IMAGE EVALUATION TEST TARGET (MT-3) A {/ / :a 1.0 I.I 1.25 2,5 IM 2.0 11111= U 11 1.6 Photographic Sciences Corporation 33 WEST MAIN STREET WEBSTER, NY. 14580 (716) 872-4503 ^^ iV \\ IV CLARK & CO., 9 FRONT STREET WEST, 1882. Entered according to Act of the Parliament of Canada, in the year one thousand eight hundred and eighty-two, by Copp, (Jlark & Co., Toronto, Ontario, in the Office of the Minister of A gri culture. PEEFACE All the text-books on Chemistry authorized for use in the Public and High Schools of Ontario contain far too much matter for class purposes, and as a consequence many teachers have been compelled to teach the subject by the use of notes. This little book has been prepared chiefly for the purpose of lessening the labor of note-making on the part of teachers, and of note-taking on the part of pupils. It will require to be supplemented by explanations from the teacher, for whose use most of the ordinary text-books on Chemistry seem designed. -• No apology is necessary for the insertion of a large number of chemical problems. On the utility of these as a means of teaching the subject, Professor Roscoe says : ' ' My experience has led me to feel more and more strongly that by no other method can accuracy in a knowledge of Chemistry be more surely secured than by attention to the working of well-selected problems." On this same point Professor Cooke, a leading American chemist, says in his First Principles of Chemical Philosophy : ** The value of problems as means of culture and tests of attainments can hardly be over-estimated. " I have to express my indebtedness to Professor Dupuis, of Queen's College, for valuable suggestions in preparing this manual, and for kind- ness in reading the proof-sheets. KinasTON, Febroaiy, 1883. ERRATA. Page 25, Question 1, Ans., read 89 6 litres. "26. " .3. '« 5467-75 cu. in. " 26. " 4. " 1612 grains. 1 i CHEMISTRY FOR INTERMEDIATES. ♦ — t i The science which treats of elementary substances, the modes or processes by which they are combined or separated, the laws by which they act, as well as the properties of the compounds which they form, is called Chenmtry. The subject admits of a two-fold division ; viz., into Organic and Inorganic. Organic Chemistry treats of the composition and properties of substances that have been formed by the agency of animal or vegetable life. More correctly defined, it is the chemistry of the carbon compounds. Inorganic Chemistry treats of the composition and properties of bodies formed without the agency of life. It is the chemistry of water, earth and air. Atomic Theory.— All substances are supposed to be built up of very minute and indivisible particles, called atoms. It is asserted that these atoms are of different sizes, and differ from each other in weight. All substances can be divided into two classes— Simple substances or Elements, and Compound substances. A chemical element or simple substance is one that has not been decomposed into two or more dissimilar bodies. Examples : gold, sulphur, and arsenic. There are 65 of those elements ; according to some chemists 67, and from one or more of these, every substance in nature is built up. 2 6 CHEMISTRY FOR INTERMEDIATES. The following is a list of some of tl»e moHt impoi-tant of them, with their symbols and atomio weiglits : — Non- Metallic Elements. Metallic Elements. Oxygen ......0 = 16 Iron Fe = 66 HVDUOOEN H = 1 Aluminum Al = 27.5 Nitrogen N = 14 C =12 Calcium Ca = 40 Caubon Magnesium Mg = 24 Chlorine CI - 35.5 Sodium PoTjMSIUM ...... Na K - 23 Sulphur 8 = 32 =r 39.1 Phosphorus P - 31 Copper ...... Cu = 63.5 Silicon Si =28 Zinc Zn = 65.5 Tin Sn = 118 liEAD Pb = 207 Mercury Hg = 200 Silver Ag - 108 Gold All = 197 Arsenic As = 75 Antimony Sb = 122 Bismuth Bi = 210 Hie elements are usually divided into two classes, Metals and Non-Metals, there being 52 of the former, and 13 of the latter. Metals are characterized by having a metallie lustre, and some, by being malleable, ductile, &c., but no distinct line of difterence can be drawn between metals and non-metals. The Non-Metals, or Metalloids, are distinguished by the absence of these properties. Another division is 15 metalloids and 50 metals. A compound substance is one formed by the union of two or more of the above-named elements. Examples — water, earth, and wood. There are thousands of these compounds known to us. It is customary to distinguish between two kinds of compounds : — 1. Chemical Compounds. 2. Mechanical Compounds or Mechanical Mixtures. A chemical compound is one in which the elements com- posing it are united in such a way as to form a substance differing in properties from those of any of its constituent elements. For example, the gas chlorine and the metal sodium unite to form com- 4 CHEMISTRY FOR INTERMEDIATES. 7 mon salt — a substance differing in properties from those of both chlorine and sodium. A mechanical compound is one in which the particles of the substances composing it lie mixed side by side, undergo no change, and preserve their distinctive properties. Example — charcoal, sulphur and nitre in gunpowder. The force which unites the particles of a mechanical compound is called adhesion. Adhesion is somcoimes defined as the phenomenon which occurs when portions of dissimilar substances cling together. Physical States of Matter. — Every substance, whether simple or compound, exists either as a solid, a liquid, or a gas. Some substances may be made to take any of these forms, by varying their temperature. Ice, water, or steam is the same substance in three different physical states. So, most of the elements, and many compounds, may be made to take the solid liquid or gaseous form by simply altering their temperature. All of the elements except carbon have been melted ; all gases have been liquified, and possibly solidified. Cohesion is the force which makes, or tends to make, bodies take the solid form. Distinction between Vapors and Gases. — Vapors are sub- stances in the gaseous condition, which, at ordinary temperatures, are liquids or solids. Gases are substances which exist in th. gaseous condition at ordinary temperatuies. Liquefaction, is the conversion of a solid into a liquid. Solidification, is the conversion of a liquid into a solid. Vaporization, is the conversion of a liquid into a gas. Sublimation, is the conversion of a solid into a gas without liquefaction. Condensation, is the conversion of gas into the liquid or solid form. Distillation includes, first vaporization, and then condensation, and is carried on usually for the purpose of separating a liquid from impurities contained in it. 8 CHEMISTRY FOR INTERMEDIATES. CONSTITUTION OF MATTER. An atom ia the smallest particle of an element that can enter into » chemical compound. A molecule consists of two or more atoms, and is the minutest particle of a compound or of an element capable of independent exist- ence. An atom cannot exist alone, but at once unites with another atom to form a molecule. Chemical a£anity or chemism is the force that binds atoms together to form molecules, and molecules together to form definite chemical compounds. The molecule of each element consists of two atoms ; but the mole- cule of phosphorus as well as that of arsenic contains four atoms, while that of mercury and that of cadmium consists of one each. Molecules of compounds contain two or more atoms. The Volume of any substance is the space occupied by it. In chemistry, if no unit of volume be mentioned, it is frequently under- ; stood that one volume of an element or compound is the space occupied ihy one molecule of it in the gaseous condition. Chemical Notation is the art of designating chemical elements -or compounds by means of symbols. A symbol is the first letter of the name of an element. Some- times two letters ai-e used to distinguish one element from another beginning with the same letter. The symbols of important elements will be foimd on page 2. Each symbol stands also for a definite weight of each element, called its atomic weight The Atomic Weight of an element is the num ber representing how many times its atom is heavier than an atom of Hydrogen. A chemical formula consists of two or more symbols written side by side, and denotes that the elements for which the symbols . stand have united to form a chemical compound. The Symbol of an element stands for three distinct things : — (1) The name of the element. (2) One atom of the element. (3) The atomic weight of an element . 1 . i I CBEMISTRT FOR IKTERMEDIATES. 9 A small numeral written at the lower right hand comer of a sym- bol denotes that the atom and atomic weight is doubled, tripled, &c. The formula of a compound substance stands for : — (1) The name of the compound, (2) One molecule of the compound, (3) The molecular weight of the compound, (4) Two volumes of the compound in the gaseous condition. A numeral placed before a formula multiplies every atom and atomic weight in it, as far as the first comma, plus sign, or period, The molecule, Oj consists of 2 atoms. H, (( << « (( (( » « (( « « tt li cc Naj P, « 4 of the compound H^O consists of 3 atoms. KCIO, " 5 P2O5 " 7 C,«H^ « 48 " « « (( (( a6*-^32 Each of these eight molecules occupies the same space or volume in the gaseous state. A chemical equation consists of signs and formulse, and ex- presses the fact that definite weights and volumes of certain sub- stances do, of themselves, or by means of some force applied to them, decompose and re-arrange their atoms so as to form other substances. For example, the chemical equation — CaC03 4- 2 HCl = CaClj -f U^O + CO2 100 + 73 111 4- 18 -f 44 may be thus translated : mix 100 grams (or ounces) of marble with a solution of 73 grams of hydrochloric acid; it will yield 111 grams of calcic chloride, 18 grams of water, and 44 of carbonic anhydride. All the atoms on one side of the equation must be accounted for on the other. The chemical equation thoroughly understood, enables us to calculate the amount of material required to produce a given weight of any substance ; or, the quantity of the substance produced by the decomposition of a known weight of the material. 