Main Principles of General Chemistry
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Environmental science is grounded in chemistry. As one of many examples (discussed in Chapter 16), a severe reduction in stratospheric ozone—an ozone “hole”—was conﬁrmed over Antarctica in 1985. This thin, 15-mile-high layer rich in ozone (O3, depicted as three connected red spheres) screens out harmful solar ultraviolet (UV) light from reaching Earth’s surface, but Nobel-Prize winning research showed that man-made chemicals were breaking O3 apart. In a series of reaction steps, Freon-12 (CCl2F2, black sphere surrounded by two green and two yellow), escaping from air conditioners and spray cans, rises intact through the air until it reaches the stratosphere. There, UV light splits off a chlorine atom (Cl, green), which collides with an O3 molecule to form chlorine monoxide (ClO, red-green) and oxygen (O2, two red). Regenerated in a later step, the Cl can then attack another O3. With a “lifetime” of about 2 years, each Cl atom can react with over 100,000 ozone molecules. To solve this problem, Freon-12 has now been banned, and fewer Cl atoms have been detected in the ozone layer. Build Assignments Share Course Materials • Instructors can create and share materials with colleagues. Integrated eBook • An online eBook allows for anytime, anywhere access to the textbook. • Notes, highlights, and bookmarks can be managed in one place for simple, comprehensive review. • eBook merges media with the text’s narrative to engage students. TM McGraw-Hill LearnSmart™ This adaptive diagnostic learning system, powered by Connect Chemistry and based on artiﬁcial intelligence, constantly assesses a student’s knowledge of the course material. As students work within the system, McGraw-Hill LearnSmart develops a personal learning path adapted to what each student has actively learned and retained. This innovative study tool also has features to allow the instructor to see exactly what students have accomplished, with a built-in assessment tool for graded assignments. You can access LearnSmart for General Chemistry at www.; mcgraw-hillconnect.com/chemistry. Third Edition Eleventh Edition Principles of GENERAL CHEMISTRY Md. Dalim #1170290 11/07/11 Cyan Mag Yelo Black • Instructors can choose from pre-built assignments or create unique assignments using resources within Connect. • Assignments are automatically graded. • An electronic gradebook provides reports on progress. Chang Goldsby Principles of McGraw-Hill’s ConnectPlus® Chemistry offers an innovative and inexpensive eBook integrated within a unique homework and assessment system. Connect is an electronic homework and course management system designed for greater ﬂexibility, power, and ease of use than any other system. McGraw-Hill’s unique partnership with CambridgeSoft allows students to create accurate chemical structures using ChemDraw, the industry standard in chemical drawing. Third Edition GENERAL CHEMISTRY www.mcgraw-hillconnect.com/chemistry Silberberg Silberberg Martin S. Silberberg Third Edition Principles of GENERAL CHEMISTRY siL02699_fm_i_xxvii.indd 1 12/1/11 10:20 AM PRINCIPLES OF GENERAL CHEMISTRY, THIRD EDITION Published by McGraw-Hill, a business unit of The McGraw-Hill Companies, Inc., 1221 Avenue of the Americas, New York, NY 10020. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved. Printed in the United States of America. Previous editions © 2010 and 2007. No part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written consent of The McGraw-Hill Companies, Inc., including, but not limited to, in any network or other electronic storage or transmission, or broadcast for distance learning. Some ancillaries, including electronic and print components, may not be available to customers outside the United States. This book is printed on acid-free paper. 1 2 3 4 5 6 7 8 9 0 DOW/DOW 1 0 9 8 7 6 5 4 3 2 ISBN 978–0–07–340269–7 MHID 0–07–340269–9 Vice President, Editor-in-Chief: Marty Lange Vice President, EDP: Kimberly Meriwether David Senior Director of Development: Kristine Tibbetts Publisher: Ryan Blankenship Executive Editor: Jeff Huettman Director of Digital Content Development: David Spurgeon, Ph.D. Developmental Editor: Lora Neyens Executive Marketing Manager: Tamara L. Hodge Lead Project Manager: Peggy J. Selle Senior Buyer: Sandy Ludovissy Senior Media Project Manager: Tammy Juran Senior Designer: David W. Hash Cover Designer: John Joran Cover Illustration: Precision Graphics Cover Image: © Mike Embree/National Science Foundation Senior Photo Research Coordinator: Lori Hancock Photo Research: Jerry Marshall/pictureresearching.com Compositor: Lachina Publishing Services Typeface: 10/12 Times LT Std Roman Printer: R.R. Donnelley All credits appearing on page or at the end of the book are considered to be an extension of the copyright page. Library of Congress Cataloging-in-Publication Data Silberberg, Martin S. (Martin Stuart), 1945Principles of general chemistry / Martin S. Silberberg. — 3rd ed. p. cm. Includes index. ISBN 978–0–07–340269–7 — ISBN 0–07–340269–9 (hard copy : alk. paper) 1. Chemistry—Textbooks. I. Title. QD31.3.S55 2013 540—dc22 2011015577 www.mhhe.com siL02699_fm_i_xxvii.indd 2 11/29/11 10:25 AM To Ruth and Daniel, with all my love and To the memory of my brother Bruce, whose love, humor, and encouragement was invaluable and will be profoundly missed. siL02699_fm_i_xxvii.indd 3 11/29/11 10:25 AM BRIEF CONTENTS About the Author xvii Preface xviii 1 Keys to the Study of Chemistry 2 2 The Components of Matter 32 3 Stoichiometry of Formulas and Equations 71 4 Three Major Classes of Chemical Reactions 115 5 Gases and the Kinetic-Molecular Theory 148 6 Thermochemistry: Energy Flow and Chemical Change 188 7 Quantum Theory and Atomic Structure 216 8 Electron Configuration and Chemical Periodicity 245 9 Models of Chemical Bonding 276 10 The Shapes of Molecules 302 11 Theories of Covalent Bonding 328 12 Intermolecular Forces: Liquids, Solids, and Phase Changes 350 13 The Properties of Solutions 391 14 Periodic Patterns in the Main-Group Elements 425 15 Organic Compounds and the Atomic Properties of Carbon 459 16 Kinetics: Rates and Mechanisms of Chemical Reactions 498 17 Equilibrium: The Extent of Chemical Reactions 542 18 Acid-Base Equilibria 579 19 Ionic Equilibria in Aqueous Systems 617 20 Thermodynamics: Entropy, Free Energy, and the Direction of Chemical Reactions 653 21 Electrochemistry: Chemical Change and Electrical Work 687 22 Transition Elements and Their Coordination Compounds 736 23 Nuclear Reactions and Their Applications 763 Appendix A Common Mathematical Operations in Chemistry A-1 Appendix B Standard Thermodynamic Values for Selected Substances A-5 Appendix C Equilibrium Constants for Selected Substances A-8 Appendix D Standard Electrode (Half-Cell) Potentials A-14 Appendix E Answers to Selected Problems A-15 Glossary G-1 Credits C-1 Index I-1 v siL02699_fm_i_xxvii.indd 5 11/29/11 10:25 AM DETAILED CONTENTS CHAPTER 1 • Keys to the Study of Chemistry 2 1.1 Some Fundamental Definitions 3 1.2 The Properties of Matter 3 The States of Matter 5 The Central Theme in Chemistry 6 The Importance of Energy in the Study of Matter 7 The Scientific Approach: Developing a Model 9 1.3 Chemical Problem Solving 10 1.4 Units and Conversion Factors in Calculations 10 A Systematic Approach to Solving Chemistry Problems 12 Measurement in Scientific Study 14 General Features of SI Units 14 Some Important SI Units in Chemistry 14 Extensive and Intensive Properties 20 1.5 Uncertainty in Measurement: Significant Figures 21 Determining Which Digits Are Significant 21 Significant Figures: Calculations and Rounding Off 22 Precision, Accuracy, and Instrument Calibration 24 Chapter Review Guide 25 Problems 27 CHAPTER 2 • The Components of Matter 32 2.1 Elements, Compounds, and Mixtures: 2.2 2.3 2.4 An Atomic Overview 33 The Observations That Led to an Atomic View of Matter 35 Mass Conservation 35 Definite Composition 36 Multiple Proportions 37 Dalton’s Atomic Theory 37 Postulates of the Atomic Theory 38 How the Theory Explains the Mass Laws 38 The Observations That Led to the Nuclear Atom Model 39 Discovery of the Electron and Its Properties 39 Discovery of the Atomic Nucleus 41 2.5 The Atomic Theory Today 42 2.6 2.7 2.8 Structure of the Atom 42 Atomic Number, Mass Number, and Atomic Symbol 43 Isotopes 44 Atomic Masses of the Elements; Mass Spectrometry 44 Elements: A First Look at the Periodic Table 47 Compounds: Introduction to Bonding 49 The Formation of Ionic Compounds 49 The Formation of Covalent Compounds 51 Formulas, Names, and Masses of Compounds 53 Binary Ionic Compounds 53 2.9 Compounds That Contain Polyatomic Ions 56 Acid Names from Anion Names 57 Binary Covalent Compounds 58 The Simplest Organic Compounds: Straight-Chain Alkanes 58 Molecular Masses from Chemical Formulas 59 Representing Molecules with Formulas and Models 60 Classification of Mixtures 61 An Overview of the Components of Matter 62 Chapter Review Guide 63 Problems 65 vii siL02699_fm_i_xxvii.indd 7 11/29/11 10:25 AM viii Detailed Contents CHAPTER 3 • Stoichiometry of Formulas and Equations 71 3.1 The Mole 72 3.2 Defining the Mole 72 Determining Molar Mass 73 Converting Between Amount, Mass, and Number of Chemical Entities 74 The Importance of Mass Percent 77 Determining the Formula of an Unknown Compound 80 Empirical Formulas 80 Molecular Formulas 81 Isomers 84 CHAPTER 4 4.3 The Polar Nature of Water 116 Ionic Compounds in Water 116 Covalent Compounds in Water 120 Writing Equations for Aqueous Ionic Reactions 120 Precipitation Reactions 122 The Key Event: Formation of a Solid from Dissolved Ions 122 Predicting Whether a Precipitate Will Form 123 CHAPTER 5 3.4 5.3 3.5 Fundamentals of Solution Stoichiometry 99 Expressing Concentration in Terms of Molarity 99 Amount-Mass-Number Conversions Involving Solutions 100 Diluting a Solution 100 Stoichiometry of Reactions in Solution 103 Chapter Review Guide 105 Problems 108 4.4 Acid-Base Reactions 125 4.5 The Key Event: Formation of H2O from H1 and OH– 128 Proton Transfer in Acid-Base Reactions 129 Quantifying Acid-Base Reactions by Titration 130 Oxidation-Reduction (Redox) Reactions 132 The Key Event: Net Movement of Electrons Between Reactants 132 Some Essential Redox Terminology 133 4.6 Using Oxidation Numbers to Monitor Electron Charge 133 Elements in Redox Reactions 136 Combination Redox Reactions 136 Decomposition Redox Reactions 137 Displacement Redox Reactions and Activity Series 137 Combustion Reactions 139 Chapter Review Guide 141 Problems 142 • Gases and the Kinetic-Molecular Theory 148 5.1 An Overview of the Physical States 5.2 Equations 85 Calculating Quantities of Reactant and Product 89 Stoichiometrically Equivalent Molar Ratios from the Balanced Equation 89 Reactions That Involve a Limiting Reactant 93 Theoretical, Actual, and Percent Reaction Yields 97 • Three Major Classes of Chemical Reactions 115 4.1 The Role of Water as a Solvent 116 4.2 3.3 Writing and Balancing Chemical of Matter 149 Gas Pressure and Its Measurement 150 Measuring Atmospheric Pressure 150 Units of Pressure 151 The Gas Laws and Their Experimental Foundations 153 The Relationship Between Volume and Pressure: Boyle’s Law 153 The Relationship Between Volume and Temperature: Charles’s Law 154 5.4 The Relationship Between Volume and Amount: Avogadro’s Law 156 Gas Behavior at Standard Conditions 156 The Ideal Gas Law 157 Solving Gas Law Problems 158 Rearrangements of the Ideal Gas Law 162 The Density of a Gas 162 The Molar Mass of a Gas 164 The Partial Pressure of a Gas in a Mixture of Gases 165 The Ideal Gas Law and Reaction Stoichiometry 167 5.5 The Kinetic-Molecular Theory: 5.6 A Model for Gas Behavior 170 How the Kinetic-Molecular Theory Explains the Gas Laws 170 Effusion and Diffusion 175 Real Gases: Deviations from Ideal Behavior 177 Effects of Extreme Conditions on Gas Behavior 177 The van der Waals Equation: Adjusting the Ideal Gas Law 179 Chapter Review Guide 179 Problems 182 siL02699_fm_i_xxvii.indd 8 12/1/11 8:33 AM ix CHAPTER 6 • Thermochemistry: Energy Flow and Chemical Change 188 6.1 Forms of Energy and Their Interconversion 189 Defining the System and Its Surroundings 189 Energy Transfer to and from a System 190 Heat and Work: Two Forms of Energy Transfer 190 The Law of Energy Conservation 192 Units of Energy 193 State Functions and the Path Independence of the Energy Change 194 CHAPTER 7 The Wave Nature of Light 217 The Particle Nature of Light 220 Atomic Spectra 223 Line Spectra and