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 , thefirst 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.
