Problems in Physical Chemistry [antikvár]

Introduction The student who would learn to solve physicochemical problems with confidence must be prepared for a fair amount of mental effort. As in all cases where physical quantities are treated mathematically, one must first fully understand the problem, the terms, and the applicable laws. It may occasionally seem convenient to apply the first suitable looking equation that comes to hand, either from memory or from a reference, without checking the conditions under which the particular formula is valid. Extensive experiments with this method of approach have proved that it does not save time and that it results, disappointingly often, in incorrect use of equations. The student should not be disheartened by finding that he does not quite understand such a concept as "entropy," for example. Many a person who finds no difficulty in dealing with such quantities as time and electrical charge in calculations would be embarrassed if asked to define these quantities in a strictly logical way. He has become so familiar with these concepts through use that he can apply them without having to think of definitions. The student should, Hkewise, become acquainted with the thermodynamic quantities by learning the relations between them and knowing how they change with varying conditions. This done, the student is ready to start solving problems with only an occasional pause to check on forgotten laws and without being hindered too much by philosophic speculation. The reader is assumed to have a certain minimum background in physics, mathematics, and chemistry. To solve many problems and to understand fully some of the chapter introductions, it is necessary to know the fundamentals of differential and integral calculus. Graphical or numerical integrations are required in some problems; these methods are treated very briefly in the Appendix section entitled "On Numerical Calculations." The chapter introductions are intended primarily to be a collection of the necessary definitions and formulas and to give the reader a hint of what he should know before he tackles the problems in the chapter. These introductions may occasionally be insufficient for those who have no previous knowledge of the subject from other texts. We have tried to arrange the material in a logical sequence so that no problem will require knowledge given in a later chapter. However, many readers will probably prefer to go through the chapters, and through the problems within each chapter, in an order different from that used here. For example, many of the problems on equilibria in Chapters 4, 5, 7, and 8 ix