10 CHEMISTRY FOR INTERMEDIATES. The sign -f-> Jo^«*«, placed between the formulae of two substances means that the two substances are mixed together. The sign ==, in chemistry, means " yields." CHEMICAL COxMBINATION. Chemical union may take place in certain proportions by Weight, or when the substances exist in the gaseous condition in certain pro- portions by Volume, but in both cases the combination is regulated by certain laws called laws of chemical combination. They are usually stated as follows : — LAWS. I. Constant Proportion. — " The same substance consists invari- ably of the same elements," e.g., water always consists of O and H. II. Definite Proportion. — "The elements which form a chemical compound are always united in it, in the same proportion by weight," e.g., O and H are always united, in water, in the proportion of 16 to 2. By volume, the union is always 2 vols, of H to 1 of O. III. Reciprocal Proportion. — " If two elements combine in certain proportions with a third, they combine in the same propor- tion with each other." For example, CI and Na unite with O in tha proportions, 35.5, and 23, respectively, with 16 of 0, and in tbase same proportions, 35.5 to 23, with each other. IV. Multiple Proportion. — " When one element combines with another in several proportions, the higher proportions are multiples of the first, or lowest. Thus— N2O, N^Oj, N2O3, NA» NaOg = 28 : 16, 28 : 32, 28 : 48, 28 : 60, 28 : 80." There are exceptions to this law as well as to law number three. , V. Compound Proportion. — r " The combining proportion, or molecular weight, of a compound substance is the sum of the combining proportions of its constituents," e.g., the combining weight of H3O is 2 + 16 = 18. ATOMICITY OR VALENCY. We have already seen that the elements are divided into two classes — Metals, and Non-Metals. There is another classification of the elements that is even more important than the foregoing. The principle underlying this second CHEMISTRY FOR INTERMEDIATES. U cl^jasification is the number of yolumes of hydrogen that will unite with one volume of any other element in the gaseous condition. According to this principle all the elements may be divided into six classes. To the first class will belong all those which, in the gaseous condition, unite, volume for volume, with hydrogen. Such elements bear the name of Monads. To the second class will belong all elements one volume of which, in the gaseous condition, will unite, with two volumes of hydrogen. Such elements are called Diads. If elements unite with three, four, five, or six volumes of hydrogen they are termed, Triads, Tetrads, Pentads, and Hex ads, respectively. The following table gives this classification in detail. It should be committed to memory. Monads. DiADB. TaiADs. TETRiJOa. Pentads. Hrxacs. GO i Chlorine. Hydrogen. 1 Potassium Sodium. Silver. Oxygen. Carbon. Silicon. Nitrogen. Phosphorus Sulphur. °9 Calcium. Copper. Magnesium. Mercury. Zinc. Gold. Aluminun^. Lead. Tin. Iroa. Manganese. Platinum. Arsenic. Ajitimony. Bismuth. - All the above pentads also act as triads. Manganese and iron sometimes act like hexads, and are classified with them. Sulphur usually acts as a diad, and forms compounds resembling those of oxygen in chemical properties. Some of the other elements exhibit varying atomicities. 12 CHEMISTRY FOR INTBllHEDIATES. Chlorine also may be taken as the unit by which to measure the ralency of elements and radicles. In fact, chlorine must be used in those cases in which there is no known compound of hydrogen and the element. KADIOLES. A rckdicio means any substance that is the basis or common ingredient of a series of compounds. It consists of chemical elements 80 united as to act like one substance. These radicles may act as monads, diads, triads, &o. METRIC SYSTEM OF WEIGHTS AND MEASURES. This is a decimal system, hence its advantages over the English one. MEASURES OF LENGTH. The unit is one metre and is equivalent to 39-37 inches. 10 decimetres (dcm.) = 1 metre = 39-37 inches. 100 centimetres ( cm. ) = 1000 millimetres (mm.) = 1000 metres (m.) = 1 kilometre = 39370-79 inches. MEASURES OP CAPACITY. The unit is one cubic decimetre, called 1 litre = 1-76 Imperial pints, or 61-024 cubic inches. 1000 litres = 1 kUolitre. « MEASURES OP WEIGHT. The unit is the weight of 1 cb. cm. of distilled water at 4°C, called 1 gran = 15-432 grains. The commercial unit is 1000 grams =1 kilogram = 2-2046 lbs. Avoirdupois. The subdivisions of both the litre and the gram into tenths, hundredths, and thousandths, are named by prefixing deci-, centi-, and milli-, respectively to these names. SPECflFIC WEIGHT OR DENSITY. The specific weight or specific gravity of a liquid or solid is its weight as compared with the weight of an equal volume of water at 4°C. ■ ire the ised in 3n and mmon omenta act as nglish serial "m 4°C, lbs. iths, mti-, 3 its ater CHEMISTilT roil INTHRMEDIATE8. 18 In the case of gases the comparison is made with air or hydrogen. The term density is another name for sjMJcifio weight. , In comparing the weights of different gjises any volume of H might be taken, but the moHb convenient one is 11*2 litres, which, at the standard temperature and pressure of CO and 760 mm. of mercury, weigh 1 gram. The weight in grams of 1 1 -2 litres of each of the elementary gases is denoted by its atomic weight. For example : 11*2 litres of oxygen weigh 16 grams, chlorine " 35-5 " • 14 " and so on. « (( nitrogen •' The sp. gravity (or density) of a compound gas is found by taking half of its molecular weight. Thus : 11 '2 litres of steam weigh ^= 9 grams. 11-2 11-2 « ammonia gas weigh , JJ. 8i {( " carbon dioxide " ^ = 22 " and so on. THE ELEMENTS. Hydrogen : Symbol, H ; atomic weighty \ ; molecular weight, 2. 11*2 litres weigh \ gram. Preparation : 1. By electrolysis of water. 2. By decomposing water with a cold metal as K, Na, Ba, «kc., e.g., 2 H^O + Kj = 2 KHO + Hj. 3. By decomposing steam hy means of a hot metal e.g., Fe or Cu. 4 H2O 4- Fe3 = FejO^ + 4 H.,. 4. Hydrogen is usually prepared from zinc and sulphuric acid, the chemical change being represented aa follows : H2SO4 + Zn = ZnSOi + Hj. Zinc sulphate being formed and Hj being given off. Experiments : 1. Bum a jet of H. 2. Pour H upwards. !l u CHEMISTRY FOR IMTERMEDIATES. r 3. Send up soap bubbles. Ignite some of them. Properties : Hydrogen is the lightest of all substances ; is a gas without color, taste or smell; burns with a pale flame, but does not support combustion or life, though not poisonous: When mixed with half its volume of O and ignited, an explosion takes place and water is formed. Soluble in water to tvo per cent of its volume. Uses: 1. In oxy hydrogen blowpipe. 2. In gas-making from petroleum. 3. In filling balloons. Tests: Burns, but does not support combustion; unites with O to form water ; combines spontaneously with CI to form hydric chloride when a mixture of the two gases is exposed to sunlight. EXEKCISE. What weight of H can be evolved fi ' im 392 grams of sulphuric acid ? To solve this and all similar chemical problems, pupils must know the chemical equations representing the reactions that take place when an elementary or compound substance is evolved from others. The composition of sulphuric acid is : — H2 = 2 S = 32 O4 = 64 Total = 98 Now the question is, if 2 grams (or oz , «kc.) of H can be obtained from 98 of sulphuric acid, how many can be obtained from 392 ] Rule of Three : 98 (of H,SO,) : 392 (of H^SO,) : : 2 (of H) : «; (of H). Ans. — 8 grams. 1. What weight of zinc sulphate and hydrogen will be formed by acting on 100 lbs. of zinc with 98 lbs. of sulphuric acid ? Am. 161-5. Ans. 2. 2. How many grams of hydrogen will occupy 224 litres at the standard temperature and pressure ? Ans. 20. , m 'm m 18 oui be CHEMISTRY FOR INTERMEDIATES. 15 3. Steam is passed through a tube containing red hot iron filings, and 18 litres of hydrogen pass out at the other end. What volume of steam entered the tube, and how much are the iron filings increased in weight ? Ans. 18 litres. Ans. 12^ grams. 4. What weight of water and potassium must be taken to produce 560 ounces (Troy) of caustic potash ? What weight and volume of hydrogen will be produced? Ans. 180 oz. Ans. 391 oz, Ans. 10 oz. Ans. 123 cu. ft, nearly. 6. How much sulphuric acid and zinc must be taken to form 1 12 litres of hydrogen? Ans. 490 grams. Ans. 377-5. 6. In 280 5 grains of caustic potash how many grains of potassium? of hydrogen? Ans. 195-5. Ans. 5. 7. What weight of sodium must be taken to obtain 20 grains of hydrogen from a litre of water? Ans. 4G0. 8. A reservoir of hydrogen gas holds 89-6 litres. What weight of water will be formed in burning the gas in air ? What volume of air will be required for the combustion, assuming that oxygen forms ^ of the volume of air ? Ans. 72 grms. Ans. 224 litres. N. B. —When the volume of a gas is spoken of it is supposed to be at tlie staudard temperature and pressure. 0XYGE5^. Oxygen: Symbol, 0; atomic weight, 16; density, 16; inolecular weight, Oj, 32. 11-2 litres weigh 16 grams. Preparation : 1. By the electrolysis of water. 2. By decomposing some oxides by heat, e.g., HgO, MnO^, BaOg. Oxygen may be obtained by heating the red oxide of mercury (mercuric oxide) in a test tube, the equation expressing the reaction being as follows : 2HgO = Hg,+ 0,. 3. By heating potassic chlorate and MnOg in a glass retort : MnO, + 2 KCIO3 = 2 KCl + 3 O2 + MnO^. 4. Hypochlorites, chlorites, and some nitrates, will yield oxygen on being heated. Properties : It forms eight-ninths by weight of water, nearly one- fifth of the air, and about one-third of the solid crust of the earth. mmmm 16 CHEMISTBT FOR INTERMEDIATES. It is soluble to the extent of four per cent, in water, a fact of great importance in relation to aquatic plants and animals. When free it exists as an invisible gas without taste or smell. By cold and pressure it has been made to take the liquid and even the solid form; it unites with all the other elements, except fluorine, to form oxides ; powerfully supports combustion ; and is that element in air which sustains animal life, hence called vital air. In respiration we simply take oxygen into the system, and this causes slow combustion of the tissues, and consequently gives rise to animal heat. Experiments : Sulphur, potassium, phosphorus, charcoal, a piece of wood, steel-wire, and zinc foil, may be burned in jars of the gas. Ordinary combustion or burning is simply chemical action, attended by great heat and light, chemical compounds being formed. Tests : Oxygen is the great supporter of ordinary combustion. A glowing splinter of wood bursts into flame when plunged into it. Nitric oxide forms reddish fumes with oxygen. Potassic pyro- gallate absorbs oxygen, and is changed to a black color by it. OZONE. Ozone : Symbol, 0^ ; molecular weight, 48. This substance is merely a modified form of oxygen, being one in which there are supposed to be three atoms in the molecule instead of two. Preparation : 1. By the silent discharge of electricity through oxygen. Thus treated, O decreases in bulk by ^. 2. By placing a stick of clean phosphorus in a bottle of air with a little water on the bottom of it. 3. It is produced in small quantities by almost any molecular disturbance of oxygen. Properties : Ozonized oxygen has a strong, oppressive odor, corrodes india-rubber ; oxidizes silver, mercury, and many other metals, and, in doing so, undergoes no diminution in volume ; possesses mmM CHEMISTBY FOR INTERMEDIATES. 