sodium hydrate = hydrogen tartrate sodium carbonate glyceryl hydrate (glycerine) magnesium phosphate = barium nitrate = hydrogen citrate = silver arsenite = As there is in acids but one element unknown (or variable), the acids are often called by pet names, using this element as an adjective; thus, H NO 3 = nitric acid, instead of hydrogen nitrate. H 2 SO 4 = sulphuric acid, instead of hydrogen sulphate. H^SOs sulphurous acid, instead of hydrogen sulphite. In the pet name of binary acids both elements are used; as H Cl hydrochloric acid (or chlorohydric), instead of hydrogen chloride. (H Cl has still another pet name used in commerce, a commercial name, muriatic acid). As you should not call a stranger by his pet name, so it is much better for you not to call any chemical compound by its pet name till you know its composition thoroughly and its chem- ical (systematic) name Most chemical compounds have one or more pet names, used in com- merce, by miners, by workmen in the arts, by mineralogists, or by pharmacists. In works on chemistry, these names are often inserted after the chemical name (or vice versa). THEORETICAL CHEMISTRY, 31 If the molecular composition of the acids has been mastered, they may be called by their pet names hereafter. Write formulas for the following: phosphoric acid acetic acid chromic acid boracic acid citric acid pyrophosphoric acid hydrofluoric acid nitrow* acid (grouping NO 2 ) Inspection of the following questions will show that the methods of solution are the same, whether the compound is a binary or a ternary. 1. In 580 kgs. of the iron ore, ferrous carbonate (Fe CO 3 spathic iron), how much iron? Fe 56 at. wt. 116 Fe CO 3 = 56 Fe C 12 " 1 " - T ^ of 56 Fe, O 3 = 48 " 580 kgs. " ; - Ao of 56 kgs . FC; = ^Tlfi mol. wt. 28 k 8 - Ans - 2. How much zinc sulphate could be made from 130 kgs, of Zii? Zn 65 65 Zn = 161 S 32 1 Zn = ^g. of 161 ZnSO, O 4 = 64 130 kgs. Zn = ^\ of 161 kgs. Zn SO7 Zn SOl = 161 322 kgs. Am. 3. In 100 kgs. of potassium arsenate how much arseiiicum? 4. In 150 gms. of mercuric (Hg dyad) nitrate, how much mer- cury? 5. In 75 gms. of mercuroMS (Hg 2 dyad) nitrate, how much mer- cury? 6. How much lead carbonate (white lead) could be made from 50 kgs. of lead? 32 CHEMICAL PRIMER. CHAPTER XIV. We have seen that chemical changes are called reactions. There are various classes of reactions, of which the simpler should be thoroughly mastered by beginners, and the more complex let severely alone. CLASS 1. Reaction by Direct Union (or Separation). EXPERIMENT 1. Heat a small quantity of sulphur well mixed with copper fil- ings in a test tube of hard glass ; a reaction takes place and copper sulphw/e is formed. Reaction: Cu -j- S = copper sulphur (red) (yellow) CuS (atomic reaction) copper sulphide (black) EXP. 2. Burn a small piece of magnesium ribbon in the air; the oxygen of the air unites with the magnesium, forming mag- nesium oxide. Reaction: Mg -{- O magnesium oxygen Fig. 1. How much Mg O could be made by burning 30 gms. of Mg? 2. If you make 80 gms. of Mg O, how much Mg must you take? Air is composed of one part by volume of the gas oxy- gen and about four parts by volume of the gas nitrogen, REACTIONS. 33 (with traces of carbonic oxide and vapor of water, etc.) Burning, or combustion, is in general, the rapid union of a substance with oxygen. The temperature at which the substance takes fire, i. e. t unites rapidly with the oxygen of the air; is called the igniting point. Of course, the product of the burning will b>e an oxide. EXP. 3. Burn some sulphur in a bottle containing a small quantity of water; Eeaction (a): S -{- O 2 = SO.; (a gas) Close the mouth of the bottle and shake; Reaction (b): SO 2 + H. 2 O = H 2 SO 3 (an acid). Test for the acid by litmus paper. EXP. 4. Scrap_e^ some fine powder from a piece of quicklime into a test tube of water; Reaction: CaO -f- H 2 O = Ca 2 HO (a base). quicklime whter slacked lime Test for the base by litmus paper. The last two reactions reveal the fact that there are different kinds of oxides. The two principal classes of oxides are : 1. Acid-forming oxides. 2. Basic oxides. The first are oxides of negative elements and they unite directly with water to form acids, as in reaction (b) of EXP. 3. The second are oxides of positive elements (metals) and unite directly with water to form bases, as in reaction of EXP. 4. Acid-forming oxides are often called 'anhydrides (with- out water), since they may be considered as acids deprived of water. EXAMPLE. SO a = sulphurous anhydride. 34 CHEMICAL PRIMER, (The older chemists called the anhydride the acid, as SO 2 = sulphur- ous acid, but this is not now correct usage). Basic oxides are often called bases. (It is important to know that this is still correct usage. Indeed, some authors give as the definition, "Abase is a metallic oxide, " and these authors call the true base a "hydrated oxide" or "hydrated base"). Basic oxides unite with acids to form salts, just as the true bases do. and by a reaction very similar. It will be seen that the term "base" is used by chemists somewhat indefinitely. In a wide sense it is used of any substance that will unite with an acid to form a salt (or a salt and water, or a salt with free hydrogen, etc.) In this wide sense it would include: 1. Positive elements (or groupings). 2. Basic oxides. 3. Positive hydrates. The word "base" has been thus far used in this last and restricted sense. The word "alkali" is also used in a comprehensive sense. The sense of the words, however, may easily be told from the connec- tion. REACTIONS. 35 CHAPTER XV. CLASS 2. Reaction by Change of Partners. EXP. 5. Dissolve one gram of sodium chloride (common salt) in nine grams of (distilled) water (a ten per cent, solution). Dis- solve one gram of silver nitrate (lunar caustic) in nineteen grams of water (a five per cent, solution). Pour a little r.f the first solution into a small test-tube, and into it let fall a few drops taken from the second, by means of a glass tube dipped beneath the solution and closed at the opposite end by the finger. A beautiful, white, curdy solid (silver chloride) is formed by the reaction, and slowly settles to the bottom of the test tube. Fig. 4. (a) lead post, (b) rubber band. Taking this reaction as the type of its class, we may learn much from it. 36 CHEMICAL PRIMER. Just as by change of partners, ( George | *j* f Charles ) become f George ) * / Charles ) ( Lucy )' ' ( Emma } \ Emma ) " " ( Lucy j so NaC) -f AgNO 3 = NaNO 3 -f- AgCl sodium silver sodium silver chloride nitrate nitrate chloride Soluble solid N f Insoluble j and therefore / J solid, called I not preeipi- ( \ a, jtredpi- I tated, but re- f \ tate. I maining i n V " solution. / NOTE. This is a very simple and frequent method of reaction. Fil- ter, wash, and preserve all precipitates for future use in experiments, or as samples of the various compounds (see EXP. 6). Carefully label the vials in which precipitates are preserved. It will be noticed that A Cl turns dark when exposed to the light (see silver). Water favors chemical change. (There are exceptions. Water does not favor ordinary combustion). Thus, two substances in solution will react with each other, which would not, if they were mixed dry. Iron rusts (unites slowly with the oxygen of the air, forming ferric oxide Fe 2 O 3 ) if exposed to the air wet. Knives and forks must be wiped dry, else they rust. Solution divides a substance more minutely and evenly than can be done by any other method of mechanical division. Solution separates the mole- cules. For instance, if a teaspoonful of common salt be thrown into a barrel of water and dissolved, molecules of salt may be found in every drop of the entire barrel. They seem to move among the molecules of water freely, the water giving them an atmosphere in which they easily perform reactions with other substances. The water is not written in the reaction, unless it really takes some part in the atomic changes. When a substance dissolves in water, and unites chemically with the water to form another compound (as in reactions of EXP. 3 and 4), this is not a mere solution, but something more. In a mere solution the substance goes into the water (somewhat as grains of sand might be poured into a measure of peas) without uniting with the molecules of water at all. A gas, as we have already learned, may be dissolved in water as well as a solid. REACTIONS. 37 A liquid may also be dissolved in water, but we speak of the liquid not as dissolved in water, but as diluted with water (or mixed) and we do not speak of the resulting liquid as a solution (see OILS). When as much as possible of the substance is dissolved in a certain amount of water, the solution is said to be a saturated solution. Many solids and gases are insoluble in water. (Some liquids will not mix with water and therefore cannot be diluted). Often these may be dissolved in other liquids, as alcohol (ethyl hydrate), hydrochloric acid, etc. The liquid dissolving the substance is called a solvent. Whenever two substances, one at least being in solution, react, form- ing a solid insoluble in the liquid, the resulting solid, as it usually quickly falls to the bottom, is appropriately called a precipitate. If soluble solids are formed at the same time, they of course remain in solution. If gases are formed in the reaction, they come off from the liquid in bubbles. Substances which react with each other as in the above reaction, especially those that are much used in the chemical laboratory, are called reagents. EXP. 6. Into a test-tube containing silver nitrate solution let fall a few drops of hydrochloric acid. The chemicals react by change of partners, as in EXP. 5, thus: Reaction: H Cl -f AgNO~ 3 - HNO^ -f AgCl hydrogen silver hydrogen silver chloride nitrate nitrate chloride (precipitate) Precipitates may be separated from the liquid by filtration. Cut and fold some filter paper, thus: Fig. 5. and place it on a funnel (tunnel), pouring the contents of the test tube upon it. 38 CHEMICAL PRIMER. Fig. 6. Filter Stand. The precipitate remains upon the filter, while the liquid called fil- trate (by workmen in the arts often called mother liquor), passes through. Wash the precipitate, to free it entirely from the filtrate, by forcing with the breath water in fine spray from wash bottles upon it. Remove the precipitate and dry upon glass, or dry before removing, as is sometimes more convenient. Bottle for cold water. Fig. 7. Flask for hot water. REACTIONS. 39 CHAPTER XVI. CLASS 2. (continued). EXP. 7. Place ierroiis sulphide (previously washed by gkt in water) in a small flask, and pour upon it dilute sulphuric acid. Reaction: FeS -j- H 2 SO 4 FeSO 4 H 2 S Fig. 8 Making solution of hydrogen sulphide. As H 2 S is a gas, it comes off in bubbles. Close the mouth of the flask by a rubber cork, through which a fine, glass tube passes. By means of a rubber tube allow the gas to pass into water. As the gas is soluble (three volumes in one of water), we have a so- lution of the gas. Set this aside as a re- agent. Caution. H 2 S is a^^igt-poisonous gas, and EXP. 7 should be per- formed under a gas chimney, or near a window with an outward draft. (To breathe a very small quantity mixed with air will, however, do no harm). This gas is largely used in the laboratory, and chemists are often more careless with it than is consistent with health. Learn to be cautious and careful in performing all experiments, follovnng direc- tions minutely. EXP. 8. To a solution of lead acetate in test tube add drop by drop solution of H 2 S. Reaction: Pb2C. 2 H :i O 2 -f H 2 S PbS -f 2HC.jH 3 O. 2 lead hydrogen lead hydrogen acetate sulphide sulphide acetate (black precipitate) It will be noticed, that when the hydrogen changes partners with 40 CHEMICAL PRIMER. the lead atom and takes the acetate grouping, the hydrogen and acetate grouping being univalent, they are matched one to one, giving us two molecules of acetic acid. It would be incorrect to write H 2 2 C 2 H 3 O 2 . Never put two monads with two monads in reactions, but always one monad with one monad, and if there be two of each, double the molecule. Just as we must take two monads to match one dyad in a binary, so we must take two molecules containing monad partners to react with one molecule containing dyad partners. Reagents are hereafter pre- sumed to be in solution. EXP. 9. To mercuric chloride (corrosive sublimate) add drop by drop potassium iodide. Reaction: Hg Cl , -f- 2KI = HgI 2 -f 2 K Cl mercuric potassium mercuric potassium chloride iodide iodide chloride (red precipitate) If too little is added, the precipitate dissolves; if too much is added, the precipitate dissolves, i. e. the precipitate dissolves in excess of either reagent. Notice that the molecule of mercuric chloride contains dyad partners (Hg = a dyad, and C1 2 two monads a dyad), while potassium iodide contains monad partners; therefore, we must take two molecules of the latter to react with one of the former. EXP. 10. Into a solution of arsenows oxide let fall a few drops of dilute hydrochloric acid. Reaction (a): As 2 O 3 + 6 H Cl = 2 As Cl -f- 3H,O As u O 3 , a molecule containing hexad partners, requires six molecules of H Cl to react with it. As C1 3 , arsenous chloride, being soluble in water, does not appear as a precipitate. Into the test tube drop solu- tion of H 2 S. Reaction (b): 2 As C1 3 + 3HJ3 = As,S 3 -f 6HC1 (lemon yellow precipitate) In reaction (b) we must take two molecules containing triad partners (As C1 3 ) to react with three molecules containing dyad partners (H 2 S), just as we take two triad elements to match three dyad elements in forming binaries. In the second member of the equation we must be careful to match the atoms according to their "strength" and to mul- tiply the molecules afterward, so that the number of atoms of any element shall be the same in both members. EXP. 11. To lead acetate (sugar of lead) add magne- sium sulphate. REACTIONS. 41 Reaction: Pb2C 2 H a O, + MgSO 4 = PbSO 4 + 3 insoluble and soluble, but hartn- therefore harmless. less salt. (white precipitate) Inspection of this last reaction will reveal the exact nature of a chemical antidote. Let the test tube represent the stomach. A chemical antidote is a substance, which will unite with the poison, forming insoluble or harmless compounds, or both (see chap, xxxviii). EXP. 12. To calcium hydrate (lime water) add ammonium carbonate. Reaction: Ca2HO + (HJN) 2 CO - CaGO -f white precipitate (chalk) Inspection of the following questions and the method of solving them will open to the attentive student a wide field for careful and accurate work. To such a student the problems are not difficult. 