the Rydberg Equation 223 The Bohr Model of the Hydrogen Atom 224 The Energy Levels of the Hydrogen Atom 226 Spectral Analysis in the Laboratory 228 CHAPTER 8 Atoms 246 The Electron-Spin Quantum Number 246 The Exclusion Principle and Orbital Occupancy 247 Electrostatic Effects and Energy-Level Splitting 247 The Quantum-Mechanical Model and the Periodic Table 249 Building Up Period 1 249 Building Up Period 2 250 siL02699_fm_i_xxvii.indd 9 6.4 6.5 Hess’s Law: Finding DH of Any Reaction 203 6.6 Standard Enthalpies of Reaction (DHrxn) 205 Formation Equations and Their Standard Enthalpy Changes 205 Determining DH rxn from DH f Values for Reactants and Products 206 Fossil Fuels and Climate Change 207 Chapter Review Guide 209 Problems 211 7.3 The Wave-Particle Duality of Matter 7.4 and Energy 229 The Wave Nature of Electrons and the Particle Nature of Photons 229 Heisenberg’s Uncertainty Principle 231 The Quantum-Mechanical Model of the Atom 232 The Atomic Orbital and the Probable Location of the Electron 232 Quantum Numbers of an Atomic Orbital 234 Quantum Numbers and Energy Levels 235 Shapes of Atomic Orbitals 237 The Special Case of Energy Levels in the H Atom 239 Chapter Review Guide 240 Problems 241 • Electron Configuration and Chemical Periodicity 245 8.1 Characteristics of Many-Electron 8.2 6.3 Constant Pressure 195 The Meaning of Enthalpy 195 Exothermic and Endothermic Processes 196 Calorimetry: Measuring the Heat of a Chemical or Physical Change 197 Specific Heat Capacity 197 The Two Common Types of Calorimetry 198 Stoichiometry of Thermochemical Equations 201 • Quantum Theory and Atomic Structure 216 7.1 The Nature of Light 217 7.2 6.2 Enthalpy: Chemical Change at Building Up Period 3 251 Similar Electron Configurations Within Groups 252 Building Up Period 4: The First Transition Series 253 General Principles of Electron Configurations 254 Intervening Series: Transition and Inner Transition Elements 256 8.3 Trends in Three Atomic 8.4 Properties 258 Trends in Atomic Size 258 Trends in Ionization Energy 260 Trends in Electron Affinity 263 Atomic Properties and Chemical Reactivity 265 Trends in Metallic Behavior 265 Properties of Monatomic Ions 266 Chapter Review Guide 271 Problems 272 11/29/11 10:25 AM x Detailed Contents CHAPTER 9 • Models of Chemical Bonding 276 9.1 Atomic Properties and Chemical 9.2 9.3 Bonds 277 Types of Bonding: Three Ways Metals and Nonmetals Combine 277 Lewis Symbols and the Octet Rule 278 The Ionic Bonding Model 280 Why Ionic Compounds Form: The Importance of Lattice Energy 280 Periodic Trends in Lattice Energy 281 How the Model Explains the Properties of Ionic Compounds 283 The Covalent Bonding Model 284 The Formation of a Covalent Bond 284 Bonding Pairs and Lone Pairs 285 CHAPTER 10 Lewis Structures 303 Applying the Octet Rule to Write Lewis Structures 303 Resonance: Delocalized Electron-Pair Bonding 306 Formal Charge: Selecting the More Important Resonance Structure 308 Lewis Structures for Exceptions to the Octet Rule 309 Valence-Shell Electron-Pair Repulsion (VSEPR) Theory and Molecular Shape 312 Electron-Group Arrangements and Molecular Shapes 312 CHAPTER 11 Electronegativity and Bond Polarity 293 Electronegativity 293 Bond Polarity and Partial Ionic Character 294 The Gradation in Bonding Across a Period 296 Chapter Review Guide 297 Problems 298 The Molecular Shape with Two Electron Groups (Linear Arrangement) 313 Molecular Shapes with Three Electron Groups (Trigonal Planar Arrangement) 314 Molecular Shapes with Four Electron Groups (Tetrahedral Arrangement) 314 Molecular Shapes with Five Electron Groups (Trigonal Bipyramidal Arrangement) 316 Molecular Shapes with Six Electron Groups (Octahedral Arrangement) 317 10.3 Using VSEPR Theory to Determine Molecular Shape 318 Molecular Shapes with More Than One Central Atom 319 Molecular Shape and Molecular Polarity 320 Bond Polarity, Bond Angle, and Dipole Moment 321 Chapter Review Guide 322 Problems 324 • Theories of Covalent Bonding 328 11.1 Valence Bond (VB) Theory and Orbital Hybridization 329 The Central Themes of VB Theory 329 Types of Hybrid Orbitals 330 9.5 Between the Extremes: • The Shapes of Molecules 302 10.1 Depicting Molecules and Ions with 10.2 9.4 Properties of a Covalent Bond: Order, Energy, and Length 285 How the Model Explains the Properties of Covalent Substances 288 Using IR Spectroscopy to Study Covalent Compounds 289 Bond Energy and Chemical Change 290 Changes in Bond Energy: Where Does DH rxn Come From? 290 Using Bond Energies to Calculate DH rxn 290 11.2 Modes of Orbital Overlap and the 11.3 Molecular Orbital (MO) Theory and Types of Covalent Bonds 335 Orbital Overlap in Single and Multiple Bonds 335 Orbital Overlap and Molecular Rotation 337 Electron Delocalization 338 The Central Themes of MO Theory 338 Homonuclear Diatomic Molecules of Period 2 Elements 341 Chapter Review Guide 345 Problems 346 siL02699_fm_i_xxvii.indd 10 11/29/11 10:25 AM xi CHAPTER 12 • Intermolecular Forces: Liquids, Solids, and Phase Changes 350 12.1 An Overview of Physical States and 12.2 12.3 Phase Changes 351 Quantitative Aspects of Phase Changes 354 Heat Involved in Phase Changes 354 The Equilibrium Nature of Phase Changes 357 Phase Diagrams: Effect of Pressure and Temperature on Physical State 360 Types of Intermolecular Forces 362 How Close Can Molecules Approach Each Other? 362 Ion-Dipole Forces 362 Dipole-Dipole Forces 363 CHAPTER 13 12.4 12.5 Forces and Solubility 392 Intermolecular Forces in Solution 393 Liquid Solutions and the Role of Molecular Polarity 394 Gas Solutions and Solid Solutions 396 Why Substances Dissolve: Understanding the Solution Process 397 Heats of Solution: Solution Cycles 397 siL02699_fm_i_xxvii.indd 11 12.6 The Solid State: Structure, Properties, and Bonding 373 Structural Features of Solids 373 Types and Properties of Crystalline Solids 379 Bonding in Solids I: The Electron-Sea Model of Metallic Bonding 382 Bonding in Solids II: Band Theory 382 Chapter Review Guide 385 Problems 386 • The Properties of Solutions 391 13.1 Types of Solutions: Intermolecular 13.2 The Hydrogen Bond 364 Polarizability and Induced Dipole Forces 366 Dispersion (London) Forces 366 Properties of the Liquid State 369 Surface Tension 369 Capillarity 370 Viscosity 370 The Uniqueness of Water 371 Solvent Properties of Water 371 Thermal Properties of Water 371 Surface Properties of Water 372 The Unusual Density of Solid Water 372 13.3 13.4 Heats of Hydration: Ionic Solids in Water 397 The Solution Process and the Change in Entropy 399 Solubility as an Equilibrium Process 401 Effect of Temperature on Solubility 401 Effect of Pressure on Solubility 402 Concentration Terms 404 Molarity and Molality 404 Parts of Solute by Parts of Solution 405 Interconverting Concentration Terms 406 13.5 Colligative Properties of Solutions 408 Nonvolatile Nonelectrolyte Solutions 408 Using Colligative Properties to Find Solute Molar Mass 413 Volatile Nonelectrolyte Solutions 414 Strong Electrolyte Solutions 415 Chapter Review Guide 417 Problems 419 11/29/11 10:25 AM xii Detailed Contents CHAPTER 14 • Periodic Patterns in the Main-Group Elements 425 14.1 Hydrogen, the Simplest Atom 426 14.2 14.3 14.4 Where Hydrogen Fits in the Periodic Table 426 Highlights of Hydrogen Chemistry 426 Group 1A(1): The Alkali Metals 427 Why the Alkali Metals Have Unusual Physical Properties 427 Why the Alkali Metals Are So Reactive 427 The Anomalous Behavior of Period 2 Members 429 Group 2A(2): The Alkaline Earth Metals 430 How the Alkaline Earth and Alkali Metals Compare Physically 430 How the Alkaline Earth and Alkali Metals Compare Chemically 430 Diagonal Relationships 432 Group 3A(13): The Boron Family 432 How the Transition Elements Influence Properties 432 CHAPTER 15 14.5 14.6 14.7 and the Characteristics of Organic Molecules 460 The Structural Complexity of Organic Molecules 460 The Chemical Diversity of Organic Molecules 461 The Structures and Classes of Hydrocarbons 462 Carbon Skeletons and Hydrogen Skins 462 Alkanes: Hydrocarbons with Only Single Bonds 464 Constitutional Isomerism and the Physical Properties of Alkanes 467 Chiral Molecules and Optical Isomerism 468 siL02699_fm_i_xxvii.indd 12 14.8 14.9 How the Oxygen and Nitrogen Families Compare Chemically 446 Highlights of Oxygen Chemistry 447 Highlights of Sulfur Chemistry 447 Group 7A(17): The Halogens 448 How the Halogens and the Alkali Metals Contrast Physically 448 Why the Halogens Are So Reactive 448 Highlights of Halogen Chemistry 450 Group 8A(18): The Noble Gases 452 Physical Properties 452 Why Noble Gases Can Form Compounds 452 Chapter Review Guide 452 Problems 454 • Organic Compounds and the Atomic Properties of Carbon 459 15.1 The Special Nature of Carbon 15.2 Features That First Appear in This Group’s Chemical Properties 432 Group 4A(14): The Carbon Family 434 How the Type of Bonding in an Element Affects Physical Properties 434 How Bonding Changes in the Carbon Family’s Compounds 436 Highlights of Carbon Chemistry 436 Highlights of Silicon Chemistry 438 Group 5A(15): The Nitrogen Family 439 The Wide Range of Physical Behavior 439 Patterns in Chemical Behavior 439 Highlights of Nitrogen Chemistry 441 Highlights of Phosphorus Chemistry 443 Group 6A(16): The Oxygen Family 444 How the Oxygen and Nitrogen Families Compare Physically 446 15.3 15.4 Alkenes: Hydrocarbons with Double Bonds 469 Alkynes: Hydrocarbons with Triple Bonds 470 Aromatic Hydrocarbons: Cyclic Molecules with Delocalized π Electrons 471 Some Important Classes of Organic Reactions 472 Properties and Reactivities of Common Functional Groups 474 Functional Groups with Only Single Bonds 474 Functional Groups with Double Bonds 478 Functional Groups with Both Single and Double Bonds 480 Functional Groups with Triple Bonds 482 15.5 The Monomer-Polymer Theme I: 15.6 Synthetic Macromolecules 483 Addition Polymers 484 Condensation Polymers 484 The Monomer-Polymer Theme II: Biological Macromolecules 486 Sugars and Polysaccharides 486 Amino Acids and Proteins 487 Nucleotides and Nucleic Acids 490 Chapter Review Guide 492 Problems 494 11/29/11 10:25 AM xiii CHAPTER 16 • Kinetics: Rates and Mechanisms of Chemical Reactions 498 16.1 Focusing on Reaction Rate 499 16.2 Expressing the Reaction Rate 501 16.3 16.4 Average, Instantaneous, and Initial Reaction Rates 501 Expressing Rate in Terms of Reactant and Product Concentrations 503 The Rate Law and Its Components 505 Some Laboratory Methods for Determining the Initial Rate 505 Determining Reaction Orders 505 Determining the Rate Constant 512 Integrated Rate Laws: Concentration Changes Over Time 512 Integrated Rate Laws for First-, Second-, and Zero-Order Reactions 513 CHAPTER 17 17.3 17.4 Equilibrium Constant 543 The Reaction Quotient and the Equilibrium Constant 545 Changing Value of the Reaction Quotient 545 Writing the Reaction Quotient 546 Expressing Equilibria with Pressure Terms: Relation Between Kc and Kp 550 Comparing Q and K to Predict Reaction Direction 552 siL02699_fm_i_xxvii.indd 13 16.6 16.7 Catalysis: Speeding Up a Reaction 530 The Basis of Catalytic Action 531 Homogeneous Catalysis 531 Heterogeneous Catalysis 532 Catalysis in Nature 533 Chapter Review Guide 534 Problems 536 • Equilibrium: The Extent of Chemical Reactions 542 17.1 The Equilibrium State and the 17.2 16.5 Determining Reaction Orders from an Integrated Rate Law 514 Reaction Half-Life 515 Theories of Chemical Kinetics 519 Collision Theory: Basis of the Rate Law 519 Transition State Theory: What the Activation Energy Is Used For 522 Reaction Mechanisms: The Steps from Reactant to Product 525 Elementary Reactions and Molecularity 526 The Rate-Determining Step of a Reaction Mechanism 527 Correlating the Mechanism with the Rate Law 528 17.5 How to Solve Equilibrium 17.6 Problems 554 Using Quantities to Find the Equilibrium Constant 554 Using the Equilibrium Constant to Find Quantities 556 Problems Involving Mixtures of Reactants and Products 561 Reaction Conditions and Equilibrium: Le Châtelier’s Principle 562 The Effect of a Change in Concentration 563 The Effect of a Change in Pressure (Volume) 565 The Effect of a Change in Temperature 567 The Lack of Effect of a Catalyst 568 The Industrial Production of Ammonia 570 Chapter Review Guide 572 Problems 573 11/29/11 10:25 AM xiv Detailed Contents CHAPTER 18 • Acid-Base Equilibria 579 18.1 Acids and Bases in Water 580 18.2 18.3 Release of H1 or OH2 and the Arrhenius Acid-Base Definition 580 Variation in Acid Strength: The AcidDissociation Constant (Ka) 581 Classifying the Relative Strengths of Acids and Bases 583 