17 great disinfecting powers, and is a powerful bleaching agent. If breathed in small quantities it is said to be beneficial in the treatment of affections of the throat and lungs. Test : Ozone turns a mixture of iodide of potassium and starch a blue color, but this test is not reliable. EXERCISE. 1. How many lbs. of potassic chlorate must be taken to obtain 144 lbs. of oxygen? Ans. 367-8. 2. I want 220 grams of oxygen. If I obtain it from potassic chlorate, how mach of it must I use ? If from water, how much ? If from mercuric oxide, how much? Ans. 561'9. Ans. 247 5. Awa, 2970. 3. A gas bag is capable of containing 56 litres, how much potassic chlorate must be taken to procure enough oxygen to fill it ? Ans. 204^ grams. 4. 25 litres of oxygen are exploded with 36 of hydrogen. What volume vi any gas (if any) remains ? What volume of steam is produced ? And what is its weight? Ans. 7 litres of O. Ans. .36. Ans. 44 8. 5. How much oxygen can be obtained from 435 grams of manganese dioxide by heating it to a red heat? Ans. 53 '.S. 6. What volume will 80 grams of oxygen occupy at the standard tem- perature and pressune ? Ans. 56 litres. NOMENCLATURE. Chemical Nomenclature is the system of naming chemical compounds. I. In naming binary compounds, or compounds of two elements, we attach both prefixes and affixes to the names of the elements. 1. -ic is generally attached to the name of the first element. 2. -IDE is attached to the name of the second element. For example, KCl is named potass-ic chlor-iDE. -uret is an old ending, sometimes used instead of -ide. 3. Compounds of oxygen with other elements, when one, two, three, four, or five atoms of oxygen enter into the compound, are, with some exceptions, called respectively mon-oxide, dioxide, tri- oxide, tetr-oxide, pent-oxide, of the first element. 4. Another mode of designating the compounds of oxygen is by using the endings -ous and -ic, both being attached to the fii-st 18 CHEMISTRY FOR INTERMEDIATES. element ; the former, when a smaller quantity of oxygen enters into the compound ; the latter, when a larger quantity. 5. Sesqui-oxide and sub-oxide are old terms. EXERCISE. Name the followiag binary compounds : NaOl, CuS, NjO, NjOa, NaOs, N,0^, NaOo, HCl, HaS, CO, COj, CaClj, CSj, P^0„ CuO, HgO, KaO. FeO, FCaOa, AsaOg, ASaOj. II. Hydrates or Hydroxides are compounds formed by the union of an element, or radicle, with the radicle, OH (Hydroxyl), e.g. : KHO is called potassic hydrate. Ca (011)2, is called calcic hydrate. Hydrates are divided into two great classes : Acids and Bases, Generally speaking hydrates of the metals are bases, and hydrates of non-metals are acids. We can also divide oxides into acid oxides and basic oxides, according as the corresponding hydrate is an acid or a base. Acids possess the following properties : 1. They have usually a sour taste, if soluble. 2. They change blue litmus solution red. 3. They act upon a metal giving up hydrogen, which they all contain, for a metal. 4. They act upon basic oxides forming water, and neutral com- pounds, called salts. In naming acids the terminations -ous and -ic, and the prefixes HYPO- and PER-, are used, e.g. : HCIO is called hypo-chlorous acid. HCIO2 is called chlorous acid. HCIO3 is called chloric acid. HCIO4 is called perchloric acid. For the least amount of O present in the above compounds, HYPO ous is used ; -ous, for more oxygen; -ic, for still more of it; and PER IC, for the greatest amount. ' • a 81 CHEMISTRY FOR INTERMEDIATES. IQ Bases : 1. Have an alkaline taste*. 2. Restore to blue the color reddened by an acid. 3. Have generally properties the opposite to those of an acid. Salts are neutral compounds, that is, possess properties that are neither acid nor basic. They are formed by acids acting upon : 1. A basic hydrate. 2. A basic or neutral oxide. 3. A metal. 4. Theoretically, by replacing the H of an acid with a metal. For example, the acid HNO3, with the metal K, forms the salt KNO3. Salts are named chiefly from the acids which form them. If the acid end in -ic, the salt ends in -ate. If the acid end in -ova, the salt ends in -ite. ^he prefix of the acid is retained in naming the salt, e.g.: Acid. Nahb. HCIO HaSOg HN03 HCIO, hypochlor-ous acid, sulphur-ous acid, nitr-ic acid, perchloric acid. Name. potassic HYPO-chlor-iTB. sodic sulph-iTE. argentic nitr-ATB, potassic PER-chlor-ATE, EXERCISE. The principle of atomicity may be employed in fonning the theoretical in a smgle naolecule of water one atom of a monad metal for one atom of afo3\ . " ^'^^/"*'' ^"' '^' ^*^-^ ^' ^ --d -tL fo the two atoms o hydrogen to form an oxide. In two molecules of water, we must substitute one atom of a d ad metal for two atoms of hydrogen to firm "he hydrate, and two atoms of a diad metal for the four atoms of hydr^n to form the oxide. For example : "j'urogen w> '^m^ Hydrate. Oxide. H,0 KHO K,0 ^^'^ Ca(HO), CaO I f \ 30 OHUMISTRT FOR INTERMEDIATES. 1. Apply this principle and form the hydrates aud oxides of the following metals: Sodium, silver, mercury, magnesium, iron, tin, platinum. 2. Name the compounds thus formed. COMPOUNDS OF OXYGEN AND HYDUOOEN. Those are two in number, but the only impoiiiant one is water. WATER. Formula^ H^O ; molecular weight, 18; ap. gr. at i^C, 1 ; «/>. gr, in gaseous state, 9 ; freezes at 0°C ; ami vaporizes at \OQ°C : point of maximum density, i°C. Properties : It is a tastoloss, inodorou.s liquid, of a bluish-gi*een colour, and can be obtained pure by distillation only ; rain water is the product ot natural distillation, but even this con- tains traces of carbonic acid, ammonia, nitric acid, and gases of the air. Impurities : Spring water contains sodic chloride (salt), c. ^oic car- bonate, calcic sulphate, small quantities of magnesic carbonate and sulphate, silica, and a variety of other substances. The solid soluble impurities of water may be removed by dis- tillation ; insoluble impurities, by filtration. Liquid impurities can, as a general rule, only be removed with extreme difficulty. Gaseous impurities may be removed in large part by boiling or by filtration through charcoal or spongy iron. The impurities in city well water are ammonia, the nitrites and nitrates of calcium and sodium, and worst of all the drainage from animal refu«e. Running water is fitter for drinking than stagnant, because its motion exposes a fresh surface to the air, so tha ; oxygen is continually absorbed and oxidizes the animal and vegetable matter in the water, forming innoxious compounds. The temporary hardness of water is due to the presence of calcic or magnesic carbonates in it, and may be removed by boiling or by treating with lime. Permanent hardness is due to salts of calcium and magnesium, other than the carbonates, such as sulphates and nitrates, and may be removed by adding washing soda (sodic carbonate). CHEMISTRY FOR INTERMEDIATES. 21 Water of crystallization is that which a salt requires in order to crystallize. AnhydroUS substances are ihose free from water in combination. Water may be decomposed into oxygen and hydrogen by means of electricity. When this is done, and the products weighed, we observe that the one volume of oxygon weighs 8 times as heavy as the two volumes of hydrogen produced in the process. The syn- thesis of water by the Eudiometer shows that 2 vols, of hydrogen . unite with 1 of oxygen to form two of water, hence the specific weight of water in the gaseous condition is 9. In the analysis of water, the one vol. of oxygen weighs 8 times as heavy as the two of hydrogen, hence vol. for vol., oxygen is 16 times as heavy a.s hydrogen. Law op Avogadro.— Equal vols, of gases at equal tempera- tures and pressures contain the same number of molecules. From this law it follows, that one molecule of O weighs 16 times as heavy as one of H. Hence also the atom of O is 16 times heavier than the atom of H. The presence of any considerable amount of ammonia in water renders the advisability of using such water for culinary purposes very doubtful. AmmOiiia can b . detected in water by applying the following test ; Nessleb's Test for Ammonia. — "To a solution of potassic iodide add solution of mei'curic chlojide until the precipitate formed is nearly all re-dussolved, tJien add an equal volume solution of caustic potash, and allow the wholo to stand until clear. A few droi)s of this solution will givt; a yellowish-brown precipitate, with even the slightest trace of ammonia." NITEOGEN. Nltrojen: Symbol, N" ; atomic weight, 14; density, 14; mole(.ular . weight, 28. 11*2 Hires weigh li grams. Preparation : 1. It is obtained by burning phosphorus, or some other combus- tible, in a bell-jar over water, the oxygen being burned out and nitrogen remaining. 8 22 CHEMISTRY FOR INTERMEDIATES. 2. By passing puri6ed air over red hot copper. 3. By heating a strong solution of ammonium nitrite : NH^NO, = Nj + 2 H2O. Experiments : 1. Show that it will not support ordinary combustion. 2. Show that it will not burn. Properties t Nitrogen has neither colour, taste nor smell ; is a llittle ligliter than air ; will not support life ; constitutes four- Ififths of the aii-, thus diluting the O ; has been liquefied by cold .and j)ressure ; does not suj^x>rt ordinaiy combustion ; soluble in water to tlie extent of two per cent, of its volnnie. Does :not unite readily and dii-ectly with other elements^ excej)t ;boi-on and titanium, to form nitrides ; found in plants, being a < constituent of some of the strongest poisons and medicines, such :as prussic acid and strychnine; component also of biead, milk and Hesb of animals.. 'Tests : It does not support cwnmoo combusticwi, and is distinguished in a general way by its negative properties. EXlOPwCISE. 1 . What weight and volume of uitrogen caji be obtained from 448 grams oi nitrite of ammonia? Ans. 196 grams ; 15& S litres. 2. Assuming that nitTogea constitutes % oS the volume of air, what weight of cupric oxide woidd be formed in obtaiiuDg 84 grams of uitrogen by passing a sufficient quantity oi. air through s^ tube containing coji^er fihngs t Ans. 119*25 grams. 3. How many litres will 210 grams of mtrogen occupy t Ans. 168 litres. CX)MP0UND8 OP NITROGEJf. .Ammonia : [Spirit* &f Hartshorn) Formula, NH^ ; atomic weight, IT ; density^ 8 '5. 11 '2 litres weigh &'5 grams. It occura in urea and in some other products of animals, also in air as the i-esult of the decay or combustion of animal matter. . Preparation : 1. Formerly obtained by distilling portions of bone ivory, born, parchment, feathers, silk. oY CHEUISTRT FOB INTERMEDIATES. 