1. From 542 mgs. of mercuric chloride, how much mercuric iodide could be made by adding potassium iodide? Reaction: Hg C1 2 + 2 K I = HgI 2 -f 2 K Cl 200 200 71 254 27l mol. wt. 454 mol. wt. (will m ke) 271 mgs. Hg CL 2 - 454 mgs. Hg I a 1 " " -- lJ f T of 454 Hgl. 2 542 " ' = |4f- of 454 mgs. HgI 2 = 908 mgs. Am. 2. How much mercuric chloride will be required to make 150 gms. of mercuric iodide (adding K I)? Reaction: Hg C1 2 -f 2 K I = Hg I 2 -f- 2 K Cl 200 200 _Z1 254 271 454 (would require) 454HgLj = 27lHgCL 2 1 " = 4^4 f 271 H S C1 ' 150 gms. " r- J!-of271gms. " = 89-iff gms. Ans. 3. How much potassium iodide would be required to make 227 gms. of HgI 2 ? : Ana. 166 gms. 4. How much potassium chloride could be made by using 996 gms. of potassium iodide ? Ans. 447 gms. 4 42 CHEMICAL PRfMEtt. CHAPTER XVII. CLASS 3. Reaction of Acid and Base. When an acid and base are united, the result is a salt and water. The acid is said to neutralize the base (or vice versa}. EXP. 13. To barium hydrate add drop by drop sulphuric acid. Reaction: Ba2HO base = BaSO 4 -f 2H 2 O salt water (white precipitate) EXP. 14. To oxalic acid add calcium hydrate. Reaction: H 2 C 2 O 4 -f- Ca 2 HO = CaC 2 O 4 -j- 2H 2 O acid base salt water (white precipitate) EXP. 15. To sodium hydrate add drop by drop acetic acid, till solution is neutral to litmus paper. Reaction: Na HO + H C 2 H 3 O 2 = Na C, H 3 O 2 -f H 2 O base acid salt water There is no precipitate, be- cause sodium acetate is soluble in water. Filter to remove any slight solid impurities and evaporate to dryness in evaporating dish (or beaker) over a water bath. (See Fig. 9). Sodium acetate, a solid, remains. CLASS 3 is only another form of CLASS 2. In reactions of CLASS 3 the same law holds good, viz. : "that two molecules containing monad partners must be taken to react with one molecule containing dyad partners, etc. " Fig. 9. Water Bath. REACTIONS. 43 CLASS 4. Reactions of Acids and Carbonates. In these reactions, the carbonate grouping breaks up. When an acid unites with a carbonate, the result is a salt, water, and carbonicjDxidej'a, gas). The law in regard to molecules containing partners of different strengths holds good, as in the last two cases. This reaction is frequently used by the druggist and pharmacist. EXP. 16. To acetic acid add sodium carbonate (solid or in solution) till effervescence ceases. (Effervescence is the bubbling caused by the rapid separation of a gas from a liquid). _ Reaction: Na 2 CO 3 + 2HC;H 3 O. 2 = 2 Na C 2 H 3 O.j -f- H 2 O -}- CO a carbonate . acid salt water carbonic (soluble) oxido Filter, evaporate filtrate, and preserve. The salt is obtained as in EXP. 15. The heat of evaporation entirely expels any C O^ that may be held in solution after the reaction. EXP. 17. Into dilute citric acid let fall calcium carbonate till effervescence ceases. Filter, evaporate, and preserve as before. Reaction: 3 Ca CO 3 -f 2 H 3 C 6 H 5 O 7 = Ca 3 2 C 6 H 5 O 7 -j-3 H 2 O-{-3 CO 2 carbonate acid salt water carbonic oxide NOTE. Three molecules containing dyad partners (Ca // CO 3 // ) must react with two molecules containing triad partners (H 3 /// C e H 5 O 7 /// ), as before. Notice, in evaporating, that this salt (calcium citrate) is less soluble in hot than in cold water; an exception to the general rule, that "for equal volumes, hot water dissolves more of a solid than cold water." A.S a rule, "hot water dissolves less of a gas than an equal volume of cold water." Indeed, many gases not only will not dissolve at all in boiling water, but may be completely expelled from water, in which they may have been previously dissolved, by boiling it. 44 CHEMICAL PRIMER. Before leaving these chapters on reactions, the student should be able to write promptly any reaction belonging to either of the four classes, provided he has the names of the two substances given and t/te two reference tables before Mm. MISCELLANEOUS PROBLEMS. 1. Write formulas for five binary acids. 2. Write formulas for ten ternary salts. 3. Write formulas for two binary salts. 4. Write formulas for six ternary acids. 5. Write formulas for five bases. 6. In 150 gms. arsenous oxide, how much As? 7. In 1000 gms. of silver chloride, how much silver? 8. How much mercuric sulphide could be made by using 50 kgs. of mercury (Hg /7 )? 9. Reaction when phosphorus burns in air? 10. When carbon burns? Reactions when the following are united: 11. Stannous chloride (Sn x/ ) and hydrogen sulphide? 12. Copper sulphate and sodium hydrate ? 13. Sodium carbonate and hydrochloric acid? 14. Ammonium carbonate and calcium hydrate? 15. Potassium hydrate and sulphuric acid? 16. Calcium hydrate and citric acid? 17. Potassium carbonate and tartaric acid? 18. Acetic acid and magnesium carbonate? 19. To make 190 gms. of magnesium chloride* (by adding^ H Cl), how much magnesium carbonate must ba taken? 20. How much arsenous oxide, As ,O 3 (white arsenic) was contained in a vessel full of water, from which 15 mgs. of arsenous sulphide was precipitated (by adding H Cl and H 2 S)? OXYGEN. 45 CHAPTER XVIII. OXYG-EN. EXP. 18. Carefully pulverize in a mortar a small quantity of potas- sium chlorate, and having mixed it thoroughly with an equal bulk of pure manganese dioxide, introduce into a small copper retort. Heat by a strong alcohol flame, or flame from a Bunsen's burner. Collect O in receivers over a pneumatic tub, as represented in Fig. JO. Reaction: K Cl (X, = K Cl -f- O 3 Fig. 10. Making Oxygen. (a)-retort stand; (b) retort; (u)-receiver; (u>-pneuuiatic tub; (e)-receiver removed. NOTE. The presence of MnO 2 causes the O to come off more steadily and at a lower temperature, but as it takes no part in the reaction, it is not written. The first bubbles that come off are com- posed principally of air from the retort. The O often looks cloudy, because small particles of the salt and oxide are carried over by the draft. These gradually dissolve or settle into the water. Instead of a copper retort a glass flask placed on a sand bath (iron basin filled with sand) may be used. Three or four receivers should be inverted, and as fast as filled removed by*means of a small cover, holding a little water, to prevent the escape of the gas. Small quantities of O may be con- veniently made by using test tubes as retorts, test tubes, or bottles, as receivers, and a beaker as a pneumatic tub. 46 CHEMICAL PRIMER. i Caution. K Cl Oj-Tmnrntotrfre heated alone. Commercial Mn O. 2 is sometimes adulterated M ith carbon (pounded coal) and when mixed with K C1O 3 and heated, the mixture explodes violently. The delivery tube must be removed from the water before the heat is taken from the retort, otherwise as the gas in the retort cools and contracts, the water is forced back along the tube by atmospheric pressure. The first that falls into the highly heated retort is instantly converted into steam, causing an explosion. Ordinary care will prevent any serious acci- dent. The chief danger in breaking glass retorts is to the eyes. Learn here, that an explosion is (generally) caused by the sudden conversion of matter from the solid or liquid to the gaseous state. Oxygen is a colorless gas, without odor or taste. As we have inferred from the formulas thus far used, it is a very abundant element. ]t exists free (uncombined) in the air, forming one-fifth its volume. Chemically com- bined with other elements, it forms by weight eight-ninths of water, one-half of minerals, three-fourths of animal tissues, and four-fifths of vegetable tissues; in short, so far as we know, about two-thirds of the earth. EXP. 19. Into a receiver (bottle) of O, pliwige a taper having a live coal upon the end, it immediately bursts into a blaze. Quickly remove and blow out the flame. Repeat the experiment from twenty to forty imes, as may easily be done before the gas is exhausted. OXYGEN. 47 Wood, oil. tallow, etc., (things that we ordinarily burn) are composed principally of H and C, and are therefore called hydrocarbons. When hydrocarbons (as the taper in the experiment) burn, two reactions take place, viz. : TT -f- O HO fatpamM Gaseous n 2 t- \J - njj (steam, l productllot p -4- O PO (f\ frfta\ f the corn - u -h v, - ' uu, (& gas; ) bustion> Immediately after the O is exhausted, pour into the receiver a very small quantity of water, and closing its mouth, shake at intervals. The C O 2 gradually dissolves. Reaction: CO.,, + H 2 O = H 2 CO 3 acid forming acid oxide Test by litmus paper, but as H 2 CO 3 is a very weak acid, litmus paper must remain a little time in it. O is a yigorous supporter of combustion. O is heav- ier than air, for we hold the mouth of the receiver upward to retain the gas. Water is the standard of specific gravity for solids and liquids, but air for gases. Sp. gr. of air is 1, of O 1.1 -K But in chemistry hydrogen is made the standard for gases. EXP. 20. Straighten a steel (Fe) watch spring and tip the end with a little S (kindling wood for the steel, as S has a, much lower igniting point). Ignite the S and plunge the spring into a receiver of O. The steel burns brilliantly. Reaction: Fe 3 -j- O 4 = Fe 3 O 4 (triferric tetroxide, black or maiiietit; iron oxide) As this oxide of iron does not unite with water, the water shaken up in the receiver has no effect upon litmus paper. This reaction is an irregular one (strength of iron apparently not according to Table). If the air were pure O undiluted with N, our iron stoves would take fire, and a general conflagration would spread over the earth. We could not, for any length of time, breathe pure O, as it would so stimulate the vital 48 CHEMICAL PRIMER. processes as to produce speedy death. A small animal placed in a jar of constantly renewed O, dies in a few hours. EXP. 21. Charcoal bark, a small part of which has been heated to a live coal, plunged into O (by means of a Cu wire twisted about it), bursts into a vivid combustion. EXP. 22. Repeat EXP. 3 in jar of O. (Place S on chalk in a combustion spoon. Copper wire twisted about a piece of chalk makes a good combustion spoon). EXP. 23. Cut under water, quickly and carefully dry between pieces of blotting paper, a small piece of phosphorus (not larger than a grain of wheat). Place in a combustion spoon, ignite by hot wire, while lowering into a large jar of O, containing at the bottom a little water. A blinding light is caused by the combustion. Fig. 12. Reaction: P a -{- O 5 = P 2 <>5 dense white fiunes In ;i sh jrt time these fumes are dissolved in the water, and the follow- ing reaction slowly takes place: acid forming oxide 2H 3 P0 4 acid Test by litmus paper. Caution. Handle P with great care, on no account touching it. The heat of the hand may inflame it, and its burns are dangerous. Its vapor is highly poisonous, as is also its oxide P a O[,. The dense, white fumes should be immediately snut in by stopple attached to combustion spoon. (Fig. 12). O is an exceedingly active gas. It alone supports all ordinary burning that takes place in the air. To bring this gas in contact with the Hood is the object of respiration in animals. The blood absorbs and carries O to all the tissues, the most prominent chemical change taking place in the body being that of oxidativn. (See EXP. 57), HYDROGEN. There is a peculiar form of condensed O, called Ozone. It is O in an allotropic state. It may be made in various ways, especially by the action of electricity on common O. It occurs in minute quantities in the air. It is even more active than O and is a powerful disinfectant. In it tainted meat in a few moments loses its putrescent odor, because the foul material is oxidized, forming relatively wholesome compounds. The molecule of ozone may be represented thus | ^Q with three atoms, that of oxygen being | QQ | composed of two atoms. CHAPTER XIX. HYDROGEN. EXP. 24. Place in a small flask, or large test tube, (hydrogen genera^ tor) some granulated Zn. Upon it pour dilute (10 per cent.) sulphuric acid. Close mouth of flask with perforated rubber cork, through which passes a nxe glass tube. Collect H over pneumatic tub, as in Fig. 13. Zn + H 2 S0 4 Fig. IS. Making H) drogen ZnSO; -f H 2 NOTE. Collect several receiv- ers of the gas, and after the reaction has ceased, filter the liquid remaining in the flask; evaporate filtrate, and the white salt, zinc sulphate, is obtained. If a drop of the filtrate is placed on a piece of glass and set aside, away from the dust, beautiful crystals of the salt are left upon CHEMICAL PRIMER. Hydrogen is a colorless gas, without odor or taste (when *j pure). It is the essential constituent, as we have seen, I*-' in acids. Indeed, acids have sometimes been defined as i f "salts of hydrogen." H does not exk^reg, It has been condensed by cold and pressure, first, to a liquid and then to a r w1tQ'solid. H is not poisonous, but destroys life, just as water does, by shutting out the O. The lungs may be inflated with the pure gas without harm. (Caution. Gases made by beginners must never be breathed. As a rule, a gas is obtained absolutely pure with great difficulty. For methods of obtaining gases pure see larger text-books or some treatise). Chemists take hydrogen as the stand- ard of specific gravity for gases. / With this standard, j i^UfJL ^"one-half its molecular weight is the sp. gr. of any gas"/ EXP. 25. Remove a jar of H, holding the mouth downward, and into it plunge slender lighted taper. The H takes fire and burns at the mouth of jar, but the taper is extinguished in the gas above. It may be relighted by the burning H as it is being removed. H is lighter than air, for we Jaetfl the gas by keeping the mouth of the receiver downward. H is Yery inflam- mable, i. e, its igniting point is low It does not support combustion (ciLJijuliui^^ NOTE. Combustible bodies and supporters of combustion are relative terms. A jet of O would burn in a jar of H just as well as a jet of H in a jar of O. One as well as the other, could be called the supporter of the combustion. EXP. 26. Pour H upward from one test tube into another, displac- ing the air. Test by igniting. EXP. 27. Collect H from generator in test tube by displacement of air. Test. EXP. 28. Attach a clay pipe (old or varnished) to generator and blow soap bubbles with H. They ascend and may be ignited in the H YDROGEN. 