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Thermodynamics and Chemistry THERMODYNAMICS AND CHEMISTRY SECOND EDITION HOWARD DEVOE Thermodynamics and Chemistry Second Edition Version 10, January 2020 Howard DeVoe Associate Professor of Chemistry Emeritus University of Maryland, College Park, Maryland [email protected] The first edition of this book was previously published by Pearson Education, Inc. It was copyright ©2001 by Prentice-Hall, Inc. The second edition, version 10 is copyright ©2020 by Howard DeVoe. This work is licensed under a Creative Commons Attribution 4.0 International License: https://creativecommons.org/licenses/by/4.0/ The book was typeset using the LATEX typesetting system and the memoir class. Most of the figures were produced with PSTricks, a related software program. The fonts are Adobe Times, MathTime, and Computer Modern Typewriter. A Solutions Manual is available at the Web site linked below. I thank the Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland for hosting the Web site for this book: http://www.chem.umd.edu/thermobook SHORT CONTENTS Biographical Sketches 15 Preface to the Second Edition 16 From the Preface to the First Edition 17 1 Introduction 19 2 Systems and Their Properties 27 3 The First Law 57 4 The Second Law 105 5 Thermodynamic Potentials 138 6 The Third Law and Cryogenics 153 7 Pure Substances in Single Phases 166 8 Phase Transitions and Equilibria of Pure Substances 195 9 Mixtures 225 10 Electrolyte Solutions 287 11 Reactions and Other Chemical Processes 304 12 Equilibrium Conditions in Multicomponent Systems 367 13 The Phase Rule and Phase Diagrams 418 14 Galvanic Cells 449 Appendix A Definitions of the SI Base Units 470 Appendix B Physical Constants 472 4 SHORT CONTENTS 5 Appendix C Symbols for Physical Quantities 473 Appendix D Miscellaneous Abbreviations and Symbols 477 Appendix E Calculus Review 480 Appendix F Mathematical Properties of State Functions 482 Appendix G Forces, Energy, and Work 487 Appendix H Standard Molar Thermodynamic Properties 505 Appendix I Answers to Selected Problems 508 Bibliography 512 Index 521 CONTENTS Biographical Sketches 15 Preface to the Second Edition 16 From the Preface to the First Edition 17 1 Introduction 19 1.1 Physical Quantities, Units, and Symbols . 19 1.1.1 The International System of Units . 19 1.1.2 Amount of substance and amount . 19 1.1.3 The SI revision of 2019 . 20 1.1.4 Derived units and prefixes . 21 1.2 Quantity Calculus . 22 1.3 Dimensional Analysis . 24 Problem . 26 2 Systems and Their Properties 27 2.1 The System, Surroundings, and Boundary . 27 2.1.1 Extensive and intensive properties . 28 2.2 Phases and Physical States of Matter . 30 2.2.1 Physical states of matter . 30 2.2.2 Phase coexistence and phase transitions . 31 2.2.3 Fluids . 32 2.2.4 The equation of state of a fluid . 33 2.2.5 Virial equations of state for pure gases . 34 2.2.6 Solids . 36 2.3 Some Basic Properties and Their Measurement . 36 2.3.1 Mass . 36 2.3.2 Amount of substance . 37 2.3.3 Volume . 38 2.3.4 Density . 39 2.3.5 Pressure . 39 2.3.6 Temperature . 40 2.4 The State of the System . 46 6 CONTENTS 7 2.4.1 State functions and independent variables . 47 2.4.2 An example: state functions of a mixture . 47 2.4.3 More about independent variables . 48 2.4.4 Equilibrium states . 49 2.4.5 Steady states . 51 2.5 Processes and Paths . 