23 2. Now from the waste liquors produced hy the destructive distillation of coal. 3. May be obtained in the laboratory by heating sal-ammoniac (ammonic chloride) and quick lime : 2 NH3HCI + CaO = 2 NH3 + CaCl^ + H.p. 4. Most conveniently obtained by simply heating some liquor ammoniae. Experiments : 1. Pass the gas into a solution of turmuric, and into one of reddened litmus. 2. Show its rapid solubility in HgO, using a narrovv-ueckcJ bottle, 3. Show the white cloud produced with a volatile acid, e.g., HCl. Properties : Is a colorless gas with an alkaline taste and pungent smell ; soluable to upwards of 700 times its bulk in water at 15°C, which is then called liquor ammoniaB ; is powerfully alkaline ; becomes liquid at - 40°, may even freeze at - 75°. Tests : Its smell ; its solubility in water. See Nessler's test, under the notes on water. Ammonium Ilifchate, NHJIO, or NH^, H^O. ^* Liquor Ainmoniai." This compotind is formed by dissolving NH3 in water, and is a most powerful base or alkali. EXERCISE. 1. Calculate what volume 51 grams of ammonia gas will occupy? Ans. 67 2 litres. 2. 112 litres of ammonia gas are decomposed in a eudiometer ; what volume will its constituent gases occupy ? Ans. 28 litres of nitrogen ; and 84 litres of hydrogen. 3. -What weight and volume of ammonia gas can be obtained from 214 grams of ammonic chloride? Ans. 68 grams ; 89*6 litres. 4. If 85 grams of ammonia gas be decomposed in a eudiometer, and 22*4 litres of oxygen gas be added to the constituent gases, and the mixture exploded, what will be the volume of the resulting gases at CO. Ans. 28 litres of nitrogen ; and 39*2 of hydrogen. 24 CHEMISTRY FOR INTERMEDIATES. 5. What weight of quick-lime is required to decompose 107 grams of ammonic chloride, and what will be the weight of the calcic chloride and water produced? What volume of ammonia gas will be evolved? Ans. 66 grams of lime ; 1 1 1 of calcic chloride ; 18 of water ; and 44 8 litres of ammonia. COMPOUNDS OF OXYGEN AND NITROGEN. Oxygen forms with nitrogen five known compounds ; Names. Formulae, Older Names. Corresponding Acids. Nitrogen Monoxide. •* Dioxide. N^O. NO. Nitrous Oxide. Nitric Oxide. UNO Hyponitrous Acid (not eliminated). Trioxide. " Tetroxide. N,0,. NO^. Nitrous Anhydride. Nitrogen Peroxide. HNO^ Nitrous Arid (not eliminated). *' Pentoxide. N,0,. Nitric Anhydride. HNO^ Nitt ic Acid (well known). The fii-st three oxides are important. Nitric acid is also. Nitrous Oxide {''Laughing gas") : Formula, NM ; molecular weighty 44 ; density, 22. 11-2 litres weigh 22 grams. Preparation : Heat ammonium nitmte in a retort. Reaction : NH,N03=2 H^O + KA Experiments .- 1 . Phinge a lighted taper into a jar of the gas. 2. Burn P in it. 3. Ex]>lode a mixture of N.^O and hydrogen. Properties : A colorless gas with a pleasant smell and sweet taste. Supports combustion, and when inhaled produces transient intoxication and insensibility. Used as an anaesthetic. Tests : Distinguished from oxygen by its greater solubility. Phos- phorus burnt in N.p takes out oxygen, without lessening the volume. I i CHEMISTRY FOR INTERMEDIATES. iff Nitric Oxide, NO; molecular weight, 30; density, 15. 11-2 litres weigh 15 grams. Preparation : Act upon copper, mercury or zinc with nitric acid. Thus : Cuj + 8 HNO3 = 3 Cu (N03)2 + 4 HjO + 2 NO. Experiments: 1. Show that it will not support the combustion of a candle, but will that of phosphorus. 2. Mix the gas with air or oxygen. Properties : Supports combustion of a hot flame ; not soluble to any great extent in water ; is colorless. Test : Forms a red gas when it escapes into air, or when oxygen is added to it — product N^Oa and NO2 mixed. Nitrous Anhydride, N^O^ ; molecvlar weight, 76 ; density, 38. 11*2 litres weigh 38 grams. Preparation : 1. Mix 4 volumes of NO with 1 volume O. Thus : 4NO + Oj = 2NA. 2. Act upon starch, or AsjjOg with HNO3. Properties : A reddish-orange colored gas ; easily condensed into a liquid by a temperature of -18°C. When passed into ice water it dissolves to a blue liquid and to NitrOUS Acid, the type of a series of salts called Nitrites. Test : Its color when pure and when dissolved in ice water. EXERCISE. 1. A dentist wishes to obtain 56 litres of nitrous oxide, how much ammonium nitrate must be used to evolve it ? Ans. 200 grams. 2. Calculate what volume of nitrous oxide can be obtained from 320 grama of ammonium nitrate. Ans. 79-41 litres. 3. In question (2) calculate the volume in cubic inches. Ans. 557 '77 cubic inches. 26 CHEMISTRY FOR INTERMRDIATRS. 4. How inaoh copper and nitric acid must be used in order to obtain 180 grams of nitric oxide ? Aks. 571 "5 and 1687 5 grams respectively. 5, If a piece of phosphorus be burned in 22 grams of nitrous oxide, what gas and what volume of it will remain ? Ans. 1 1 2 litres of N. Niti'ic Acid : Formula, II NO^ ; molecular weight, 63 ; specific gravity of liquid, 1-52; hailing pointy Mb° ', Freezing, -40°. Preparation : 1. It is prepared for use in the arts from the minerals sotlic or potassic nitrates by treating them with sulphuric acid, and distilling ; the reaction being as follows : 2 K NO3 + H^SO^ = HKSO^ + HNO3 + KNO3. The acid distils over. By applying more heat the HKSO4 -f KNOs = K2SO4 + HNO3. 2. Sodic nitrate may be used instead of potassic nitrate in tho above equations. Experiments : 1. Add HNO3 to phosphorus. 2. Tlirow burning charcoal upon fuming HNO3. 3. Add HNO3 to carbolic acid. Note.— (These experiments must be performed with care). Properties : When pure it is colorless ; is easily decomposed ; is a strong oxidizing agent ; and dissolves or attacks nearly all the common metals, forming salts with them. Nearly all strong acids act similarly. Uses : Is used in dyeing, metallurgy, medicine, and in chemical analysis. Test : It bleaches indigo. With sulphuiic acid it imparts a brown purple or black color to a solution of ferrous sulphate (FeSO^). EXERCISE. The principle of atomicity may be employed in forming theoretical salts, by replacing one atom of the hydrogen of an acid with one atom of a monad metal ; two atoms of the hydrogen of an acid with one atom of a diad metal, and so on. For example : Acid. Salt. Name of Salt. HNOJ HaSO* AgNO, ZnSO^ Silver Nitrate. Zinc Sulphate. CIIEMISTUY FOR INTERMEDFATES. 27 » i 1. In the same way symbolize the salts wliich nitric acid may form with tho following metala : I'otasiium, calcium, copper, lead. 2. Name these salts. 3. Syraholizo and name the salts which chloric (HCIO3), and sulphuric (HjSO^) acids may theoretically form with sodium, potassium, magnesium, copper, lead, calcium and iron. EXERCISE. 1. What weight of nitric acid can be obtained by the decomposition of 50r>J grams of nitre by sul^diuric acid, and at a moderate temperature. Ans. 315. 2. If ISO grama of nitric acid and 408 3 grams of hydro-potasaic sulphate are produced in obtaining nitric acid from nitre and sulphuric acid, what quantities of these ingredients must have been used ? Ans. 303*3 grams of nitre; and 294 of acid. 8. What weiglit <-' "laughing gas " can be got from 240 grams of ammonic nitrate ? What weight of water is produced in the decomposition ? Ans. 132 gi'ams ; and 108 grams water. 4. What volume will 132 grams of nitrous oxide occupy? Ans. 67 "2 litres. f*i yVh^^ volume will 120 grams of nitric oxide occupy? Ans. 89 6 litres. (i. Ifow iq^oi^ ifitriu Qxi^c Qari be Qbt^incd from 504 grams of nitric acid by HtldJug it to n tmditimiti f^wSftfcJf V 9f P<^pper? Ans. 60. !:i THE .V TMOSPHERE. 11 "2 litres weigh 14*44 grama. The atmosphere is an ocean of mixed gases pressing with a weight of 1 1 "7 lbs. upon every square inch of the earth's surface. That tho gases composing it are mixed — not combined chemically — is proved Vjy the following considerations : 1. Tliere is no simple relation in volume or weight between the gases composing it, 2. On mixing its constituent gases in y>roper proportions, no visible or thermotic changes occur. 3. The air dissolved in water does not contain oxygen and nitrogen in the same proportions as they are found in the atmosphere. 4. Nitric oxide passed into free oxygen or air forms red fumes — never when passed into compounds of oxygen and nitrogen. ';)1 I ^ 28 CHEMlSTftV fO& iNTEftMEDIATES. The average composition of air is about as followa : Oxygen, including Ozone 2061 cub. centimetres Nitrogen 779-5 Aqueous vapor 14' Carbon dioxide "4 Traces of ammonia, nitric acid |^ and sulphuretted hydrogen. i Total 1000- In large towns, sulphurous anhydride and siilpliuretted hydrogen are present in air in small quantities. Minute particles of solid organic matter are also found floating through it, such as spores or fungi, and the supposed germs of disease. The source of carbon dioxide in air is respiration, combustion and decay, &c. It supplies carbon to plants. The source of ammonia is the decay of organic matter. It furnishes nitrogen to the soil, and thence to plants and animals. Carbon : Symholj C ; atomic weight, 1 2 ; specific gravity ^ as diamond ^ ,i„„„i,,i,i. I,, iihout 3-4, ^^^^v Occurs in three allotropic forms : 1. GrystaJline, as diamond. 2. Graphitic, as graphite, plumbago or black-lead; and 3. AmOiphoUS, as charcoal and coke. It is the characteristic element in all organic compounds. Dia- mond is pui*e carbon crystallized, and may be burned in the arc of the voltaic battery — product, carbonic anhydride. PlumbagO is found as a mineral ; used for making drawing pencils, for stove polish, and for making crucibles when mixed with clay. There sire many varieties of the amorphous form of carbon. The following are the principal ones : (a) Pit Ooa], composed of carbon in large proportion, oxygen in smaller quantity, hydrogen in smaller, nitrogen in still less, and a variable proportion of saline and earthy matter ; has been formed ■y >■ ^ |! I ^ I CHEMISTRY FOH INTERMEDFATES. 29 by the submersion of huge forests under the sea, long ages ago, the wood being slowly changed into coal by the combined action of the pressure of water uj)on it and moderate heat from the interior of the earth. (b) Anthracite coal contains about 90 per cent, of carbon. When bituminous coal is heated in closed iron cylinders free from air, a large quantity of gas and tar is formed, containing th(! oxygen, hydrogen, nitrogen, and some of the carbon of the coal ; the residue is called Coke. This is how coal gas is njanufactured. This process of destructive distillation of coal may be applied to wood also, when an inflammable gaseous product will be given olf ; wood-tar, vinegar and WOOd-naptha, are the liquid products; tht black porous mass left behind is called charcoal. (c) Lamp-black, the basis of printer's ink is another i\mn of carbon. (d) Animal OhafCOal or ivor)/ black is made by heating tlio bones and flesh of animals in iron retorts, and is used in refiuin-^ sugar, and as a decolorizing agent. Uses : Its chief use is, of course, for fuel. Charcoal is a irool aiain/ectarU and antiseptic, on account of its absorbent and purifying power. Its purifying power is due to the action of the oxygen ooudenaed from the surrounding air within the pores of the oharooal. Oharooal is used for making water filters, and is also the great reducing agmt of the metallurgist. COMPOUNDS OF CARBON AND OXYGEN. Carbon Monoxide (Carbonic Oxide); Formula, CO; molecidar weight, 28 j density, 14. l\-2 litres weigh li grams. This gas is formed by ordinary combustion in our coal stoves, and causes the " blue blazes " that are seen flickering over the top of coal fires. Preparation : 1. By passing carbon dioxide over i-ed hot charcoal. 