51 Hydrogen is the lightest substance known, being about 14J times lighter than air. EXP. 29. Attempt to blow soap bubbles, using a new clay pipe and letting the gas come slowly. The H escapes by diffusion through the clay so rapidly, that the bubbles cannot be blown. Quickly substitute the oft/ pipe (whose pores are closed) and the bubbles are blown with- out difficulty. All gases possess power of diffusion, but the power is possessed by H in an extreme degree- The difFusibility of gases is C1 '-inversely as the square roots of their densities," the density (or sp. gr.) of any gas being half its molecular weight. EXAMPLE. \/ ^ \/ " l 4 1 U density * U density * * diffusibility diffusibility I of O | of H * of H of O That is, H has four times the diffusive power of O, or dif- fuses four times as rapidly. H may leak through vessels that would retain O permanently. EXP. 30. Close generating flask by a rubber stopple, through which passes a hard glass tube, with fine opening. After the air has been expelled by the H, ignite the jet. The apparatus is the "Philosopher's Lamp." Over the flame invert a cold, dry test tube. It is bedewed with moisture. Fig. 14. Philosopher's lamp. H 2 -j- O = When H burns, the product is water (steam). The H flame gives little light, but great heat. The alcohol (ethyl hydrate) flame gives little light and great heat, because alcohol contains much H. The flame of the oxy-hydrogen blowpipe melts many substances (as platinum), infusible in ordinary fire, the alcohol flame, or the flame from a Bunsen's burner. 52 CHEMICAL PRIMER, Fig. 15. Section of oxy-hydrogen blowpipe. The H from the gasholder is first turned on and ignited, and after- ward the O is turned on. EXP. 31. Fill over a pneumatic tub a stout quart fruit jar one- third with O, and the remainder with H. Wrap about it a cloth; remove, and holding the mouth downward, quickly ignite by means of a taper. A sharp explosion ensues. There are two reports heard as one, the second so closely follows the first. The first is caused by the suddsn (but not greater than a few volumes) expansion of the gases heated by their union; the second is caused by (the steam suddenly condensing) the rush of the air from all sides to fill the partial vacuum. Caution. Of course, H explodes when mixed with air. Care must b3 taken to expel all air from appa- ratus before igniting jets of H. Never ignite large quantities of the gas. nA/V <*v C^/Crf Q. **- EXP. 32. Repeat the experiment of decomposing water as explained in connection with Fig. 1. This proves by Analysis the composition of water. If we explode two volumes of H with one of O and find we have nothing but water left, we prove the composition of water by Synthesis. Water H 2 O The wonderful power of chemical affinity is shown in this compound. A union of the most inflammable sub- stance known, with the most vigorous supporter of com- bustion, forms another substance used to extinguish fires. We have called this substance by its pet name, because it is so commpn a substance and so generally distributed. Its systematic name (hydrogen oxide) is seldom used. We HYDROGEN. 53 have already learned that water is the general solvent in nature, dissolving most gases and solids and diluting most liquids. Hard water contains minerals in solution; soft water does not. Hardness produced by earthy (Ca. Mg. Sr. Ba. etj.) carbonates is called "temporary hardness," because the carbonate may be precipitated by boiling, leaving the water soft. EXP. 33. Expose on a deep plate in the school-room for 24 hours distilled (soft) water. Carbonic oxide (CO 2 ) from the air dissolves in it. Shake up with this water a considerable quantity of finely pulver- ized marble (Ca C O 3 ). Filter. The filtrate is water of u temporary hardness." (Carbonates dissolve in water containing C O 2 , but not in pure water). Boil in a deep beaker. The C O 2 is driven off, and a white precipitate of Ca C O 3 falls. The "fur" upon the teakettle is a precipitated carbonate. Hardness produced by earthy sulphates is called "per- manent hardness," because the water cannot be made soft by boiling. (See SOAP). The water held in suspension by the atmosphere is essen- tial, not only to plant life, but to animal life as well. The earth would be a vast desert, were it not that tons of water are constantly being carried up from the ocean by evap- oration, so that the air currents may distribute it, not alone to fall as rain, but also to keep the atmosphere every- where moist. Many substances, when they crystallize (assume a sym- metrical shape in solidifying), take up a definite amount of water, called water of crystallization. This may be expelled by heat, but the essential properties of the sub- stance are not changed. EXP. 34. Heat in a porcelain dish crystals of copper sulphate pre- viously carefully weighed; the water of Crystallization is expelled 54 CHEMICAL PRIMER. and the blue color disappears. Weigh the sulphate. It has lost over one-third its weight, as the formula of crystallized copper sulphate is Cu S O 4 , 5 H 2 O. Touch with a drop of water, the color returns. Dissolve in a small quantity of water, evaporate slightly, and set aside to cool. Beautiful crystals of copper sulphate form as the solution cools. Fine crystals of various substances may be formed in this way, viz., by making saturated solution of the substance, slightly evaporat- ing and setting aside for a few days. Making a collection of crystals will be found a very profitable exercise. Water of crystallization is not written in ordinary reactions of substances in solution, but must be taken into account in dealing with the dry solids. Of course, a larger quantity of the crystallized solid must be taken to equal a smaller quantity of the uncrystallized, if the xolid takes up water of crystallization. Some substances, such as sodium acetate (NaC a H 8 O,. 3H 2 O), sodium carbonate (Na 2 CO 3 , 1()H 2 O), etc., when exposed to the air, lose their water of crystallization arid crumble to powder. These are said to be efflorescent. Some substances, as potassium carbonate (K 2 C O 3 ). when exposed to the air, absorb moisture and dissolve (or par- tially dissolve). These are said to be deliquescent. The law of physics, that "heat expands and cold con- tracts" does not hold with water in cooling from about 4 (C) to 0, through which space it steadily expands, until it freezes (crystallizes) at 0. The importance of this exception cannot be over-estimated, for it makes ice lighter than water, and so prevents lakes and rivers from freezing solid. Water, containing impurities in solution, may be puri- fied by distillation. The water is placed in a retort, or "still," is heated, rises as steam (at 100), which, pas- sing through the condenser, (supplied with cold water in direction of arrows, Fig. 16), condenses, and is collected in NITROGEN. a receiver. Steam ("dry steam") is an invisible gas. That which is seen and often miscalled steam, is steam con- densed (or partially condensed) into minute globules of water and held in suspension (like dust) by the air (or by the invisible steam, in which case the steam is called "wet steam \ Fig: 10. Retort, or "still," and condenser. * Current of cold water. CHAPTER XX. NITROGEN. EXP. 35. ^lace a piece of chalk on a tripod wire-holder, standing in a deep plats of water. Upon the chalk place a small piece of P. Ignite by hot wire and quickly invert a receiver over it. P, -f 5 = P,0 5 soluble white fumes. 66 CHEMICAL PRIMEli. The P unites with the O iu the jar. The phosphoric oxide dissolves and the water rises by atmospheric pressure and fills one-fifth of the receiver, the space before occupied by the O. N remains in the receiver above the water. Leave over night, that the small quantity of O left, when the flame of P is extinguished, may unite with the remaining P. Of Fur. 17.-Making nitrogen. ^^ the N ^ obtained ^ ^ pure. Remove receiver, and over a pneumatic tub fill a smaller jar with the gas. Remove small jar, and test by passing a lighted taper up into the gas. The flame is extinguished and the N does not take fire. Nitrogen is a colorless gas, without odor or taste. It forms by volume ^ of the atmosphere. N is not poison- ous, and destroys life only by shutting out O. It is not inflammable and it does not support combustion. It is a very inert element. It dilutes the active O of the ajr, and the mechanical mixture is thus fitted for respiration. Some of its compounds are by no means inert. For example. " nitro-glyeerine " the violent explosive is glyceryl nitrate, and the deadly poison, prussic acid, is hydrogen cyanide. No one can predict with certainty the character of a chemical compound from the nature of its constitu- ents. It might be supposed that, N being lighter than O, the air would separate in to two layers, the heavier, O, sink- ing. The two gases, however, are kept thoroughly mixed by the law of diffusion of gases. N forms with O five oxides, viz. : N 2 O, hyponitrous oxide (acid-forming). N 2 O 2 nitrogen dioxide. N 2 O 3 nitrous oxide (acid-forming). N 2 O 4 nitrogen tetroxide (or peroxide). N,O 5 nitric oxide (acid-forming). NITROGEN. 57 These oxides illustrate well the great law of multiple proportions. When one substance unites chemically with another, it is in some definite proportion, or multiple of that proportion. Whenever substances are united phys- ically (mechanically, as in alloys of metals, etc.) they may be united (mixed) in any proportion. NOTE. We see from the above that there is a third class of indif- ferent oxides (as N.,O 2 , N 2 O 4 ), neither acid-forming nor basic. The pupil need not give much attention, however, to this class. All the positive indifferent oxides, as Mn O. 2 , Ba O 2 , K 2 O 4 , Pb O 2 , having more O than the basic, are called peroxides. For preparation of N 2 O 3 and N. 2 O 5 see larger text books. EXP. 36. Heat in flask ammonium nitrate and collect gas over pneu- matic tub of warm water. H 4 N NO 3 = 2 H 2 O -|- N 2 O Hyponitrous oxide ("nitrous oxide" "laughing gas,") inhaled with a small proportion of O, produces a peculiar intoxication, hence its name of "laughing gas." If the pure gas is inhaled, it soon produces insensibility. It is much used as an anaesthetic by dentists and by surgeons in minor operations. It is kept condensed in liquid state in iron cylinders. EXP. 37. To small pieces of copper add dilute (25 per cent.) nitric acid, red fumes appear in generator (see EXP. 38), but a colorless gas collects over the tub. _ / Reaction (irregular) : Cu 3 + 8 H N O 3 = 3 Cu 2 N O 3 -f- 4 H 2 O + N 2 O 2 [Filter water in flask, evaporate, and obtain blue crystals of 'Cu8NO&]. EXP. 38. Admit to test tube containing N. 2 O 2 a bubble of O (or air). Red fumes of N. 2 O 4 appear. N 2 2 + 2 N 2 oT These fumes are soluble in water, and the water slowly rises to take the place of the dissolved gas. 5 68 (CHEMICAL EXP. 39. Into a small retort put 4 gins, of sodium nitrate (or K NO 3 ) and 2 gms. of sulphuric acid (previously diluted to 90 per cent. ) Carefully heat. Collect nitric acid (impure and slightly diluted) in well cooled test tube, as in Fig. 18. 2HNO, Fig. 18. Making nitric aui 08" CHEMICAL PRIMER complex substance, from which the aniline dyes, carbolic acid, etc., are obtained. H,, N may be removed by passing through water (or H Cl, old method), C O 2 by passing through "pans" of lime (Ca O), and the sulphur compounds by passing over ferric hydrate. The last reaction may be represented thus: Fe, 6 H O ferric hydrate liydui-en sulplmb ferrous hydrate a O s free nlphu Fig. 25. Section of Gas Meter. The three arrows represent the rotation of the chambers: the solitary arrow the escape of the gas from chamber. Gas enters through the U-shaped center. On exposure to the air, ferrous hydrate becomes ferric hydrate, and the material may be repeatedly used till the free sulphur forms from 40 to 50 per cent. The tar vapor condenses and runs into the "tar well." The refuse (coke) is left behind in the retoits. The purified gas is measured by the meter and passes into the holder, from which it is distributed to consumers. Illuminating gas is also made from crude petroleum, more complex machinery being used. Bunsen's Burner is represented in Fig. 9 and is used when heat, not light, is wanted. The gas is mixed with the air, drawn in through openings at the side. The flame is condensed, is much hotter, and does not smut cold glass. EXP. 02. Heat in ex- treme tip of blowpipe flame the end of a copper wire. It turns black, i. e., is oxi- dized, forming Cu O. Heat in the midst of flame nearer the blowpipe. The CuO is reduced (deoxidized) and the bright metallic copper appears. By means of the blowpipe we may do two things, oxidize most metals (a very small portion is sufficient for tests) and reduce their oxide?. ;. 26. CARBON. At A a substance may be oxidized because here we have an excess of O thrown forward from the blowpipe and highly heated. The flame at B is reducing, for here there is an excess of highly heated carbon The reducing flame is best produced by holding the nozzle of blowpipe a very short distance from the flame instead of in it. The blowpipe is a very valuable instrument in the analysis of ores. EXP. 63. Two inches above a gas burner hold a fine wire gauze and ignite jet of gas above the gauze. It burns above, but not below. The wire being a good conductor of heat reduces the gas below the igniting point, and the flame cannot pass through the gauze. Davy's Safety Lamp used by miners is essentially a lamp surrounded by a wire gauze. The flame cannot pass through this to ignite the "fire damp" (C H 4 marsh gas). This dangerous gas explodes vio- lently when mixed with air and ignited. EXP. 64. Into a flask put a small quan- tity of oxalic acid crystals and cover with strong sulphuric acid. Heat gently and pass gases through wash bottle containing strong solution of K H O. Collect over water. +CO'' The sulphuric acid absorbs H 2 O from the oxalic acid breaking up the molecule. The KHO solution absorbs the C O 2 becoming K 2 CO 3 (and H.,0) and the CO is collected in receiver. Test by lighted taper. It burns with bluish flame. Carbonous oxide C O, (old name carbonic oxide) is a colorless poisonous gas formed by burning C in a close atmosphere. Escaping from hot stoves through the pores of the iron into ill- ventilated rooms, it causes headache. In large quantities it speedily produces coma and death. The pale, lambent flame that plays over a bed of glowing coals after the brighter flame is spent, is the flame of this gas. 70 CHEMICAL PRIMER. NOTE. Organic chemistry may be considered as carbon continued. The previous rules for writing formulas and names, which hold so gen- erally in inorganic chemistry, fail in numberless instances to meet the requirements of organic chemistry, as we shall see (see ORGANIC CHEMISTRY). CHAPTER XXII. BINARY ACID- AND SALT-FORMERS. FLUORINE, CHLORINE, BROMINE, IODINE, AND CYANOGEN. EXP. 65. Into a small flask on a sand bath, put equal weights of common salt and manganese dioxide, well mixed. Add sufficient water to make thin paste. Pour in through funnel a small quantity of sul- phuric acid (90 per cent. ) and collect gas in large test tube over hot water, or by displacement of air in deep receivers. Heat should be applied to flask to drive off the last (and greater portion) of the gas. A double reaction takes place: _ _ (1) H. 2 SO 4 + 2NaCl Na 2 SO 4 -f- 2HC1 / (2) MnO, + 4HC1 - Mn CL, -f- 2H,O -f- Cl, The gas may be freed from H Cl by passing through wash bottle (see Fig. 27) of cold water. It may be dried, if desired, by passing through strong H.j S O 4 in the same manner, and then collected by displacement of air. Caution. Care should be taken not to breathe (except in minute quantities) chlorine, cyanogen, or, in short, any gases or products that are poisonous. Small quantities of such gases should be used in experiments. If larger quantities are desired, they should be made under a "gas chimney," or near a window with outward draft. BIN A RY A CID- A ND SA L T-FORMERS. 