Autoionization of Water and the pH Scale 584 The Equilibrium Nature of Autoionization: The Ion-Product Constant for Water (Kw) 584 Expressing the Hydronium Ion Concentration: The pH Scale 585 Proton Transfer and the BrønstedLowry Acid-Base Definition 588 Conjugate Acid-Base Pairs 589 Relative Acid-Base Strength and the Net Direction of Reaction 590 CHAPTER 19 18.4 Solving Problems Involving Weak-Acid 18.5 18.6 What a Buffer Is and How It Works: The Common-Ion Effect 618 The Henderson-Hasselbalch Equation 622 Buffer Capacity and Buffer Range 623 Preparing a Buffer 625 Acid-Base Titration Curves 626 Monitoring pH with Acid-Base Indicators 627 Strong Acid–Strong Base Titration Curves 627 siL02699_fm_i_xxvii.indd 14 18.7 Acid-Base Properties of Salt 18.8 Solutions 603 Salts That Yield Neutral Solutions 604 Salts That Yield Acidic Solutions 604 Salts That Yield Basic Solutions 604 Salts of Weakly Acidic Cations and Weakly Basic Anions 605 Salts of Amphiprotic Anions 605 Electron-Pair Donation and the Lewis Acid-Base Definition 607 Molecules as Lewis Acids 607 Metal Ions as Lewis Acids 608 Chapter Review Guide 609 Problems 611 • Ionic Equilibria in Aqueous Systems 617 19.1 Equilibria of Acid-Base Buffers 618 19.2 Equilibria 593 Finding Ka Given Concentrations 593 Finding Concentrations Given Ka 594 The Effect of Concentration on the Extent of Acid Dissociation 595 The Behavior of Polyprotic Acids 597 Weak Bases and Their Relation to Weak Acids 597 Molecules as Weak Bases: Ammonia and the Amines 598 Anions of Weak Acids as Weak Bases 599 The Relation Between Ka and Kb of a Conjugate Acid-Base Pair 600 Molecular Properties and Acid Strength 601 Acid Strength of Nonmetal Hydrides 601 Acid Strength of Oxoacids 602 Acidity of Hydrated Metal Ions 602 19.3 Weak Acid–Strong Base Titration Curves 629 Weak Base–Strong Acid Titration Curves 632 Equilibria of Slightly Soluble Ionic Compounds 633 The Ion-Product Expression (Qsp) and the Solubility-Product Constant (Ksp) 634 Calculations Involving the SolubilityProduct Constant 635 Effect of a Common Ion on Solubility 637 19.4 Effect of pH on Solubility 639 Predicting the Formation of a Precipitate: Qsp vs. Ksp 639 Ionic Equilibria and the Acid-Rain Problem 641 Equilibria Involving Complex Ions 643 Formation of Complex Ions 643 Complex Ions and Solubility of Precipitates 645 Chapter Review Guide 646 Problems 648 11/29/11 10:25 AM xv CHAPTER 20 • Thermodynamics: Entropy, Free Energy, and the Direction of Chemical Reactions 653 20.1 The Second Law of Thermodynamics: Predicting Spontaneous Change 654 The First Law of Thermodynamics Does Not Predict Spontaneous Change 654 The Sign of DH Does Not Predict Spontaneous Change 655 Freedom of Particle Motion and Dispersal of Particle Energy 655 Entropy and the Number of Microstates 656 Entropy and the Second Law of Thermodynamics 659 Standard Molar Entropies and the Third Law 659 Predicting Relative S° of a System 660 CHAPTER 21 20.2 Calculating the Change in Entropy 20.3 21.3 Cells 688 A Quick Review of Oxidation-Reduction Concepts 688 Half-Reaction Method for Balancing Redox Reactions 689 An Overview of Electrochemical Cells 692 Voltaic Cells: Using Spontaneous Reactions to Generate Electrical Energy 693 Construction and Operation of a Voltaic Cell 694 Notation for a Voltaic Cell 696 Cell Potential: Output of a Voltaic Cell 697 Standard Cell Potentials 697 Relative Strengths of Oxidizing and Reducing Agents 700 siL02699_fm_i_xxvii.indd 15 20.4 Calculating Standard Free Energy Changes 669 The Free Energy Change and the Work a System Can Do 671 The Effect of Temperature on Reaction Spontaneity 671 Coupling of Reactions to Drive a Nonspontaneous Change 674 Free Energy, Equilibrium, and Reaction Direction 676 Chapter Review Guide 681 Problems 682 • Electrochemistry: Chemical Change and Electrical Work 687 21.1 Redox Reactions and Electrochemical 21.2 of a Reaction 664 Entropy Changes in the System: Standard Entropy of Reaction (DSrxn) 664 Entropy Changes in the Surroundings: The Other Part of the Total 665 The Entropy Change and the Equilibrium State 667 Spontaneous Exothermic and Endothermic Changes 667 Entropy, Free Energy, and Work 668 Free Energy Change and Reaction Spontaneity 668 21.4 21.5 21.6 Writing Spontaneous Redox Reactions 701 Explaining the Activity Series of the Metals 704 Free Energy and Electrical Work 705 Standard Cell Potential and the Equilibrium Constant 705 The Effect of Concentration on Cell Potential 707 Changes in Potential During Cell Operation 709 Concentration Cells 710 Electrochemical Processes in Batteries 713 Primary (Nonrechargeable) Batteries 713 Secondary (Rechargeable) Batteries 714 Fuel Cells 716 Corrosion: An Environmental Voltaic Cell 717 The Corrosion of Iron 717 21.7 Protecting Against the Corrosion of Iron 718 Electrolytic Cells: Using Electrical Energy to Drive Nonspontaneous Reactions 719 Construction and Operation of an Electrolytic Cell 719 Predicting the Products of Electrolysis 720 Purifying Copper and Isolating Aluminum 724 Stoichiometry of Electrolysis: The Relation Between Amounts of Charge and Products 726 Chapter Review Guide 728 Problems 730 11/29/11 10:25 AM xvi Detailed Contents CHAPTER 22 • Transition Elements and Their Coordination Compounds 736 22.1 Properties of the Transition 22.2 Coordination Compounds 743 Elements 737 Electron Configurations of the Transition Metals and Their Ions 738 Atomic and Physical Properties of the Transition Elements 739 Chemical Properties of the Transition Elements 741 CHAPTER 23 23.3 Stability 764 The Components of the Nucleus: Terms and Notation 764 Modes of Radioactive Decay; Balancing Nuclear Equations 765 Nuclear Stability and the Mode of Decay 768 The Kinetics of Radioactive Decay 772 The Rate of Radioactive Decay 772 Radioisotopic Dating 774 Nuclear Transmutation: Induced Changes in Nuclei 776 Appendix A Common Mathematical Operations in Chemistry A-1 Appendix B Standard Thermodynamic Values for Selected Substances A-5 Appendix C Equilibrium Constants for Selected Substances A-8 siL02699_fm_i_xxvii.indd 16 Crystal Field Theory 752 Transition Metal Complexes in Biological Systems 757 Chapter Review Guide 758 Problems 759 • Nuclear Reactions and Their Applications 763 23.1 Radioactive Decay and Nuclear 23.2 22.3 Complex Ions: Coordination Numbers, Geometries, and Ligands 744 Formulas and Names of Coordination Compounds 745 Isomerism in Coordination Compounds 747 Theoretical Basis for the Bonding and Properties of Complexes 750 Applying Valence Bond Theory to Complex Ions 750 23.4 Effects of Nuclear Radiation 23.5 23.6 on Matter 778 Effects of Ionizing Radiation on Living Tissue 778 Sources of Ionizing Radiation 779 Applications of Radioisotopes 780 Radioactive Tracers 780 Additional Applications of Ionizing Radiation 782 The Interconversion of Mass and Energy 783 The Mass Difference Between a Nucleus and Its Nucleons 783 Appendix D Standard Electrode (Half-Cell) Potentials A-14 Appendix E Answers to Selected Problems A-15 23.7 Nuclear Binding Energy and the Binding Energy per Nucleon 784 Applications of Fission and Fusion 786 The Process of Nuclear Fission 786 The Promise of Nuclear Fusion 789 Chapter Review Guide 790 Problems 792 Glossary G-1 Credits C-1 Index I-1 11/29/11 10:25 AM About the Author Martin S. Silberberg received a B.S. in Chemistry from the City University of New York and a Ph.D. in Chemistry from the University of Oklahoma. He then accepted a research position in analytical biochemistry at the Albert Einstein College of Medicine in New York City, where he developed advanced methods to study fundamental brain mechanisms as well as neurotransmitter metabolism in Parkinson’s disease. Following his years in research, Dr. Silberberg joined the faculty of Bard College at Simon’s Rock, a liberal arts college known for its excellence in teaching small classes of highly motivated students. As Head of the Natural Sciences Major and Director of Premedical Studies, he taught courses in general chemistry, organic chemistry, biochemistry, and liberal arts chemistry. The close student contact afforded him insights into how students learn chemistry, where they have difficulties, and what strategies can help them succeed. Prof. Silberberg applied these insights in a broader context by establishing a text writing, editing, and consulting company. Before writing his own text, he worked as a consulting and developmental editor on chemistry, biochemistry, and physics texts for several major college publishers. He resides with his wife and son in the Pioneer Valley near Amherst, Massachusetts, where he enjoys the rich cultural and academic life of the area and relaxes by cooking, singing, and hiking. xvii siL02699_fm_i_xxvii.indd 17 11/29/11 10:25 AM Preface As the new century unfolds, chemistry will play its usual, crucial role in dealing with complex environmental, medical, and industrial issues. And, as the complexities increase and more information is needed to understand them, many chemistry instructors want a more focused text to serve as the core of a powerful electronic teaching and learning package. This new, Third Edition of Principles of General Chemistry is the ideal choice, designed to cover key principles and skills with great readability, the most accurate molecular art available, a problem-solving approach that is universally praised, and a supporting suite of electronic products that sets a new standard in academic science. How Principles and Chemistry Are the Same Principles of General Chemistry was created from its parent text, Chemistry: The Molecular Nature of Matter and Change, when four expert chemistry teachers—three consulting professors and the author—joined to distill the concepts and skills at the heart of general chemistry. Principles covers all the material a science major needs to continue in premedical studies, engineering, or related fields. It maintains the same high standards of accuracy, clarity, and rigor as its parent and adopts the same three distinguishing hallmarks: 1. Visualizing chemical models. In many places in the text, concepts are explained ﬁrst at the macroscopic level and then from a molecular point of view. Placed near many of these discussions, the text’s celebrated graphics depict the phenomenon or change at the observable level in the lab, at the atomic level with superbly accurate molecular art, and at the symbolic level with the balanced equation. 2. Thinking logically to solve problems. The problem-solving approach, based on a four-step method widely approved by chemical educators, is introduced in Chapter 1 and employed consistently throughout the text. It encourages students to ﬁrst plan a logical approach, and only then proceed to the arithmetic solution. A check step, universally recommended by instructors, fosters the habit of considering the reasonableness and magnitude of the answer. For practice and reinforcement, each worked problem has a matched follow-up problem, for which an abbreviated, multistep solution—not merely a numerical answer— appears at the end of the chapter. 