044-Chemistry-for-Engineering-Students-Larry-Brown-Tom-Holme-Edisi-2-2010.pdf

Chemistry for Engineering Students This page intentionally left blank Chemistry for Engineering Students SECOND EDIT...

Chemistry for Engineering Students This page intentionally left blank Chemistry for Engineering Students SECOND EDITION Lawrence S. Brown Texas A&M University Thomas A. Holme Iowa State University Australia Brazil Japan Korea Mexico Singapore Spain United Kingdom United States  Chemistry for Engineering Students, © 2011, 2006 Brooks/Cole, Cengage Learning Second Edition ALL RIGHTS RESERVED. No part of this work covered by the copyright herein Lawrence S. Brown, Thomas A. 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Inset graphene molecule: Jannik Meyer Compositor: Pre-Press PMG Printed in the United States of America 1 2 3 4 5 6 7 13 12 11 10 09 About the Authors Larry Brown is a Senior Lecturer and coordinator for the General Chemistry for Engineering Students course at Texas A&M University. He received his B.S. in 1981 from Rensselaer Polytechnic Institute, and his M.A. in 1983 and Ph.D. in 1986 from Princeton University. During his graduate studies, Larry spent a year working in what was then West Germany. He was a Postdoctoral Fellow at the University of Chicago from 1986 until 1988, at which time he began his faculty career at Texas A&M. Over the years, he has taught more than 10,000 general chemistry students, most of them engineering majors. Larry’s excellence in teaching has been recognized by awards from the Association of Former Students at Texas A&M at both the College of Science and University levels. A version of his class has been broadcast on KAMU-TV, College Station’s PBS affiliate. From 2001 to 2004, Larry served as a Program Officer for Education and Interdisciplinary Research in the Physics Division of the National Science Foundation. He also coordinates chemistry courses for Texas A&M’s engineering program in Doha, Qatar. When not teaching chemistry, he enjoys road bicycling and coaching his daughter Stephanie’s soccer team. Tom Holme is a Professor of Chemistry at Iowa State University and Director of the ACS Examinations Institute. He received his B.S. in 1983 from Loras College, and his Ph.D. in 1987 from Rice University. He began his teaching career as a Fulbright Scholar in Zambia, Africa and has also lived in Jerusalem, Israel and Suwon, South Korea. His research interests lie in computational chemistry, particularly as applied to understanding processes important for plant growth. He is also active chemical education research and has been involved with the general chemistry for engineers course at both Iowa State University and at the University of Wisconsin–Milwaukee where he was a member of the Chemistry and Biochemistry Department. He has received several grants from the National Science Foundation for work in assessment methods for chemistry, and the “Focus on Problem Solving” feature in this textbook grew out of one of these projects. He served as an Associate Editor on the encyclopedia “Chemistry Foundations and Applications.” In 1999 Tom won the ACS’s Helen Free Award for Public Outreach for his efforts doing chemical demonstrations on live television in the Milwaukee area. v  Brief Contents 1 Introduction to Chemistry 1 OPENING INSIGHT THEME: Aluminum 2 CLOSING INSIGHT THEME: Material Selection and Bicycle Frames 24 2 Atoms and Molecules 30 OPENING INSIGHT THEME: Polymers 31 CLOSING INSIGHT THEME: Polyethylene 56 3 Molecules, Moles, and Chemical Equations 64 OPENING INSIGHT THEME: Explosions 65 CLOSING INSIGHT THEME: Explosives and Green Chemistry 91 4 Stoichiometry 99 OPENING INSIGHT THEME: Gasoline and Other Fuels 100 CLOSING INSIGHT THEME: Alternative Fuels and Fuel Additives 117 