71 Chlorine is a greenish-yellow, poisonous gas of a suf- focating odor. When very dilute it produces coughing (relieved by cautiously inhaling ammonia), and breathed in larger quantities inflammation of the trachea and bron- chial tubes. It is 2.5 times heavier than air. It is an abundant element, but is not found free in nature. EXP. 66. Into a jar of Cl plunge a lighted pitch-wood taper. It burns awhile with smoky flame. The Cl unites with H of the taper, setting the C free as smoke. Test by blue litmus. EXP. 67. Burn a jet of H in Cl and test product by blue litmus. H Cl HClf EXP. 68. Into a iar of Cl Fiij. 28. introduce a piece of blotting paper moistened with frexh and warm turpentine (C 10 H 16 ). The Cl unites with the H so vigorously as to cause it to take fire, but the C is set free as a dense cloud of smoke. C 10 H lt; + Cl,, ; 16HC1 -|- CN, Test by litmus. 01 has a "great affinity for H. Upon this affinity depends its value as a disinfectant. H is an essential con- stituent of many foul gases. Cl destroys them as it destroys coloring matters. (See EXP. 72). EXP. 69. Upon paper containing printer's ink write with common ink (iron tannate Fe&C 2 7H T ,O 17 ) and lower into a jar of Cl. " The common ink is bleached, but the printer's ink (linseed oil and lamp black, C) is unaffected. EXP. 70. Into a black bottle containing cold water pass Cl gas (purified of H Cl). The Cl dissolves (3 vols.) and forms "chlorine water. " Set aside as a reagent. 72 CHEMICAL PRIMER. EXP. 71. Expose a test tube of chlorine water to the sunlight for a few hours. Place it beside a test tube of fresh chlorine water, and to each add a piece of blue litmus paper. The fresh chlorine water bleaches, the other turns the litmus red. The light enabled the Cl to decompose the water thus: C1 2 + H 2 = 2HC1 + O. ("Light favors chemical change.") EXP. 72. Into a beaker of chlorine water let fall a few drops of water colored by cochineal (or indigo, aniline purple, etc.,) or introduce a piece of calico. The color is discharged. Chlorine is a powerful bleaching agent, and for this purpose is largely used in the arts. It bleaches (and dis- infects) in two ways: 1. By removing H from the substance. 2. By removing H from water setting free "nascent" O which bleaches. (Thus Cl bleaches by proxy). Dry Cl does not bleach. .Bleaching powder, "chloride of lime," is mixture of calcium hypo-chlorite (Ca 2 CIO) and calcium chloride (Ca C1 2 ). A dilute acid sets chlorine free with promptness. Moisture and exposure sets chlorine free slowly, therefore bleaching powder is used as a disin- fectant. EXP. 73. Into a jar of Cl, sprinkle antimony (powdered with a pocket knife). It takes fire and fills the jar with white fumes. (Sb C1 5 , poisonous). Cl has a r great affinity for the metals. (Sb is semi- metal). Most of them burn in chlorine, forming chlorides. EXP. 74. Into a test tube containing a little common salt, pour slightly dilute (75 per cent.) sulphuric ac'd, and gently heat. Collect gas, dried by wash bottle of strong H 2 S U 4 , in a small test tube over mercury, or collect in narrow-mouthed bottle by displacement of air. _ 7 2NaCl -I- H 2 S0 4 = Na 2 SO< + 2 H Cl NOTE. Chisel out of hard wood a trough 4 inches long, f of an inch wide, and 1 inch deep. Nail a lead post to one or both ends to support small teat tube. This makes a very good mercuric pneumatic tub. BINA RY A CTD AND 8 A L T-FO RMERS. 73 Fig. 29. Mercuric Tub. EXP. 75. Introduce into test tube of H Cl over mercury, a few drops of water by means of pipette. The water dissolves the gas and tlu; mercury rises to take its place. A solution of HC1 in water remains above the mercury. EXP. 76. A fountain similar to the "ammonia fountain " of EXP. 46 may be made, only blue litmus turns red. Hydrochloric acid, (hydrogen chloride, chlorohydric acid, muriatic acid) is a colorless irrespirable, acid gas, very soluble in water (450 vols. in one at 15). The liquid called hydrochloric acid is really a solution of the gas in water (a mere solution). EXP. 77. Dip a glass rod into strong ammonia water, and another into strong H Cl and bring the rods together. Dense white fumes of ammonium chloride appear. Omitting water, the reaction is: H 3 N + HC1 H^NCl This is a fair text for H Cl or for free ammonia. EXP. 78. Boil in H Cl a small piece of gold leaf. It doys not dis- solve. Add a drop of H N O 3 , a yellow solution of gold chloride (Au C1 3 ) appears. H Cl and H N O 3 form aqua regia, the solvent of gold. EXP. 70. Repeat Exp. 5 and 6, and also use other soluble chlorides. Soluble chlorides precipitate silver as silver chloride. EXP. 80. Heat a small piece of KCib ;! upon charcoal. The coal burns explosively. 2KClO a C 3 2KC1 -f 3CO 2 The chlorates, as well as the nitrates, are good oxidiz- 6 74 CHEMICAL PRIMER. ing agents. Potassium chlorate is one of the most important of the chlorates. EXP. 81. In a deep test tube thoroughly mix a little pulverized K Br and Mn O 2 , adding H 2 S O 4 (90 per cent.) and gently heating. The reddish and irritating fumes of bromine appear. These may be condensed into a liquid in deep test tube cooled in ice water. (]) H 2 gTix; + 2KBr = K 2 SO7 + 2 H Br (2) MnO, + 4HBr = MnBr. -f 2 H a O -f Br a Bromine is a volatile, poisonous, dark red liquid, very similar in its properties to chlorine, but less active. Many experiments analogous to those under Cl maybe performed with bromine vapor. Thus, Br bleaches and unites with^ H to form hydrobromic acid. H Br and other soluble bromides precipitate silver as yellow silver bromide, which blackens in sunlight like silver chloride. (Perform experi- ments and write reactions). Br is not a very abundant element. EXP. 82. Boil a very small piece of starch (C 6 H 10 O 5 ) in water, and add a drop of the starch solution to bromine water. A yellow solution of bromide of starch appears. Starch solution is a very good test for free bromine (see EXP. 85). EXP. 83. Repeat EXP. 81, substituting K I for K Br, violet colored vapor of iodine appears and condenses as a solid on sides of test tube. Iodine is a greyish- black solid with metallic lustre. It is a comparatively rare element. EXP. 84. To tincture (solution in alcohol) of .iodine very dilute,* add dilute solution of starch paste. Blue iodide of starch appears. [That the compound is not a very stable one, may be shown by gently heat- ing. The blue color disappears (if solution was dilute), but reappears as the solution cools], Starch is a very delicate test for free iodine (See EXP. 85). Soluble iodides precipitate silver as silver iodide which blackens in sunlight. EXP. 85. Into a test tube put solution of K Br, and into second test tube K I. Add to each two or three drops of starch solution. BINARY ACID- AND SALT-FORMERS. 75 N o yellow or blue color appears, because the Br and I are combined with K. To each add one drop of chlorine water. The yellow and the blue colors appear because the Cl Unites with the K setting the Br and I free. (1) K Br -f Cl = K Cl -f Br (free). (2) K I -f Cl = K Cl -f- I (free). The free Br and I then unite with the starch forming the yellow and the blue color respectively. This experiment shows the superior cliemism (chemical affinity) or activity of chlorine. Fluorine is the only element which does not unite chemically with oxygen. It is supposed to be a colorless gas, but so great is its chemical affinity that it has not been satisfactorily isolated (set free). EXP. 86. In a platinum or lead crucible plase two grams of Fluor Spar (Ca F 2 ) and cover with strong H 2 S O 4 . Coat a piece of glass at a gentle heat with beeswax, and having written with a zinc point (which will not scratch the glass) a word upon the wax, gently heat crucible, and removing lamp, cover with glass. Leave over night. The word is etched upon the glass. (1) CaF 2 -f H,S0 4 = CaSO; -f 2 H F (2J-4-HF -f SiO 2 = 2H 2 O -f Si F. of the _ glass (Na 4 Si 04) Hydrofluoric acid (H F) is used for etching letters or beautiful designs upon glass. If the gas is used the letters or designs are left rough ; but if a solution of the gas in water (kept in gutta percha bottles) is used, the etched portion is smooth. EXP. 87. In a tube of hard glass place a small quantity of mercuric cyanide (Hg 2 C N). Heat carefully to dull redness and collect gas in test tube over mercury. Test by lighted taper. The gas burns with reddish-purple flame. _ (1) Hg2CN = Hg -f- (CN) a (2)-CN + O, = CO, H 76 CHEMICAL PRIMER. Cyanogen (T H- H 2 SO 4 = HNaSO~ -f- acid sodium sulphate In general, by adding an excess of the acid (which is the same as taking less of the other substance), an acid salt may be obtained. Acid salts, as a rule, react with carbonates like acids, that is, forming a salt, (normal), water and carbonic oxide, as: 2HKC 4 H 4 6 -f- K.CO 3 = 2K 2 C 4 H 4 O 6 + H,O -f- CO, acid salt carbonate normal water carbon salt dioxide A double salt is one which is formed by replacing part, or all of the replaceable hydrogen of the acid by two posi- tive elements or groupings. EXAMPLE. H 2 C 4 H 4 O 6 = tartaric acid. K Na C 4 H 4 OK = potassium sodium tartrate = double salt. ("Rochellesalt") H 3 P O 4 = phosphoric acid. H Na H 4 N P O 4 hydrogen sodium ammonium phosphate = double salt (microcosmic salt). A dauble salt may be at the same time an acid salt, like the last. A double salt may be formed by an acid salt of one metal acting on the carbonate of the other, thus: X Na 2 C O 3 + 2 H K C 4 H 4 O 6 = 2 K Na C 4 H 4 O 6 -f- H^ O -f- C O 3 sodium acid double water carbonic .carbonate potassium salt oxide tartrate Acids containing one, two, three, etc., atoms of replaceable hydro- gen are said to be respectively monobasic, dibasic, tribasic, etc. 78 CHEMICAL PRIMER. EXAMPLE. H NO 3 =' mono-basic acid. H 2 S O 4 dibasic acid. H 3 P O 4 tribasic acid. H 4 SiO 4 tetrabasic acid. NOTE. A tribasic acid may form twy acid salts, as: H 2 NaPO 1 dihydrogen sodium phosphate acid salt. H Na 2 P O 4 = hydrogen disodium phosphate = acid salt. A basic salt is one which may be formed by replacing one or more hydrate groupings of the base by a negative grouping. (This definition is a narrow one, covering most but not all basic salts). EXAMPLE. Pb 2 HO lead hydrate base. Pb HO NO 3 = lead hydro-nitrate = basic salt. Al.jSHO = aluminum hydrate = base. A1 2 2 H O Si O , = alumnium hydro-silicate = basic salt. Sulph- and Selen-acids and salts. In all formulas for ternaries thus far used, oxygen has been the last element. It is supposed to be principally a linking or connecting element. Now there are a few other dyad elements that can perform this office of linking, especially sulphur and selenium. To write the formula for a sulph- or a selen- acid or salt, the same reference table may be used, only sulphur or selenium, as the case may be, must be substi- tuted atom for atom, in place of oxygen. EXAMPLE. K^C O 3 potassium carbonate = salt. K 2 C S 3 = potassium sulpho-carbonate =' sulph-salt. Ag 3 As O 4 = silver arsenate = salt. Ag 3 AsS 4 silver sulph-arsenate = sulph-salt. K 3 SbO 3 = potassium antimonite salt. K 3 Sb Se 3 = potassium selen- antimonite = selen-salt. NORMAL SALTS, ACID SALTS, ETC. 79 H 3 As 84 = hydrogen sulph-arseiiate sulph-acid. NOTE. Instead of sulph-, thio- (Greek thion, sulphur) is used by some chemists, as K 2 C S 3 potassium thio-carbonate. The sulph- and sel en-acids and salts are few compared to those con- taining oxygen. MISCELLANEOUS QUESTIONS. 1. Reaction in making O ? 2. How many litres of O can be made from 150 grains of K Cl O 3 Y (NOTE. A litre of H weighs .0896 grams (at O c and barometer 760mm), and a litre of O weighs 16 times as much, a litre of N 14 times as much, etc. , accordi ng to the atomic weight of the gas. To find the weight of compound gases, multiply th. weight of H by one-half the mo- lecular weight of the g 24 H 2 O) containing much water of crystallization. Ammonium alum (A1 2 (H 4 N) 2 4 S 6 4 , 24 H 2 O) is also somewhat common. Alum is much used in dyeing as a "mordant " (see DYEING). Cryolite is A1 2 F 6 + 6 Na F. Magnesium (sp. gr. 1.75, fus. pt. about 2000, but ignit- ing point is low, the Hame of a candle being sufficient to set it on fire) is a silver- white metal not found native, but in combination is widely distributed. Mg burns in the air with a brilliant light (Exp. 2), forming Mg O (magnesia. In general, the ending a means (1) the oxide, (2) the carbon- ate, (3) the hydrate of the metal). Its light is rich in chemical (actinic) rays, and hence is used for photographing in dark caves, etc. Arsenicum is never found with it, and the metal is used instead of Zn in important tests for As (see Marsh's test). 2 is found in sea water. Mg S O 4 , 7 H 2 O (Epsom salt) is found in many mineral waters. "Magnesia alba" is an artificial mix- ture of Mg C O 3 and Mg 2 H O, principally the former. (See magnes- ite, hornblende, meerschaum, soapstone, talc, serpentine, dolomite, etc. , in cyclopaedia). 8 106 CHEMICAL PRIMER. CHAPTER XXXI. CALCIUM, STRONTIUM, AND BARIUM. Calcium (sp. gr. 1.58) is a ligKt-yellow ductile metal. It oxidizes in moist air and consequently is not found native (free). Its compounds are widely diffused, Calcium oxide [Ca O, quicklime, a basic oxide (Exp. 4)] is prepared by heating the native carbonate (Ca C O 3 ) in "kilns" till CO 2 is all expelled. S CaCO 3 = CaO + C O 2 It is used for making mortar, cements, etc. CaO + H 2 = Ca2HO ''water slacked lime, " mortar When exposed to the air, this absorbs C O 2 and hardens. Ca2HO + CO 2 - CaCO, + H 2 O "water slacked from "air slacked evaporates lime" air liine" dried mortar CaO falls to a powder when gradually air-slacked by exposure. It first absorbs water and then C O 2 as in above reactions. Ca O is used in the laboratory for drying gases (Exp. 45, 56, and illuminating gas) and in the "lime light, "-the flame of the oxy-hydro- gen blowpipe raising it to the wltite heat and causing it to emit an intense light. Calcium carbonate (Ca C O 3 ) is found as marble, limestone, shells, (chalk is formed by beds of tiny shells), stalactites, etc., also with Ca 3 2 PO 4 in bones (see HARD WATER and EXP. 51). Ca S O 4 (anhy- drite, calcium sulphate) and Ca S O 4 , 2 H a O (gypsum, plaster, ala- baster) occur native. When heated to 120, gypsum parts with its water of crystallization, forming *' plaster of Paris." This plaster CALCIUM, STRONTIUM AND BARIUM. 