com Physical Chemistry Fourth Edition www. Silbey Class of 1942 Professor of Chemistry Massachusetts Institute of Technology Robert A. Alberty Professor Emeritus of Chemistry Massachusetts Institute of Technology Moungi G. Bawendi Professor of Chemistry Massachusetts Institute of Technology John Wiley & Sons, Inc.com ACQUISITIONS EDITOR Deborah Brennan SENIOR PRODUCTION EDITOR Patricia McFadden SENIOR MARKETING MANAGER Robert Smith SENIOR DESIGNER Kevin Murphy NEW MEDIA EDITOR Martin Batey This book was set in 10/12 Times Roman by Publication Services, Inc. and printed and bound by Hamilton Printing. The cover was printed by Lehigh Press, Inc. This book is printed on acid-free paper.䊊 ⬁ Copyright 2005 John Wiley & Sons, Inc. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center Inc. 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 646-8600. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030-5774, (201) 748-6011, fax (201) 748-6008. To order books or for customer service, call 1(800)-CALL-WILEY (225-5945).com The objective of this book is to make the concepts and methods of physical chem- istry clear and interesting to students who have had a year of calculus and a year of physics. The underlying theory of chemical phenomena is complicated, and so it is a challenge to make the most important concepts and methods understandable to undergraduate students. However, these basic ideas are accessible to students, and they will find them useful whether they are chemistry majors, biologists, engi- neers, or earth scientists. The basic theory of chemistry is presented from the view- point of academic physical chemists, but many applications of physical chemistry to practical problems are described. One of the important objectives of a course in physical chemistry is to learn how to solve numerical problems. The problems in physical chemistry help emphasize features in the underlying theory, and they illustrate practical applications. There are two types of problems: problems that can be solved with a hand- held calculator and COMPUTER PROBLEMS that require a personal computer with a mathematical application installed. There are two sets of problems of the first type. The answers to problems in the first set are given in the back of the textbook, and worked-out solutions to these problems are given in the Solutions Manual for Physical Chemistry. The answers for the second set of problems are given in the Solutions Manual. In the two sets of problems that can be solved using hand-held calculators, some problems are marked with an icon to indi- cate that they may be more conveniently solved on a personal computer with a mathematical program. There are 170 COMPUTER PROBLEMS that require a personal computer with a mathematical application such as MathematicaTM , MathCadTM , MATLABTM , or MAPLETM installed. The recent development of these mathematical applications makes it possible to undertake problems that were previously too difficult or too time consuming. This is particularly true for two- and three-dimensional plots, integration and differentiation of complicated functions, and solving differential equations. The Solutions Manual for Physical Chemistry provides MathematicaTM programs and printouts for the COMPUTER PROBLEMS. The MathematicaTM solutions of the 170 COMPUTER PROBLEMS in digi- tal form are available on the web at http://www.com/college/silbey. They can be downloaded into a personal computer with MathematicaTM installed. Students iv Preface can obtain Mathematica at a reduced price from Wolfram Research, 100 Trade Center Drive, Champaign, Illinois, 61820-7237. A password is required and will be available in the Solutions Manual, along with further information about how to access the Mathematica solutions in digital form. Emphasis in the COMPUTER PROBLEMS has been put on problems that do not require complicated program- ming, but do make it possible for students to explore important topics more deeply. Suggestions are made as to how to vary parameters and how to apply these pro- grams to other substances and systems. As an aid to showing how commands are used, there is an index in the Solutions Manual of the major commands used. MathematicaTM plots are used in some 60 figures in the textbook. The leg- ends for these figures indicate the COMPUTER PROBLEM where the program is given. These programs make it possible for students to explore changes in the ranges of variables in plots and to make calculations on other substances and sys- tems. One of the significant changes in the fourth edition is increased emphasis on www.com the thermodynamics and kinetics of biochemical reactions, including the dena- turation of proteins and nucleic acids. In this edition there is more discussion of the uses of statistical mechanics, nuclear magnetic relaxation, nano science, and oscillating chemical reactions. This edition has 32 new problems that can be solved with a hand-held calcula- tor and 35 new problems that require a computer with a mathematical application. There are 34 new figures and eight new tables. Because the number of credits in physical chemistry courses, and therefore the need for more advanced material, varies at different universities and colleges, more topics have been included in this edition than can be covered in most courses. The Appendix provides an alphabetical list of symbols for physical quanti- ties and their units. The use of nomenclature and units is uniform throughout the book. SI (Système International d’Unités) units are used because of their advan- tage as a coherent system of units. That means that when SI units are used with all of the physical quantities in a calculation, the result comes out in SI units without having to introduce numerical factors. The underlying unity of science is empha- sized by the use of seven base units to represent all physical quantities. HISTORY Outlines of Theoretical Chemistry, as it was then entitled, was written in 1913 by Frederick Getman, who carried it through 1927 in four editions. The next