3. Applying ideas to the real world. For today’s students, who may enter one of numerous chemistry-related ﬁelds, especially important applications—such as climate change, enzyme catalysis, materials science, and others—are woven into the text discussion, and real-world scenarios are used in many worked in-chapter sample problems as well as end-of-chapter problems. Principles and Chemistry also share a common topic sequence, which provides a thorough introduction to chemistry for science majors: • Chapters 1 through 6 cover unit conversions and uncertainty, introduce atomic structure and bonding, discuss stoichiometry and reaction classes, show how gas behavior is modeled, and highlight the relation between heat and chemical change. • Chapters 7 through 15 take an “atoms-first” approach, as they move from atomic structure and electron configuration to how atoms bond and what the resulting molecules look like and why. Intermolecular forces are covered by discussing the behavior of liquids and solids as compared with that of gases, and then leads the different behavior of solutions. These principles are then applied to the chemistry of the elements and to the compounds of carbon. • Chapters 16 through 21 cover dynamic aspects of reaction chemistry, including kinetics, equilibrium, entropy and free energy, and electrochemistry. • Chapters 22 and 23 cover transition elements and nuclear reactions. How Principles and Chemistry Are Different Principles presents the same authoritative coverage as Chemistry but in 240 fewer pages. It does so by removing most of the boxed application material, thus letting instructors choose applications tailored for their course. Moreover, several topics that are important areas of research but not central to general chemistry were left out, including colloids, polymers, liquid crystals, and so forth. And mainstream material from the chapter on isolating the elements was blended into the chapter on electrochemistry. Despite its much shorter length, Principles of General Chemistry includes all the pedagogy so admired in Chemistry. It has all the worked sample problems and about twothirds as many end-of-chapter problems, still more than enough problems for every topic, with a high level of relevance and many real-world applications. The learning aids that students ﬁnd so useful have also been retained— Concepts and Skills to Review, Section Summaries, Key Terms, Key Equations, and Brief Solutions to Follow-up Problems. xviii siL02699_fm_i_xxvii.indd 18 11/29/11 10:25 AM Preface In addition, three aids not found in the parent Chemistry help students focus their efforts: • Key Principles. At the beginning of each chapter, short bulleted paragraphs state the main concepts concisely, using many of the same phrases and terms (in italics) that appear in the pages to follow. A student can preview these principles before reading the chapter and then review them afterward. • “Think of It This Way . . .” with Analogies, Mnemonics, and Insights. This recurring feature provides analogies for difﬁcult concepts (e.g., the “radial probability distribution” of apples around a tree) and amazing quantities (e.g., a stadium and a marble for the relative sizes of atom and nucleus), memory shortcuts (e.g., which reaction occurs at which electrode), and useful insights (e.g., similarities between a saturated solution and a liquid-vapor system). • Problem-Based Learning Objectives. The list of learning objectives at the end of each chapter includes the end-ofchapter problems that relate to each objective. Thus, a student, or instructor, can select problems that review a given topic. What’s New in the Third Edition To address dynamic changes in how courses are structured and how students learn—variable math and reading preparation, less time for traditional studying, electronic media as part of lectures and homework, new challenges and options in career choices—the author and publisher consulted extensively with students and faculty. Based on their input, we developed the following ways to improve the text as a whole as well as the content of individual chapters. Global Changes to the Entire Text Writing style and content presentation. Every line of every discussion has been revised to optimize clarity, readability, and a more direct presentation. The use of additional subheads, numbered (and titled) paragraphs, and bulleted (and titled) lists has eliminated long unbroken paragraphs. Main ideas are delineated and highlighted, making for more efficient study and lectures. As a result, the text is over 20 pages shorter than the Second Edition. More worked problems. The much admired—and imitated—four-part (plan, solution, check, practice) Sample Problems occur in both data-based and molecular-scene format. To deepen understanding, Follow-up Problems have worked-out solutions at the back of each chapter, with a road map when appropriate, effectively doubling the number of worked problems. This edition has 15 more sample problems, many in the earlier chapters, where students need the most practice in order to develop confidence. siL02699_fm_i_xxvii.indd 19 xix Art and figure legends. Figures have been made more realistic and modern. Figure legends have been greatly shortened, and the explanations from them have either been added to the text or included within the figures. Page design and layout. A more open look invites the reader while maintaining the same attention to keeping text and related figures and tables near each other for easier studying. Section summaries. This universally approved feature is even easier to use in a new bulleted format. Chapter review. The unique Chapter Review Guide aids study with problem-based learning objectives, key terms, key equations, and the multistep Brief Solutions to Followup Problems (rather than just numerical answers). End-of-chapter problem sets. With an enhanced design to improve readability and traditional and molecular-scene problems updated and revised, these problem sets are far more extensive than in other brief texts. Content Changes to Individual Chapters • Chapter 2 presents a new figure and table on molecular modeling, and it addresses the new IUPAC recommendations for atomic masses. • Discussion of empirical formulas has been moved from Chapter 2 to Chapter 3 so that it appears just before molecular formulas. • Chapter 3 has some sample problems from the Second Edition that have been divided to focus on distinct concepts, and it contains seven new sample problems. • Chapters 3 and 4 include more extensive and consistent use of stoichiometry reaction tables in limiting-reactant problems. • Chapter 4 presents a new molecular-scene sample problem on depicting an ionic compound in aqueous solution. • Chapter 5 includes a new discussion on how gas laws apply to breathing. • Chapter 5 groups stoichiometry of gaseous reactions with other rearrangements of the ideal gas law. • Chapter 17 makes consistent use of quantitative benchmarks for determining when it is valid to assume that the amount reacting can be neglected. Acknowledgments For the third edition of Principles of General Chemistry, I am once again very fortunate that Patricia Amateis of Virginia Tech prepared the Instructors’ Solutions Manual and Student Solutions Manual and Libby Weberg the Student Study Guide. The following individuals helped write and review goal-oriented content for LearnSmart for general chemistry: Erin Whitteck; Margaret Ruth Leslie, Kent State University; and Adam I. Keller, Columbus State Community College. 11/29/11 10:25 AM xx Preface And, I greatly appreciate the efforts of all the professors who reviewed portions of the new edition or who participated in our developmental survey to assess the content needs for the text: DeeDee A. Allen, Wake Technical Community College John D. Anderson, Midland College Jeanne C. Arquette, Phoenix College Yiyan Bai, Houston Community College Stanley A. Bajue, Medgar Evers College, CUNY Jason P. Barbour, Anne Arundel Community College Peter T. Bell, Tarleton State University Vladimir Benin, University of Dayton Paul J. Birckbichler, Slippery Rock University Simon Bott, University of Houston Kevin A. Boudreaux, Angelo State University R. D. Braun, University of Louisiana, Lafayette Stacey Buchanan, Henry Ford Community College Michael E. Clay, College of San Mateo Michael Columbia, Indiana University Purdue University Fort Wayne Charles R. Cornett, University of Wisconsin, Platteville Kevin Crawford, The Citadel Mapi M. Cuevas, Santa Fe Community College Kate Deline, College of San Mateo Amy M. Deveau, University of New England, Biddeford Jozsef Devenyi, The University of Tennessee, Martin Paul A. DiMilla, Northeastern University John P. DiVincenzo, Middle Tennessee State University Ajit Dixit, Wake Technical Community College Son Q. Do, University of Louisiana, Lafayette Rosemary I. Effiong, University of Tennessee, Martin Bryan Enderle, University of California, Davis David K. Erwin, Rose-Hulman Institute of Technology Emmanuel Ewane, Houston Community College Kenneth A. French, Blinn College Donna G. Friedman, St. Louis Community College, Florissant Valley Herb Fynewever, Western Michigan University Judy George, Grossmont College Dixie J. Goss, Hunter College City University of New York Ryan H. Groeneman, Jefferson College Kimberly Hamilton-Wims, Northwest Mississippi Community College David Hanson, Stony Brook University Eric Hardegree, Abilene Christian University Michael A. Hauser, St. Louis Community College, Meramec Eric J. Hawrelak, Bloomsburg University of Pennsylvania Monte L. Helm, Fort Lewis College Sherell Hickman, Brevard Community College Jeffrey Hugdahl, Mercer University Michael A. Janusa, Stephen F. Austin State University Richard Jarman, College of DuPage Carolyn Sweeney Judd, Houston Community College Bryan King, Wytheville Community College Peter J. Krieger, Palm Beach Community College John T. Landrum, Florida International University, Miami Richard H. Langley, Stephen F. Austin State University Richard Lavallee, Santa Monica College Debbie Leedy, Glendale Community College Alan Levine, University of Louisiana, Lafayette Chunmei Li, Stephen F. Austin State University Alan F. Lindmark, Indiana University Northwest Donald Linn, Indiana University Purdue University Fort Wayne Arthur Low, Tarleton State University David Lygre, Central Washington University Toni G. McCall, Angelina College Debbie McClinton, Brevard Community College William McHarris, Michigan State University Curtis McLendon, Saddleback College Lauren McMills, Ohio University Jennifer E. Mihalick, University of Wisconsin, Oshkosh John T. Moore, Stephen F. Austin State University Brian Moulton, Brown University Michael R. Mueller, Rose-Hulman Institute of Technology My friends that make up the superb publishing team at McGraw-Hill Higher Education have again done an excellent job developing and producing this text. My warmest thanks for their hard work, thoughtful advice, and support go to Publisher Ryan Blankenship and Executive Editor Jeff Huettman. I lost one wonderful Senior Developmental Editor, Donna Nemmers, early in the project and found another wonderful one, Lora Neyens. Once again, Lead Project Manager Peggy Selle created a superb product, this time based on the clean, modern look of Senior Designer David Hash. Marketing Manager Tami Hodge ably presented the final text to the sales staff and academic community. siL02699_fm_i_xxvii.indd 20 Kathy Nabona, Austin Community College Chip Nataro, Lafayette College David S. Newman, Bowling Green State University William J. Nixon, St. Petersburg College Eileen Pérez, Hillsborough Community College Richard Perkins, University of Louisiana, Lafayette Eric O. Potma, University of California, Irvine Nichole L. Powell, Tuskegee University Parris F. Powers, Volunteer State Community College Mary C. Roslonowski, Brevard Community College E. Alan Sadurski, Ohio Northern University G. Alan Schick, Eastern Kentucky University Linda D. Schultz, Tarleton State University Mary Sisak, Slippery Rock University Joseph Sneddon, McNeese State University Michael S. Sommer, University of Wyoming Ana Maria Soto, The College of New Jersey John E. Straub, Boston University Richard E. Sykora, University of South Alabama Robin S. Tanke, University of Wisconsin, Stevens Point Maria E. Tarafa, Miami Dade College Kurt Teets, Okaloosa Walton College Jeffrey S. Temple, Southeastern Louisiana University Lydia T. Tien, Monroe Community College Thomas D. Tullius, Boston University Mike Van Stipdonk, Wichita State University Ramaiyer Venkatraman, Jackson State University Marie Villarba, Glendale Community College Kirk W. Voska, Rogers State University Edward A. Walters, University of New Mexico Kristine Wammer, University of St. Thomas Shuhsien Wang-Batamo, Houston Community College Thomas Webb, Auburn University Kurt Winkelmann, Florida Institute of Technology Steven G. Wood, Brigham Young University Louise V. Wrensford, Albany State University James A. Zimmerman, Missouri State University Susan Moyer Zirpoli, Slippery Rock University Tatiana M. Zuvich, Brevard Community College Expert freelancers made indispensable contributions as well. My superb copyeditor, Jane Hoover, continued to improve the accuracy and clarity of my writing, and proofreaders Janelle Pregler and Angie Ruden gave their consistent polish to the final manuscript. And Jerry Marshall helped me find the best photos, and Gary Hunt helped me create an exciting cover. As always, my wife Ruth was involved every step of the way, from helping with early style decisions to checking and correcting content and layout in page proofs. And my son Daniel consulted on the choice of photos and the cover. 