51 2.6 The Energy of the System . 53 2.6.1 Energy and reference frames . 53 2.6.2 Internal energy . 54 Problems . 56 3 The First Law 57 3.1 Heat, Work, and the First Law . 57 3.1.1 The concept of thermodynamic work . 58 3.1.2 Work coefficients and work coordinates . 60 3.1.3 Heat and work as path functions . 61 3.1.4 Heat and heating . 62 3.1.5 Heat capacity . 63 3.1.6 Thermal energy . 63 3.2 Spontaneous, Reversible, and Irreversible Processes . 63 3.2.1 Reversible processes . 63 3.2.2 Reversibility and the surroundings . 66 3.2.3 Irreversible processes . 68 3.2.4 Purely mechanical processes . 69 3.3 Heat Transfer . 69 3.3.1 Heating and cooling . 69 3.3.2 Spontaneous phase transitions . 71 3.4 Deformation Work . 71 3.4.1 Gas in a cylinder-and-piston device . 72 3.4.2 Expansion work of a gas . 75 3.4.3 Expansion work of an isotropic phase . 76 3.4.4 Generalities . 77 3.5 Applications of Expansion Work . 77 3.5.1 The internal energy of an ideal gas . 77 3.5.2 Reversible isothermal expansion of an ideal gas . 78 3.5.3 Reversible adiabatic expansion of an ideal gas . 78 3.5.4 Indicator diagrams . 80 3.5.5 Spontaneous adiabatic expansion or compression . 81 3.5.6 Free expansion of a gas into a vacuum . 82 3.6 Work in a Gravitational Field . 82 3.7 Shaft Work . 84 3.7.1 Stirring work . 85 3.7.2 The Joule paddle wheel . 87 3.8 Electrical Work . 89 3.8.1 Electrical work in a circuit . 89 3.8.2 Electrical heating . 91 3.8.3 Electrical work with a galvanic cell . 92 CONTENTS 8 3.9 Irreversible Work and Internal Friction . 93 3.10 Reversible and Irreversible Processes: Generalities . 97 Problems . 100 4 The Second Law 105 4.1 Types of Processes . 105 4.2 Statements of the Second Law . 106 4.3 Concepts Developed with Carnot Engines . 109 4.3.1 Carnot engines and Carnot cycles . 109 4.3.2 The equivalence of the Clausius and Kelvin–Planck statements . 112 4.3.3 The efficiency of a Carnot engine . 114 4.3.4 Thermodynamic temperature . 117 4.4 The Second Law for Reversible Processes . 119 4.4.1 The Clausius inequality . 119 4.4.2 Using reversible processes to define the entropy . 122 4.4.3 Alternative derivation of entropy as a state function . 125 4.4.4 Some properties of the entropy . 126 4.5 The Second Law for Irreversible Processes . 127 4.5.1 Irreversible adiabatic processes . 127 4.5.2 Irreversible processes in general . 128 4.6 Applications . 130 4.6.1 Reversible heating . 130 4.6.2 Reversible expansion of an ideal gas . 130 4.6.3 Spontaneous changes in an isolated system . 131 4.6.4 Internal heat flow in an isolated system . 131 4.6.5 Free expansion of a gas . 132 4.6.6 Adiabatic process with work . 133 4.7 Summary . 133 4.8 The Statistical Interpretation of Entropy . 134 Problems . 136 5 Thermodynamic Potentials 138 5.1 Total Differential of a Dependent Variable . 138 5.2 Total Differential of the Internal Energy . 139 5.3 Enthalpy, Helmholtz Energy, and Gibbs Energy . 141 5.4 Closed Systems . 143 5.5 Open Systems . 145 5.6 Expressions for Heat Capacity . 146 5.7 Surface Work . 147 5.8 Criteria for Spontaneity . 148 Problems . 151 6 The Third Law and Cryogenics 153 6.1 The Zero of Entropy . 153 6.2 Molar Entropies . 155 6.2.1 Third-law molar entropies . 155 6.2.2 Molar entropies from spectroscopic measurements . 158 CONTENTS 9 6.2.3 Residual entropy . ..
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