5 Gases 125 OPENING INSIGHT THEME: Air Pollution 126 CLOSING INSIGHT THEME: Gas Sensors 148 6 The Periodic Table and Atomic Structure 158 OPENING INSIGHT THEME: Incandescent and Fluorescent Lights 159 CLOSING INSIGHT THEME: Modern Light Sources: LEDs and Lasers 192 7 Chemical Bonding and Molecular Structure 200 OPENING INSIGHT THEME: Materials for Biomedical Engineering 201 CLOSING INSIGHT THEME: Molecular Scale Engineering for Drug Delivery 234 8 Molecules and Materials 240 OPENING INSIGHT THEME: Carbon 241 CLOSING INSIGHT THEME: The Invention of New Materials 272 9 Energy and Chemistry 280 OPENING INSIGHT THEME: Energy Use and the World Economy 281 CLOSING INSIGHT THEME: Batteries 308 vi 10 Entropy and the Second Law of Thermodynamics 318 OPENING INSIGHT THEME: Recycling of Plastics 319 CLOSING INSIGHT THEME: The Economics of Recycling 335 11 Chemical Kinetics 347 OPENING INSIGHT THEME: Ozone Depletion 348 CLOSING INSIGHT THEME: Tropospheric Ozone 379 12 Chemical Equilibrium 391 OPENING INSIGHT THEME: Concrete Production and Weathering 392 CLOSING INSIGHT THEME: Borates and Boric Acid 427 13 Electrochemistry 436 OPENING INSIGHT THEME: Corrosion 437 CLOSING INSIGHT THEME: Corrosion Prevention 465 14 Nuclear Chemistry 474 OPENING INSIGHT THEME: Cosmic Rays and Carbon Dating 475 CLOSING INSIGHT THEME: Modern Medical Imaging Methods 498 Appendixes A International Table of Atomic Weights 507 B Physical Constants 509 C Electron Configurations of Atoms in the Ground State 510 D Specific Heats and Heat Capacities of Some Common Substances 511 E Selected Thermodynamic Data at 298.15 K 512 F Ionization Constants of Weak Acids at 25°C 518 G Ionization Constants of Weak Bases at 25°C 520 H Solubility Product Constants of Some Inorganic Compounds at 25°C 521 I Standard Reduction Potentials in Aqueous Solution at 25°C 523 J Answers to Check Your Understanding Exercises 526 K Answers to Odd-Numbered End-of-Chapter Exercises 529 Brief Contents vii  Contents Preface xix Student Introduction xxvii 1 Introduction to Chemistry 1 1.1 INSIGHT INTO Aluminum 2 1.2 The Study of Chemistry 4 The Macroscopic Perspective 4 The Microscopic or Particulate Perspective 6 Symbolic Representation 8 Courtesy of Zettl Research Group, Lawrence Berkeley National Laboratory, and the University of California 1.3 The Science of Chemistry: Observations and Models 9 Observations in Science 9 Interpreting Observations 10 Models in Science 11 1.4 Numbers and Measurements in Chemistry 12 Units 13 Numbers and Significant Figures 16 at Berkeley 1.5 Problem Solving in Chemistry and Engineering 18 Using Ratios 18 Ratios in Chemistry Calculations 19 Conceptual Chemistry Problems 21 Visualization in Chemistry 22 1.6 INSIGHT INTO Material Selection and Bicycle Frames 24 Focus on Problem Solving 25 Summary 26 Key Terms 26 Problems and Exercises 27 2 Atoms and Molecules 30 2.1 INSIGHT INTO Polymers 31 2.2 Atomic Structure and Mass 33 Fundamental Concepts of the Atom 33 Atomic Number and Mass Number 34 Isotopes 34 Atomic Symbols 35 Atomic Masses 36 2.3 Ions 38 Mathematical Description 38 Ions and Their Properties 39 viii  2.4 Compounds and Chemical Bonds 40 Chemical Formulas 40 Chemical Bonding 42 © Cengage Learning/Charles D. Winters 2.5 The Periodic Table 44 Periods and Groups 44 Metals, Nonmetals, and Metalloids 46 2.6 Inorganic and Organic Chemistry 47 Inorganic Chemistry—Main Groups and Transition Metals 48 Organic Chemistry 49 Functional Groups 52 2.7 Chemical Nomenclature 53 Binary Systems 53 Naming Covalent Compounds 53 Naming Ionic Compounds 54 2.8 INSIGHT INTO Polyethylene 56 Focus on Problem Solving 58 Summary 59 Key Terms 59 Problems and Exercises 60 3 Molecules, Moles, and Chemical Equations 64 3.1 INSIGHT INTO Explosions 65 3.2 Chemical Formulas and Equations 