11/29/11 10:25 AM xxi Preface 13.3 • Solubility as an Equilibrium Process A Guide to Student Success: How to Get the Most Out of Your Textbook P1 7 Organizing and Focusing Chapter Outline The chapter begins with an outline that shows the sequence of topics and subtopics. A P2 P2 Quantum Theory and Atomic Structure B C Figure 13.10 The effect of pressure on gas solubility. Key Principles to focus on while studying this chapter Key Principles a piston-cylinder assembly with a gas above a saturated aqueous solution of the gas (Figure 13.10A). At equilibrium, at a given pressure, the same number of gas molecules enter and leave the solution per unit time: • In a vacuum, electromagnetic radiation travels at the speed of light (c) in waves. The properties of a wave are its wavelength (l, distance between corresponding points on adjacent waves), frequency (n, number of cycles the wave undergoes per second), and amplitude (the height of the wave), which is related to the intensity (brightness) of the radiation. Any region of the electromagnetic spectrum includes a range of wavelengths. (Section Gas 7.1) 1 solvent BA saturated solution • In everyday experience, energy is diffuse and matter is chunky, but certain phenomena—blackbody radiation (the light emitted by hot objects), the photoelectric effect (the flow of current when light strikes a metal), and atomic spectra (the specific colors emitted from a substance that is excited)—can only be Light from Excited Atoms In a fireworks display and explained if energy consists of “packets” (quanta) that occur in, and thus change by, fixed amounts. The energy of a quantum is related to its frequency. many other everyday phenomena, we see the result of (Section 7.1) atoms absorbing energy and then emitting it as light. In this chapter, we explore the basis of these phenomena • According to the Bohr model, an atomic spectrum consists of separate lines and learn some surprising things about the makeup of because an atom has certain energy levels (states) that correspond to electrons in orbits around the nucleus. The energy of the atom changes when the electron the universe. moves from one orbit to another as the atom absorbs (or emits) light of a specific frequency. (Section 7.2) gas • Wave-particle duality means that matter has wavelike properties (as shown by the de Broglie wavelengthgas and electron diffraction) and energy has particle7.1 The Nature of Light like properties (as shown by photons of light having momentum). These Wave Nature of Light 5wekH 3 Pgas Particle Nature of Light properties are observable only on the atomic scale, and because S ofgas them, can never simultaneously know the position and speed of an electron in an atom 7.2 Atomic Spectra (uncertainty principle). (Section 7.3) Line Spectra and the Rydberg Equation H Bohr Model of the Hydrogen Atom • According to the quantum-mechanical model of the H atom, each energy level Energy of the atom is associated with an atomic orbital (wave function), a mathematical gas gas Levels of the Hydrogen Atom H Spectral Analysis description of the electron’s position in three dimensions. We21 can know the 21 7.3 The Wave-Particle Duality of Matter and Energy probability that the electron is within a particular tiny volume of space, but not its Wave Nature of Electrons and Particle Nature of Photons exact location. The probability is highest for the electron being near the nucleus, Heisenberg’s Uncertainty Principle and it decreases with distance. (Section 7.4) 7.4 The Quantum-Mechanical Model of the Atom • Quantum numbers denote each atomic orbital’s energy (n, principal), shape Atomic Orbital and Probable Location of the Electron (l, angular momentum), and spatial orientation (ml, magnetic). An energy level Quantum Numbers of an Orbital consists of sublevels, which consist of orbitals. There is a hierarchy of quantum Quantum Numbers and Energy Levels numbers: n limits l, which limits ml. (Section 7.4) Shapes of Atomic Orbitals • InProblem the H atom, there is only one type pressure of electrostatic of interaction: the attraction The partial carbon dioxide gas inside a bottle The Special Case of of the Hcola Atom is 4 atm at between nucleus and electron. Thus, for the H atom only, the energy levels 258C. What is thequantum solubility CO7.4) depend solely on the principal number (n).of (Section 2? The Henry’s law constant for CO2 in water is The main principles from the chapter are given in concise, separate paragraphs so you can keep them in mind as you study. You may also want to review them when you are finished. 9.1 • Atomic Properties and Chemical Bonds W hy do substances behave as they do? That is, why is table salt (or any other ionic substance) a hard, brittle, high-melting solid that conducts a current only when molten or dissolved in water? Why is candle wax (along with most covalent substances) low melting, soft, and nonconducting, even though diamond (as well as a few other exceptions) is high melting and extremely hard? And why is copper (and most other metals) shiny, malleable, and able to conduct a current whether molten or solid? The answers lie in the type of bonding within the substance. In Chapter 8, we examined the properties of individual atoms and ions. But the behavior of matter really depends on how those atoms and ions bond. Push down on the piston, and you disturb the equilibrium: gas volume decreases, so gas pressure (and concentration) increases, and gas particles collide with the liquid surface more often. Thus, more particles enter than leave the solution per unit time (Figure 13.10B). More gas dissolves to reduce this disturbance (a shift to the right in the preceding equation) until the system re-establishes equilibrium (Figure 13.10C). Henry’s law expresses the quantitative relationship between gas pressure and solubility: the solubility of a gas (S ) is directly proportional to the partial pressure Outline of the gas (P ) above the solution: 277 (13.3) CONCEPTS & SKILLS TO REVIEW where k is the Henry’s law constant and is specific for a given gas-solvent combination at a given temperature. With S in mol/L and P in atm, the units of k are mol/Latm (that is, molL atm ). before studying this chapter • characteristics of ionic and covalent compounds; Coulomb’s law (Section 2.7) • polar covalent bonds and the polarity of water (Section 4.1) • Hess’s law, DH 8rxn, and DH 8f (Sections 6.5 and 6.6) • atomic and ionic electron configurations (Sections 8.2 and 8.4) • trends in atomic properties and metallic behavior (Sections 8.3 and 8.4) 9.1 • Atomic ProPerties And chemicAl Bonds Before we examine the types of chemical bonding, we should start with the most fundamental question: why do atoms bond at all? In general, bonding lowers the potential energy between positive and negative particles (see Figure 1.3), whether they are oppositely charged ions or nuclei and electron pairs. Just as the strength of attractions and repulsions among nucleus and electrons determines the properties of an atom, the type and strength of chemical bonds determine the properties of a substance. Sample Problem 13.2 Concepts and Skills to Review 3.331022 mol/Latm at 258C. This prepare forsothe upcoming Planunique We know P feature (4 atm) and helps the value ofyou k (3.3310 mol/Latm), we substitute them into Equation 13.3 to find S . chapter by referring to key material from earlier chapSolution S 5 k 3 P 5 (3.3310 mol/Latm)(4 atm) 5 0.1 mol/L The you units areshould correct. We rounded to one significant figure to you match the numberreading tersCheck that understand before start in the pressure. A 0.5-L bottle of cola has about 2 g (0.05 mol) of dissolved CO . theFollow-UP current one. Problem 13.2 If air contains 78% N by volume, what is the solubility of N CO2 CO2 in water at 258C and 1 atm (kH for N2 in H2O at 258C 5 7A 8A (17) (18) 3A 4A 5A 6A (13) (14) (15) (16) Nonmetals Metalloids Sample Problems Li Be Na Mg 3B (3) 4B (4) 5B (5) 6B (6) 7B (7) H He • • B C N O F Ne (8) 1B 2B 8B (9) (10) (11) (12) Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn A, Location within the periodic table. B, Relative magnitudes of some atomic properties across a period. A worked-out problem appears whenever an important new concept or skill is introduced. The step-by-step approach is shown consistently for every sample problem in the text. • Plan analyzes the problem so that you can use what is known to find what is unknown. This approach develops the habit of thinking through the solution before performing calculations. • In many cases, a Road Map specific to the problem is shown alongside the plan to lead you visually through the needed calculation steps. • Solution shows the calculation steps in the same order as they are discussed in the plan and shown in the road map. • Check fosters the habit of going over your work quickly to make sure that the answer is reasonable, chemically and mathematically—a great way to avoid careless errors. • Comment, shown in many problems, provides an additional insight, and alternative approach, or a common mistake to avoid. • Follow-up Problem gives you immediate practice by presenting a similar problem that requires the same approach. Fr Ra Ac Rf Db Sg Bh Hs Mt Ds Rg Cn 113 114 115 116 Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np Am Cm Bk Cf Es Fm Md No Lr A siL02699_fm_i_xxvii.indd 21 Pu 118 B PROPERTY METAL ATOM NONMETAL ATOM Atomic size Larger Smaller Zeff Lower Higher IE Lower Higher EA Less negative More negative mol/Latm)? 2 Summary of Section 13.3 Step-By-Step Problem Solving Using this clear and thorough problem-solving approach, you’ll learn to think through chemistry problems logically and Figure 9.1 A comparison of metals systematically. and nonmetals. 731024 216 dencies to lose or gain electrons. Such differences occur between reactive metals [Groups 1A(1) and 2A(2)] and nonmetals [Group 7A(17) and the top of Group 6A(16)]. A metal atom (low IE) loses its one or two valence electrons, and a nonmetal atom (highly negative EA) gains the electron(s). Electron transfer from metal to nonmetal occurs, and each atom forms an ion with a noble gas electron configuration. The electrostatic attractions between these positive and negative ions draw them into a threedimensional array to form an ionic solid. Note that the chemical formula of an ionic compound is the empirical formula because it gives the cation-to-anion ratio. Metals CO2 2 A bulleted list of statements conclude each section, immedi1. Metal with nonmetal: electron and ionic bonding (Figure next ately reiterating thetransfer major ideas just9.2A, covered. page). We observe ionic bonding between atoms with large differences in their ten- 2A (2) H 22 2 In general, there is a gradation from atoms of more metallic elements to atoms of more nonmetallic elements across a period and up a group (Figure 9.1). Three types of bonding result from the three ways these two types of atoms can combine: Key: 22 H CO2 Section Summaries Types of Bonding: Three Ways Metals and Nonmetals Combine 1A (1) Using Henry’s Law to Calculate Gas Solubility solutionthatcontainsthemaximumamountofdissolvedsoluteinthepresence A of excess undissolved solute is saturated. A saturated solution is in equilibrium with excess solute, because solute particles are entering and leaving the solution at the same rate. Most solids are more soluble at higher temperatures. • AllgaseshaveanegativeDHsolninwater,soheatinglowersgassolubilityinwater. • enry’s law says that the solubility of a gas is directly proportional to its partial H pressure above the solution. 3.5 • Fundamentals of Solution Stoichiometry 103 Stoichiometry of Reactions in Solution Solving stoichiometry problems for reactions in solution requires the additional step of converting the volume of reactant or product in solution to amount (mol): 1. 2. 3. 