00.^ + = 2 CO. 2. By heating oxalic acid and sulphuric acid in a retort. Tlio latter takes from oxalic acid the elements of water, and ^'.>1 :H !0 CHEMISTRY FOR INTERMEDIATES. the residue breaks up, forming a mixture of the two gases — carbon dioxide and carbonic oxide. Thus : C^H^O, + H2SO4 = H2O, H2SO4 4- COj + CO. The carbon dioxide is absorbed on passing the mixed gases through a solution of caustic potash. Properties : It is a colorless, tasteless gas, and violently poisonous when breathed. It burns with a pale blue flame, taking up oxygen and forming carbon dioxide. Experiments : 1. Bum a jet of the gas. 2. Pass the gas through benzine and then burn it. Tests : The color of its flame. The product (COj) of the com- bustion of this gas turns lime water a milky color. The gas itself does not affect lime water. Carbonic Anhjdruh {Carbon dioxide, carbonic acid gas, choke-damp): Sijmbol, CO.j^; atomic weight, ii ; density, 22; 11-2 litres weigh 22 grains, Preparation : 1. Is usually made by treating chal): or marble with hydro- chloric acid, the decomposition being : CaCOg + 2 HCl = CaClj + HgO + CO.,. 2. By pouring a strong acid upon any carbonate, e.g., K2CO3, Na^COg, ifcc. In respiration, this gas is given off" abundantly ; the air which has been breathel once contains from 3 to 4 per cent, of it. Fermen- tation, as well as all ordinary combustion, gives rise to it. It accumulates in old pits, wells, and mines, and issues sometimes from Assures in the earth. It does not support combustion. Experiments : 1. Place a lighted taper in a jar of the gas. 2. Pour the gas from one jar to another. 3. Pass the gas through lime water. 4. Pass air from the lungs through lime water. 5. Absorb some of the gas with caustic potash. two ases lOUS up 3111- gas p): igh ro- as fl- it ni i ^ CHEMISTRY FOR INTEKMEDIATE8. 31 Properties : Carbonic anhydride is a lieavy transparent gas, with- out color. It may be condensed to a liquid by applying cold and a pressure of 40 atmospheres, or generated as a liquid in strong iron tubes ; it may even be frozen to a snow-white solid, which, when mixed with ether, produces a freezing mixture of -75°. When heated it accumulates in the upper part of the room, and therefore, in ventilating a room, openings should be made for its escape, near the ceiling, whilst fresh air should be admitted near the floor. Its vitiating eflfects upon the atmosphere are only prevented by the action of plants upon it, which, in presence of sunlight, decompose it, retain the carbon and give out the oxygen. Test : The test for this gas is lime water, which it renders turbid, owing to the fonnation of cimlk. It does not bum, cannot be bn^athed pure, but mixed (from 3 to 4 per cent.) with air, it acts as a narcotic poison, and produces death. EXERCISE, 1. How much potassium will be required to decompose 110 grams of carbon dioxide ? Ans. 391 grams. 2. If 10 litres of carbon dioxide be passed over red hot charcoal, what gas, and how many litres of it, will be formed ? Wliat weight of it ? Aj^s. 20 litres ; 25 grams of CO. 3. 20 litres of carbonic oxide are burned in oxygon gas. What gas is pro- duced, and what volume and weight of it ? Ans. 20 litres ; 39*2 grams of G0„_. 4. How much carbon can be obtained from 261 grams of carbon dioxide ? Ans. 72 grams. 5. What volume of oxygen is required to burn 60 grams of carbon ? Ans. 123-2 litres. 6. In question (5) what volume of air would be needed for the combustioiv? Ans. 616 litres. 7. What volume do 110 grams of carbon dioxide occupy? Ans, 56 litres. 8. What volume do 140 grams of carbonic oxide occupy? Ans. 112 litres. 9. What weight of carbon dioxide can be obtained from 250 grains of pura limestone by treating with hydric chloride ? Ans. 110 grains. 10. What weights of carbonate of lime and hydric chloride must be decom- posed to produce 352 grams of carbon dioxide. Ans. 800 ; 584 grams. 32 CHEMISTRY FOR INTERMEDIATES. 11. What volume will 98 grams of carbonic oxide occupy? Ans. 78*4 litres. 12. If 270 grai..9of oxalic acid be decomposed by sulphuric acid, find the volume and weights of the gases produced. Ans. 132 grams ; 67 2 litres of 00 j. Ans. 84 grams: 67 2 litres of CO. 13. What volume of carbon dioxide will be produced by the combustion of 24 grams of carbon in oxygen gas. Ans. 44*8 litres. 14. Calculate the weight and volume of carbon dioxide produced by the combustion of 42 grams of caibonic oxide. Ans. 66 grams ; 33*6 litres. COMPOUNDS OP CARBON AND HYDROGEN (HYDROCARBONS). Marsh Gas (Light carbtiretted hydrogen, '^ Fire-damp^'), Gffi', molecular weight, 16; density, 8. 11 '2 litres weigh 8 grams. This substance is generated in marshes by the decomposition of vegetable matter containing carbon and hydrogen. Formed in coai mines also, and on being mixed with air and ignited, causes fearful explosions — product CO2 and vapor of H^O. To prevent tliese, Sir H. Davy invented his Safety Lamp. Prdparation : Strongly heat sodic acetate, sodic hydrate, and quick lime. Reaction : NaCaHjOj + NaHO = Na^COg + CH,. The quick lime probably acts by catalysis. Properties : Colorless, invisible, odorless gas ; scarcely soluble in H2O ; does not support combustion or respiration ; burns with a pale, almost non-luminous, flame. Experiments : 1. Bum a jar full of the gas. 2. Explode a mixture of 1 vol. of CH4 and 2 vols, of O. Its combustion : CH4 + 2 Oj = CO2 + 2 H2O. Remembering that every molecule occupies two volumes, this equation may be translated thus : Two vols, of CH^.burnt with four vols, of O yields tv o vols. CO2, and four vols, of vapor of HjO. Assuming that O constitutes \ of the air, it will require 10 vols, of air to furnish oxygen enough to burn one vol. of CH4. brea. ad the CO. iiion of ires. >y the rea. NS). cular >n of coai arful >, Sir uick e in with that be f O ling f to ^ { I CHEMISTRY FOR INTERMEDIATES. 33 Tests: Pale flame, and deposition of black soot upon porcelain held in its flame. This latter distinguishes it from H. When passed through a tube containing intensely hot pumice stone, one vol. of it breaks up into two vols, of H, and C is deposited on the stone. EXERCI8K. I. Calculate what quantities of sodic acetate and sodic hydrate must be decomposed to yield 134-4 litres of marsh gas. Ans. 492 and 240 grams resijectively. 2 If 10 htres of marsh gas be passed tluough a tube containing intensely heated pumice stone, what gas and what volume of it will be eliminated ? Ans. 20 litres of H. 3. If 15 htres of marsh gas be mixed with an equal volume of oxygen and If the mixture be exploded at ordinary temperatures, what gas, and what volume of -It will remain ; and what gas, and what volume of it will be pro- ^ *^"'"''* • A^«- 75 litres of CH, ; and 7-5 htres of CO,. 4. What volume will 48 grams of marsh gas occupy ? Ans. C7-2 litres. 5. 70 litres of marsh gas are burnt in air, what weight and volume of carbon dioxide will be produced ? Ans. 70 htres, or 137 5 grams. Ethyhne {Etiiene. Olefiant yaa. Light carhuretted hydrogen), CJ/^; molecular weight, 38 ; density/, 14. 11-2 litres weigh 14 grains. It is called ol^^ant, because it unites with chlorine gas to form a heavy oily liquid, called " Dutch Liquid." Preparatiou : 1. By heating coal in a closed vessel. When obtained in this way, the gas is mixed with many others. 2. By heating alcohol mixed with double its volume of sulphuiic aoid : Experiments : 1. Burn ajar full of the gas. 2. Mix equal volumes of the gas and chlorine. 3. Explode 1 vol. of aM^ and 3 vols, of O. 1^ 34 CHEMISTRX FOR INTERMRDIATEfl. Properties: ColorloHS, Hlightly sweetish tjisto, scarcely soluble in HjO, does not support combustion or rcspinition, burns with a dense bright flume. Its combustion in oxygen may Ixi thus represented : CjH4 + 3 0j=2COj+2H,0. From this it will bo seen that one vol. of O.^TI^ requires for its combustion three vols, of O, or 15 vols, of air. Tests: Its faint smell; its luminous flame; its forming '* Dut»'h Liquid." EXr-]RClSE. 1. I desire to obtain H3 G litres o' ethylene, how much puro alcohol must 1 use? Ans. 69 graniB, 2. How much oxygen is recinired cr the perfect combustion of 10 litres of olefiant gas; anil what weiglit ami vohnno of g:i3 is produced at ordinary temperatures? Ans. 30 litres of O ; 20 litres or 39 '2 grams of 00.^. 3. How many valuinos of hydrogen can hu olitaincd from 18 litres of olefiant gas ? Ans. 36 litres. 4. Calcvilate what volume \'2i\ gratiH of ethylene will occupy. An8. 100-8 litres. 5. What weight an«l volutnc of carl)on dioxide and steam will bo produced by burning 50 litres of oleliant gas in oxygen? • Ans. 100 litres or 196 "4 grams of carbon dioxide. Ans. 100 litres or 803 grams of steam reduced to CO + 760 ra.m. 6. On burning a (piantity of olefiant gas in air, it was observed that 88 grams of carbon dioxi«le were produced, what volume of ethene was con- sumed? Ans. 22 "4 litres. (M)AL (IAS. Coal gas is a mixture of several gasos, its average composition being somewhat as follows : Hydrogen 45* Marsh gas •'^•'» • Carbonic oxide Olefiant gas ^' Butylene 24 Hydrio sulphide -3 Nitrogen 25 Carbon dioxide 3-8 TotJil 100- vols. iblo in with li K) tllUH for its Dutch muat I ■ainB. itrcs of rdinary UOj. ' trcfl of tres. trcB. ixluccd trcs or educed hat 8S 8 con- ^.res. sition iiiiip mm mm W 1 II \ CHEMISTRY FOR INTERMEDIATES. 35 Formed by distilling coal in large iron retorts, the products being (a) coal gas, (b) coal tar, and ammoniacal liquor, and (o crude coke. From coal tar are obtained, aniline, creosote, benzole, napt/mline, etc. The impurities of coal gas are chiefly sulpht.retied hydroge,., carbon dioxide, ammonia, and carbon disulphide. The two former may be partially removed by passing the gas through vessels coti- tamaig slaked lime. The ammonia is easily separated, but tho carbon disulphide cannot be re«ioved by any practicable means. (JOMBUSTIOX. The term combustion in its wi. lest signiKcation means the union of an element with an element, or of an element with a compound, or of a compound with a compound— the union being always attended with the production of heat, and frequently of lif/ht. Ordinary combustion means the union of the oxygen of th(j air with the elements of wood or coal in stoves, or its union with the elements of coal oil in onr lamps, or tallow in otu- candles. Extraordinary combustion may be defined as meaning all other cases of chemical union. If union goes on very rapidly, great heat is evohod, as in the casc^ of the explosion of gunpowder, or of a mi.xture of hydrogen and oxygen gas. But the union may go on very slowly, as in the rusting of iro,., and then, though, a fixed amount of heat is always evolved for a given weight of the uniting substances, y.