67 © Cengage Learning/Charles D. Winters Writing Chemical Equations 67 Balancing Chemical Equations 68 3.3 Aqueous Solutions and Net Ionic Equations 72 Solutions, Solvents, and Solutes 72 Chemical Equations for Aqueous Reactions 76 Acid–Base Reactions 78 3.4 Interpreting Equations and the Mole 81 Interpreting Chemical Equations 81 Avogadro’s Number and the Mole 82 Determining Molar Mass 83 3.5 Calculations Using Moles and Molar Masses 84 Elemental Analysis: Determining Empirical and Molecular Formulas 86 Molarity 88 Dilution 90 3.6 INSIGHT INTO Explosives and Green Chemistry 91 Focus on Problem Solving 92 Summary 93 Key Terms 93 Problems and Exercises 93 4 Stoichiometry 99 4.1 INSIGHT INTO Gasoline and Other Fuels 100 4.2 Fundamentals of Stoichiometry 103 Obtaining Ratios from a Balanced Chemical Equation 104 Contents ix  4.3 Limiting Reactants 108 4.4 Theoretical and Percentage Yields 113 4.5 Solution Stoichiometry 114 4.6 INSIGHT INTO Alternative Fuels and Fuel Additives 117 Focus on Problem Solving 118 Summary 119 Key Terms 119 Problems and Exercises 119 5 Gases 125 5.1 INSIGHT INTO Air Pollution 126 Properties of Gases 128 5.2 Pressure 129 Measuring Pressure 130 Units of Pressure 130 5.3 History and Application of the Gas Law 132 Units and the Ideal Gas Law 135 5.4 Partial Pressure 136 5.5 Stoichiometry of Reactions Involving Gases 139 STP Conditions 140 5.6 Kinetic–Molecular Theory and Ideal Versus Real Gases 141 Postulates of the Model 141 Real Gases and Limitations of the Kinetic Theory 145 Correcting the Ideal Gas Equation 146 5.7 INSIGHT INTO Gas Sensors 148 Capacitance Manometer 148 Thermocouple Gauge 149 Ionization Gauge 149 Mass Spectrometer 151 Focus on Problem Solving 151 Summary 152 Key Terms 152 Problems and Exercises 152 6 The Periodic Table and Atomic Structure 158 6.1 INSIGHT INTO Incandescent and Fluorescent Lights 159 6.2 The Electromagnetic Spectrum 161 The Wave Nature of Light 161 The Particulate Nature of Light 165 6.3 Atomic Spectra 169 The Bohr Atom 172 x Contents  6.4 The Quantum Mechanical Model of the Atom 173 Potential Energy and Orbitals 175 Quantum Numbers 176 Visualizing Orbitals 178 6.5 The Pauli Exclusion Principle and Electron Configurations 181 Orbital Energies and Electron Configurations 182 Hund’s Rule and the Aufbau Principle 183 6.6 The Periodic Table and Electron Configurations 185 6.7 Periodic Trends in Atomic Properties 187 Atomic Size 187 Ionization Energy 188 Electron Affinity 191 6.8 INSIGHT INTO Modern Light Sources: LEDs and Lasers 192 Focus on Problem Solving 194 Summary 194 Key Terms 195 Problems and Exercises 195 7 Chemical Bonding and Molecular Structure 200 7.1 INSIGHT INTO Materials for Biomedical Engineering 201 7.2 The Ionic Bond 202 Formation of Cations 202 Formation of Anions 204 7.3 The Covalent Bond 207 Chemical Bonds and Energy 207 Chemical Bonds and Reactions 209 Chemical Bonds and the Structure of Molecules 209 7.4 Electronegativity and Bond Polarity 211 Electronegativity 212 Bond Polarity 213 7.5 Keeping Track of Bonding: Lewis Structures 215 Resonance 220 7.6 Orbital Overlap and Chemical Bonding 221 7.7 Hybrid Orbitals 224 7.8 Shapes of Molecules 226 7.9 INSIGHT INTO Molecular Scale Engineering for Drug Delivery 234 Focus on Problem Solving 235 Summary 235 Key Terms 236 Problems and Exercises 236 Contents xi  8 Molecules and Materials 240 8.1 INSIGHT INTO Carbon 241 8.2 Condensed Phases—Solids 243 8.3 Bonding in Solids: Metals, Insulators, and Semiconductors 249 Models of Metallic Bonding 249 Band Theory and Conductivity 251 Semiconductors 252 8.4 Intermolecular Forces 256 Forces Between Molecules 256 Dispersion Forces 256 Dipole–Dipole Forces 258 Hydrogen Bonding 258 8.5 Condensed Phases—Liquids 261 Vapor Pressure 261 Boiling Point 263 Surface Tension 264 