107 soon hardens ("sets") when mixed with water and hence is used as cement, and for taking casts. (See WATER permanently hard). Ca C1 2 has so strong an attraction for water, that it is deliquescent. It is used for drying gases. (See BLEACHING POWDER). Harilim (sp. gr. 4) and Strontium (sp. gr. 2.5) resemble calcium. EXP. 131. Dissolve a bari- um salt in a little dilute H Cl and making a loop with plati- num wire introduce into the lower and outer flame of Bun- sen's burner. The flame is colored green, EXP. 132. Pulverize sepa- rately with great care Ba 2 N O 3 (oxidizing and coloring agent) K Cl O 3 (oxi- dizing agent) and gum shellac, (C and H principally, combus- tible body). Mix carefully Fig. 35. Green Fire. and thoroughly equal bulk of each upon piece of paper. Place in small mortar and ignite using the paper as a fuse. It gives green fire. Barium salts are used to give the color in green fire [in pyrotechny] and this color is a very good test for solu- ble or volatilizable salts of Ba. Heavy spar (Ba S O 4 ) is often used to adulterate white lead (F?bC O 3 ). Ba C1 2 is test for soluble sulphates. (Exp. 96.) EXP. 133. Repeat EXP. 131, using Sr salt instead of Ba salt. The flame is colored red, EXP. 1 ST. Repeat EXP. 132, using Sr 2 N O 3 instead of Ba2 N O 3 . Red fire results. Strontium salts are used to give the color in red fire, and this color is a very good test for soluble or volatilizable salts of Sr. 108 CHEMICAL PRIMER. CHAPTER XXXII. POTASSIUM, SODIUM, AMMONIUM. Potassium (sp. gr. .87, fus. pt. 63) is a light, bluish- white metal, soft enough (at 15) to be spread with a knife. EXP. 135. Cut a small piece of clean K and throw upon water in beaker, covering with glass plate (impurities cause spattering.) The affinity of K for O is so great that it must be kept under naptha (C le H 16 containing no O). EXP. 135 proves that it cannot be found free or native. The compounds of K are widely distributed. They are constituents of all plants and of the bodies of animals. K H O ( 6i caustic pot- ash ") is a white solid made from K 2 C O 3 by action of Ca 2 H O (and heat). K 2 CO 3 -f CaSHO = 2KHO -J- CaCO 3 It is largely used in the manufacture of soap. It is one of the strongest alkalies known. (See SOAP and ANTIDOTES). K.j, CO 3 (" pearlash") is prepared by leaching wood ashes, evapor- ating the " lye" in large pots (heuce potash), and purifying by crys- tallization. It is a deliquescent salt, with a strong alkaline reaction. It (or Na^CO 3 ) is largely used in chemical analysis. [See ANA. CHARTS, silver, lead, etc.] It reacts with insoluble silicates by change of partners. The metallic tassium potassium , The metallic silicate + * = J -j- carbonate (insoluble) (soluble.) H K CO ; (bicarbonate of potash, " saleratus," acid salt with alkaline reaction) may be prepared by passing C O 2 through strong solution of the normal salt (K 2 C O 3 ). H 2 O + CO, = H 2 C0 3 KCO 3 + H 2 CO, = 2HKC0 3 POTASSIUM. 109 Potassium nitrate (KNO 3 saltpetre, nitre) is formed by the decomposition of refuse organic matter. The white incrustation often seen about such matter is principally K N O 3 . It is a strong anti- septic, and is used with Na Cl (common salt) for preserving meat. It is largely used in the manufacture of gunpowder. When gun- powder burns, the reaction may be represented thus : 2KNO solid oxidizing C 3 = K 2 S -f- N 2 + SCO, solid iibustible nhstance. solid combustible substance. ga at teinperatur of explosioi Fireworks are composed of gunpowder containing an excess of C and S with coloring matter. Potassium chlorate (K Cl O 3 ) is a good oxidizing agent. (Exp. 80 and 100, and MATCHES. ) K 2 Cr 2 O 7 forms chrome yellow with lead salts. (ANA. CHARTS.) The intensely poisonous K C N dissolves gold and silver cyanides for electroplating. K Cl resembles Na CL Potassium salts are largely used in medi- cine. Sodium (sp. gr. .97) is a light, silver-white, soft metal. EXP. 136. Place a small clean piece of Na on water and quickly press below mouth of inverted test tube by means of wire gauze at- tached to wire. The water is decomposed and the H, set free, collects in test tube. (If Na is thrown on hot water the liberated H im- mediately takes fire.) H. Fitr. .'Hi. Decomposing Water Na -|- H 2 O Na H O -f Sodium resembles K. It is not found free and must be kept under naptha. It is used as a reducing agent in pre- paring Si, B, Mg, and A.l. Sodium imparts a yellow tinge to flame. 110 CHEMICAL PRIMER. EXP. 137. Repeat^Exp. 131, using sodium salt and potassium salt respectively instead of barium salt. Sodium gives yellow and potassium purple flame. Sodium chloride (Na Cl, common salt) is the most abundant of the sodium compounds. It is the source from which most compounds and sodium itself are obtained. Its distribution in larger or smaller quantities is almost universal, traces which the spectroscope reveals being found in the atmosphere. It is obtained from immense deposits or beds, from saline springs and sea-water (by evaporation). It crys- tallizes in cubes [Chap. XXXIII]. It is one of our most common antiseptics. Sodium sulphate (Na- 2 S O 4 10 H 2 O, Glauber's salts) is remark- ably efflorescent. Sodium carbonate (Na 2 C O 3 10 H_, O, sal soda) is extensively used in the arts. It is made by Leblanc's process : (1.) Common salt and sulphuric acid are'heated, 2NaCl -f H,S0 4 = Na 2 SO 4 + 2HC1 The hydrochloric acid is saved by being absorbed (See EXP. 75, 70, and comments) in tower of coke wet with constantly falling water. (2.) The Na 2 S O 4 is heated with Ca C O 3 (equal wt.) and C (half its wt. ) in a reverberatory furnace. / (a.)Na 2 S0 4 -f C, Na, S -f SCO, reducing agent. (b.)Na a S -f- CaCO, Na. 2 C O 3 -f CaS insoluble The Na 2 C O 3 is then washed out (lixiviated) from the " black ash" and purified by crystallization (one of the most valuable known means of purifying crystallizable solids). Acid sodium carbonate (H Na C O 3 , bicarbonate of soda, " soda" of cook-room) has alkaline reaction, and is prepared by pass- ing C O 2 into the normal salt (see H K C O 3 ). Sodium hydrate (Na H O, . caustic soda) is made from sodium car- bonate (just as K H O from K 2 C O 3 ) and is used in the manufacture of hard soap. Sodium nitrate (Na N O 3 . Chilian saltpeter) is a deliquescent salt. AMMONIUM. Ill Ammonium (H 4 N, a hypothetical metal), as we have seen, is a compound radical, closely allied to K and Na. It has never been isolated. Its salts (H 4 N 01, sal ammo- niac, H,NNO 3 , (HaNJ.COa), etc., and its hydrate (H 4 NHO, c; ammonia water") are well known com- pounds (Exp. 37, 45, and ANTIDOTES). 112 CHEMICAL PRIMER. CHAPTER XXXIIL THE ALLOYS, SPECTRUM ANALYSIS, AND SYSTEMS OF CRYSTALLIZATION. The most important alloys (with their usual proportions) are : Aluminum Bronze Cu (9) Al (1) Bell-Metal Cu (9) Sn (2) Brass . . .Cu (2) Zn (1) Bronze Cu (95) Sn (4) Zn (1) Coin (Gold) Au (90) Cu (9) Ag (1) Coin (Silver) Ag (9) Cu (1) Fusible Metal Bi (see) Pb Sn German Silver Cu (5) Zn (2) Ni'(2) v brass ' Hard Solder Cu (1) Zn (1) Pewter Sn (4) Pb (1) Phosphor-Bronze Cu (88) Sn (10) P (1.5) Pb (.5) Shot Pb (99.5) As (.5) Soft Solder Pb (1) Sn (1) Type-Metal Pb (70) Sb (20) Sn (10) The spectroscope, next to the balance, is the most useful instrument for original chemical research. It consists of a prism, mounted upon a stand, carrying a tube with tine, adjustable slit, through which light (the rays being made parallel by a lens) falls upon the prism. The . THE SPECTROSCOPE. 113 light, refracted by the prism, is received by a small telescope, which magnifies the spectrum ("rainbow," if solar spectrum, i. e., if light is sunlight) before it reaches the eye. The spectrum of the sun has dark lines (Fraunhofer's lines), crossing it at right angles all along from the red to the violet portion, but at irregular intervals. The relative position of these lines has been accurately determined. If, instead of sunlight, the light from the sodium flame (Exp. 137) enters the slit no colored bands from red to violet, as in the solar spectrum, are seen. Instead, the spectrum is totally dark except a brilliant yellow line (d >uble) crossing the spectrum where before (in solar spectrum) was the dark line D (double). If the light of the potassium flame enter the slit, three lines appear on the dark spectrum : a bright purplish line at (what was before) the violet end, and at the other end two red lines the outer, bright ; the inner, faint. Spectra of Red range Yellow Green Blue Indigo Violet A B D E b Yellow line. Sun with few dark lines shown. Sodium. Potassium. Red lines. Purplish line. All the other metals and non-metals have characteristic spectra, but some substances require more heat than the flame of the Buusen's burner to volatilize them, and the electric flame is used. With a small spectroscope the student can easily obtain the spectra of Na, K, Ba, Sr, Co, and other metals whose chlorides are easily volatil- ized. Many rare metals have been discovered by means of the spec- troscope (caesium, rubidium, thallium, indium, etc.). By it the light of the heavenly bodies reveals the presence in those far-off suns of many elements common upon the earth (Celestial Chemistry). 114 CHEMICAL PRIMER^ Most chemical substances, when they pass from the liquid to the solid state, assume some definite form and are said to crystallize (see EXP. 34 and connection). It has been found possible to arrange all crystals in six systems, according to the arrangement of their sides and angles around certain imaginary axes, intersecting at the center of the crystals. These axes are shown only in Plates I and n of Fig. 37. 1. Regular System. Three axes all equal and all at right angles. Plates i, n, and Hi. Ex. : Common salt, alum, garnet. 2. Hexagonal System. Four axes, three equal and in one plane, making angles of 60, and one, longer or shorter, at right angles to the plane of the other three. Plates iv and v. Ex.: sodium nitrate, quartz, and ice. 3. Quadratic System. Three axes all at right angles, and one shorter or longer than the other two. Plates vi and vn. Ex.: Potas- sium ferrocyanide and tin dioxide. 4. Rhombic System. Three axes all unequal and all at right angles. Plates vin and ix. Ex. : potassium nitrate, barium sulphate, and sulphur, crystallized from solution in carbon bisulphide. 5. Monoclinic System. Three axes all unequal. Two cut each other obliquely, and one is at right angles to the plane of the other two. Plate x. Ex. : Sodium carbonate, sodium phosphate, ferrous sulphate, borax, cane sugar, and sulphur from fusion. 6. Triclinic System. Three axes, all unequal and all oblique. Plates xi and xn. Ex. : copper sulphate, manganese sulphate, boracic fvirl o-nrl -rvrk-f aaoii-iTYfc VYI rV* YTkm a+.A acid and potassium bichromate. Certain substances, like S, crystallize in two systems, and are said to be dimorphous. A very few substances are trimorphous. Anything without crystalline form is amorphous (as 'plastic sulphur). Different substances that crystallize in the same form are isomorphous (as com- pounds of the halogens with the same metal). A crystalline body splits more readily in a certain direction than others. This splitting is called cleavage. The powder of a crushed or scratched mineral is called its streak. THE ALLOYS. 115 Fig. 37. 1 10 CHEMICAL PRIMFAt. CHAPTER XXXIV. STARCH, SUG-AR, ETC. ORGANIC chemistry treats of those compounds (composed principally of C, H, N, and O, but all containing C and H) which are formed chiefly by animals or plants in their processes of growth or partial decay No line can be sharply drawn between organic compounds and inorganic. Many compounds which formerly were supposed to be pro- duced only by the " vital force" of the plant or animal, have been formed recently in the laboratory. As a rule, inorganic substances have few atoms in the molecule, while molecules of organic substances frequently contain a very large number of atoms. Often different organic substances contain the same elements in the same proportion. Thus the "empirical forlhula'' (expressing only the proportions of the elements) of cane suyar is pre- cisely the same as that of gum arabic, namely: Ci 2 H 22 O n . This peculiar relation is called isomeiism. Butyric acid and ethyl acetate, two well-known compounds, are isomeric, having the empirical for- mula: C 4 H 8 O 2 , but the "rational formula" (which attempts to rep- resent in some way the rr4 iron taimate oxalic acid tanuic acid iron oxalate (ink) acid (soluble) The iron oxalate and tannic acid formed should be immediately washed out of the cloth, else the cloth will be corroded. Oxalic acid 124 CHEMICAL PRIMER. readily dissolves metallic oxides, forming oxalates, and hence is used to clean brass and copper, and to remove spots of iron-rust. It is made on a large scale by heating sawdust and caustic potash (K HO). Salts of tartaric acid (H 2 C 4 H 4 O 6 ), also minute quantities of the free acid, exist in many fruits, and especially in the grape (as acid potassium tartrate, H K C 4 H 4 O 6 ). It settles during fermentation, form- ing a crust ("argol," "bitartrate of potash") which, when puritied, is cream of tartar (HKC^H^Og). Tartar emetic is a double salt: potassium antimonyl tartrate (K Sb O C 4 H 4 O,;). Rochelle salt is (KNaC 4 H 4 (i ) Citric acid (H 3 H 5 O 7 H 2 O) is the acid of the lemon, lime, etc. Its salts are also present. Malic acid (H 3 C 4 H 3 O 5 ) occurs (together with potassium malate) in most unripe fruits, especially unripe apples. Tanilic acid (H d C 27 H 19 O 17 tribasic?), or tannin, is found in the leaf and bark of most trees and of many shrubs (oak especially, in nut galls, hemlock, etc.), together with a little gallic acid (H 3 C 7 H 3 O 5 , H 2 O). EXP. 143. To a solution of tannic acid add a solution of gelatin ; a yellowish-white precipitate of gelatin tannate falls. In the process of tanning, the tannic acid unites with the gelatin of the hide, forming a tough compound (leather). EXP. 144. To a solution of tannic acid add copperas solution. Ink is formed, becoming darker by exposure to the air. (Ous salts of Fe have a tendency to oxidize and form peculiar and, as a, rule, less soluble "oxy-salts. ") 3FeSO 4 + 2H 3 C 27 H 19 O n = Fe 3 2 C 27 H, 9 O 17 +3H 2 SO 4 copperas tannic acid INK corrodes pens. Leather is blackened by washing one side with solution of iron sul- phate, thus covering it with ink. Creosote or corrosive Miblimate (Hg C1 2 ), antiseptics, are used to keep ink from moulding. The alkaloids are organic bases (see comments EXP. 3 and 4) and they form salts on the ammonia type. Many of them have a bitter taste, are powerful poisons, and valuable medicines (see ANTIDOTES). The liquid alkaloids ALKALOIDS. 