4. Balance the equation. Find the amount (mol) of one substance from the volume and molarity. Relate it to the stoichiometrically equivalent amount of another substance. Convert to the desired units. Sample Problem 3.25 Calculating Quantities of Reactants and Products for a Reaction in Solution Problem Specialized cells in the stomach release HCl to aid digestion. If they release too much, the excess can be neutralized with an antacid. A common antacid contains magnesium hydroxide, which reacts with the acid to form water and magnesium chloride solution. As a government chemist testing commercial antacids, you use 0.10 M HCl to simulate the acid concentration in the stomach. How many liters of “stomach acid” react with a tablet containing 0.10 g of magnesium hydroxide? Plan We are given the mass (0.10 g) of magnesium hydroxide, Mg(OH)2, that reacts with the acid. We also know the acid concentration (0.10 M) and must find the acid volume. After writing the balanced equation, we convert the mass (g) of Mg(OH)2 to amount (mol) and use the molar ratio to find the amount (mol) of HCl that reacts with it. Then, we use the molarity of HCl to find the volume (L) that contains this amount (see the road map). Solution Writing the balanced equation: Mg(OH)2(s) 1 2HCl(aq) -£ MgCl2(aq) 1 2H2O(l) Converting from mass (g) of Mg(OH)2 to amount (mol): 1 mol Mg(OH)2 Amount (mol) of Mg(OH)2 5 0.10 g Mg(OH)2 3 5 1.731023 mol Mg(OH)2 58.33 g Mg(OH)2 Converting from amount (mol) of Mg(OH)2 to amount (mol) of HCl: 2 mol HCl 5 3.431023 mol HCl 1 mol Mg(OH)2 Converting from amount (mol) of HCl to volume (L): 1L 5 3.431022 L Volume (L) of HCl 5 3.431023 mol HCl 3 0.10 mol HCl Check The size of the answer seems reasonable: a small volume of dilute acid (0.034 L of 0.10 M) reacts with a small amount of antacid (0.0017 mol). Comment In Chapter 4, you’ll see that this equation is an oversimplification, because HCl and MgCl2 exist in solution as separated ions. Amount (mol) of HCl 5 1.731023 mol Mg(OH)2 3 Road Map Mass (g) of Mg(OH)2 divide by (g/mol) Amount (mol) of Mg(OH)2 molar ratio Amount (mol) of HCl divide by M (mol/L) Volume (L) of HCl Follow-UP Problem 3.25 Another active ingredient in some antacids is aluminum hydroxide. Which is more effective at neutralizing stomach acid, magnesium hydroxide or aluminum hydroxide? [Hint: “Effectiveness” refers to the amount of acid that reacts with a given mass of antacid. You already know the effectiveness of 0.10 g of Mg(OH)2.] Except for the additional step of finding amounts (mol) in solution, limitingreactant problems for reactions in solution are handled just like other such problems. Sample Problem 3.26 Solving Limiting-Reactant Problems for Reactions in Solution Problem Mercury and its compounds have uses from fillings for teeth (as a mixture with silver, copper, and tin) to the production of chlorine. Because of their toxicity, however, soluble mercury compounds, such as mercury(II) nitrate, must be removed from industrial wastewater. One removal method reacts the wastewater with sodium sulfide solution to produce solid mercury(II) sulfide and sodium nitrate solution. In a laboratory simulation, 0.050 L of 0.010 M mercury(II) nitrate reacts with 0.020 L of 0.10 M sodium sulfide. (a) How many grams of mercury(II) sulfide form? (b) Write a reaction table for this process. 11/29/11 10:25 AM 403 percent) of dissociated HA molecules that increases with dilution. NK OF IT THIS WAY Weak acids dissociating to a greater extent as they are diluted is analogous to the shift in a gaseous reaction when the container volume increases (Section 17.6). In the gaseous reaction, an increase in volume as the piston is withdrawn shifts the equilibrium position to favor more moles of gas. In the case of HA dissociation, the increase in volume as solvent is added shifts the equilibrium position to favor more moles of ions. Are Gaseous and -Acid Equilibria Alike? xxii Preface Sample Problem 18.9 uses molecular scenes to highlight this idea. (Note that, in order to depict the scenes practically, the acid has a much higher percent dissociation than any real weak acid does.) Sample Problem 18.9 UsingMolecularScenestoDeterminetheExtent ofHADissociation Problem A 0.15 M solution of HA (blue and green) is 33% dissociated. Which scene represents a sample of that solution after it is diluted with water? Chapter 16 • Chapter Review Guide Key Terms 535 These important terms appear in boldface in the chapter and are defined again in the Glossary. Section 16.1 chemical kinetics (499) reaction rate (499) Section 16.2 average rate (502) instantaneous rate (503) initial rate (503) Section 16.3 rate law (rate equation) (505) rate constant (505) reaction orders (505) Section 16.4 integrated rate law (512) half-life (t1/2) (515) Section 16.5 collision theory (519) Arrhenius equation (519) activation energy (Ea) (520) effective collision (522) frequency factor (522) transition state theory (522) transition state (activated complex) (522) reaction energy diagram (523) Section 16.6 reaction mechanism (525) elementary reaction (elementary step) (526) molecularity (526) unimolecular reaction (526) bimolecular reaction (526) rate-determining (ratelimiting) step (527) reaction intermediate (527) Section 16.7 catalyst (530) homogeneous catalyst (531) heterogeneous catalyst (532) hydrogenation (532) enzyme (533) active site (533) Unique to Principles of General Chemistry: Molecular-Scene Sample Problems These problems apply the same stepwise strategy to help you interpret molecular scenes and solve problems based Key Equations and Relationships on them. 16.1 Expressing reaction rate in terms of reactant A (501): 16.6 Calculating the time to reach a given [A] in a zero-order Numbered and screened concepts are listed for you to refer to or memorize. Rate 5 2 1 2 3 Plan We are given the percent dissociation of the original HA solution (33%), and we know that the percent dissociation increases as the acid is diluted. Thus, we calculate the percent dissociation of each diluted sample and see which is greater than 33%. To determine percent dissociation, we apply Equation 18.5, with HAdissoc equal to the number of H3O1 (or A2) and HAinit equal to the number of HA plus the number of H3O1 (or A2). Solution Calculating the percent dissociation of each diluted solution with Equation 18.5: Solution 1. Percent dissociated 5 4/(5 1 4) 3 100 5 44% Solution 2. Percent dissociated 5 2/(7 1 2) 3 100 5 22% Solution 3. Percent dissociated 5 3/(6 1 3) 3 100 5 33% reaction (rate 5 k) (513): D 3A 4 Dt 3A 4 t 2 3A 4 0 5 2kt 16.7 Finding the half-life of a first-order process (516): ln 2 0.693 t1/2 5 5 k k 16.8 Relating the rate constant to the temperature (Arrhenius equation) (519): 16.2 Expressing the rate of a general reaction (503): 1 D 3B 4 1 D 3C 4 1 D 3D 4 1 D 3A 4 52 5 5 Rate 5 2 c Dt a Dt b Dt d Dt 16.3 Writing a general rate law (in which products do not appear) (505): Rate 5 k 3A 4 m 3B 4 n . . . k 5 Ae2Ea /RT 16.9 Relating the heat of reaction to the forward and reverse activation energies (520): DHrxn 5 Ea(fwd) 2 Ea(rev) 16.4 Calculating the time to reach a given [A] in a first-order reaction (rate 5 k[A]) (513): 3A 4 0 ln 5 kt 3A 4 16.10 Calculating the activation energy (rearranged form of Arrhenius equation) (521): Ea 1 k2 1 ln 5 2 a 2 b k1 R T2 T1 t 16.5 Calculating the time to reach a given [A] in a simple secondorder reaction (rate 5 k[A]2) (513): Therefore, scene 1 represents the diluted solution. Check Let’s confirm our choice by examining the other scenes: in scene 2, HA is less dissociated than originally, so that scene must represent a more concentrated HA solution; scene 3 represents another solution with the same percent dissociation as the original. FOllOW-UP PrOblem 18.9 The scene in the margin represents a sample of a weak acid HB (blue and purple) dissolved in water. Draw a scene that represents the same volume after the solution has been diluted with water. 1 1 2 5 kt 3A 4 t 3A 4 0 Brief SolutionS to follow-up proBlemS 16.1 Compare your own solutions to these calculation steps and answers. (a) 4NO(g) 1 O2(g) -£ 2N2O3(g); rate 5 2 D 3O2 4 1 D 3NO 4 1 D 3N2O3 4 52 5 Dt 4 Dt 2 Dt D 3O2 4 1 D 3NO4 1 (b) 2 52 5 2 (21.60310 mol/Ls) Dt 4 Dt 4 5 4.00310 25 mol/Ls 16.2 Brief Solutions to Follow-up Problems First order in Br2, first order in BrO32, second order in H1, fourth order overall. These provide multistep solutions at the end of the chapter, not just a one-number answer at the back of the book. This fuller treatment provides an excellent way for you to reinforce problem-solving skills. 16.4 (a) The rate law shows the reaction is zero order in Y, so the rate is not affected by doubling Y: rate of Expt 2 5 0.25310–5 mol/Ls. (b) The rate of Expt 3 is four times that of Expt 1, so [X] doubles. 16.3 Rate 5 k[H2]m[I2]n. From Expts 1 and 3, m 5 1. From Expts 2 and 4, n 5 1. Therefore, rate 5 k[H2][I2]; second order overall. 4.6 • Elements in Redox Reactions 16.5 1/[HI]1 2 1/[HI]0 5 kt 111 L/mol 2 100. L/mol 5 (2.4310221 L/mols)(t) t 5 4.631021 s (or 1.531014 yr) 16.6 (a) 139 Visualizing Chemistry Figure 4.15 A more reactive metal (Cu) displacing the ion of a less reactive metal (Ag) from solution. Three-Level Illustrations A Silberberg hallmark, these illustrations provide macroscopic and molecular views of a process to help you connect these two levels of reality with each other and with the chemical equation that describes the process in symbols. Copper wire coated with silver Copper wire Copper nitrate solution Silver nitrate solution 12.6 • The Solid State: Structure, Properties, and Bonding 375 Cu2 + Ag+ A Simple cubic B Body-centered cubic C Face-centered cubic Ag+ 2e– Ag atoms coating wire Cu atoms in wire 0 +1+5 –2 2AgNO3(aq) + Cu(s) 5 –2 0 +2 +5 –2 Cu(NO3)2(aq) + 2Ag(s) Consider the metals we’ve just discussed: Li, Al, and Ni lie above H2, while Ag lies below it; also, Zn lies above Cu, which lies above Ag. The most reactive metals on the list are in Groups 1A(1) and 2A(2) of the periodic table, and the least reactive are Cu, Ag, and Au in Group 1B(11) and Hg in 2B(12). Cutting-Edge Molecular Models 2 2 2 2 Thus, elemental chlorine can oxidize bromide ions (below) or iodide ions from solution, and elemental bromine can oxidize iodide ions: 1 0 0 1 2Br(aq) Cl2(aq) ±£ Br2(aq) 2Cl(aq) Combustion Reactions ombustion is the process of combining with oxygen, most commonly with the release C of heat and the production of light, as in a flame. Combustion reactions are not classified by the number of reactants and products, but all of these reactions are redox processes because elemental oxygen is a reactant: 2CO(g) 1 O2(g) -£ 2CO2(g) The combustion reactions that we commonly use to produce energy involve coal, petroleum, gasoline, natural gas, or wood as a reactant. These mixtures consist of substances with many C-C and C-H bonds, which break during the reaction, and siL02699_fm_i_xxvii.indd 22 each C and H atom combines with oxygen to form CO and H O. The combustion Strength as reducing agent Author andSeries artist worked byof side and decreases employed The Activity of the Halogens side Reactivity the elements down the Group 7A(17), so we have most advanced computer-graphic software to provide accuF . Cl . Br . I rate molecular-scale models and vivid scenes. A halogen higher in the group is a stronger oxidizing agent than one lower down. Li K Can displace H2 Ba from water Ca Na Mg Al Mn Coordination number = 8 Coordination number = 12 Coordination number = 6 Can displace H2 Zn from steam 1 1 1 – – – 8 atom Cr 8 atom 8 atom at 8 corners at 8 corners at 8 corners Fe Cd 1 – 1 atom Co 2 atom at 6 faces at center Ni Can displace H2 from acid Sn 1 1 1 1 Atoms/unit cell = ( 8– x 8) + 1 = 2 Atoms/unit cell = ( 8– x 8) + ( 2– x 6) = 4 Atoms/unit cell = 8– x 8 = 1 Pb H2 Figure 12.23 The three cubic unit cells. A, Simple cubic unit cell. face-centered atoms yellow. Third row: A unit cell (shaded blue) in an B, Body-centered cubic unit cell. C, Face-centered cubic unit cell. Top expanded portion of the crystal. The number of nearest neighbors around Cu row: Cubic arrangements of atoms in expanded view. Second row: one particle (dark blue in center) is the coordination number. Bottom row: Hg Cannot Space-filling view of cubic arrangements. All atoms are identical The total numbers of atoms in the actual unit cell. The simple cubic has displace Hthese 2 but, for clarity, corner atoms are blue, body-centered atoms pink, and one atom, the body-centered has two, and the face-centered has four. from any source Ag Au Figure 4.16 The activity series of the metals. The most active metal (strongest reducing agent) is at the top, and the least active metal (weakest reducing agent) is at the bottom. 11/29/11 10:25 AM Preface xxiii 417 Chapter 13 • Chapter Review Guide Reinforcing The Learning Process chapter review Guide Learning Objectives Chapter Review Guide 1. Explainhowsolubilitydependsonthetypesofintermolecularforces(like-dissolves-likerule)andunderstandthecharacteristicsofsolutionsconsistingofgases,liquids,orsolids (§13.1)(SP13.1)(EPs13.1–13.12) 2. UnderstandtheenthalpycomponentsofDHsoln,the dependenceofDHhydronchargedensity,andwhyasolution processisexothermicorendothermic(§13.2)(EPs13.13– 13.15,13.18–13.25,13.28) 3. Comprehendthemeaningofentropyandhowthebalance betweenDHandDSgovernsthesolutionprocess(§13.2) (EPs13.16,13.17,13.26,13.27) 4. Distinguishamongsaturated,unsaturated,andsupersaturated solutionsandexplaintheequilibriumnatureofasaturated solution(§13.3)(EPs13.29,13.35) • Learning Objectives are listed, with section, sample problem, and end-of-chapter problem numbers, to help you focus on key concepts and skills. • Key Terms are boldfaced within the chapter and listed here by section (with page numbers); they are defined again in the Glossary. • Key Equations and Relationships are highlighted and numbered within the chapter and listed here with page numbers. Key Terms Chapter 13 • The Properties of Solutions 13.79 What is the minimum mass of glycerol (C3H8O3) that must be dissolved in 11.0 mg of water to prevent the solution from freezing at 2158C? (Assume ideal behavior.) 