8.6 Polymers 265 Addition Polymers 266 Condensation Polymers 268 Copolymers 270 Physical Properties 271 Polymers and Additives 272 8.7 INSIGHT INTO The Invention of New Materials 272 Focus on Problem Solving 274 Summary 275 Key Terms 275 Problems and Exercises 275 9 Energy and Chemistry 280 9.1 INSIGHT INTO Energy Use and the World Economy 281 9.2 Defining Energy 284 Forms of Energy 284 Heat and Work 285 Energy Units 285 9.3 Energy Transformation and Conservation of Energy 286 Waste Energy 288 9.4 Heat Capacity and Calorimetry 289 Heat Capacity and Specific Heat 289 Calorimetry 293 9.5 Enthalpy 295 Defining Enthalpy 295 DH of Phase Changes 296 xii Contents  Vaporization and Electricity Production 298 Heat of Reaction 299 Bonds and Energy 299 Heats of Reaction for Some Specific Reactions 300 9.6 Hess’s Law and Heats of Reaction 301 Hess’s Law 301 Formation Reactions and Hess’s Law 303 9.7 Energy and Stoichiometry 305 Energy Density and Fuels 307 9.8 INSIGHT INTO Batteries 308 Focus on Problem Solving 310 Summary 311 Key Terms 312 Problems and Exercises 312 10 Entropy and the Second Law of Thermodynamics 318 10.1 INSIGHT INTO Recycling of Plastics 319 10.2 Spontaneity 320 Nature’s Arrow 320 Spontaneous Processes 321 Enthalpy and Spontaneity 321 10.3 Entropy 322 Probability and Spontaneous Change 322 Definition of Entropy 324 Judging Entropy Changes in Processes 324 10.4 The Second Law of Thermodynamics 326 The Second Law 326 Implications and Applications 326 10.5 The Third Law of Thermodynamics 327 10.6 Gibbs Free Energy 330 Free Energy and Spontaneous Change 330 Free Energy and Work 333 10.7 Free Energy and Chemical Reactions 333 Implications of DG° for a Reaction 335 10.8 INSIGHT INTO The Economics of Recycling 335 Focus on Problem Solving 338 Summary 339 Key Terms 339 Problems and Exercises 339 11 Chemical Kinetics 347 11.1 INSIGHT INTO Ozone Depletion 348 11.2 Rates of Chemical Reactions 350 Concept of Rate and Rates of Reaction 350 Contents xiii  Stoichiometry and Rate 351 Average Rate and Instantaneous Rate 352 11.3 Rate Laws and the Concentration Dependence of Rates 353 The Rate Law 354 Determination of the Rate Law 355 11.4 Integrated Rate Laws 358 Zero-Order Integrated Rate Law 359 First-Order Integrated Rate Law 360 Second-Order Integrated Rate Law 362 Half-Life 364 11.5 Temperature and Kinetics 366 Temperature Effects and Molecules That React 366 Arrhenius Behavior 368 11.6 Reaction Mechanisms 373 Elementary Steps and Reaction Mechanisms 374 Mechanisms and Rate: The Rate-Determining Step 376 11.7 Catalysis 376 Homogeneous and Heterogeneous Catalysts 377 Molecular Perspective of Catalysis 377 Thomas A. Holme Catalysis and Process Engineering 379 11.8 INSIGHT INTO Tropospheric Ozone 379 Focus on Problem Solving 381 Summary 381 Key Terms 382 Problems and Exercises 382 12 Chemical Equilibrium 391 12.1 INSIGHT INTO Concrete Production and Weathering 392 12.2 Chemical Equilibrium 394 Forward and Reverse Reactions 394 Mathematical Relationships 397 12.3 Equilibrium Constants 398 The Equilibrium (Mass Action) Expression 398 Gas Phase Equilibria: Kp vs. Kc 399 Homogeneous and Heterogeneous Equilibria 400 Numerical Importance of the Equilibrium Expression 401 Mathematical Manipulation of Equilibrium Constants 402 Reversing the Chemical Equation 402 Adjusting the Stoichiometry of the Chemical Reaction 403 Equilibrium Constants for a Series of Reactions 404 Units and the Equilibrium Constant 405 12.4 Equilibrium Concentrations 405 © Cengage Learning/Charles D. Winters Equilibrium Concentrations from Initial Concentrations 406 Mathematical Techniques for Equilibrium Calculations 409 12.5 LeChatelier’s Principle 410 Effect of a Change in Concentration of Reactant or Product on Equilibrium 410 Effect of a Change in Pressure on