A Text-Book of Elementary Chemistry

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER VIII. Chemical Units Of Weight. Formula. 86. As we have seen (p. 49), when the volumes occupied by substances in the gaseous condition, rather than the weights, are taken as the basis of measurement, the combining proportions are simple and are expressible by small whole numbers (Gay-Lussac's law)....
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Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER VIII. Chemical Units Of Weight. Formula. 86. As we have seen (p. 49), when the volumes occupied by substances in the gaseous condition, rather than the weights, are taken as the basis of measurement, the combining proportions are simple and are expressible by small whole numbers (Gay-Lussac's law). This shows that there must be some relationship, connected with chemical combination, between the amounts of different substances contained as gases in equal volumes. It suggests that we might do well to take such amounts (weights of equal volumes) as the standard or unit quantities for chemical purposes. Now this is precisely what the chemist has found it in practice most convenient to do, and the present chapter deals with the units of material based upon comparing equal volumes. 86. Illustrations of Gay-Lussac's Law. Let us first familiarize ourselves with the volume-measuring point of view in chemical actions. The following are a few observed facts, beginning with the union of hydrogen and oxygen already discussed (pp. 48-9): (1) Hydrogen (2 vols.) + 0xygen (1 vol.) ? Steam (2 vols.). (2) Hydrogen (1 vol.) + Chlorine (1 vol.) - Hydrogen chlo ride (2 vols.). (3) Chlorine monoxide (2 vols.) -Chlorine (2 vols.) + 0xygen (1 vol.). (4) Mercuric oxide (not volatile) - Mercury (2 vols.) + 0xygen (1 vol.). If deemed desirable, the systematic study of this chapter may be omitted. The various conclusions reached in it may be briefly explained as each comes into use in later chapters. (5) Phosphorus (1 vol.) + 0xygen (5 vols.) ? Phosphorus pentoxide (1 vol.) (see 119). (6) Zinc (at 1000, 2 vols.) + Sulphur (at 1000, 1 vol.) - Zinc sulphide (at 1000, not volatile) (see 118). It will be noted that in some cases, like (2), there is no cha...