Chemical Education Today
Book & Media Reviews The Bases of Chemical Thermodynamics, Volumes 1 and 2 by Michael Graetzel and Pierre Infelta Universal Publishers: Parkland, FL, 2000. Vol. 1: 298 pp. ISBN 1-58112-772-3. $25.95. Vol. 2: 300 pp. ISBN 1-58112-771-5. $25.95. reviewed by Gerald R. Van Hecke
Rarely does one pick up a text and find in it so many of one’s favorite pedagogical devices. Graetzel and Infelta was a treat to read. The text offers many new and clever derivations of the well-worn equations of chemical thermodynamics and for this reason alone the text should be on the bookshelf of every serious teacher of thermodynamics. The writing is easy to read: not terse, but carefully worded as a thermodynamics text should be. There are no fancy sidebars or tidbits, just a straightforward presentation of material that is frankly refreshing. A brief description of the text should come next, for it consist of two volumes. You find in Volume 1 introductory material, the laws of thermodynamics, auxiliary functions, molar and partial molar quantities, gases, and component phase equilibria; in Volume 2, the energetics of chemical reactions, chemical equilibria, properties of ideal and nonideal mixtures, and an introduction to statistical mechanics. The authors make careful definitions of those slippery concepts, systems, states, and extensive and intensive variables, and use those definitions to show how the thermodynamic state of a system can be described in a minimum number of variables. A pedagogical feature that makes a hit with me is the authors’ disuse of deltas. They explicitly write Ufinal – Uinitial instead of just good old ∆U, which really tells a reader nothing. How much better our students would understand thermodynamics if we were to ban ∆’s remains to be seen. The authors are consistent in their disuse of ∆’s except for standard expressions such as ∆rG °. Entropy, every beginning student’s random nightmare, is introduced by the concept of arrangements available to the system. The number of arrangements can be quantified by various permutation formulas. Thank the authors for sticking with arrangements that can be calculated and not trying to discuss randomness, which cannot. The second law is introduced via traditional heat engines with arguments as thorough as those of K. G. Denbigh in his classic Chemical Thermodynamics text. However, the authors use quite different examples, which are highly readable. The overworked term “entropy of the universe” has been abandoned in favor of “global entropy”, meaning a combination of the system and surroundings. The term works for me. In addition to the Carnot cycle, there are compelling expositions on the Otto, Stirling, and Joule cycles. When discussing chemical reactions, extensive use is made of the extent of reaction concept. In fact a very clever derivation of the temperature dependencies of ∆rG °, ∆rH °,
and ∆rS ° is offered using the temperature dependency of the extent of reaction. Still on the topic of chemical equilibrium, the authors provide an example (and make the point quite clearly) of how in cases involving simultaneous chemical equilibria, it is quite possible to drive a reaction with a positive ∆rG ° toward completion through the device of coupling the reaction with other favorable reactions. For biochemical systems this is the reason for life. Having (I hope) intrigued the reader of this review to this point, I’d better describe something more of the text. The two volumes would need to be used as companions in the sense that while Volume 1 could be used alone, Volume 2 definitely refers to crucial material contained in Volume 1. The separation into two volumes does seem a bit odd; and in fact, the volumes are continuously numbered. Each volume contains fully worked-out examples pertinent to the material in that volume. The examples, which the authors call problems but that is a stretch, are not the typical three-line, use the formula, plug-and-chug variety, but very elaborate applications of the principles discussed in the text. The examples could be studied on their own, without the benefit of the text. The text proper has very few worked-out examples and virtually none of those involve numerical calculations. I cannot decide whether to prefer a volume of principles and a separate volume of examples, or one volume containing everything. No doubt students would eventually find the use of the two volumes as inconvenient I have. Who would profitably use these volumes? Clearly teachers looking for deeper understanding and different approaches would appreciate the authors’ efforts here. These volumes would not be a good absolute first introduction to thermodynamics. A senior-level or an introductory graduate course in chemical thermodynamics is probably the right place for this presentation. Teachers using this text would probably want to discuss additional examples, especially numerical ones. There are some points of concern to be raised, however. All of the thermodynamic variables, U, H, G, A, and S as well as the traditional directly experimentally observable variables T, p, and V, are introduced in the first chapter largely as mathematically functions. This presentation would be appreciated by students who have heard of these variables, but others will wonder what is the purpose, since no examples using the variables are presented. Some teachers will wonder what the Schwarz theorem is and whatever happened to Maxwell’s relationships. The use of Lagrangian multipliers when deriving the criteria for phase equilibria in terms of chemical potentials, while mathematically elegant, is probably overkill. The discussion of osmotic pressure, which is little more than one page long, is far too brief in today’s biologically steeped environment. In discussing the phase rule f = c + 2 – p, the authors unfortunately let c represent components or species. Nothing is more confusing to students applying the phase rule than the distinction between species and components. To use the same symbol for both invites disaster. The use of matrix algebra to determine the number of independent
JChemEd.chem.wisc.edu • Vol. 78 No. 9 September 2001 • Journal of Chemical Education
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Chemical Education Today
reactions relating chemically reacting species is one of my favorite pedagogical devices, but the examples in the text do not go far enough to teach first-time students the methodology. Other points could be raised but this review needs to end, so only one more criticism. The chapter on statistical mechanics, although it ends well with the appropriate formulas and applications, needs help in the introduction section. I found the switching between microcanonical and canonical too subtle for a first exposure to this subject. Also there is little point to introducing Bose–Einstein and Fermi–Dirac statistics
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unless some examples are discussed. This chapter on statistical methods is just 31 pages long and tries to do too much in the short space. I would say that students deserve this text. I hope they would not find it so different from their current generation of ever glossier and slicker textbooks as to dismiss the powerful presentation contained in its simple pages. Gerald R. Van Hecke is at Harvey Mudd College, Claremont, CA 91711;
[email protected].
Journal of Chemical Education • Vol. 78 No. 9 September 2001 • JChemEd.chem.wisc.edu