125 (few) contain C, H and N, while the solid (nearly all) con- tain C, H, N, and O. Their salts e occur in the plants from which the are obtained. XOTE. The theory of types has done much to advance the science of chemistry. The pupil, however, must distinguish between theory a,ndfact. The formation of compounds on the water type is strictly represented thus: H H O = water N0 2 H O nitric acid in which the negative radical, iiitryl (N O.,), replaces an atom of H in the molecule of water. So: SO, I: O., = two molecules of water, O., = sulphuric acid in which two atoms of H in the water have been replaced by the neg- ative radical sulphury 1, S O 2 . The reaction in EXP. 15, written strictly to represent the water type, becomes: Na H O -f C ., H 3 O H H H It is easily seen how the negative radical, usually considered by chemists as the replaceable and replacing quantity in reactions, is ob- tained from the negative "grouping," viz. : by subtracting one atom of O from monad groupings, two from dyad groupings, etc. Negative radicals usually take the termination, yl. Again, binary acids and salts can not in any strict senxe be referred to the water type as in this book, but must be referred to the hydrochloric acid type. The formation of compounds on the ammonia type is shown in the following formulas, the connecting element being the triad, nitrogen. The examples given are artificial compounds (alkaloids) : H H H N ammonia H H phenyl- C,H 5 N amiiie H (aniline) H N ethylamine 0,5 N dieth y 1 - amin e C 2 H 5 N triethyl-amine. If the H of ammonia (one or more atoms) is replaced by a positive radical, an amine results; if by a negative radical, an amide; if a pos- itive and a negative both take part in the replacement, an aikalamide all giving rise to very hard na'mes. The ammonia type should be 126 CHEMICAL PRIMER. considered only in this respect by beginners. Ammonia forms salts with the acids, without replacing the hydrogen of the acid. The alkaloids do the same thing. Ex. : H 3 N -}- H Cl = H 4 N Cl. Ammonium chloride may be written, H NH Cl; chloride of ammonia, so C 6 H 7 N, HC1 = chloride of aniline, and C 17 H 19 N O 3 H Cl, 3 H 2 O chlo- ride (or "hydrochlorate") of morphia (with water of crystallization). (For fuller account of each alkaloid, see cyclopedia.) Morphia (C n H 19 N O 6 , H, O), or morphine, is the principal alka- loid in opium, the dried juice of the poppy. In small doses it acts as a xedative; in large doses, as a narcotic poison. It is combined with me- conic acid in the plant as meconate of morphia. A salt of morphia, (sulphate or chloride, usually) is sold at the drug stores as ' 'morphia," and the same is true of many other alkaloids. Laudanum is tincture of opium; paregoric, a camphorated tincture, flavored with aromat- ics. Many patent concoctions for "soothing" children contain opium, and are very pernicious. On i nia, or quinine (C 20 H 24 N 2 O 2 3 H 2 O), is obtained from the bark of the cinchona, a tree found native in Peru. It is largely used in medicine, especially in feyers. It has a bitter taste. Aeonitia, or aconite (C 54 H 40 N O 2 ), is obtained from aconite leaves and root. It is used in fevers to cause perspiration (sudorific). It is one of the most violent poisons known. Strychnia, or strychnine (C 21 H^N. 2 O 2 ) is the alkaloid in mix vomica (seeds) and the St. Ignatius bean. It also is one of the most poison- ous of the alkaloids. It is largely used in medicine as a nervous tonic. It is intensely bitter. Atropia (C 17 H. 23 N O 3 ) exists in belladonna, or Deadly Nightshade, as malate of atropia. Nicotia, or nicotine (C w H 14 N.J, is the volatile liquid alkaloid of the tobacco plant. It is intensely poisonous, but unfortunately, being so volatile, its smoke does not kill. The human system at length becomes tolerant of the presence of the poison, even in the stomach. As a rule, it stupifies and clouds the intellect, especially of persons not full grown. Those boys who are great smokers rarely take a high standing in their classes. The alkaloids are very numerous, as are also the vegetable acids. For tests see larger text-books. DYEING. 127 CHAPTER XXXVI. DYEING. EXP. 145. Dissolve a little aniline blue (C 20 H 16 (C 6 H5) 3 N 3 ) in alco- hol, and dip clean, white silk thread into it. Expose the thread to the air, the alcohol evaporates and leaves the blue color adherent to every fiber of the silk. Aniline (C 6 H 5 H 2 N) is a volatile, oily liquid; colorless, when pure, but by oxidation, action of chemical agent*, etc., aniline black, red, (magenta), orange, yellow, green, blue, and violet (mauve) are produced. The reactions in the formation of the wonderful "aniline dyes" are by far too complex for introduction here. EXP. 146. Upon fine zinc filings in a beaker place a minute quantity of blue indigo, add a moderately strong solution of potassium hydrate (potash) and heat. (b)-H 2 + C 1H H W N 2 2 = C lt; H 12 N 2 2 reducing blue indigo white indigo agent Dip a piece of clean, white woolen (or cotton) cloth in the solution of white indigo and expose to the air, blue indigo is formed in its fibers by oxidation and adheres, that is, is a "fast " color (does not wash out in warm soap-suds). C 16 H 12 N 2 2 + O = C^H^N.O, -f H 2 white indigo blue indigo evaporates EXP. 147. Divide a dilute (1 per cent.) solution of picric acid (C 6 H 3 N 3 O 10 ) into two portions. Into one dip a piece of woolen yarn, into the other dip cotton yarn. Remove each and wash. The first is dyed a brilliant yellow, the second is not colored. Substances that dye directly are called substantive colors. Coloring substances may form colored compounds with the fibers of the cloth, or (usually) may merely adhere to the fibers. Cotton and linen often require different treatment from wool or silk to produce the same color, and, in general, are dyed with more difficulty. 128 CHEMICAL PRIMER. EXP. 148. Divide a solution of alum into two parts. To the first add H 4 N H O, a flocculent precipitate of aluminum hydrate (A1 2 6 HO) falls. To the second acid a few drops of solution of cochineal (car>ii(i- ink), and then H 4 N H O. Al, 6 H O is precipitated as before, and slowly settles, carrying all the coloring matter down with it, forming a "tofe." 8ome other metallic hydrates (or oxides),, especially of tin and of iron, have the same great affinity for organic coloring matter. The compounds they form with coloring matters are called lakes. The hydrates also have "great affinity for" (adherence to) the fibers of cloth. Every one knows, that, though "dirt" can be readily washed from a white apron, iron rust is removed with great difficulty (only In- chemical agents see OXALIC ACID). Hydrates (or salts, from which the hydrates may be produced), that have a great affinity for coloring mut- ter and also for the fiber of cloth, are called mordants, and a color that will not dye directly, but needs a mordant, is called an adjective color. Coloring by means of mordants is the usual method. The most common mordants are copperas, tin salts, and alum. The cloth is first dipped into a solution of the mordant and then into the dye. Different mordants produce different colors, when used with the same dye. The mordants may be applied by means of stamps (or rollers) and any pat- tern (as for calico) brought out in the various colors. EXP. 149. Boil a piece of Fe S O 4 in nitric acid (90 per cent.), till red flumes cease to appear; dilute and filter. Preserve filtrate (Fe.,3 SO + . "persulphate of iron "). Dip clean silk into this ferric sulphate (mor- dant) and leave for a few minutes. Drain, and immerse in solution of potassium ferro-cyanide (dye). It is colored a deep blue (Prussian blue). 2Fe,3SO i -f 3K 4 Fe(CN) (; = 6K,SO 4 + (Pe 2 ) 2 3Fe (C N) (i mordaut dye ferric ferro cyanide Prussian Mm- The reactions of the organic dyes with their mordants are too com- plex to be written out. Indeed, many of them are unknown. The most common coloring substances are madder (coloring principle aliza- rin, now made artificially from coal-tar), cochineal (dried insects from cactus of Central America, coloring principle, carmine), logwood, indigo, litmus, etc. (See DYEING, in cyclopedia). OILS, FATS, RESINS, KTC. 129 CHAPTER XXXVII. OILS, FATS, RESINS, ETC. There are two great classes of oils: Fixed and Volatile (or Essential). Fixed oils cannot be distilled without decomposition into various hydrocarbons. Volatile oils can be readily distilled. Fixed oils are salts (using the term in a wide sense). Hard fat is principally glyceryl stearate (" stearin"), soft fat, glyceryl palmitate ("palmitin"), and liquid fat, gly- ceryl oleate ("olein"). Fixed oils, when boiled with an alkali (K, Na, etc, hydrate), react with the alkali to form a "soap," and "glycerine." (TABLE No. 2). Exr. 150. Mix a strong solution of caustic potash (K H O) with olive oil and boil for about twenty minutes. 3KHO + C 3 H 5 3C 18 H 33 0. = 3KC 18 H 33 O 2 -f C 3 H 5 3HO potassium glyceryl oleate potassium oleate glyceryl hydrate hydrate (olive oil) (soft soap, because it is a (glycerine) ("lye") deliquescent salt) Set aside to cool, the .soap and glycerine separate. Olive oil contains some glyceryl palmitate, so that the soap is partly potassium palmitate. If tallow be taken in place of olive oil, the soap is principally potassium stearate. Inspection of the reaction reveals the whole story of soap-making. If "caustic soda" is taken with tallow, the reaction becomes caustic soda glyceryl stearate hard soap glycerine (not deliquescent) Potassium forms a soft soap and sodium a hard soap. Ca forms an insoluble "lime soap." M.g also forms an insol- 130 CHEMICAL PRIMES. uble soap. Insoluble soaps are sometimes used in medicine and in the arts. Solutions of soluble soaps (K and Na) are good solvents of the cuticle and of many forms of "dirt," and hence are valuable cleansing agents. They must be used, however, with soft water. If soft soap (for instance) is put into hard water (i. e., containing Ca S O 4 , or other soluble sulphate), the soap is destroyed, and an insoluble ''lime soap" formed by the following reaction: CaSO, + 2KC 18 H M O 2 = K. 2 SO 4 + Ca2C 18 H M O 2 insoluble li A similar reaction takes place, if the water is only of temporary hardness (see EXP. 33). Water of temporary hardness, as we have seen, is softened by boiling. Water of permanent hardness may be softened (for washing pur- poses) by adding borax (Na, B 4 O 7 ), or washing soda (Na, C O 3 , 10 H 2 O). If the last, CaSO, + Na,C0 3 = Na, S O 4 + Ca C O, cause of (remaining in solution precipitate hardness but not affecting the soap) In making "lye" from wood ashes, the ashes are leached in a large tub containing "lime" (Ca 2 H O) at the bottom. The K, C O 3 of the ashes is carried by the hot water down through lime, and the reaction is: Ca2HO + K.CO, = 2KHO + CaCO :i "lye" If no lime is used of course the lye is potassium carbonate (impure solution), and in making soap from K, C O 3 we have (if olive oil is used) 3 K 2 C O 3 + 3 H 2 O -f 2 C 3 H 5 3 C ]8 H 33 O 2 = 6KC 18 H 33 2 -f 2C 3 H 5 3HO + SCO, M>ap Soap usually contains an excess of the alkali. Home-made soap con- tains both alkali and glycerine and is very variable in its composition, containing several fat acids united to the alkali. Soap is insoluble in salt-water and hence separates if salt be added to the "suds." OILS, FATS, RESINS, ETC. 131 " Stearin" candles are made (chiefly) of stearic acid by decompos- ing the tallow by superheated (285 P ) steam. + C 3 H 5 3C 18 H a5 2 = 3HC 18 H 35 O 2 + C 3 H 5 3HO .stf.'iiii tallow stearieacid glyceiine (stearin candles) t There are two great classes of fixed oils, drying oils and non-drying oils. A drying oil (as linseed oil, i. e., flax-seei oil), when exposed to the air, oxidizes to a hard resinous substance. A non-drying oil does not oxidize to a resinous body when exposed to the air, but instead suffers a fermentation that sets the acid of the oil free, that is, the oil becomes "rancid." For instance, the purest olive oil is not entirely free from nitrogenous material, and fungus germs, creeping in, cause the following reaction : Q, H 5 3 C,g H 33 O, -f 3H 2 = 3 H G 18 H., 3 O, + C 3 H,3HO olive oil moisture oleic acid glycerine from air As we have seen, glycerine (C 3 H 5 3HO) is a "by- product" in the manufacture of soap. Glycerine is classed by chemists as an alcohol. It is a viscid, sweet liquid, a good solvent and a valuable antiseptic. Jt is useful in dressing wounds, because it is not volatile, but protects from the air and keeps the part moist. Glycerine, treated with nitric and sulphuric acids, becomes the fearful explos- ive nitro- glycerine (C 3 H 5 3 N O 3l glyceryl nitrate). Volatile oils (or Essential oils) are of vegetable origin. They exist in the petals of flowers, in leaves (of mint), in seeds (of carraway). in rind of fruit (of orange, lemon) and in the root (of sassafras). They are usually obtained by distilling with water (passing steam over), from the part of the plant containing them. They do not make soaps. Their "solution" in alcohol is called an essence. Adulteration with a fixed oil is easily discovered by evap- orating on white paper and noticing that a grease spot is left. Oil of Turpentine (C 10 H 16 "spirits of turpentine") is obtained from the "pitch" of pines by distillation." It is an excellent ftolrr.nt, 132 CHEMICAL PRIMER. dissolving the resins to form varnishes. A large class of volatile oils are pure hydro-carbons, many having the same empirical formula with oil of turpentine, though widely different in properties. Of a second class Camphor (C U1 H 16 O) is a type, as oil of bitter almonds, fcinnamon, spearmint, etc. These all contain O. A third class of "strong smelling'" volatile oils contain S. Ex : Oil of mustard, horse-radish, onion, etc. A resill is an essential oil oxidized. ("Rosin" is the resin of "tur- pentine"). A balsam is an oleo-resin, i. e., a resin dissolved in a volatile oil, or a volatile oil partially oxidized. Ia balsam is distilled, the essen- tial oil passes over, leaving the resin behind. Shellac is a resin obtained from lac, the juice of an East India tree. Amber is a fossil resin. (J inn resins are milky exudations from many plants, which after- ward solidify in the air. Gutta-percha is obtained from the juice of an East India tree, as is also gum-benzoin, the chief source of beiizoic acid (HC T H 5 O,) India-rubber (caoutchouc) is the solidified juice of certain tropical trees. Vulcanized rubber is made by heating the rubber with sulphur ((loodyear's patent). CHAPTER XXXVIII. ANTIDOTES. When a person is taken suddenly and violently ill after eating some- thin g, poisoning may be suspected. A poison is a substance, which, if introduced into the animal system, may produce morbid or deadly effects. We give antidotes, either (1) to get rid of the poison at once (bv means of an emetic, or cathartic a mechanical anti dote), or (2) to hinder its absorption (as when we give a chemical antidote to form an insoluble compound with the poison: see EXP. 11), or (3) to counteract its effect (as when we give stimulants for the poison of serpent bites, for nar- cotic poisons, etc.). ANTIDOTES. 