A series of chemical problems with key for use in colleges and schools / by T.E. Thorpe. Rev. and enl. by W. Tate ; with a preface by H.E. Roscoe.

  • Thomas Edward Thorpe
Date:
1891
Catalogue details

Licence: Public Domain Mark

Credit: A series of chemical problems with key for use in colleges and schools / by T.E. Thorpe. Rev. and enl. by W. Tate ; with a preface by H.E. Roscoe. Source: Wellcome Collection.

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    CHEMICAL EQUATIONS; TO CALCULATE THE AMOUNT OF MATERIAL REQUIRED TO PRODUCE A GIVEN WEIGHT OF ANY SUBSTANCE OR THE QUANTITY OF THE SUBSTANCE PRODUCED BY THE DECOM- POSITION OF A KNOWN WEIGHT OF THE MATERIAL. Chemical equations;—The resulls of any chemical actions arc represented by equations in which the signs + - and = are used in the same sense as in algebra, so far as regards the weights of matter represented by the symbols. The meaning of such an equation will be best shown by examples.— 1. ILSO^ -f- BaCl2 = BaSOi + 2 IICl. This equation indicates not only tliat sulphuric acid and barium chloride react to produce barium sulphate and hydrochloric acid, but, further, that the molecular weight of sulphuric acid reacts with the molecular weight of barium chloride to produce the molecular weight of barium sulphate and twice the molecular weight of hydrochloric acid ; hence 98 jiarts by weight of sulphuric acid react with 208 parts by weight of barium chloride to form 233 ]iarts by weight of barium sulphate and 73 parts by weight of hydrochloric acid gas. The number of atoms of each element must be the same on either side of the equation, consequently the total number of atoms must be the same on cither side. The numbers of molecules before and after a reaction are not necessarily the same. 2. IL+ Civ = 2 11 Cl. Here, as in (i), it is indicated that 2 parts by weight of hydrogen combine with 71 parts by weight of chlorine to jiroducc 73 parts by weight of hydrochloric acid. But the equation signifies more: as we know the molecular weights