four editions were written by Farrington Daniels. In 1955, Robert Alberty joined Far- rington Daniels. At that time, the name of the book was changed to Physical Chemistry, and the numbering of the editions was started over. The collaboration ended in 1972 when Farrington Daniels died. It is remarkable that this textbook traces its origins back 91 years. Over the years this book has profited tremendously from the advice of physi- cal chemists all over the world. Many physical chemists who care how their subject is presented have written to us with their comments, and we hope that will con- tinue. We are especially indebted to colleagues at MIT who have reviewed various sections and given us the benefit of advice. These include Sylvia T. Garland, Mario Molina, Keith Nelson, and Irwin Oppenheim. Preface v The following individuals made very useful suggestions as to how to im- prove this fourth edition: Kenneth G. Stine (University of Missouri–St. Terry (Western Illinois University), and Worth E. We are also indebted to reviewers of earlier editions and to people who wrote us about the third edition. The following individuals made very useful suggestions as to how to improve the MathematicaTM solutions to COMPUTER PROBLEMS: Ian Brooks (Wol- fram Research), Carl W. Martin McClain (Wayne State University), Kathryn Tomasson (University of North Dakota), and Worth E. We are indebted to our editor Deborah Brennan and to Catherine Donovan and Jennifer Yee at Wiley for their help in the production of the book and the www.com solutions manual. We are also indebted to Martin Batey for making available the web site, and to many others at Wiley who were involved in the production of this fourth edition. Cambridge, Massachusetts Robert J. Silbey January 2004 Robert A. Bawendi CONTENTS www.com PART ONE THERMODYNAMICS 1. Zeroth Law of Thermodynamics and Equations of State 3 2. First Law of Thermodynamics 31 3. Second and Third Laws of Thermodynamics 74 4. Fundamental Equations of Thermodynamics 102 5. Thermodynamics of Biochemical Reactions 254 PART TWO QUANTUM CHEMISTRY 9. Molecular Electronic Structure 396 12. Rotational and Vibrational Spectroscopy 458 14. Electronic Spectroscopy of Molecules 502 15. Magnetic Resonance Spectroscopy 537 16. Statistical Mechanics 568 Contents vii PART THREE KINETICS 17. Kinetic Theory of Gases 613 18. Experimental Kinetics and Gas Reactions 641 19. Chemical Dynamics and Photochemistry 686 20. Kinetics in the Liquid Phase 724 PART FOUR MACROSCOPIC AND MICROSCOPIC STRUCTURES www. Electric and Magnetic Properties of Molecules 786 23. Solid-State Chemistry 803 24. Surface Dynamics 840 APPENDIX A. Physical Quantities and Units 863 B. Values of Physical Constants 867 C. Tables of Physical Chemical Data 868 D. Useful Information on the Web 898 G. Symbols for Physical Quantities and Their SI Units 899 H. Answers to the First Set of Problems 912 INDEX 933 This page intentionally left blank www.com P A R T O N E Thermodynamics T hermodynamics deals with the interconversion of various kinds of energy and the changes in physical properties that are involved.com Thermodynamics is concerned with equilibrium states of matter and has nothing to do with time. Even so, it is one of the most powerful tools of physical chemistry; because of its importance, the first part of this book is devoted to it. The first law of thermodynamics deals with the amount of work that can be done by a chemical or physical process and the amount of heat that is absorbed or evolved. On the basis of the first law it is possible to build up tables of enthalpies of formation that may be used to calculate enthalpy changes for reactions that have not yet been studied. With information on heat capacities of reactants and products also available, it is possible to calculate the heat of a reaction at a temperature where it has not previously been studied. The second law of thermodynamics deals with the natural direction of processes and the question of whether a given chemical reaction can occur by itself. The second law was formulated initially in terms of the efficiencies of heat engines, but it also leads to the definition of entropy, which is important in determining the direction of chemical change. The second law provides the basis for the definition of the equilibrium constant for a chemical reaction. It provides an answer to the question, “To what extent will this particular reaction go before equilibrium is reached?” It also provides the basis for reliable predictions of the effects of temperature, pressure, and concentration on chemical and physical equilibrium. The third law provides the basis for calculating equilibrium constants from calorimetric measurements only. This is an illustration of the way in which thermodynamics interrelates apparently unrelated measurements on systems at equilibrium. After discussing the laws of thermodynamics and the various physical quantities involved, our first applications will be to the quantitative treatment of chemical equilibria. These methods are then applied to equilibria between different phases. This provides the basis for the quantitative treatment of distillation and for the interpretation of phase changes in mixtures of solids. Then thermodynamics is applied to electrochemical cells and biochemical reactions. This page intentionally left blank www.com 1 Zeroth Law of Thermodynamics and Equations of State www.1 State of a System 1.2 The Zeroth Law of Thermodynamics 1.3 The Ideal Gas Temperature Scale 1.4 Ideal Gas Mixtures and Dalton’s Law 1.5 Real Gases and the Virial Equation 1.6 P –V –T Surface for a One-Component System 1.8 The van der Waals Equation 1.9 Description of the State of a System without Chemical Reactions 1.10 Partial Molar Properties 1.11 Special Topic: Barometric Formula Physical chemistry is concerned with understanding the quantitative aspects of chemical phenomena. To introduce physical chemistry we will start with the most accessible properties of matter—those that can readily be measured in the labora- tory.
