A manual of chemistry : theoretical and practical, inorganic and organic, adapted to the requirements of students of medicine / by Arthur P. Luff and Hugh C.H. Candy.

  • Arthur P. Luff
Date:
1910
Catalogue details

Licence: In copyright

Credit: A manual of chemistry : theoretical and practical, inorganic and organic, adapted to the requirements of students of medicine / by Arthur P. Luff and Hugh C.H. Candy. Source: Wellcome Collection.

Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.

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    rise; this rise of temperature will accelerate the action; the increased amount of action will be attended by increased evolution of heat, which in turn will cause increased rise of temperature, and so on, in a vicious cycle, till the action becomes a fire. Conversely, a reduction of temperature retards chemical action, and at the very low temperatures more recently reached, in the neighbourhood of —200° C, this action is almost arrested. NATURE OF HEAT—ENERGY—CONSERVA- TION OF ENERGY In the preceding paragraph, as well as in that referring to latent heat (p. 4), the relation of heat to chemistry has been sufficiently indicated for the present purpose, although we have by no means exhausted the subject. Indeed, this relation is now regarded as so intimate and extensive that whole text-books are devoted to thermal chemistry in which this aspect of the science is specially studied. We shall proceed now to consider the nature of heat. Heat is now regarded not as something unique, but as one of the many forms of energy. We are unable to create energy or to destroy it, but we are often able to convert one form of energy into another ; thus we frequently convert chemical energy into electrical, and vice versa. When, for instance, we work a Grove's or a Bunsen's cell, the element zinc dissolves in the sulphuric acid with formation of a new compound, the sulphate of zinc. While the zinc and sulphuric acid existed apart, the world possessed a certain amount of potential energy. After combination this potential energy is lost to the world. In return for the sacrifice of this, which we may < ;i|] chemical energy, since its disappearance is con- nected with the formation of a chemical compound,