par Sutcliffe, Brian T. 
;Guy Woolley, R.
Référence Philosophy of Chemistry, Elsevier, page (387-426)
Publication Publié, 2012
;Guy Woolley, R.Référence Philosophy of Chemistry, Elsevier, page (387-426)
Publication Publié, 2012
Partie d'ouvrage collectif
| Résumé : | This chapter starts by giving a brief account of the development of the atomic-molecular conception of chemistry. An essential backdrop to the whole discussion is the importance throughout human history of the practical chemical arts that have informed the production of the whole range of useful materials and stimulated enquiry into the theoretical aspects of chemical processes. Chemistry is concerned with the composition and properties of matter, and with the transformations of matter that can occur spontaneously or under the action of heat, radiation or other sources of energy. From the results of chemical experiments the chemist singles out a particular class of materials that have characteristic and invariant properties. Such materials are called pure substances and may be of two kinds, viz: compounds and elements. Elements may be defined as substances which have not been converted either by the action of heat, radiation, or chemical reaction with other substances, or small electrical voltages, into any simpler substance. Compounds are formed from the chemical combination of the elements, and have properties that are invariably different from the properties of the constituent elements; they are also homogeneous. This characteristic chemical notion of a pure substance is based on an ideal conception of the chemical and physical properties of matter and their changes under specified experimental conditions. © 2012 Elsevier B.V. All rights reserved. |
