An Introduction to Chemical Science

339. The La Place Theory.--This theory supposes that at one time the earth and the other planets, together with the sun, constituted a single mass of vapor, extending billions o...

Experiment 26.--Hold a porcelain dish or a plate in the flame of a candle, or of a Bunsen burner with the openings at the bottom closed. After a minute examine the deposit. It i...

288. Classification.--Rocks may be divided, according to their origin, into three classes: (1) Aqueous rocks. These have been formed by deposition of sedimentary material, layer...

Experiment 82.--Examine a candle flame, holding a dark object behind it. Note three distinct portions: (1) a colorless interior about the wick, (2) a yellow light-giving portion...

171. Gaseous Weights and Volumes.--A liter of H, at 0 degrees and 760 mm., weighs nearly 0.09 g. This weight is called a crith. Find the weight of H in the following, in criths...

265. Ores and Irons.--As Fe occurs native only in meteorites and in small quantities of terrestrial origin, it is obtained from its ores. There are four of these ores--magnetite...

Experiment 13.--Take 5 g. of crystals of potassium chlorate (KClO3) and, without pulverizing, mix with the same weight of pure powdered manganese dioxide (MnO2). Put the mixture...

226. Order of Derivation.--Though K is more metallic, or electro- positive, than Na, the compounds of Na are more important, and will be considered first. The only two compounds...

Experiment 74.--Put into a t.t., or a bottle with a d.t. and a thistle-tube, 10 or 20 g. CaCO3, marble in lumps; add as many cubic centimeters of H2O, and half as much HCl, and...

Experiment 4.--Examine a few crystals of sugar, and crush them with the fingers. Grind them as fine as convenient, and examine with a lens. They are still capable of division. P...

Experiment 20.--Prepare apparatus as for making O. Be sure that the cork perfectly fits both d.t. and t.t., or the H will escape. Cover 5 g. granulated Zn, in the t.t., with 10...

13. About Seventy Different Elements are now recognized, half of which have been discovered within little more than a century. These differ from one another in (1) atomic weight...

Experiment 103.--To a solution of 2 g. of sodium sulphide,, Na2S2 in 10 cc. H2O add 3 or 4cc. HCl, and look for a ppt. Filter, and examine the residue. It is lac sulphur, or mil...

Experiment 47.--Into a flask put 10 g. coarse NaCl, and add 20 cc. H2SO4. Connect with Woulff bottles [Woulff bottles may be made by fitting to wide-mouthed bottles corks with t...

207. Separation. Experiment 115.--Draw out into two parts in the Bunsen flame a piece of glass tubing 20cm long and 1 or 2cm in diameter. Into the end of one of the ignition tub...

NOTE.--Phosphorus should be kept in water, and handled with forceps, never with the fingers, except under water, as it is liable to burn the flesh and produce ulcerating sores....

258. Occurrence and Preparation.--Mg is very widely distributed, but does not occur uncombined. Its salts are found in rocks and soils, in sea water and in the water of some spr...

Experiment 55.--Having fitted a cork with four or five perforations to a large t.t., pass a d.t. from three of these to three smaller t.t., leaving the others open to the air, a...

319. Carbon and Water.--Some very important organic compounds have H and O, in the proper proportion to form water, united with C. The three leading ones are sugar, C12H22O11 or...

71. Acids and Bases are usually Opposite in Character.--When two forces act in opposition they tend to neutralize each other. We may see an analogy to this in the union of the t...

249. Occurrence.--The above are the chief compounds of Ca. The element itself is not found uncombined, is very difficult to reduce (page 141), is a yellow metal, and has no use....

Experiment 39.--Pour a few drops of chlorhydric acid, HCl, into a clean evaporating-dish. Add 5 cc. H2O, and stir. Touch a drop to the tongue, noting the taste. Dip into it the...

304. Source.--The three main elements in combustion are O, H, C. Air supplies O, the supporter; C and H are usually united, as hydro-carbons, in luminants and combustibles. H gi...

284. Descriptive.--The silver halogens, AgCI, AgBr, AgI, are very sensitive to certain light rays. Red rays do not affect them; hence ruby glass is used in the "dark room."

278. Occurrence.--Copper occurs both native and in many compounds, being diffused in rocks and, in minute quantities, in soils, waters, plants, and animals. Spain, Chili, and th...

Experiment 98.--Put into a t.t. 2 or 3 g. of powdered KI mixed with an equal bulk of MnO2, add H2SO4 enough to cover well, shake together, complete the apparatus as for making B...

Experiment 87.--Put into a t.t. 5 g. of fine granular MnO2 and 10 cc. HCl. Apply heat carefully, and collect the gas by downward displacement in a receiver loosely covered with...

335. Growth.--The chemistry of organic life is very complex, and not well understood. A few of the principal points of distinction between the two great classes of living organi...

Experiment 61.--Dissolve 3 g. sodium carbonate, Na2CO3, in 10 or 15 cc. H2O in an e.d., and bring it to the boiling-point. Then add to this a mixture of 1 or 2 g. calcium hydrat...

328. Ferments.--A large number of chemical changes are brought about through the direct agency of bodies called ferments; their action is called fermentation. Ferments are somet...

