Basic physical chemistry for the atmospheric sciences

219 Pages·1995·14.223 MB·English

by  Hobbs, Peter Victor

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CAMBRIDGE
UNIVERSITY PRE��
studies of the atmosphere oceans, and earth and planetary
Modern ,
demand a sound knowledge of basic chemical principles. This
systems
pro ides a clear, concise review of these principles, particularly
book v
to the atmosphere. Students with little formal training in
relating
can work through the chapters and numerous exercises
chemistry
this book before accessing the standard texts in the atmospheric
within
environmental sciences
and .
Physical Chemistry for the Atmospheric Sciences covers the
concepts of chemical equilibria, chemical thermodynam­
funBdaasmice ntal
chemical kinetics, solution chemistry, acid and base chemistry,
ics,
oxidation-reduction reactions, and photochemistry. Over 160 exer­
are contained within the text, including 50 numerical problems
cises
in the te t and 112 e ercises for the reader to work on
solved x x with
and solutions provided in an appendix.
hints
Physical Chemistry for the Atmospheric Sciences is written
byB aans iicn ternationally known atmospheric science researcher and suc­
textbook author. Whether used in an introductory class in
cessful
or for self-instruction as a supplementary workbook this
chemistry
be an invaluable resource for a broad range of students.
book will

BASIC PHYSICAL CHEMISTRY FOR THE
ATMOSPHERIC SCIENCES

BASIC PHYSICAL CHEMISTRY
FOR THE ATMOSPHERIC
SCIENCES
PETER V. HOBBS
University of Washington
""' ..... CAMBRIDGE
UNIVERSITY PRESS
Published by the Press Syndicate of the University Cambridge
The Building, Trumpington Street, am dge CB2 IRP, England
of
40 West 20th Street, New York, 10011-4211, USA
Pitt C bri
10 Stamford Road, Oakleigh, Melbourne 3166, Australia
NY
©Cambridge University Press 1995
p shed 1995
u
First bli
Printed in the nted States of America
U i
Libraoryf Congress Cataloging-iDna-tPau blication
Hobbs, Pet r Victor, 1936-
Ba c phys l chemistry for the atmospheric sciences Peter
e
o b
si ica I
p. cm.
V. H b s.
Includes index.
ISBN 0-521-47387-X. -ISBN 0-521-47933-9 (pbk.)
Atmospheric sciences. 2. A os he chemistry. 3. Chemistry,
Physical and thetoretical. I. Title.
I. m p ric
QC861.2.H63 1995
ll----Oc20 94-19216
CIP
551.5'
A cataog record for this available from the Library.
l book is British
ISBN 0-521-47387-X hardback
0-521-47933-9 paperback
Contents
Preface
IX
Chemical equilibrium
1 1.1 Some introductory concepts 1
1.2 Equilibrium constants 3
1.3 Reaction quotient 8
1.4 LeChatelier's principle 10
Exercises 11
2 Chemical thermodynamics 17
2.1 The first law of thermodynamics; enthalpy 17
2.2 Enthalpies of reaction and formation 21
2.3 Entropy and the second law of thermodynamics 22
2.4 The third law of thermodynamics; absolute entropies 26
2.5 Criteria for equilibrium and spontaneous transformation 27
2.6 Standard free energy changes 30
2.7 Free energy change and the equilibrium constant 31
2.8 Chemical potential; homogeneous nucleation of
water-vapor condensation 34
Exercises 38
Chemical kinetics 43
3
3.1 Reaction rates 43
3.2 Reaction mechanisms 46
3.3 Reaction rates and equilibria 50
3.4 Collision theory of gaseous reactions 52
3.5 The effect of temperature on reaction rates:
the Arrhenius' relation 56
v
vi Contents
3.6 Catalysis 57
3.7 Half-life, residence time, and renewal time 58
Exercises _61
Solution chemistry and aqueous equilibria 68
4
4.1 Definitions and types of solutions 68
4.2 Solution concentrations 69
4.3 Factors affecting solubility 70
4.4 Colligative properties 71
4.5 Aqueous solutions; electrolytes 72
4.6 Aqueous equilibria 73
4.7 Strong and weak electrolytes; ion-product
constant for water 78
Exercises 80
5 Acids and bases 83
5.1 Some definitions and concepts 83
5.2 The nature of H + (aq) 86
5.3 The BrjZlnsted-Lowry theory; conjugate acid-base pairs 86
5.4 The Lewis theory 87
5.5 Strengths of acids and bases; acid-dissociation
(or ionization) constant 87
5.6 The pH scale 89
5.7 Polyprotic acids
90
5.8 Hydrolysis 91
5.9 Buffers 93
5 .10 Complex ions 96
5 .11 Mass balance and charge balance relations 97
5.12 The pH of rainwater 98
Exercises 101
6 Oxidation-reduction reactions 104
6.1 Some definitions 104
6.2 Oxidation numbers 105
6.3 Balancing oxidation-reduction reactions 108
6.4 Half-reactions in electrochemical cells 115
6.5 Strengths of oxidants and reductants; standard cell
and half-cell potentials 116
6.6 Standard cell potentials and free-energy change 124
6.7 The Nernst equation 126
6.8 Redox potentials; Eh-pH diagrams 128
Contents vii
6.9 Gram-equivalent weight and normality 130
Exercises 132
Photochemistry 137
7
7.1 Some properties of electromagnetic waves 137
7.2 Some photochemical terminology and principles 139
Quantum yields 142
7.3
7 .4 Rate coefficients for photolysis 143
7 .5 Photostationary states 144
7.6 Stratospheric ozone and photochemistry; depletion
of stratospheric ozone 145
Exercises 154
Appendix International system of units (SI) 157
I
Appendix Some useful numerical values 158
II
Appendix Atomic weights 159
Ill
Appendix IV Equilibrium (or dissociation) constants
for some chemical reactions 162
Appendix V Some molar standard Gibbs free energies of
formation, molar standard enthalpies (or heats)
of formation and molar absolute entropies at
25°C and 1 atmosphere 169
Appendix VI Names, formulas, and charges of some
common ions 172
Appendix VII Answers to exercises and hints and solutions
to selected exercises 173
Index 189