This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1894 edition. Excerpt: ...acid, HC1, from sodium chloride, NaCl (common salt), and sulphuric acid, H2S04 (see Exp. 61), is represented by the equation 2 NaCl + H2S04 = 2 HC1 + Na2S04. (4) Again, the formation of chlorine from sodium chloride, NaCl, sulphuric acid, H2S04, and manganese dioxide, MnOa as in Exp. 68, may be expressed by the equation 2 NaCl + Mn02 + 2 H2S04 = Na2S04 + MnS04+2Cl+2H20. (5) These equations are short and concise ways of expressing chemical facts: Equation (1) expresses the fact that water is decomposed, yielding hydrogen and oxygen. Equation (2) expresses the fact that hydrogen and oxygen unite to form water. Equation (3) expresses the fact that potassium chlorate is broken up, forming oxygen and potassium chloride. Equation (4) expresses the fact that sulphuric acid acts upon sodium chloride, and forms hydrochloric' acid and sodium sulphate, Na2S04. Equation (5) expresses the fact that sodium chloride, manganese dioxide, and sulphuric acid react upon one another, producing sodium sulphate, manganese sulphate, MnS04, chlorine gas, and water. In each case these facts are expressed in a much briefer way by the equation. But the equation tells us still more than this; for as we have seen, the formula of a compound shows its component elements, and when the combining weights are known, shows the percentage composition of the compound. Again, when the equation is balanced, --that is, when numerical coefficients are introduced, before the formulae of some of the compounds, so that the amount of each element shall be the same in both members of the equation, --the equation indicates the exact proportions by weight in which all the substances react with one another in the change. Let us take for example Equation (5) given above. The combining...