222. Comparison of Metals and Non-Metals.--The majority of elements are metals, only about a dozen being non-metallic in their properties. The division line between the two clas...

Experiment 8.--Lay the tubing on a flat surface, and draw a sharp three-cornered file two or three times at right angles across it where it is to be broken, till a scratch is ma...

58. Examine untarnished pieces of iron, silver, nickel, lead, etc.; also quartz, resin, silk, wood, paper. Notice that from the first four light is reflected in a different way...

244. Occurrence and Preparation.--Potassium occurs only in combination, chiefly as silicates, in such minerals as feldspar and mica. By their disintegration it forms a part of s...

66. Avogadro's Law of Gases.--Equal volumes of all gases, the temperature and pressure being the same, have the same number of molecules. This law is the foundation of modern ch...

313. Sources and Kinds of Oils and Fats.--Oils and fats are insoluble in water; the former are liquid, the latter solid. Most fats are obtained from animals, oils from both plan...

Experiment 80.--Provide a glass tube 40 or 50 cm long and 3 or 4 cm in diameter. Fit to each end a cork with two perforations, through one of which a long tube passes the entire...

Examine galena, lead protoxide and dioxide, red-lead, lead carbonate, acetate, and nitrate. Note especially the colors of the oxides, the cubical crystallization and cleavage of...

218. Glass is an Artificial Silicate.--Si02 alone is almost infusible, as is also Ca0; but mixed and heated the two readily fuse, forming calcium silicate. Ca0 + SiO2 = ? Notice...

96. Preparation of Bases.--We have seen that many acids are made by acting on a salt of the acid required, with a stronger acid. This is the direct way. The following experiment...

65 parts by weight of Zn are required to liberate 2 parts by weight of H; or, by using 65 g Zn with 73 g HCl, we obtain 2 g H. If twice as much Zn (130 g) were used, 4 g H could...

214. Comparison of Si and C.--The element Si resembles carbon in valence and in allotropic forms. It occurs in three forms like C, a diamond form, a graphite, and an amorphous....

Experiment 18.--Fasten a piece of electric-light pencil, or of crayon, to a wire, as in Experiment 15, and bend the wire so it will reach half-way to the bottom of a receiver. U...

Experiment 130.--Introduce 20 cc.of molasses into a flask of 200 cc, fill it with water to the neck, and put in half a cake of yeast. Fit to this a d.t., and pass the end of it...

Experiment 108.--Put a gram of ferrous sulphide (FeS) into a t.t. fitted with a d.t., as in Figure 32. Add 10cc. H2O and 5cc. H2SO4. H2S is formed. Write the equation, omitting...

178. Diffusion of Gases.--Oxygen is 16 times as heavy as H. If the two gases were mixed, without combining, in a confined space, it might be supposed that O would settle to the...

Experiment 38.--Arrange "in series" two or more cells of a Bunsen battery (Physics, page 164), [References are made in this book to Gage's Introduction to Physical Science.] and...

Experiment 66.--Put into a flask, holding 200cc, lOg of ammonium nitrate, NH4NO3; heat it over wire gauze or asbestus in an iron plate, having a d.t. connected with a large t.t....

285. Platinum is much rarer than gold, and is about two-thirds as costly as the latter. It is found alloyed with other metals, as An, and is obtained from sand, in which it occu...

1. The Metric System is the one here employed. A sufficient knowledge of it for use in the study of this book may be gained by means of the following experiments, which should b...

9. Molecules are Extremely Small.--It has been estimated that a liter of any gas at 0 degrees and 760 mm. pressure contains 10^24 molecules, i.e. one with twenty-four ciphers.

85. Preparation. Experiment 52.--To 10 g. KNO3 or NaNO3, in a flask, add 15 cc. H2SO4. Securely fasten the cork of the d.t., as HNO3 is likely to loosen it, and pass the other e...

Experiment 72.--Put into a flask, of 200 cc., 5 g. of oxalic acid crystals, H2C2O4, and 25 cc. H2SO4. Have the d.t. pass into a solution of NaOH in a Woulff bottle (Fig. 31), an...

130. Constituents.--The four chief constituents of the atmosphere are N, O, H2O, CO2, in the order of their abundance. What experiments show the presence of N, O, and CO2 in the...

169. Halogens Compared.--The elements F, Cl, Br, I, form a natural group. Their properties, as well as those of their compounds, vary in a step-by-step way, as seen below. F is...

Experiment 78.--Scrape off the oxide from the surface of a piece of phosphorus 2 cm long, put it into a wide-mouthed bottle, half cover the P with water, cover the bottle with a...

Experiment 96.--Pulverize 2 or 3 g. KBr, and mix it with about the same bulk of MnO2. After putting this into a t.t, add as much H2SO4, mix them together by shaking, attach a d....

113. Weight and Volume.--We have seen that water contains two parts of H by volume to one part of O; or, by weight, two parts of H to sixteen of O. These proportions are invaria...

Order of derivation.--Occurrence and preparation of sodium chloride; uses.--Sodium sulphate: manufacture and uses. --Sodium carbonate: occurrence, manufacture, and uses.-- Sodiu...