-t, the pi^cess of union being spread over a comparatively great length of time, the heat generated never becomes so apparent as when union is instantaneous. Heat is, therefore, intensified in two ways : i. By shortening the time in which a given weight of matl«u- is consumed. 2. By diminishing the sj)a<3e. STRUCTURE OF FLAMl-l The flame of a common candle may be considei- of all other flames. It consists of three cones-tho two outer ones enveloping the central one : wmmmmmmmmn :iG CHEMISTRY FOR INTERMEDIATES. 1. Tlie central cone, called the cone of non-COmbustion, is lmr tlioxide is usually < btained as foil * .vs : 2 H,S04 + Ou - OuSO, + 2 H.p + SOj. Jt is used for bleaching articles that would be ruined if 01 were used. Chlorine destroys the coloring matter, SOj uoefci not. The laUer uieaches by reuioviug oxygen. Experiments : 1, Place a lighted taper in the gas. It is extinguished. 2, Pass the gas into an infusion of litmus. 3, Pour the gas downwards upon a lighted taper placed in the bottom of a jar. Properties : It is colorless, transparent, not inflammable, and has a pungent, suflx)cating odor. It forms, with water, sulphurous acid. Thus ; SO2 -r HjO = H2SO3. T33tS : Its weight, smell, acid properties when united with water, and its bleaching properties. •Sulphuric Acid : Formula, If^SO^ ; molecular weiyht, 98 ; specific gravity of liquid, 1-846. This is the most important of all the acids, and the most exten- sively used in our manufactures. Preparation : 1. Nordhauscn Sulphuric Acid is made by the distillation of dried sulphate of iron (green vitriol). 2. The great bulk of the acid of commerce is manufactured as follows : Sulphurous anhyJiide, steam, air, and nitric oxide, are passed into an immense chamber. "The nitric oxide in jji'esence of oxygen ii ^nediately becomes nitrogen peroxide, and this, when mixed with sulphurous anhydride and a large quantity of water, furnishes sulphuric acid and nitric oxide. The ' ulphiric acid remains dissolved in vhe water, while the nitric oxide, by absorbing oxygen from the Jiir, ag..iii 'icc-oi'^es nitrogen peroxide; this combines with fresh I ;i ed if itter, I the I has irous ater, ific Lten- n of d as , are e in cide, id a itric iter, .'lir, resh i^ !| I'l 1; wmmm CHEMISTRY FOR INTERMEDIATES. 43 sulphurous anhydride, which, when acted ou by water, becomes sulphuric acid, the nitric oxide being again liberated, to go through the same series of changes with fresli portions of oxygen and sulphurous anhydride as long as any remain in presence of each other uncombined : NO, -f SO2 + a:HaO = NO + (x-i) H2O + H2SO4." This acid gives rise to a large class of salts, called sulphates. If one atom of hydrogen, in the molecule of H2SO , be replaced by one atom of a monad metal, there is formed what is called an Acid sulphate ; if all the hydrogen be replaced by a metal, a Normal or Neutral sulphate. Properties : The oil of vitriol of com erce is a dense oily-looking colorless liquid, without odor, is intensely caustic, and chars almost all organic substances, " owing to its powerful atti'action for moisture." Test : Baric chloride gives with sulphuric acid, or any soluble sulphate, a white precipitate insoluble in all acids. Sulphuric acids chars organic compounds. Hydric Sulphide [Sulphuretted hydrogen): Formula, H^S; molecular weight, 34; density, 17. \\"1 litres weigh 17 grams. Is found free in volcanic countries, and also dissolved in spring water. Also called Hydrosulphuric acid. Pi eparation : 1. Ferrous sulphide treated with dilute sulphuric acid. Thus : FeS + HaSOi = FeSOi + H^S. 2. By treating antimony sulphide with hydrochloric acid : SbaSg + 6 HCl =. 2 SbCJg + 3 H2S. Experiments : 1 . A jet of the gas burns with a blue flame. 2. Explode a mixture of 2 vols, of HjS with 3 vols, of 0. '6. Pass a stream of the gas into solutions of cupric sulp^mte, ferrous sulphate, zinc sulphate, and acetate of lead, and observe the effects. t ! "; f ( ! , ■ 44 CHEMISTRY FOR INTERMEDIATES. Properties : Is a colorless, transparent gas, with the odor of rotten eggs. Soluble in water to about the extent of 4^ times its own volume ; and burns with a blue flame. It has an acid reaction. Test : It blackens acetate of lead paper. This, with its smell, distinguishes it from all othei gases. EXERCISE. 1. Calculate tht percentage composition of sulphur dioxi ""e'. Ans. 50 of O and 50 of S. 2. What volume will 112 grains of sulphur dioxide occupy? Ans, 39-2 litres. 3. Find the weigiit and volume of sulphixr dioxide that can be obtained from 588 grams of sulphuric acid and 10 Iba. of copper. Ans. 192 grams ; 67*2 litres. 4. If sulphur trioxide be passed through a tube heated to a hif;!^ tempera- ture it breaks up into sulphur dioxide and oxygen gas. Find liow much oxygen can be obtained in this way from 320 grams of sulphur trioxide. Ans. 48 grams ; 33 '6 litres. 5. How many litres of sulphur dioxide must be dissolved in water to pro- duce 410 grams of sulphurous acid ? Ans. 10 litres. 6. If 48 grams of suljihur be completely oxidized in presence of vapor of water, what compound, and what weight of it, will be produced ? Ans. 147 grams of H2SO3. 7. Every volume of sulphuretted hydrogen requires for its combustion one and a half volumes of oxygen ; what comjiound and wbat weight of it will be formed by the combustion of 78*4 litres of this gas ? Ans. 287 grams of H.,S03. 8. How much suljibido of iron and sulphuric acid must be used to evolve 89 '6 litres of sulphuretted hydrogen' Ans. 352 grams ; 392 grams respectively. COMPOUND OF CARBON AND SULPHUR. Covhon disulpftide {Carbonic sulphide, sulphocarhonic acid) : Formula, CS2 ; molecidar weight, 7G ; den&ity of vap&r, 38. Preparation : This substance is formed by passing sulphur vapor over red hot charcoal and condensing the pro ^ a^ IMAGE EVALUATION TEST TARGET (MT-3) % A {./ / <^ // ^^ -^ A fA 1.0 i^lll^ 112.5 I.I 2.2 " lii ilio 1.25 JL4 III 1.6 V] "*?> r^^^ ^ w ^ c^ 48 CHEMISTRY FOR INTERMEDIATES. I when heated with water takes up another molecule of water and forms orthophosphoric acid. This substance, H3PO4, is interesting as illustrating what is called a tri-basic acid; that is, an acid which is capable of forming three kinds of salts, according as one, two, or three of its hydrogen atoms are replaced by one, two, or three atoms of a monad metal. For example : NaH^PO^ is called dihydro sodic phosphate. Na^HPO^ is called hydro disodic phosphate. /->ra3P04 is called trisodic phosphate. The basicity of an acid, therefore, depends upon the number of exchangeable atoms of hydrogen which its molecule contains. Nitric acid, HNO3, is mono-basic ; sulphuric acid is bi-basic. COMPOUND OF PHOSPHORUS AND HYDROGEN. Phosphoretted hydrogen {Phosphine) : Formula, PII^ ; molecular weight, 34; density, 17. 11-2 litres weigh 17 grams. Preparation : 1. Heat phosphorous acid in a small retort : 4H3PO,=:3H3P04 + PH3. 2. Boil some small pieces of phosphorus in a solution of sodic hydrate, or of slaked lime. Experiments : 1. Carefully allow bubbles of the gas to escape into air. Spon- taneous combustion rei-iults, and a beautiful ring of white smoke is produced. 2. Keep a quantity of the gas over water for a few days. Properties : When prepared by the first of the above methods the gfis is not spontaneously inflammable. It possesses a strong offensive odor, like garlic; is slightly soluble in water; and burns with a brilliant white flame. It is analogous to ammonia in some of its chemical relations. Its combustion may be symbolized as follows : PH3+2 02=H3PO,. and ting acid one, , or r of itric )dic >on- lite the mg md nia be ! 1 !( CHEMISTRY FOR INTI^RMICDIATES. 49 Test: Its flame; its odor; and its spontaneous inflammability when prepared by the second of tlie above methods. The gas loses this property when kep^ standing over water for some time. EXERCISE. 1. What weight and volume of phosphine can be obtained from 41 grams of phosphorous acid ? ^^^,. ^.^, ^^^^^ . ^.g ^^f^^' 2. What volume will 51 grams of the gas occupy ? Ans. 336 litres. 3. If 28 htres of phosphoretfced hydrogen be decomposed into its con- stituent elements, what volume will they occupy in the gaseous condition at the standard temperature and pressure ? Ans. 4 litres of P ; and 24 of H. 4. If i56 litres of phosphine be burned in oxygen, what compound and what weight of It wiU be produced ? Ans. 225 grams of H3PO,. 5. What weight of metaphosphoric acid can be formed from 38 5 grams of phosphorus pentoxide ? ^^^^ ^ ^^^^^ EXERCISE. What is the percentage composition of each of the following named substances : 1. Arsenious oxide, As^Og. Ans. 7575 arsenic ; 24 25 oxygen. 2. Chloride of gold, AuClg. Ans. 35-14 gold ; 64 86 chlorine. 3. Arseniuretted hydrogen, AsHg. Ans. 96-15 arsenic ; 3-85 hydrogen. 4. Potassium ferrocyanide, K^FeCgNe. Ans. 42-45 potassium ; 15-2 iron; 19-55 carbon; 22 8 nitrogen, 5. Epsom salts, MgSO^. Ans. 20 magnesium ; 26 67 sulphur ; 53-33 oxygen. A substance upon analysis yields the following percentage composition • Potassium, 28-73; hydrogen, 73: oxygen, 47-02; sulphur, 23-52. Calculate its empirical formula. To solve this and all similar problems observe the following rule : 1. Divide the percentage amount of each constituent element by its own atomic weight. 2. Divide each of the quotients thus obtained by the lowest of them. 3. Reduce this second set of quotients to their simplest ratios, and the mmb€r$ obtained will express the number of atoms of each element in the compound. i! 5") CHEMISTRY FOR INTERMEDIATES. lu solving the above question proceed as follows : Potassium 28-73 -f- 39-1 = -73 Hydrogen '73 4- 1 = '73 Oxygen 4702 -r 16 = 293 Sulphur 23-52 ■^ 32 = -73 Now the smallest of these quotients is -73, and dividing each of them by this, we obtain one for K, one for H, one for S, and four for O. The empirical formula is, therefore, KHSO4, and the sub- stance is hydro potassic sulphate. The problems in the following exercise can all be solved in a similar manner. EXERCISE. Calculate the empirical formula and name the substances which yield upon analysis the following percentages of the elements named : 1. Carbon, 42*86 ; oxygen, 57-14. Ans. CO, carbon monoxide. 