Entropy: The significance of the concept of entropy and its applications

atom provided by electrolysis, radioactive decay and the bombardment of metal foil with charged helium atoms is quickly sur- veyed in the first chapte...
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layman when they write for the beginning student. Ryschkewitsch's aim is to pr* vide the student not only with information but with a measure of intellectual stimulation. The evidence for the constitution of the atom provided by electrolysis, radioactive decay and t,he bombardment of metal foil with charged helium atoms is quickly s u c veyed in the first chapter, and the periodic arrangement of the elements by atomic numbers is presented. The second chapter deals with the electronic structures of atoms. The first point developed is the difficultyin accounb ing for the fact that electrons are held t o atoms by using simple electrostatic theory; next, the quantum nature of electromagnetic radistion; then, logically, to the conclusion that the energies of the atoms themselves have distinct values. This brings the reader up to 1913, one of the most important dates in the present century. Then come Heisenberg's Uucertainty Principle, de Broglie's mrttterwaves, and the full application of the mathematical theory of waves to the description of electrons in atoms by Heisenberg and Schraedinger. The ooncept of the orbital, replacing theideaof a strictly d e h e d orbit for an electron, is introduced next, along with the idea of four quantum numbers and Pauli's Exclusion Principle. A summary of the electron configurations of neutral isolated atoms is presented in the format of a periodic table. Each chapter in this book is substautially longer than the one preceding it. The t,l>irdchapter deals with ionic bonding and discusses such topics as ionization potential, electron affinity, dependence of crystal geometry on ion siaos and ion charges, and the Born-Haber cyole. The fourth and last chapter devotes 47 pages to covalent bonding. The topics discussed in the first half of the chapter include orbital overlap, the octet rule and its limitations, electron pair donation, odd electron molecules, multiple bonding, formal charge, dipole moments, and electrouegativity. These are discussed quite dearly and should be understandable to competent and interested first-year 001lege students. The concluding 22 pages are devoted to molecular geometry. Bond lengths, bond angles and covalent radii are discussed, with meaningful examples; and i t is shown how molecular geometries are accounted for from a consideration of electrostatic repulsions of electron pairs. The necessitv for the concent of hvbridization is explained and the sigma and pi bonding in ethylene are described. Resonance structures, electron delocalization, and the attendant increase in stability are the concluding topics. Ryschkewitseh writes well and he includes useful diagrams and tables. A well-chosen list of selected readings is added as an appendix. In spite of its small size the book is cs.refully indexed. I t is a valuable supplement for a. student whose introductory text does not adequately or systematically discuss the correlation of structure with properties.

P. EBLIN LAWRENCE Ohio University Athens 442

!Journal

of Chemical Education

Entropy: The Significance of the Concept of Entropy a n d Its Applications in Science and Technology

J. D. Fast, Technical University, Eindhoven, MoGrrtw-Hill Book Co., 313 pp. Inc., New York, 1962. vii Figs. and tables. 16 X 23.5 cm. $10.75.

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This is a. nice book. I t is well written; the viewpoint is mature; it is rich in examples; and throughout, the pace and level of presentation are well suited to the author's purpose, which is "to reach all those students and researchers to whom thermodynamics and statistical mechanics seem a little frightening, although a certain knowledge of these subjects is indiepensable to them." Science students that possess an ordinary knowledge of calculus and a normal interest in their subject should find this an enjoyable book to study. Beyond that, students with a particular bent toward physical chemistry, or metallurgy, or the solid state, mrty find in i t a deep source of understanding and, stemming from this, an inner sshisfaction and inspiration t o explore further in these areas the applications of thermodynamics and statistical mechanics. The book is an introduction to both disoiplines and also to quantum mechanics. The baok is divided into six chapters of sppraximately equal length. It opens, after a brief general introduction, with a conventional, but readable discussion of classical, Clausius-Kelviu-type "black box" thermodynamics. Internal energy and entropy are introduced through a discussion of thermodynamic systems, state^. and variables. exact and inexact differentials, reversible and irreversible changes, and Carnot's cycle. The second chapter, The Strttistical Significance of the Entropy Concept, nioely illustrates how to blend mathematical logic with apt examples to achieve a treatment that is both humane and robust. Dr. Fast treats large numbers and most probable states clearly and in some detail without getting bogged down in mathematical details. Included, also, is a disoussion of Einstein's Solid (and the The third chapter, Applications of the Cuncept of Entropy, mrty strike many teachers in this country-although not necessarily their students-as the least conventional chapter in the book. Not to be found is a discussiou of Maxwell's relations, the Gibbs-Helmholtz equation, the Clausius-Clapeyran equation, calligative properties, the phsse rule, or partial mold quantities. Instead, the examples chosen-the author says, "mare or less a t random," although there is to them a unity this statement does not reflect-include the following: the "free enthalpy" (G-H-TS), chemical equilibrium (illustrated chiefly by the reactions of oxygen with met& and carbon); paramagnetism and low temperatures (an unusually clear discussion of adiabatic demagnetization); interstitial &oms in body-centered cubic metals (probably

the most autharative section of the baok); substitutiond alloys and ferromagnetism; vacancies and diffusion in solids; elasticity of rubber; solutions of polymers; black body radiation; and fuel cells and heat pumps. The fourth chapter, Quantum Mechanics and Statistics, contains brief, but lucid, discussions of the uncertainty principle, the wave equation, and the statistics of Fermi-Dirac, Bose-Einstein, and Maxwell-Boltemann. Appropriately, the particle in a box is treated in cansiderable detail. The chapter closes with nine pages on electrons in solids. The last two chapters, The Entropy of Monatomic Gases and The Entropy of Diatomic Gases, contain more modern physical chemistry than one might suspect from their titles. Teachers and students dike should find these two chapters pmticularly useful for their well-worked out numerical examples. Cover to cover, this carefully written book nioely illustrates the view that while a study of broad theories, such as statistical mechanics, which apply to many phenomena, is indeed often profitable, it is sometimes equally profitable and probably mare in keeping with the general character of a growing science to focus attention a t times upon a phenomenon, such as entropy, to which many theories apply. "Entropy" could probably be used in some schools in a beginning physical chemistry course, if not as a text (it contains no problems), then as a reference or supplemental reading. Graduate students reviewing for examinations in physical chemistry should 6nd it very useful; there is much in it they should know. HENRY A. BENT Uniuei.sity of Minnesota .Ilinnmpolis

Inorganic Qualitative Analyrir: Short Course for Introductory Chemistry

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Richard B . Hahn, Wayne State University, Detroit, Michigan, and Frank J. Welcher, Indiana University, Bloomington. D. Van Nostrand Co., Inc., 304 pp. Figs. New York, 1963. ix and tables. 14.5 X 21.5 cm. $4.95.

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The authors state that this book was designed especially for courses in general chemistry which include qualitative analysis as the laboratory portion of the second semester. Their objectives are (1) to acquaint the student with the properties of common inorganic substances; (2) t o apply this knowledge in the development of a system of inorganic qualitative analysis; (3) to study chemical equilibrium as i t is applied to qualitative analysis; and (4) to teach useful laboratory techniques. The book is divided into two parts: Theory and Laboratory. Part One consists of six chapters which cover the nature of qualitative analysis, solutions and colloids, and ohemical equilibrium. Part Two presents some preliminary