133 EXP. 151. Shake up thoroughly the white of an egg in a bottle half filled with water and filter. The filtrate is a solution of albumen. Arrange test tubes containing very slightly ac'd solution of soluble salts of Hg (corrosive sublimate), Cu,TZn, Sn, Fe (copperas), Ag (nitrate), Pb and As respectively. Into each let fall two or three drops of albumen solution. Insoluble compounds (of albumen and the metal, formula too complex to be written) are precipitated. Albumen (milk, Hour and water, and especially raw eggs) is an excellent chemical antidote for metallic salts. As precipitates are not absolutely insoluble in the stomach, they should be immediately removed by an emetic. The best emetic is the common one, "mustard" (a tea- spoon t'ul in a cup of preferably warm water). When- ever poisons are to be removed by an emetic, warm water should be freely drank to rinse out the stomach thor- oughly. Oils (fats, butter, and lard) and mucilaginous drinks (as flax-seed tea) are always beneficial, both immediately and for treatment afterward. In general, whatever would be good treatment for a burned, bruised, or injured skin, is good treatment for the mucous mem- brane of the alimentary canal, burned and irritated by some poison. If silver nitrate or corrosive sublimate are quite strong, the antidote must be given within a few seconds, or the poison will have done its worst, and recovery, if it takes place at all, must depend upon after treatment. A rather large dose of a mild cathartic (as castor oil) is much to be preferred to the emetic whenever strong solution of either sublimate or nitrate has been taken. The best antidote for silver nitrate is salt and water, as we have inferred from EXP. 5. If the other metallic salts (except, see cyanides below) have been swallowed, especially in the solid state (powder), the antidote may be given later (from ten to twenty minutes) with hope of its doing good. But the danger rapidly increases with tli" lapse of time. Most salts of Zn and Sb (also Cu S Oj are fortunately emetics themselves, but if vomiting does not occur, prompt action must be resorted to. The best autidote for zinc, copper, or iron sulphate is sodium carbonate, "washing soda " (followed by emetic). 134 CHEMICAL PRIMER. ZnSO -f N ai C0 3 = Na S O -f Zn C O insoluble The best antidote for arsenic (or Sb) is fresh, moist ferric hydrate, Fe.j 6 H O. It is best precipita^d when needed (by mixing H Cl solution of ferric chloride and sodium carbonate). An. insoluble ferric arsenate (Fe 2 & As O 4 ) is formed in the stomach. Chalk and oil mixed may be given to envelop the particles of As mechanically, but the thing to be depended upon ordinarily is the emetic. "Carefully prepared iron filings (Exp. 125) is a good antidote for cop- per compounds (with emetic)." Attfield. A careful dose of potassium ferrocyanide, is also a good antidote, as Cu,, Fe (C N) 6 is insoluble. Magnesium sulphate (Epsom salt) [Exp. 11] is the best antidote for lead and barium compounds (\vith emetic). Ammonium carbonate (small dose of 5 per cent, solution, as itself is poisonous) is the best antidote for tin compounds (with emetic). Example : f Sn C1 2 -f (H 4 N), C 5 -f H, O = 2 H, N Cl + Sn 2 HO + C O, precipitate The antidote for acids sulphuric, nitric, hydrochloric, etc.) is magnesium carbonate (see Reaction, class 4), chalk, lime-water or soapsuds. The antidote must be given within a few seconds if the acids are strong. For oxalic acid, lime-water (Exp. 14) or chalk is the best antidote. Prussic acid (K C N) and other cyanides require stimulants, as cold douche to ille spine, dilute ammonia water inhaled and ammonium car- bonate given in small d '-^x (see snake poison below). If prussic acid is strong there is no antidote. Give no emetics with acids (unless acid is very dilate), but administer oil freely (olive). The antidote for alkalies (caustic potash ("lye"), caustic soda, etc.) is a dilute acid, preferably the most common one vinegar (acetic). KHO + HC. 2 H :( 0., = KC, H 3 O, -f H, O soluble but harmless salt Or tartaric acid, "cream of tartar," citric acid (lemon juice) etc. (If these are not at hand and the mineral acids are given, the acid must be very dilute and given sparingly. A n overdo*' would he substituting one poison for another}. ANTIDOTES. 135 If the caustic alkalies are strong, the antidote must follow in a few seconds, or it will be of no avail. Give no emetic with alkalies, (unless they are very dilute, and no other remedies as the above, or oil, can be had). For narcotic poisons (as opium, morphine, cholera medicines, : 'soothing syrups"), and the alkaloids in gen- eral, the emetic is to be relied upon chiefly, though tannic acid (strong tea or coffee) may be given, as it forms an insoluble compound with many alkaloids. The narcotic poisons require in addition to the emetic, stimulants (strong coffee, brandy, ammonium carbonate avoid overdose of latter, see below) and vigorous efforts to keep the patient awake. Aconite calls for stimulants. Strychnine requires above all the emetic, also the inhala- tion of chloroform or ether to check spasms. Patient must be kept as quiet as possible. The emetic should be promptly given in case of poisoning by unhealthy fish or meat. Oils should follow (and paregoric in severe cases). Phosphorus poisoning requires the emetic and mucilaginous drinks with magnesium hydrate, followed by large doses of the cathar- tic (purgative) castor oil. It is not generally known that carbolic acid is a more dangerous poison than strychnine. Strichnine kills "deliberately" and with a smaller dose, but carbolic acid does its work quick. Strychnine gives time (10 to 30 mimites) to hunt up antidotes, or call a physician; but if a teaspoonful of strong carbolic acid is taken, usually no remedy will save life after thirty seconds have elapsed. As it is frequently used in sick rooms for bathing purposes (diluted), its well known odor is no protection in such cases. Olive oil (butter, lard, etc. ) freely given, followed by castor oil (cathartic) is its best antidote. Give no emetic. For the bite of poisonous serpents (poison, a powerful sedative), stimulants, as alcoholic liquors, but best of all, ammonium car- bonate (a teaspoonful of 10 per cent, solution, which may be carried in small vial, tightly corked, in the vest pocket) should be taken within a few second*. The dose of ammonium carbonate should be 136 CHEMICAL PRIMER. repeated twice at intervals of ten minutes. If possible, the wound should be immediately cauterized (by nitric acid, caustic potash, etc.), or a ligature put about the limb above, and the poison sucked out from the wound (the poison is harmless in the stomach). The pupil will notice, that in most cases of poisoning, the emetic is given. He should charge his memory with the few exceptions [moder- ately strong acids, alkalies (also silver nitrate, corrosive sublimate) and carbolic acid], and give emetics in all other cases. A physician should be called in all cases of serious poisoning to direct the after-treatment. Poisons should never be left within the reach of children. They should be kept by themselves, apart from non-poison- ous medicines. They should be kept plainly labeled as poisons, and any substance in an unlabeled bottle should be promptly destroyed. Whenever a poison is bought, its antidote should be bought, placed beside it and plainly labeled. After this is done, it should be remembered that "an ounce of prevention is worth a hundred pounds of cure." MISCELLANEOUS QUESTION S. 1. Tell what you know of S O., (3 lines). 2. Tell what you know of H.^ S. 3. What is glass ? How annealed ? 4. How might you tell whether, or not, a white powder was As^O :1 '! 5. Give Marsh's test for "arsenic." How told from antimony ? 6. What is an alloy? amalgam? metal? 7. What three methods of "mining for gold ?" and tell much more about each than you find in this Primer (20 lines). 8. For what is platinum used ? 9. What would you do, if you had taken by mistake nitrate of Ag ? 10. How would you test for corrosive sublimate (Hg C1 2 ) ? 1 1 . Why can some metals be cast, while others can not ? 12. What is "white lead," and how made? 1 3. What is the antidote for lead acetate ? 14. Give Bessemer 's process for making steel. 15. What is "galvanized iron?" "tinware?" 16. What is fusible metal ? 17. Difference between water-slacked and air-slacked lime ? 18. Give reaction in making soft soap (use TABLE). 19. How is brown sugar refined ? 20. Reactions in alcoholic and acetic fermentations (CoH^O,; sugar). 21. Why is soap wasted when hard water is used in washing? 22. What is rosin ? a resin ? balsam ? tincture ? 23. What would you do, if one had taken an overdose of morphine ? 24. In what cases of poisoning should no emetic be given ? 25. What makes the bread "rise?" Explain fully. ADDITIONAL EXPERIMENTS. 137 APPENDIX. ADDITIONAL EXPERIMENTS. EXP. 1. Repeat EXP. 30 with a test tube of the right size and the H flame "siugs." It sets the column of air in vibration within the test tube. EXP. 2. Ignite a small jet of H by holding in it platinum sponge [previously heated to expel absorbed gases which (especially ammonia) hinder the action]. EXP. 3. Place a sounding tuning-fork in a jar of H; the tone is raised to a shrill pitch. EXP. 4. Burn a minute jet of O (driven by reservoir (1) from holder (3) as in frontispiece) in a jar of H, quickly igniting the jet by pass- ing through burning H at the mouth. (See note EXP. 25). EXP. 5. Connect H and O holders with oxy-hydrogen blowpipe, and igniting the H first, turn on the O. Place small piece of fine Pt wire (fused into glass holder) in the flame. It melts. [The rubber cork in the H holder should be well oiled and firmly bound down by strong twine fastened to shoulder of the bottle. The H should be drawn into a test tube over water and tested before it is burned in the blowpipe. If it burns quietly after taking fire it is safe to ignite jet. If it burns explosively, it is mixed with air and must not be ignited. The holder is first filled completely with water and the H or O (from generator as frontispiece 2) pressed backward expelling the water, the reservoir being kept so that the water in it shall be only about a decimeter above the water in the holder]. EXP. 6. Into a tube closed at one end (through which Pt wires are fused) filled and inverted over mercury, put 2 cu. cm. of O and 4 cu. cm. of H %nd explode by electric current. The mercury rises and with the water above completely fills the tube (except perhaps a bubble of gas, which is the result of inaccurate measurement). Composition of water is proved by synthesis, as nothing is found dissolved in the water. 10 138 ' CHEMICAL PRIMER. EXP. 7. Mix in the dark, dry Cl and dry H in a stout bottle, and with care explode by sudden exposing to direct sunshine. H Cl fumes are formed. EXP. 8. In a flask place a few minute pieces of P and cover with strong solution of caustic potash. Displace the air in the flask by passing H through the stopple of flask until the bubbles caught over pneumatic tub burn quietly. Close by wire spring the rubber tube through which H is admitted arid heat flask. 3KHO -f P, -f 3H 2 = 3KH.P0 2 -f H : , P The hydrogen phosphide (phosphine) takes fire because vapor of liquid P 2 H 4 is present and the beautiful white rings of smoke ascend. Pure H 3 P is not spontaneously inflammable. Remove heat and pass H as before and throw away poisonous liquid. CAUTION. Perform in well ventilated room (better in open air) and immediately open doors and windows after the Exp. EXP. 9.- The best test for the element P (paste, rat poison) is that of distillation. Add dilute sulphuric acid and pass vapor through a condenser (made of glass) in a perfectly dark room (and into water). The vapor is distinctly phosphorescent if even a minute quantity of free P is present. In cases of poisoning this test must be applied with- out long exposure to air, as P in presence of organic matter and air rapidly oxidizes. Exr. 10. Heat to dull redness on platinum foil, bread containing alum, boil residue in dilute H Cl, filter, neutralize with ammonium hydrate; a flocculent precipitate of Al a 6 H O falls. EXP. 11. Heat in oxy -hydrogen blowpipe the sharpened end of a stick of quicklime, a dazzling light is emitted (" lime light "). (Do not look directly at the light). EXP. 12. Add a small quantity of albumen (Exp. 151) to distille^ water, or to animal secretion filtered. Upon pure, colorless, nitric acid, in test tube of small diameter, slightly inclined, allow the liquid to trickle from a pipette. A sharp, Avhite zone appears at the junction of the two liquids, not dissipated by heat. This is an excellent test for albumen. (Urates, if present in excess, produce a somewhat similar white zone, but the zone is dissipated by heat much less than the boil- ing point. Be careful not to mistake the mere mixing of the zone by boiling, for dissipation). ADDITIONAL EXPERIMENTS. 