2. Hydrogen, 273 ; chlorine, 97 '27. Aks. HCl, hydric chloride. 3. Hydrogen, 83 ; sodium, 19*17 ;' sulphur, 26-66 ; oxygen, 5333. Ans. HNaSO^, hydro sodic sulphate. 4. Sodium, 39'3l ; chlorine, 60-69. Ans. NaCl, sodic chloride. 5. Nitrogen, 82'35 ; hydrogen, 17-66. Ax.s. NH3, ammonia. 6. Phosphorus, 91 "17; hydrogen, 8-83. Ans. PHj, phosphine. 7. Carbon, 26-67; hydrogen, 222; oxygen, 71-11. Ans. CjHaOi, oxalic acid. 8. Carbon, 75 ; hydrogen, 25. Ans. CH4, marsh gas. 9. Carbon, 12 ; calcium, 40 ; oxygen, 48. Ans. CaCO,, calcic carbonate. MISCELLANEOUS EXERCISE. 1. 30 litreekof hydrogen are mixed in a flask with 20 litres of oxygen. Which gas remains in excess after explosion, and how many litres of steam are produced ? Ans. 5 litres O remain ; 30 litres of steam. 2. Mix 10 litres of hydrogen with 15 of chlorine, and calculate the total volume of the gases after explosion. Ans. 20 litres HCl ; 5 litres of CI. 3. A. certain volume of sulphuretted hydrogen required for its combustion 75 litres of oxygen. Find that volume, and also the weight of the substance produced. Ans. 50 ; and 183 grams of H, SO 3. h of four sub- in a upon ie. ie. te. ie. ia. ae. id. as. te. ^gen. team m. total Dl. stion :ance ),. 1 ; i; wm II m CHEMISTRY FOR INTERMEDIATES. 61 4. Assuming that \ the volume of air is oxygen, calculate how many litreg of air It will take to bum 20 litres of (a) carbonic oxide, {b) phosphine, (c) oleliant gas. ^^g. 60 ; 200 ; and 300 litre* respectively. 5. If 10 volumes of carbon dioxide be passed over red hot charcoal, what gas and how many volumes of it vrill be formed ? Ans. 20 vols, of CO. 6. 26 volumes of steam are passed into a tube containing red hot iron filmgs, what gas will pass out, and how many volumes of it ? Ans. 25 vols, of H. 7. A series of electric sparks passed into a 20 litre jar of ammonia gas decomposed it. Find the volume of the constituent gases. Ans. 5 litres of N ; and 16 of H. 8. 24 grams of carbon are burned in oxygen gas. Find the volume of the «^ Produced. ^^g 4^.g j.^^^^ 9. 80 grams of sulphur are mjwie to bum in 66 litres of nitric oxide gas Fmd the resulting volume of gas formed, and the volume (if any) of nitrous oxide remaining. Ans. 66 litres SO, formed ; and 56 litres of 1. 10. How many litres of oxygen and nitrogen respectively can be obtained from 30 litres of nitrogen tetroxide ? Ans. 10 of N ; 20 of O. 11. How many cubic inches oJ: hydrogen and nitrogen respectively can be obtamed from one litre of ammonia gas ? Ans. 15-25 N ; and 4577 of H. 12. If 10 litres of oxygen be united with 6 of sulphur vapor, what wiU be the volume of the resulting compound gas at standard temperature and ^'''''''^' Ans. 10 litres. Iff" I'l [53] EXAMINATION QUESTIONS. The following sets of quettiom have been selected from the Kkmentary Papern. on Chemistry given at Queen's College. I. 1. Describe carefully how the composition of water is determined synthe- tically and analytically. 2. Taking a molecule of water as a type, explain fully the composition of an acid, a base, and a salt ; give examples. What practical diflferences are there between these three compounds ? 3. What is meant by a substance in its nascent state and what are its properties ? Give cases in iUustration. 4. Give all the chemical changes, where known, and any visible phenomena when :-(a) zinc is put into sulphuric acid ; (6) copper is put into nitric acid under a bell-jar; (c) electric sparks are passed through air; (rf) potassic chlorate is acted on by hydrochloric acid ; (e) wood is heated in close vessels. 6. How would you determine the proportion of oxygen in the air ? How prove that it is not in combination ? 6. Explain the action going on in the several parts of a common flame. What IS the eflfect of too little air upon it ? Of too much air ? 7. What volume of ammonia can be obtained from 100 grams of ammonia chloride. II. 1. Give the length of a metre in inches, and show its relation to the gram-, and litre. ° 2. How many times is the gas 01,0^ heavier than air ? Ans. 4-67. 3. Explain the meaning of the terminations, -ous, -ic, -ide, -ite, -ate. 4. (a) Show how to obtain nitric acid. (6) Given nitric acid and other necessaries obtain N^O, N,Oa, and N.O,, giving formulae. 5. What gaa and what weight of it wiD be obtained by acting on marble bv 100 grams of HOI ? ^ o j Jl^T'"''^ ^"""^^ ^'^^ * ^°'°''y ^*°'*- ^^P^*^° *^« cause of (a) the heat, (6) the hght, (c) the smoke. How may the smoke be prevented ? 7. Describe sulphuric acid and explain its formation. 8. If a molecule of water consists of 3 atoms, show that a molecule of hydrogen consists of 2. State Avogadro's law. 54 CHEMISTRY FOK INTERMEDIATES. III. 1. Give general differences between chemical compounds and mechanical mix'-ures. 2. Upon what basis does Avogadro's law rest ? Shew how from it you can find the density of the gas OaHoO. 3. How would you distinguish certainly botween : — Oxygen and nitrous oxide ; nitrogen and carbon dioxide ; hydrogen and carbon monoxide ; phos- phine and arsine. 4. Show how to obtain liquor ammonise. Of what is it a hydrate ? 5. Describe Bunsen's burner, and explpm its action. 6. You are given "salt," alcohol, manganic dioxide, and sulphuric acid. How will you obtain hydrochloric acid, chlorine, oxygen, defiant gas ? 7. 100 grams of oxalic acid is decomposed by sulphuric acid, and the escaping gases are passed through lime water. What weight of calcic carbonate will be formed. Aks. 111^ grams. IV. 1. If one volume each of the following gases be burned with oxygen, what gases, and what volume of each will be formed? — marsh gas, olefiant gas, phosphine, hydric sulphide. 2. Give the composition of the following, and state how they are obtained : ozone, laughing gas, bleaching powder. 3. Give the principal constituents of the atmosphere, with their uses ; and show how the relative amounts of oxygen, carbon dioxide, and water- vapour may be obtained. 4. Give the reaction, and products when : — (a) zinc is put into hydrochloric acid ; (b) tin is acted upon by nitric acid. 6. What takes place when : — (a) magnesium is heated in air ; (b) ammonia is added to CuSO^ solution. 6. When does a gas become a vapour, and vice versa ? State their simi- larities and differences. ' A The following questions have been selected from the Examination Papers of Toronto University for the years 1878, 1879, and 1880. 1878. I. 1, Define specific gravity, and state how that of solids is obtained. 2. Explain the use of symbols, and give those of eight elements whose names begin witma 'ji- CHEMISTRY FOR INTERMEDIATES. 09 The following are the questions set at the Intermediate and Second-Class Examinations from July, 1S76, to July, 18S1, inclusive : JULY, 1876. 1. How would you prepare hydrogen? State fully by what means you would show its most important properties. 2. Describe fully the modes of decomposing water which you have seen. You are asked to say whether a given specimen of water is hard or soft, how will you determine the fact ? If the water is hard, describe (with reasons) all the means by which you can make it soft. 3. State all the forms in which carbon is found in nature. By what experi- ments would you show its important properties? You are given a black substance like coal, and asked to say whether it is carbon or not ; how will you determine this ? 4. How would you obtain carbonic acid from chalk — represent the reaction by an equation. A current of atmospheric air passes up througli a bright coal fire, state all the changes which it undergoes till it enters the atmosphere again. 5. How is chlorine prepared ? State the experiments by which you would show its properties. On what does its bleaching power depend? You are given a piece of calico, and requested to bleach it— state fully how you would proceed. 6. When an ordinary friction match is lighted, what gases are given off? Describe the properties of any of them. 7. State what substances are represented by the following formulas, and mention any experiments in which you have seen any of them occur : MnOa, FejO^, PaOg, ZnSO^, NH^Cl, CaCog. DECEMBER, 1876. 1. Describe and explain some method of obtaining oxygen. How would you shew its principal properties ? What quantity of oxygen is required for the complete combustion of 100 grs. of pure charcoal : 2. Explain what is meant by the combining measure of a gas, and state what the combining measure of hydrogen, chlorine and hydrochloric acid will be if we assume that of oxygen to bo ] . .3. Descrih'" aiid explain any experiments that illustrate the action o.f plants and animals upon the air. What substances are found in the air in addition to the two principal gases ? 4. It was anciently believed that fiie, earth, air and water were elements, state the views which now prevail as to. the nature of each of these things, What is now meant by the term element ? 60 CHEMISTRY FOR INTERMEDIATES. IB ' 'i 1' 0. Explain a metlicMl of preparing nitric aoid, and stato its composition by weight. What is a nitrate ? Show how the presence of a nitratu in a liquid may be detected. G. Name and give the formulae of the oxides of nitrogen, sulphur and carbon. 7. Calculate the percentage of the various elements contained in nitric acid, ammonia, sulphuric acid and common salt. 8. Explain the terms acid, alkali, salt. JULY, 1877. 1. Give two methods of preparing hydrogen. By what experiments would you show its most important properties ? 2. How would you prepare nitric acid? Describe any experiments with nitric acid which you have seen. .S. State the different forms in which carbon occurs in nature. Port wine filtered through charcoal is deprived of its color ; give the reasons of this. How is charcoal used as a disinfectant ? Give the theory of its action. 4. How would you prepare carbonic acid from chalk and sulphuric acid ? Express the reaction by an equation. Bread is raised by the liberation of carbonic acid. Explain. 5. What is meant by combustion ? Explain fully the substances formed when a candle is burned (1) in oxygen, (2) in a limited supply of air. 6. Write down the formulee and molecular weights of water, ammonia, hydrochloric acid, sulphuric acid, ferrous sulphate, phosphoric acid. 7. (1) How many grams of oxygen are required to burn 24 grams of carbon and 32 grams of sulphur? (2) How many lbs. of ainc are there in 350 lbs. of zinc sulphate ? 8. Describe any two experiments which you have performed yourself, and the purpose for which you performed them. 9. How would you obtain chlorine from common salt ? Give the equation respecting the reaction. Describe any experiments with chlorine you may have seen. DECEMBER, 1877. 