180 Calculate the molality and van’t Hoff factor (i) for the following aqueous solutions: (a) 1.00 mass % NaCl, freezing point 5 20.5938C (b) 0.500 mass % CH3COOH, freezing point 5 20.1598C 13.81 Calculate the molality and van’t Hoff factor (i) for the following aqueous solutions: (a) 0.500 mass % KCl, freezing point 5 20.2348C (b) 1.00 mass % H2SO4, freezing point 5 20.4238C 13.82 In a study designed to prepare new gasoline-resistant coatings, a polymer chemist dissolves 6.053 g of poly(vinyl alcohol) in enough water to make 100.0 mL of solution. At 258C, the osmotic pressure of this solution is 0.272 atm. What is the molar mass of the polymer sample? 13.83 The U.S. Food and Drug Administration lists dichloromethane (CH2Cl2) and carbon tetrachloride (CCl4) among the many cancer-causing chlorinated organic compounds. What are the partial pressures of these substances in the vapor above a solution of 1.60 mol of CH2Cl2 and 1.10 mol of CCl4 at 23.58C? The vapor pressures of pure CH2Cl2 and CCl4 at 23.58C are 352 torr and 118 torr, respectively. (Assume ideal behavior.) Comprehensive Problems 13.84 The three aqueous ionic solutions represented below have total volumes of 25. mL for A, 50. mL for B, and 100. mL for C. If each sphere represents 0.010 mol of ions, calculate: (a) the total molarity of ions for each solution; (b) the highest molarity of solute; (c) the lowest molality of solute (assuming the solution densities are equal); (d) the highest osmotic pressure (assuming ideal behavior). + – – + – – + + + – – + + 2+ – – 2+ – – 2+ – + B A – – – – + – C 2+ – 13.85 Gold occurs in seawater at an average concentration of 1.131022 ppb. How many liters of seawater must be processed to recover 1 troy ounce of gold, assuming 81.5% efficiency (d of seawater 5 1.025 g/mL; 1 troy ounce 5 31.1 g)? 13.86 Use atomic properties to explain why xenon is 11 times as soluble as helium in water at 08C on a mole basis. 13.87 Which of the following best represents a molecular-scale view of an ionic compound in aqueous solution? Explain. + + + + A + – – + B – + + – These are concepts and skills to review after studying this chapter. Related section (§), sample problem (SP), and upcoming end-of-chapter problem (EP) numbers are listed in parentheses. A rich catalog of study aids ends each chapter to help you review its content: 422 The following sections provide many aids to help you study this chapter. (Numbers in parentheses refer to pages, unless noted otherwise.) C 13.88 Four 0.50 m aqueous solutions are depicted. Assume the solutions behave ideally: (a) Which has the highest boiling point? These important terms appear in boldface in the chapter and are defined again in the Glossary. Section 13.1 solute(392) solvent(392) miscible(392) solubility(S)(392) like-dissolves-likerule(393) hydrationshell(393) (b) Which has the lowest freezing point? (c) Can you determine ion–induceddipole which one has the highest osmotic pressure? Explain. force(393) 2+ dipole–induceddipole – – + – + force(393) 2+ – – – – + alloy(396) – 2+ – – – Section 13.2 + 2+ – A B heatofsolution (DH soln)(397) 2– solvation(397) hydration(398) heatofhydration (DHhydr)(398) chargedensity(398) entropy(S)(399) Section 13.3 saturatedsolution(401) unsaturatedsolution(401) supersaturatedsolution(401) Henry’slaw(403) Section 13.4 molality(m)(404) masspercent[%(w/w)] (405) boilingpointelevation (DTb)(410) freezingpointdepression (DTf)(411) semipermeablemembrane (412) osmosis(412) osmoticpressure (P)(413) ionicatmosphere(415) 2– 2+ Key Equations and Relationships 2+ 2– C Numbered and screened concepts are listed for you to refer to or memorize. D 13.1 Dividingthegeneralheatofsolutionintocomponent 13.89 “De-icing salt” is used to melt snow and ice on streets. The enthalpies(397): highway department of a small town is deciding whether to buy NaCl or CaCl2, which are equally effective, to use for this purpose. The town can obtain NaCl for $0.22/kg. What is the maximum the town should pay for CaCl2 to be cost effective? 13.90 Thermal pollution from industrial wastewater causes the temperature of river or lake water to increase, which can affect fish survival as the concentration of dissolved O2 decreases. Use the following data to find the molarity of O2 at each temperature (assume the solution density is the same as water): Temperature (°C) Solubility of O2 (mg/kg H2O) 0.0 20.0 40.0 Density of H2O (g/mL) 14.5 9.07 6.44 0.99987 0.99823 0.99224 13.91 A chemist is studying small organic compounds for their potential use as an antifreeze. When 0.243 g of a compound is dissolved in 25.0 mL of water, the freezing point of the solution is 20.2018C. (a) Calculate the molar mass of the compound (d of water 5 1.00 g/mL). (b) Analysis shows that the compound is 53.31 mass % C and 11.18 mass % H, the remainder being O. Calculate the empirical and molecular formulas of the compound. (c) Draw a Lewis structure for a compound with this formula that forms H bonds and another for one that does not. 13.92 Is 50% by mass of methanol dissolved in ethanol different from 50% by mass of ethanol dissolved in methanol? Explain. 13.93 Three gaseous mixtures of N2 (blue), Cl2 (green), and Ne (purple) are depicted below. (a) Which has the smallest mole fraction of N2? (b) Which have the same mole fraction of Ne? (c) Rank all three in order of increasing mole fraction of Cl2. A volumepercent [%(v/v)](405) molefraction(X)(405) Section 13.5 colligativeproperty(408) electrolyte(408) nonelectrolyte(408) vaporpressurelowering (DP)(408) Raoult’slaw(409) idealsolution(409) 2+ 2+ 2– 5. Describetheeffectoftemperatureonthesolubilityof solidsandgasesinwaterandtheeffectofpressureonthe solubilityofgases(Henry’slaw)(§13.3)(SP13.2)(EPs 13.30–13.34,13.36) 6. Expressconcentrationintermsofmolarity,molality,mole fraction,andpartsbymassorbyvolumeandbeableto interconverttheseterms(§13.4)(SPs13.3–13.5)(EPs 13.37–13.58) 7. Describeelectrolytebehaviorandthefourcolligative properties,explainthedifferencebetweenphasediagrams forasolutionandapuresolvent,explainvapor-pressure loweringfornon-volatileandvolatilenonelectrolytes,and discussthevan’tHofffactorforcolligativepropertiesof electrolytesolutions(§13.5)(SPs13.6–13.9)(EPs13.59– 13.83) B C 13.94 Four U tubes each have distilled water in the right arm, a solution in the left arm, and a semipermeable membrane between arms. (a) If the solute is KCl, which solution is most concentrated? 13.5 Definingconcentrationintermsofmolality(404): Molality(m) 5 DHsoln5DHsolute1DHsolvent1DHmix 13.2 Dividingtheheatofsolutionofanioniccompoundinwater intocomponententhalpies(398): 13.6 Definingconcentrationintermsofmasspercent(405): Masspercent3%(w/w)4 5 DHsoln5DHlattice1DHhydroftheions 13.3 Relatinggassolubilitytoitspartialpressure(Henry’slaw) (403): Sgas5kH3Pgas massofsolute 3 100 massofsolution 13.7 Definingconcentrationintermsofvolumepercent(405): 13.4 Definingconcentrationintermsofmolarity(404): Molarity(M) 5 amount(mol)ofsolute mass(kg)ofsolvent Volumepercent3%(v/v)4 5 volumeofsolute 3 100 volumeofsolution amount(mol)ofsolute volume(L)ofsolution End-of-Chapter Problems An exceptionally large number of problems ends each chapter. These are sorted by section, and many are grouped in similar pairs, with one of each pair answered in Appendix E (along with other problems having a colored number). Following these section-based problems is a large group of Comprehensive Problems, which are based on concepts and skills from any section and/or earlier chapter and are filled with applications from related sciences. 21.2 • Voltaic Cells: Using Spontaneous Reactions to Generate Electrical Energy Here are some memory aids to help you connect the half-reaction with its electrode: 1. The words anode and oxidation start with vowels; the words cathode and reductionstart with consonants. 2. Alphabetically, the A in anode comes before the C in cathode, and the O in oxidation comes before the R in reduction. 3. Look at the first syllables and use your imagination: Think of It This Way Analogies, memory shortcuts, and new insights into key ideas are provided in “Think of It This Way” features. 693 THINK OF IT THIS WAY Which Half-Reaction Occurs at Which Electrode? ANode, OXidation; REDuction, CAThode =: AN OX and a RED CAT Summary of Section 21.1 • n oxidation-reduction (redox) reaction involves the transfer of electrons from a A reducing agent to an oxidizing agent. • he half-reaction method of balancing divides the overall reaction into halfT reactions that are balanced separately and then recombined. • herearetwotypesofelectrochemicalcells.Inavoltaiccell,aspontaneousreaction T generateselectricityanddoesworkonthesurroundings.Inanelectrolyticcell,the surroundingssupplyelectricitythatdoesworktodriveanonspontaneousreaction. • Inbothtypesofcell,twoelectrodesdipintoelectrolytesolutions;oxidationoccurs at the anode, and reduction occurs at the cathode. 21.2 • Voltaic cells: Using spontaneoUs Reactions to geneRate electRical eneRgy siL02699_fm_i_xxvii.indd 23 When you put a strip of zinc metal in a solution of Cu21 ion, the blue color of the solution fades and a brown-black crust of Cu metal forms on the Zn strip (Figure 21.3). During this spontaneous reaction, Cu21 ion is reduced to Cu metal, while Zn metal is oxidized to Zn21 ion. The overall reaction consists of two half-reactions: 12/1/11 8:33 AM xxiv Preface McGraw-Hill Connect®Chemistry back are all saved online—so students can continually review their progress and plot their course to success. ConnectPlus® Chemistry www.mcgraw-hillconnect.com/chemistry McGraw-Hill Connect® Chemistry is a web-based assignment and assessment platform that gives students the means to better connect with their coursework, with their instructors, and with the important concepts that they will need to know for success now and in the future. The chemical drawing tool found within Connect Chemistry is CambridgeSoft’s ChemDraw®, which is widely considered the gold standard of scientific drawing programs and the cornerstone application for scientists who draw and annotate molecules, reactions, and pathways. This collaboration of Connect and ChemDraw features an easy-to-use, intuitive, and comprehensive course management and homework system with professional-grade drawing capabilities. With Connect Chemistry, instructors can deliver assignments, quizzes, and tests online. Questions from the text are presented in an auto-gradable format and tied to the text’s learning objectives. Instructors can edit existing questions and author entirely new problems. They also can track individual student performance—by question, assignment, or in relation to the class overall—with detailed grade reports; integrate grade reports easily with Learning Management Systems (LMS) such as WebCT and Blackboard; and much more. By choosing Connect Chemistry, instructors are providing their students with a powerful tool for improving academic performance and truly mastering course material. Connect Chemistry allows students to practice important skills at their own pace and on their own schedule. Importantly, students’ assessment results and instructors’ feed- siL02699_fm_i_xxvii.indd 24 Like Connect Chemistry, McGraw-Hill ConnectPlus® Chemistry provides students with online assignments and assessments, plus 24/7 online access to an eBook—an online edition of the text—to aid them in successfully completing their work, wherever and whenever they choose. LearnSmart™ This adaptive diagnostic learning system, powered by Connect Chemistry and based on artificial intelligence, constantly assesses a student’s knowledge of the course material. As students work within the system, McGraw-Hill LearnSmart™ develops a personal learning path adapted to what each student has actively learned and retained. This innovative study tool also has features to allow the instructor to see exactly what students have accomplished, with a built-in assessment tool for graded assignments. You can access LearnSmart for Chemistry at www.mcgrawhillcon nect.com/chemistry. McGraw-Hill Higher Education and Blackboard® McGraw-Hill Higher Education and Blackboard have teamed up! What does this mean for you? 1. Your life, simplified. Now you and your students can access McGraw-Hill’s Connect and Create right from within your Blackboard course—all with one single signon. Say goodbye to the days of logging in to multiple applications. 