139 Ex P. 13. Add to animal secretion containing albumen, a few drops of strong caustic potash, and filter. Add nitric acid to distinct acid reaction and boil, White coagula appear (greenish, if bile is present, brownish-red, if blood is present). A good test for albumeii. EXP. 14. Repeat sugar test, EXP. 139. Albumen, if present, must be removed by boiling and filtering. Earthy phosphates should be removed by adding caustic potash to alkaline reaction and filtering. The caustic potash used must have been kept in the best Bohemian glass bottles, and not in bottles containing lead ; otherwise Pb O falls and is mistaken for Cu 2 O. A mere yellow color is not sufficient, there must be an actual precipitate, without prolonged boiling. Perform the same experiment without heating, lout set test tube away for twelve hours instead. The Cu 2 O is precipitated. EXP. 15. Fill a test tube entirely full of clear animal secretion con- taining sugar ; add a small quantity of yeast and close the mouth of the test tube by a rubber cork, through which runs a fine glass tube half way to the bottom of the test tube. Set in a warm place for ten or twelve hours. The C O 2 , produced by the fermentation, collects in the top of the test tube, and forces the liquid out of the fine glass tube. This Fermentation Test is an excellent one for sugar in animal secretions. EXP. 16. Take the sp. gr. of a liquid containing sugar before fer- mentation and after ; every "degree" lost corresponds to the presence of 21 mgs. of sugar in 10 cu. cm. of the liquid (1 grain of sugar per fluid ounce). That is, if urinometer shows 1050 before and 1030 after fer- mentation, there are 420 mgs. of sugar in 10 cu. cm. of the liquid (or 20 grains per fluid ounce). This is an excellent quantitative test. EXP. 17. Precipitate a large amount of albumen from solution in distilled water, by adding nitric acid and boiling. Filter, wash precip- itate, and carefully dry. Arrange a dozen narrow, deep test tubes nearly filled with water. Carefully weigh out, by means of a fine pair of scales (any chemist will allow the use of his scales), 5, 10, 15 55, 60 mgs. of albumen powder, and placing in each test tube respect- ively, allow three hours for settling. By means of & very fine, sharp file, carefully mark the height of the precipitated albumen. Reserve test tubes for quantitative testing for albumen. (Phosphate should first be removed from animal secretions by alkali and filtration). For example: If 5 cu. cm. of liquid to be tested were placed in first test tube, and the precipitated albumen reaches to the mark on the test tube; 1 mg. of albumeii is present in every cu. cm. of the liquid. This is a very convenient quantitative test for albumen. Quantitative Test for Carbonic Oxide in Schoolroom* ;a* an index of the amount of poisonous " animal vapor'' present.) The proportion of carbonic oxide is generally estimated by volume and on a scale of so many parts in 10,000 of air. In pure out-door air there are about 4 parts of carbonic oxide in 10,000 of air. ^ In the schoolroom the proportion should never rise above 8 parts. Examir.ation of the following reactions and explanations will reveal the sim- plicity of the test. C, O,. 2 U> O = Ba C, O 4 -f- 4 H 2 O. -f-H, Ba 2 H O bariuin hydrate. 171 Ba 2 H O 171 rystalized barium oxalic acid. oxalate. 126 4- C O a = Ba C 3 , + H 2 O In neutralizing power . 126 gms of cr. oxalic acid = 171 gms of barium hydrate. 44gms cf C O 2 = 171 " therefore 44 gms of C O. 2 126 " of cr. oxalic acid. 1 grm C O 2 2.863 -j- gms, or 2863 mgs of cr. ox. acid. If we weigh carefully 2863 mgs of cr. oxalic acid (not deliquesced) and dissolve in 1000 cu. cm. (litre) of water, then 1 cu. )cm. of that u standard " solution will equal (in neutralizing power) 1 millegram of carbonic oxide. [Keep solution in dark bottle.] We then make a solution of barium hydrate dissolving about 5 gms in a litre of water. Suppose a jug (bottle) with tight fitting rubber ark holds 4155 cu. cm. (carefully measured), which jug we fill from the air of the schoolrom by means of a small bel- lows (blown a sufficient number of times, say 25), and take temperature of the room at the same time as 20. Into this we pour from a sp. gr. bottle (hol.iing with the glass stopple in, 100 cu. cm.) 100 cu. cm. of the barium hydrate solution and shake thoroughly at intervals. We now fill the burette (frontispiece 5) with the " standard" solution of oxalic acid, to a point a little above and run it down carefully drop by drop to the point precisely. Measuring from barium hydrate solution (by means of another sp. gr. bottle holding 50 cu. cna.) 50 cu. cm. we pour it into a clean, wide-mouthed bottle and add a little blue litmus solution. We now open the burette and allow the acid to run slowly (the last drop by drov) into the wide- mouthed bottle containing the 50 cu. cm. of barium hydrate solution. It takes say 24.5 cu. cm. of acid to neutralize the alkali (when the last drop needed is added the litmus suddenly turns red). Now carefully fill the second sp. gr. boitle (previously carefully rinsed in distilled water) with the solution taken from the jug containing the schoolroom air (but this solution sh uld previously have been poured into a bottle just big enough to hold it, excluded from the air by stopple and poured off carefully after it has completely settled. This excludes the barium carbonate, a very necessary thing in the te.vt.) Again fill the burette as before and see how many ou. cm. of the acid are required to neutralize the 50 cu. cm. taken from the jug. We find in every case it requires less, because the carbonic oxide in the jug has already neutralized part of it. It requires, say, 22 cu. cm. of the acH. 24.5 cu. cm. 22 cu. cm. =2.5 cu. cm. But from equations above we know that 1 cu. cm. of the acid corresponds to 1 mg. of carbonic oxide ; therefore as we poured out only one-half of the alkali to test there were 5 rr-gs. of carbonic ox'de in the jug. From table we see that 1 mg. of carbonic oxide at 20 occupies .544470 cu. cm. of space, therefore 5 mgs. occupy 2.72235 cu. cm. The question then becomes, If in 4055 (4155-100) cu. cm. air there are 2.72235 cu. cm. of carbonic oxide, how much carbonic oxide in 10COO cu. cm. of air? We have the proportion 4O55: 1OOOO:: .72!t5: - from which we obtain 6.7 parts in 10000 as the answer, that is the room is fairly ventilated. Space occupied by 1 mg. o/C Os at different temperatures (barom. 760 mm.) Degree. Degree Cubic Cm. Degree. Degree. Cubic Cm. Degree. Degree. Cubic Cm. c p c F F 32 .50'306 21 69.8 .546328 82.4 .559336 la 59 .535178 22 71.6 .548186 29 84.2 .561194 16 60.8 .537037 23 73.4 .550044 30 86. .563052 17 62.6 .538895 24 75.2 .551903 31 87.8 .564910 18 64.4 .540753 2,i 77. .553761 32 89.6 .560769 19 66.2 .542611 26 78.8 .5?5619 S3 91.4 .568627 20 68 .544470 27 80.6 .557477 34 93.2 .570485 35 95. .572343 A factor can be worked out for Kach jug used and for each temperature, so that by a simple multiplication of the difference shown by the burette the result i- obtained. Any bright pupil can master the test in a few hours and can apply it in a few minutes by using factors. The test can be made after school or before school the next day. Such tests regularly report d would do much to awaken an interest in having a proper system of ventilation. Abominable is too tame a word to use for the ventilation "enjoyed" by many schoolrooms. METRIC SYSTEM TABLE 2 (con.) 141 METRIC SYSTEM. LINEAR 10 Millimetres (mm. ) = 1 Centimetre (em.) j 10 Millilitre:* 10 Centimetres = 1 Decimetre (dcm) 10 Centilitres 10 Decimetres = 1 METRE 10 Decilitres 10 Metres = 1 Dekametre 10 LITRES 10 Dekametres = 1 Hektometre 10 Dekalitres 10 Hektometres = 1 Kilometre 10 Hektolitres WEIGHTS. 10 Milligrams (mg.) = 10 Centigrams = 10 Decigrams 1Q Grams = 10 Dekagrams = 10 Hektograms = 1 Centigram 1 Decigram (dcg.) 1 GRAM (m.) 1 Dekagram 1 Hektogram 1 Kilogram (kgm.) 1 Metre (meter) 1 Litre = 1 Litre 1 Gram = 1 Gram 1 Kilogram = 1 Kilogram = CAPACITY. = 1 Centilitre = 1 Decilitre = 1 LITRE = 1 Dekalitre = 1 Hektolitre = 1 Kilolitre 39.37 inches. = 61 cubie inches 1 cu. decimetre 15.43 grains = weight of 1 cu. cm. of water (4) = 2 1-5 Ibs. = weight of 1 cu. dcm.(litre) of water (4) REFERENCE TABLE No. 2 CONTINUED. NEGATIVE GROUPINGS. PO 3 = metaphosphate C 5 H 9 6 5 = valerianate j C N O = cyanate C H O 2 = formate C 4 H 7 2 = butyrate (butter) C 7 H 5 2 = berizoate [NO, = nitrite fc 3 H 4 O 3 = J lactate 4 O 3 = urate 73 J B 4 7 = tetraborate (borax) >, I MiiO 4 = manganate " | Mn 2 O 8 = permanganate 1 Cr 2 O 7 =: bichromate C 4 H 3 5 = malate v-x^ *-*-3 ^5 " * ***%? JS / C 7 H 7 = meconate (opium) j Fe (C N) = ferrocyanidt C 7 H 3 O 5 = gallate g < CAT Hi = tannate Fe 2 (C N) 12 = ferridcyanide ( roan JH,N - POSITIVE GROUPING. amidogen 142 CHEMICAL PRIMER. I. ADD H Cl. . . FILTER. Precipitate insoluble chlorides Hg 2 Cl 2 (ous) Ag Cl and Pb C1 2 . Wash, boil thoroughly and filter. Filtrate, .soluble chlorides of other metals, as As, Sb, Sn, Cu, Fe, etc. and also of Hg (ic). Precipitate. . . .Hg 2 C1 2 and Ag Cl Wash with hot water and add warm H 4 N HO (Ag Cl dissolves) Precipitate H 2 NHg 2 Cl, amido mercurous chloride, black. Add two or three drops aqua regia. Di- lute with ten drops of water, and evap- orate filtrate nearly to dryness at low heat. (Water-bath is best.) Again dilute with 20 drops of water, and filter. Test as in Ex. 121. Filtrate.. Pb Cl, Divide into three portions and to the Filtrate.. AgCl. Add HN0 3 to acid re- action. Ag Cl is re- precipitated because its solvent is neutral- ized. Wash, and fuse on charcoal with a little K 2 CO 3 K,CO 3 -j-2AgCl Ag 2 C0 3 -f 2KC1 S Ag 2 C0 3 =Ag 2 0-hC0 2 2 Ag 2 O + C = O 2 -{- Ag 4 , silver globule. No incrustation on charcoal as in lead reaction. 1st add H 2 S 4 PbCl 2 4- H 2 S0 4 = PbS0 4 + 2HC1 white precipitate 2d add K 2 Cr a 7 bichromate 2PbCr0 4 +2KCl + 2HCl :hrome yellow precipitate II. Pass H 2 S gas thro' filtrate from First Group. Precipitate . Cu Hg(ic) Pb Bi As Sb Sn (Au Pt). Collect,'wash, Digest in (H 4 N)^ Precipitate Cu Hg (ic) Pb Bi. sh, boil in HNO 3 , filter Filtrate Soluble sulphides of other metals. f Filtrate . . As Sb SrT(AuPt) I Add dilute H Cl, filter, Wash, , add strong HC1 1 boil, dilute slightly, filter. 3d add (H 4 N) s S PbCl 2 4- (H 4 N) 2 S = PbS 4- 2(H 4 NCl) brownish black pre'cipitate Fuse with little K 2 C 3 on charcoal. K 2 C0 3 -j-PbSi= PbC0 3 +K 2 vS Pb C 3 = Pb + C O 2 2PbO + C = CO, +Pb a (lead globule, malleable). Bi and Sb are brittle. Heat globule in >xidizing flame of blow-pipe ; a yellow incrustation (Pb O) appears upon the charcoal. a (ic). Black. Confirm by EXP. 121 in original filtrate. Filtrate Cu Pb Bi Add H 4 N H O, filter. Ppt, As. I Yellow. - Confirm Filtrate.. Sn Sb. Pour into H-apparatus, and obtain antimoriial spot, Exi'. 113. Precipitate PbBi Wash, add a few drops H N O 3 dilute, filter. Ppt. Bi. Fuse on charcoal with K 2 C 3 Brittle globule. Filt. Pb Dilute, add H 2 S O 4 set aside White ppt. Filtrate 1 b y s (j u jExp. Ill remains on Zn. Dissolve in hot HC1 Sb (spot). dilute, add H 2 S ; a Test as in Kxr. 113. brown ppt. of Sn S falls. in EXP. 125, j after adding a drop of sulph- uric acid. Auand Pt rarely occur in solution. Au may be tested for as in EXP. 115. Ammonium chloride gives a yellow, crystal- line precipitate with solution of Pt C1 4 . ANALYTICAL C 143 111. To Filtrate from Second Group add H 4 N H and (H 4 N'). 2 S. Warm gently and filter. Precipitate. .Co Ni Fe Mn Cr Zn Al Warm gently in dilute (5 per cent.) HC1. Filtrate. Soluble com- pounds of other metals. Precipitate. .Co Ni Fuse a portion in borax bead. Blue color indi- cates Co. Add three drops aqua regia to re- maining portion, p rec ipitate and evaporate to p e Mn Cr dryness. Warm ;p use w jth with few drops of minute Co C1 2 , and dry| qua ntity of on white paper, potassium Green color carbonate and shows Ni. j nitrate. Deep green indicates Mn (potassium manganate). Boil, filter. Filtrate Fe Mn Cr Zn Al. Evaporate nearly to dryness; add Na HO, and boil, filter. Precipitate. .Fe Add tannic acid, and boil; brownish-black solution Fe. Filtrate.. Cr Add acetic acid, boil violently; add lead acetate. Chrome-yellow ppt. indicates Cr. Filtrate.. Zn Al Add H 2 S in excess, filter. Slaty white. Filtrate Al AddHCl to acid reaction, boil, filter, and to filtrate add ammonium hydrate to alkaline reaction. A flocculent precipi- tate indicates Al ( Al- uminum hydrate). IV. To Filtrate from Third Group and H 4 NH 0, H 4 N Cl and (H 4 N) 2 CO :i . Precipitate. .Ba Sr Ca. Boil in little dilute H Cl, and filter. Ba (alone) gives green by EXP. 131. Sr, by same method, red; and if neither color is seen, Ca alone gave the precipitate of this group. (If all three are present, they are sep- arated with some difficulty.) Filtrate Soluble compounds of metals of the fifth group. To Filtrate from Fourth Group add H 4 N H O to alkaline reaction and thenHNa 2 P0 4 . Filter. A crystalline precipitate of N H 4 Mg P 4 indicates Mg. In filtrate, test for Na and K flame color. by BART MORGAN & CO Market Street Station, Oakland, Cal. Will furnish the following set of Chemicals (securely bottled and carefully labelled) and Apparatus on receipt of thirteen dollars and fifty cents ($13.50), or omitting the articles marked with a star (*) will furnish the balance for eleven dollars ($11.00). The set is sufficient for the performance (with few exceptions) of all the experiments found in this Chemical Primer. CHEMICALS. Acetic Acid 8 grms. Alcohol 1 litre. Alum 8 grins. Ammonia water 100 " Ammonium chloride 4 " " carbonate 10 " Anilineblue 1 " Antimony 4 " Tartar Emetic 1 " Arsenous oxide (white arsenic).. 2 *' Barium chloride 2 " nitrate 4 hydrate 4 Bismuth 2 Borax 4 x Carbon bisulphide 2 Citric Acid 2 Cobalt Chloride 1 Copper Sulphate ... 7 Ether (common) 5 Fluor Spar 7 Gold Leaf \ sheet Gum shellac 5 grins. Hydrochloric acid 100 Indigo 1 Iodine 1 Copperas (iron sulphate) 4 Ferrous sulphide 7 Lead acetate 10 Lead oxide (litharge) 5 " Litmus paper (red and blue( . . . 1 q. icm. Magnesium sulphate., ribbon .... Manganese dioxide. . . . Mercuric chloride. .. . *Mercuric cyanide .... Mercury .... Nickel Nitric Acid Tannic acid x Oliveoil 8 Oxalic acid 2 T Piei ic acid 1 Phosphorus Potassium (under naptha). . . Potassium bichromate Potassium carbonate Potassium chlorate Potassium ferrocyariide Potassium ludrate Potassium iodide Potassium permanganate Silver nitrate Sodium (under naptha) 5 Strontium (nitrate) 2 Sulphur (brimstone) 10 Sulphuric acid 200 Tin 2 Tin chloride 5 *Tartaric acid 2 *Turj>entine . 3 Zinc (drop) 25 5 grms. 1 dcm. 100 grms. '.".'.'.'.'. 5kgm. 1 grm. 100 " 1-20 tick .5 grins. 5 " 10 " 80 " 5 " 5 " 2 1 5 APPARATUS. 2 Flasks. (*1 Flask). 1 Alcohol Lamp. 1 Evaporating Dish. *2 Beakers. 6 Test Tubes (*3) *1 Mortar and Pestle. 1 Blow Pipe. 1 metre Glass Tubing. 3 dcm. Rubber Tubing. The above set of Chemicals and Apparatus will be forwarded by ex- press on receipt of price, expressage paid by purchaser, or will be for- warded C. 0. D. on receipt of five dollars ($5.00.) NoTE.-Marble, hydrofluoric acid stand), Plates, So can be obtained -with little difficulty. 1 Iron Wire Gauze, (\ sq. dcm..) 1 Three-cornered File. 1 Round File. 1 Platinum Wire, (1 dcm). 3 Rubber Corks. *1 Pair Scales (metric weights). 1 Measuring Glass (metric;. ' 3 dcm. Copper Wire. 3 sheets Filtering Paper. Most Complete Printing and Publishing House on the Coast. PACIFIC PRESS PUBLISHING HOUSE PR I NTS Nf ENGRAVING, BINDING, mil IllU, ELECTROTYPING, STEREOTYPING. Orders by Mail or Express receive Prompt Attention. Address, PACIFIC PRESS, Oakland, Cal. Branch Office, 527 Commercial Street, !*. F. D. RYAN, B& 1170 Broadway (near 14th St. . Oakland. SULPHURIC ACID, POTASSIUM CHLORATE, MANGANESE DIODIDE, ZINC (drop), And other Chemicals used in the Laboratory. THIS CHEMICAL PRIMER may be obtained of W. B. HARDY, lit No. 961 Broadway, Oakland, Cal. A Mingle Copy will be sent by Mail on receipt of the price. ONE DOLLAR. He st works of reference upon Chemistry, Mining, Assaying, etc., always kept on hand. Special works ordered from the East.