1. Describe any experiments you may have seen which prove (1) that chemical action generally produces a change of state ; (2) that chemical action generally produces a change of temperature. 2. Give the principal properties of oxygen. Describe its preparation from potossic chlorate, representing the reaction by an equation. 3. What quantity of oxygen by weight and also by volume can be obtained by the decomposition of 100 grains of potassium chlorate ? mby iquid and aitrio trould with wine this. acid? ou of rmed onia, irbon [)lbB. ', and ation may that bction from ained CHEMISTRY FOR INTERMEDIATES. 61 4. Give the symbol, atomic weight, and chief properties of chlorine. To what are its bleaching and deodorizing properties due? Express in words the meaning of the equation— 2 NaCl + Mn03+ 2 HaS0^ = Cla + Na.,S04 + MnS04+2H,0. 5. Give the symbol and atomic weight of sulphur. Describe any methotl of preparing sulphuric acid. How would you prepare crystals of sulphur? What would be their shape ? 6. What is the action of water upon each of the following substances : Hydrogen, carbonic anhydride, ammonia, and sodium ? 7. What weight and volume of carbonic acid gas would be produced by burning 5 grains of carbon in oxygen gas ? 8. Give a brief account of the atmosphere, including its extent, pressure, composition and chemical relations. 9. Describe minutely any chemical experiment you have yourself performed. JULY, 1878. 1. Give the names and atomic weights of the elements represented by the following symbols : Al, C, Ca, Cu, Fe, CI, Pb, S, P. 2. Explain what occurs in the distillation of water, and how the water is purified by the process. What kind of impurities will remain in the distilled water, and how can they be detected ? 3. Represent the following statement by means of an equation : If KM) grams of marble be mixed with 73 grams of hydrochloric acid it will yield 111 grams of calcic chloride, 18 grams of water, and 44 of carbonic anhydride. 4. Describe fully the preparation of O from potassic chlorate, representing the reaction by an equation. How much potassic chlorate must be taken to yield 10 lbs. of oxygen ? 5. Give the properties of hydrogen. Describe the process for o"^taining hydrogen which is represented in the equation— HjSO^ + Zn = ZnS04 + Ha. 6. Explain the chemical relations between chalk, quicklime, and slaked lime ; also the preparation of chloride of lime ; and the reactions by which that substance evolves chlorine when acted on by sulphuric acid and when exposed to the air. 7. What is the composition of lucif er matches ? What purpose does each ingredient serve, and what chemical action occurs when you strike a match T 8. A compound, on an analysis, is found to yield the following percentages : Potassium, 45 95; nitrogen, 16-45; oxygen, 37*60. Calculate its formula, and give its name. 9. State what toxperiments you have yourself performed, and describg minutely any one of them, 62 CHEMISTRY FOR INTERMEDIATES. il I iiii I 1. DECEMBER, 1878. State the laws of comVining proportions. In one ounce of each of the following gases what weight of each element would there be : Carbon mon- oxide, carbon dioxide, marsh gas (CH*), olefiant gas (CaH4), acetylene (CjHa) ? What would be the volume of an ounce of carbon dioxide if, at the same temperature and pressure, 50 cubic inches of hydrogen weigh one grain ? 2. Describe a method of preparing hydrogen. Write in symbols the reaction occurring. By what experiments could the most important properties of. hydrogen be exhibited ? 3. By what experiments could air be shown to be a mechanical mixture of two gases, oxygen and nitrogen ? Give the names and symbols of the chief compounds of oxygen and nitrogen. Write in symbols the reaction that occurs in the preparation of nitric acid from nitre, and calculate the weight of commercial nitric acid (2 HNO3, 3 HjO) that 337 oz. of nitre are capable of yielding (K = 39-l). 4. Name the allotropic fonns of carbon. In preparing carbon monoxide from oxalic acid a mixture of carbon monoxide and carbon dioxide is obtained ; how can the carbon dioxide be removed ? o. Describe a method of preparing and collecting chlorine. Represent the reaction by an equation. What are the principal properties of chlorine ? 6. Describe the preparation of sulphuric acid. How many gallons of oil of vitriol (specific gravity 1-85) could be obtained from 111 lbs. of sulphur, a gallon of water weighing 10 lbs. ? You are given two bottles, one containing sulphuric acid, the other containing nitric acid, how could you determine which held the sulphuric acid ? 7. Describe the structure of the flame of a candle. JULY, 1879. 1. What is understood in chemistry by the expression an "eleiiient," or an "elementary body?" How could you show that air is not an element? What is the difference between a mechanical mixture and a chemical com- pound ? How could you show that nitrogen monoxide is a chemical compound ? 8. Complete the following equations : FeS -f- H2SO4 = NaaSOg + S = CaO + NaaCOg + HjO - SiOa -H 4 HF = 9 Describe a mode of preparing sulphur dioxide, and give and explain the equatiouo representing the reactions. Explain the difference between the bleaching action of chlorine and sulphurous auid. 'n\ iS: 11; f ' CHEMISTRY FOR INTERMEDIATES, G2f 2. Describe any method of preparing oxygen. Write in symbols the reaction that occurs when oxygen is prepared from potassium chlorate. 5. In what respect does sulphur resemble oxygen ? By what other means, besides burning sulphur, can sulphur dioxide be prepared ? Explain its action tvith solutions (1) of potash, (2) of chlorine. 6. How much phosphorus is contained in 120 lbs. of bone ash, consisting of 88-4 per cent, of Caa (P04)a and 11-5 per cent, of CaCOs ? (Ca=40). What volume of hydrogen is contained in one ounce of microcosmic salt NaNH4HP04 , 4 HjO ? (37 grains of hydrogen to the cubic foot : Na=23). 7. What is the simplest formula that can be assigned to a substance con- taining Carbon 54 5 "j Hydrogen 9 2 V per cent. ? Oxygen 36-4 ) 8. The chimney-glass increases the brightness of the flame of the conunofl coal-oil lamp. Why does it do so? If you drive a current of air into the flame of an ordinary candle, the flame appears less bright than it did before the introduction of the air. Explain why this is the case ? JULY, 1880. 1. Describe the chief characters of (I) ammonia, (2) ammonium carbonate ; and the process by which they are usually prepared. Give also the chemical reactions which occur in these processes. 2. Describe fully the modes of decomposing water which you have seen. State how you would determine whether a given specimen of water is hard or soft. If the water is found to be hard, state (with reasons) the various means by which it could be made soft. 3. What means are best employed for the collection of nitric oxide, chlorine^, ammonia, carbonic acid, sulphur dioxide, and nitrous oxide gases. 4. Describe fully the experiment in which the reactions are given by the equation CaC03 + 2HCl=CaCl4 + HaO + CO,. 5. Describe some of the properties of sulphur, and state its atlotropio modifications, and how they are obtained. Sulphur ia said to be a dimorphous body — explain. 6. Calculate the percentage composition by weight of potassium nitrate,. and of the two oxides ol carbon. 7. Write down the atomic weight, the molecular weight, the relative weight,, the specific gravity, the atomic and the molecular volume of chlorine, and fully explain the meaning of these temu. 64 CHEMISTRY FOR INTERMEDIATES. 10. On completely decomposing by heat a certain weight of potassium chlorate, 20*246 grains of potassium chloride was obtained. What weight of potassium was used, and how much oxygen was evolved ? JULY, 1881. 1. KNOs + HaSO^rrHNOa + KHSO^. (1.) Give, first, the names of the compounds entering into the reaction represented by above equation, and, second, the names of the elements, with their combining weights, entering into the constitution of these compounds. (2.) Kepresent, by diagram, the necessary apparatus for conducting the experiment indicated by the equation. (3.) What eflfect would HaSO*, HNO3 and KNO3, each have upon a solution of blue litmus ? 2. It is required to make 3) pounds of HNOg by experiment 1. (2). How much HgSO^ is required? 3. Explain the principle of Davy's safety lamp. 4. It is required to prepare the elements hydrogen and nitrogen for class purposes: (1.) Describe the apparatus and name the substances needed for the preparation of each of the elements. (2.) Write out the equations representing the reactions occurring in their elimination. (3.) Describe the experiments you would perform to demonstrate their distinguishing properties. 5. Assign reasons for assuming that charcoal, graphite and diamond, are different modifications of the same element. 6. Complete the following equations : CaCOa + 2 (HCl) - Na + H2O - 2 (NaOl) + 2 (H3SO4) + MnOa = PaOg + 3 (H2O) = 7. Coal gas and phosphorus bum with a luminous, sulphur and hydrogen with a non-luminous flame. Account for this difference. 8. A certain quantity of zinc furnished, when treated with sulphuric acid, 3| pounds of zinc sulphate. How much zinc was employed? Zn=65. U ttasflium eight of of the >n, and, tntering %m, the luatiou. solution . How for clasB 3ded for ]uation8 ribe the iperties. )nd, are ydrogen ric acid, INDEX. Paok. Atomic Theory 6 Atom 8 Atomicity 10 Atomicity, Table of 1 1 Acids 18 Avogadro's Law 21 Atmosphere 27 Ammonia 22 Ammonium hydrate 23 Binary compounds 17 Bases 19 Bleaching powder 40 Chemical compounds 6 Chemiara 8 Chemical combination 10 Chemical combination, Laws of . . 10 Carbon 28 Carbon monoxide 29 Carbon dioxide 30 Coal gas 34 Combustion 35 Chlorine 37 Chlorine and oxygen 40 Chloric acid 40 Carbon disulphide 44 Density 13 Elements 6 Equation, Chemical 9 Ethene, or Ethylene 33 Examination Questions 53 Formula 8 Flame structure 35 Gram, weight 12 Hydrogen 13 Hydrates or Hydroxides 18 Hydrochloric acid 38 Inorganic chemistry 5 Impurities of water 20 Liquor ammonisB 23 Litre 12 Page. Metals Q Mechanical mixture 6 Molecule * 8 Metre [ ] 12 Metric system 12 Marsh gas [[[ 32 Non-metals g Notation, Chemical 8 Nomenclature 17 Nitrogen . , f 21 Nitrous oxide [[ 24 Nitric oxide .' 25 Nitrogen tri oxide 25 Nitric acid ] 26 Normal Salt " ' ' 43 Organic chemistry 5 Oxygen '■' 15 Ozone ... 16 Oxygen and nitrogen 24 Olefiant gas 33 Physical states of matter 7 Potassic chlorate 41 Phosphorus 45 Phosphorus trioxide 47 Phosphorus pentoxide 47 Phosphoric acid, "glacial " 47 Phosphoretted hydrogen 48 Radicles 12 Symbol ; 8 Specific weight 12 Salts 19 Sulphur 41 Sulphur dioxide 41 Sulphuric acid 42 Sulphuretted hydrogen 43 Uuniversity Exaan. Questions 63 Volume 8 Valency 10 Water ■ 20 COPP, CLABK ft CO., GENERAL PSINTERS, COLBORNE STREET, TORONTO.