2. Deep integration of content and tools. Not only do you get single sign-on with Connect and Create, you also get deep integration of McGraw-Hill content and content engines right in Blackboard. Whether you’re choosing a book for your course or building Connect assignments, all the tools you need are right where you want them—inside of Blackboard. 3. Seamless Gradebooks. Are you tired of keeping multiple gradebooks and manually synchronizing grades into Blackboard? We thought so. When a student completes an integrated Connect assignment, the grade for that assignment automatically (and instantly) feeds your Blackboard grade center. 11/29/11 10:25 AM Preface 4. A solution for everyone. Whether your institution is already using Blackboard or you just want to try Blackboard on your own, we have a solution for you. McGrawHill and Blackboard can now offer you easy access to industry leading technology and content, whether your campus hosts it, or we do. Be sure to ask your local McGraw-Hill representative for details. Customizable Textbooks: Create™ Create what you’ve only imagined. Introducing McGrawHill Create—a new, self-service website that allows you to create custom course materials—print and eBooks—by drawing upon McGraw-Hill’s comprehensive, crossdisciplinary content. Add your own content quickly and easily. Tap into other rights-secured third-party sources as well. Then, arrange the content in a way that makes the most sense for your course, and if you wish, personalize your book with your course name and information. Choose the best delivery format for your course: color print, black and white print, or eBook. The eBook is now viewable for the iPad! And when you are finished customizing, you will receive a free PDF review copy in just minutes! Visit McGraw-Hill Create—www.mcgrawhillcreate.com— today and begin building your perfect book. Presentation Center Within the Instructor’s Presentation Center, instructors have access to editable PowerPoint lecture outlines, which appear as ready-made presentations that combine art and lecture notes for each chapter of the text. For instructors who prefer to create their lecture notes from scratch, all illustrations, photos, and tables are pre-inserted by chapter into a separate set of PowerPoint slides. An online digital library contains photos, artwork, animations, and other media types that can be used to create customized lectures, visually enhanced tests and quizzes, compelling course websites, or attractive printed support materials. All assets are copyrighted by McGraw-Hill Higher Education, but can be used by instructors for classroom purposes. The visual resources in this collection include: • Art Full-color digital files of all illustrations in the book can be readily incorporated into lecture presentations, exams, or custom-made classroom materials. • Photos The photo collection contains digital files of photographs from the text, which can be reproduced for multiple classroom uses. siL02699_fm_i_xxvii.indd 25 xxv • Tables Every table that appears in the text has been saved in electronic form for use in classroom presentations and/ or quizzes. • Animations Numerous full-color animations illustrating important processes are also provided. Harness the visual impact of concepts in motion by importing these files into classroom presentations or online course materials. Digital Lecture Capture: Tegrity records and distributes your lecture with just a click of a button. Students can view anytime and anywhere via computer, iPod, or mobile device. Tegrity indexes as it records your slideshow presentations and anything shown on your computer, so students can use keywords to find exactly what they want to study. Computerized Test Bank Prepared by Walter Orchard, Professor Emeritus of Tacoma Community College, over 2300 test questions to accompany Principles of General Chemistry are available utilizing Brownstone’s Diploma testing software. Diploma’s software allows you to quickly create a customized test using McGraw-Hill’s supplied questions or by authoring your own. Diploma allows you to create your tests without an Internet connection—just download the software and question files directly to your computer. Instructors’ Solutions Manual This supplement, prepared by Patricia Amateis of Virginia Tech, contains complete, worked-out solutions for all the end-of-chapter problems in the text. It can be found within the Instructors Resources, on the Connect: Chemistry site. Content Delivery Flexibility Principles of General Chemistry, by Martin Silberberg, is available in other formats in addition to the traditional textbook, giving instructors and students more choices for the format of their chemistry text. Cooperative Chemistry Laboratory Manual Prepared by Melanie Cooper of Clemson University, this innovative manual features open-ended problems designed to simulate experience in a research lab. Working in groups, students investigate one problem over a period of several weeks, so they might complete three or four projects during the semester, rather than one preprogrammed experiment per class. The emphasis is on experimental design, analytic problem solving, and communication. 11/29/11 10:25 AM xxvi Preface learning system resources For Students Student Study Guide This valuable study guide, prepared by Libby Bent Weberg, is designed to help you recognize your learning style; understand how to read, classify, and create a plan for solving a problem; and practice your problem-solving skills. For each section of each chapter, the guide provides study objectives and a summary of the corresponding text. Following the summary are sample problems with detailed solutions. Each chapter has true-false questions and a self-test, with all answers provided at the end of the chapter. Student Solutions Manual This supplement, prepared by Patricia Amateis of Virginia Tech, contains detailed solutions and explanations for all problems in the main text that have colored numbers. Connect Chemistry With Connect Chemistry, you can practice solving assigned homework problems using the Silberberg problem-solving methodology applied in the siL02699_fm_i_xxvii.indd 26 textbook. Algorithmic problems serve up multiple versions of similar problems for mastery of content, with hints and feedback for common incorrect answers to help you stay on track. Where appropriate, you engage in accurate, professional-grade chemical drawing through the use of CambridgeSoft’s ChemDraw tool, which is implemented directly into homework problems. Check it out at www.mcgrawhillconnect.com/chemistry. LearnSmart/ This adaptive diagnostic learning system, powered by Connect: Chemistry and based on artificial intelligence, constantly assesses your knowledge of the course material. As you work within the system, LearnSmart develops a personal learning path adapted to what you have actively learned and retained. This innovative study tool also has features to allow your instructor to see exactly what you have accomplished, with a builtin assessment tool for graded assignments. You can access LearnSmart for general chemistry by going to www.mcgrawhillconnect.com/chemistry. Animations for MP3/iPod A number of animations are available for download to your MP3/iPod through the textbook’s Connect website. 11/29/11 10:25 AM Principles of GENERAL CHEMISTRY siL02699_fm_i_xxvii.indd 1 12/2/11 1:14 PM 1 Keys to the Study of Chemistry Key Principles to focus on while studying this chapter • M atter can undergo two kinds of change: physical change involves a change in state—gas, liquid, or solid—but not in ultimate makeup (composition); chemical change (reaction) is more fundamental because it does involve a change in composition. The changes we observe result ultimately from changes too small to observe. (Section 1.1) • Energy occurs in different forms that are interconvertible, even as the total quantity of energy is conserved. When opposite charges are pulled apart, their potential energy increases; when they are released, potential energy is converted to the kinetic energy of the charges moving together. Matter consists of charged particles, so changes in energy accompany changes in matter. (Section 1.1) • The scientific method is a way of thinking that involves making observations and gathering data to develop hypotheses that are tested by controlled experiments until enough results are obtained to create a model (theory) that explains an aspect of nature. A sound theory can predict events but must be changed if new results conflict with it. (Section 1.2) • Any measured quantity is expressed by a number together with a unit. Conversion factors are ratios of equivalent quantities having different units; they are used in calculations to change the units of quantities. Decimal prefixes and exponential notation are used to express very large or very small quantities. (Section 1.3) • The SI system consists of seven fundamental units, each identifying a physical quantity such as length (meter), mass (kilogram), or temperature (kelvin). These are combined into many derived units used to identify quantities such as volume, density, and energy. Extensive properties, such as mass, depend on sample size; intensive properties, such as temperature, do not. (Section 1.4) • Uncertainty characterizes every measurement and is indicated by the number of significant figures. We round the final answer of a calculation to the same number of digits as in the least certain measurement. Accuracy refers to how close a measurement is to the true value; precision refers to how close measurements are to one another. (Section 1.5) A Molecular View Within a Storm Lightning supplies the energy for many atmospheric chemical changes to occur. In fact, all the events within and around you have causes and effects at the atomic level of reality. Outline 1.1 Some Fundamental Definitions Properties of Matter States of Matter Central Theme in Chemistry Importance of Energy 1.2 1.3 The Scientific Approach: Developing a Model Chemical Problem Solving Units and Conversion Factors A Systematic Approach 1.4 Measurement in Scientific Study Features of SI Units SI Units in Chemistry Extensive and Intensive Properties 1.5 Uncertainty in Measurement: Significant Figures Determining Significant Digits Calculations and Rounding Off Precision, Accuracy, and Instrument Calibration 2 siL02699_ch01_002_031.indd 2 9/28/11 1:44 PM 1.1 • Some Fundamental Definitions 3 aybe you’re taking this course because chemistry is fundamental to understanding other natural sciences. Maybe it’s required for your major. Or maybe you just want to learn more about the impact of chemistry on society or even on your everyday life. For example, did you have cereal, fruit, and coffee for breakfast today? In chemical terms, you enjoyed nutrient-enriched, spoilage-retarded carbohydrate flakes mixed in a white emulsion of fats, proteins, and monosaccharides, with a piece of fertilizer-grown, pesticide-treated fruit, and a cup of hot aqueous extract of stimulating alkaloid. Earlier, you may have been awakened by the sound created as molecules aligned in the liquidcrystal display of your clock and electrons flowed to create a noise. You might have thrown off a thermal insulator of manufactured polymer and jumped in the shower to emulsify fatty substances on your skin and hair with purified water and formulated detergents. Perhaps you next adorned yourself in an array of pleasant-smelling pigmented gels, dyed polymeric fibers, synthetic footwear, and metal-alloy jewelry. After breakfast, you probably abraded your teeth with a colloidal dispersion of artificially flavored, dental-hardening agents, grabbed your laptop (an electronic device containing ultrathin, microetched semiconductor layers powered by a series of voltaic cells), collected some books (processed cellulose and plastic, electronically printed with lightand oxygen-resistant inks), hopped in your hydrocarbon-fueled, metal-vinyl-ceramic ve