Published in 2011 by Britannica Educational Publishing (a trademark of Encyclopædia Britannica, Inc.) in association with Rosen Educational Services, LLC 29 East 21st Street, New York, NY 10010. Copyright © 2011 Encyclopædia Britannica, Inc. Britannica, Encyclopædia Britannica, and the Thistle logo are registered trademarks of Encyclopædia Britannica, Inc. All rights reserved. Rosen Educational Services materials copyright © 2011 Rosen Educational Services, LLC. All rights reserved. Distributed exclusively by Rosen Educational Services. For a listing of additional Britannica Educational Publishing titles, call toll free (800) 237-9932. First Edition Britannica Educational Publishing Michael I. Levy: Executive Editor J.E. Luebering: Senior Manager Marilyn L. Barton: Senior Coordinator, Production Control Steven Bosco: Director, Editorial Technologies Lisa S. Braucher: Senior Producer and Data Editor Yvette Charboneau: Senior Copy Editor Kathy Nakamura: Manager, Media Acquisition Erik Gregersen: Associate Editor, Science and Technology Rosen Educational Services Jeanne Nagle: Senior Editor Nelson Sá: Art Director Cindy Reiman: Photography Manager Matthew Cauli: Designer, Cover Design Introduction by Erik Gregersen Library of Congress Cataloging-in-Publication Data The Britannica guide to matter / edited by Erik Gregersen. p. cm.—(Physics explained) “In association with Britannica Educational Publishing, Rosen Educational Services.” Includes bibliographical references and index. ISBN 978-1-61530-381-6 (eBook) 1. Matter—Popular works. I. Gregersen, Erik. II. Title: Guide to matter. III. Title: Matter. QC171.2.B67 2011 530.4—dc22 2010024080 Cover © www.istockphoto.com / dra_schwartz On page x: Aurora borealis as seen from Yellowknife, Northwest Territories, Canada. Auroras are a beautiful phenomenon caused by plasma in Earth’s space environment. David Brosha Photography/Flickr/Getty Images On page xviii: Bathers enjoy the hot springs in Slovakia’s Low Tatras National Park. Water is visible in three forms of matter: liquid (pooled water), gaseous (steam), and solid (ice and snow). isifa/Getty Images On pages 1, 9, 39, 56, 73, 115, 164, 197, 228, 256, 258, 267: Water in all its forms, repre- sented by the famous Blue Lagoon in Iceland. Shutterstock.com C 4 ontents Introduction x Chapter 1: Matter and Its Phases 1 General Considerations 2 System Variables 3 The Phase Rule 3 Phase Diagrams 5 Chapter 2: Properties of Gases 9 Kinetic-Molecular Picture 9 Numerical Magnitudes 10 Intermolecular Separation and Average Speed 11 Mean Free Path and Collision Rate 12 Molecular Sizes 14 Summary of Numerical Magnitudes 16 Free-Molecule Gas 18 Continuity of Gaseous and Liquid 26 States 19 Behaviour and Properties 22 Equilibrium Properties 23 Transport Properties 29 Chapter 3: Kinetic Theory of Gases 39 Ideal Gas 39 Pressure 39 Effusion 43 Thermal Transpiration 44 Viscosity 45 Thermal Conductivity 47 31 Diffusion and Thermal Diffusion 50 Boltzmann Equation 51 Deviations from the Ideal Model 53 61 Equation of State 53 Transport Properties 54 Chapter 4: Properties of Liquids 56 Transitions Between States of Matter 58 Behaviour of Pure Liquids 60 Phase Diagram of a Pure Substance 60 Representative Values of Phase- Diagram Parameters 62 Behaviour of Substances Near Critical and Triple Points 64 Surface Tension 67 Molecular Structure of Liquids 67 Speed of Sound and Electric Properties 70 Chapter 5: Liquid Solutions and Solubility 73 Classes of Solutions 75 Electrolytes and Nonelectrolytes 75 Weak Electrolytes 76 89 Endothermic and Exothermic Solutions 77 Properties of Solutions 78 Composition Ratios 79 Equilibrium Properties 82 Colligative Properties 86 Transport Properties in Solutions 90 Thermodynamics and Intermolecular Forces in Solutions 93 Energy Considerations 93 Effects of Molecular Structure 95 Molecular Structure and Charge Distribution 96 122 Effects of Chemical Interactions 98 Theories of Solutions 100 Activity Coefficients and Excess Functions 100 Regular Solutions 102 Athermal Solutions 105 Associated and Solvated Solutions 106 Solutions of Electrolytes 108 Solubilities of Solids and Gases 112 Chapter 6: Crystalline Solids and 124 Liquid Crystals 115 Basic Units of Solids 116 Long- and Short-Range Order 118 Categories of Crystals 119 Structure 120 The Unit Cell 120 Structures of Metals 121 Structures of Nonmetallic Elements 123 Structures of Binary Crystals 125 Alloys 127 Crystal Defects 129 131 Determination of Crystal Structures 132 Types of Bonds 135 148 Ionic Bonds 136 Covalent Bonds 137 Metallic Bonds 140 Molecular Binding 142 Hydrogen Bonding 144 Crystal Growth 144 Vapour Growth 145 Growth from Solution 147 Growth from the Melt 147 Dendritic Growth 151 Liquid Crystals 152 Structure and Symmetry 152 Optical Properties 159 Chapter 7: Amorphous Solids and Quasicrystals 164 Amorphous Solids 164 Distinction Between Crystalline and Amorphous Solids 165 Preparation of Amorphous Solids 168 Atomic-Scale Structure 171 162 Properties of Oxide Glasses 175 Properties and Applications of Amorphous Solids 176 Quasicrystals 183 Structure and Symmetry 183 Properties 194 Chapter 8: Plasma 197 The Development of Plasma Physics 198 Plasma Oscillations and Parameters 201 Basic Plasma Physics 204 Plasma Formation 204 200 Methods of Describing Plasma Phenomena 207 Determination of Plasma Variables 208 Waves in Plasmas 210 Applications of Plasmas 216 Natural Plasmas 219 Extraterrestrial Forms 219 Solar-Terrestrial Forms 220 Chapter 9: Clusters 228 Comparison with Bulk Matter 231 Comparison with Molecules 235 206 Methods of Study 236 Preparation of Clusters 237 Ionization and Sorting of Clusters 238 Computer Simulation of Cluster Behaviour 239 Structure 240 Clusters with Icosahedral Structures 241 Clusters of Simple Metal Atoms 242 Network Structures 243 Physical Properties 245 236 Liquid and Solid Phases 246 Electric, Magnetic, and Optical Properties 248 Chemical Properties 250 Conclusion 254 Glossary 256 Bibliography 258 Index 267 241