The Compend of Chemistry; With Which Is Included a 2D and REV. Ed. of the First Step in Chemical Principles. - Softcover
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This historic book may have numerous typos, missing text, images, or index. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. 1881. Not illustrated. Excerpt: ... is apparently decomposed, its two elements associating themselves independently with the elements of the other body. If we mix water with common quick-lime, a violent action, attended with production of much heat, ensues, and if the quantity of water is about one-third that of the lime, a dry powder results, from which no appreciable amount of water can be expelled except by a red heat. If this compound contained water in an unchanged form, a moderate heat would drive it all out; hence, chemists have regarded the compound not as CaO, H2O but as CaH2O2 which is an entirely new body, containing really neither quicklime nor water. A considerable number of oxides are capable of uniting thus with water and forming bodies known as HYDRATES. Perhaps the most scientific view of these hydrates, is to regard the water as acting the part of an acid (it might indeed be called hydric acid), and just as CaSO4 is calcium sulphate, CaH2G2 will be calcium hydrate. Water, in fact, might be written HHO, the first H being replaceable by an element according to the usual law of atomicity. A portion of the hydrogen must always remain, or the body would become an oxide. Thus, if potassium were to act upon water, according to the reaction K2-|-H2O= K2O-|-H2, or calcium were to act according to the reaction Cat H2O=CaO-(-H2 the bodies produced are not hydrates, but oxides. The oxides, which, by addition of water, produce hydrates, are called Anhydrides. By subtracting H2O from any hydrate we may reproduce the corresponding anhydride. Many of the common acids may in this way furnish anhydrides, some of which are interesting bodies. Sulphuric acid. Sulphuric anhydride. H2SO4 --H,O =SOs In the same manner the student may deduce: Sulphurous anhydride SO2 from Sulphurous acid. Carbo...
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