Chemistry comprises two related but distinct activities:
(i) the quest for an understanding of matter and material change,
(ii) the utilization of material change for human ends.
Ideally, the first activity provides the necessary know-how for the pursuit of the second, but in practice, the help it can give is only partial, and the second activity has to fall back on trial and error techniques in order to achieve its ends. This means that a good chemist is one who not only has a mastery of chemical theory, but also a good knowledge of chemical facts. With such a knowledge he can direct a trial-and error approach to practical problems in the most promising directions.
Organic chemistry is usually defined as the chemistry of compounds of carbon, inorganic chemistry being then the chemistry of all the other elements. This distinction is not a completely satisfactory one, however, since there are many compounds of carbon that are quite different from those studied by organic chemists (e.g. tungsten carbide, used for tipping cutting tools) and there are many compounds of other elements that are very similar to those studied under organic chemistry (e.g. the silicon analogues of the hydrocarbons). It is best, therefore, to think of inorganic chemistry as the chemistry of all the elements, with organic chemistry as being a more detailed study of certain important aspects of one of them - viz. the hydrocarbons and their derivatives.
Thinking of inorganic chemistry in this way brings together aspects of the chemistry of an element that would otherwise tend to become separated. For example, alcohols and ethers are usually dealt with under organic chemistry and are not thought of as being part of the chemistry of oxygen. Once they are, however, they can be set alongside the other compounds of oxygen, and a relationship immediately becomes apparent that might otherwise be lost, viz. that expressed by the formulae:
|
H–O–H |
R–O–H |
R–O–R¢ |
In parts of this course I shall make use of the quantum theory. This is the theory theoretical chemists use to describe atoms and molecules. It was developed to explain phenomena classical theories could not explain, e.g. the atomic spectrum of hydrogen. From it can be calculated the energy of an atom or molecule, and the average motion of the electrons in it. The physical basis of the theory is still obscure, but it gives remarkably accurate results.
I shall not give a detailed account of the theory. This is done in courses on theoretical chemistry.
Chemistry is a very broad subject. It extends from the scientific study of substances (“pure” chemistry) to their manufacture and use (“applied” chemistry). It requires both mental effort and practical skill. It impacts on the world both intellectually and practically. When studying any particular part of chemistry, this broader context needs to be kept continually in mind.
There are several textbooks of introductory inorganic chemistry. These are best read after this course, as a complement to it.
For a fuller discussion of the scope of chemistry, see:
P.G. Nelson, “What is chemistry?”, Education in Chemistry, 1983, Vol. 20, pp. 122-125.