Equilibrium When Gases Are Present 412 xiv Contents  Effect of a Change in Temperature on Equilibrium 414 Effect of a Catalyst on Equilibrium 415 12.6 Solubility Equilibria 415 Solubility Product Constant 415 Defining the Solubility Product Constant 416 The Relationship Between Ksp and Molar Solubility 416 Common Ion Effect 418 Reliability of Using Molar Concentrations 419 12.7 Acids and Bases 419 The Brønsted–Lowry Theory of Acids and Bases 420 The Role of Water in the Brønsted–Lowry Theory 420 Weak Acids and Bases 421 12.8 Free Energy and Chemical Equilibrium 425 Graphical Perspective 425 Free Energy and Nonstandard Conditions 426 12.9 INSIGHT INTO Borates and Boric Acid 427 Focus on Problem Solving 428 Summary 429 Key Terms 429 Problems and Exercises 429 13 Electrochemistry 436 13.1 INSIGHT INTO Corrosion 437 13.2 Oxidation–Reduction Reactions and Galvanic Cells 438 Oxidation–Reduction and Half-Reactions 438 Building a Galvanic Cell 440 Terminology for Galvanic Cells 441 Atomic Perspective on Galvanic Cells 441 Galvanic Corrosion and Uniform Corrosion 442 13.3 Cell Potentials 444 Thomas A. Holme Measuring Cell Potential 444 Standard Reduction Potentials 445 Nonstandard Conditions 449 13.4 Cell Potentials and Equilibrium 450 Cell Potentials and Free Energy 450 Equilibrium Constants 452 13.5 Batteries 453 Primary Cells 453 Secondary Cells 455 Fuel Cells 457 Limitations of Batteries 457 13.6 Electrolysis 458 Electrolysis and Polarity 458 Passive Electrolysis in Refining Aluminum 458 Active Electrolysis and Electroplating 460 13.7 Electrolysis and Stoichiometry 461 Current and Charge 461 Calculations Using Masses of Substances in Electrolysis 463 Contents xv  13.8 INSIGHT INTO Corrosion Prevention 465 Coatings 465 Cathodic Protection 466 Preventing Corrosion in Space 466 Focus on Problem Solving 467 Summary 467 Key Terms 467 Problems and Exercises 468 14 Nuclear Chemistry 474 14.1 INSIGHT INTO Cosmic Rays and Carbon Dating 475 14.2 Radioactivity and Nuclear Reactions 476 Radioactive Decay 476 Alpha Decay 477 Beta Decay 478 Gamma Decay 479 Electron Capture 479 Positron Emission 480 14.3 Kinetics of Radioactive Decay 481 Radiocarbon Dating 483 14.4 Nuclear Stability 485 14.5 Energetics of Nuclear Reactions 487 Binding Energy 487 Magic Numbers and Nuclear Shells 488 14.6 Transmutation, Fission, and Fusion 489 Transmutation: Changing One Nucleus into Another 489 Fission 490 Nuclear Reactors 492 Lawrence S. Brown Nuclear Waste 493 Fusion 494 14.7 The Interaction of Radiation and Matter 495 Ionizing and Penetrating Power of Radiation 495 Methods of Detecting Radiation 497 Measuring Radiation Dose 498 14.8 INSIGHT INTO Modern Medical Imaging Methods 498 Focus on Problem Solving 500 Summary 500 Key Terms 501 Problems and Exercises 501 Appendixes A International Table of Atomic Weights 507 B Physical Constants 509 C Electron Configurations of Atoms in the Ground State 510 D Specific Heats and Heat Capacities of Some Common Substances 511 xvi Contents E Selected Thermodynamic Data at 298.15 K 512 F Ionization Constants of Weak Acids at 25°C 518 G Ionization Constants of Weak Bases at 25°C 520 H Solubility Product Constants of Some Inorganic Compounds at 25°C 521 I Standard Reduction Potentials in Aqueous Solution at 25°C 523 J Answers to Check Your Understanding Exercises 526 K Answers to Odd-Numbered End-of-Chapter Exercises 529 Glossary 553 Index 565 Contents xvii This page intentionally left blank Preface The Genesis of This Text As chemists, we see connections between our subject and virtually everything. So the idea that engineering students should learn chemistry strikes most chemists as self- evident. But chemistry is only one of many sciences with which a practicing engineer must be familiar, and the undergraduate curriculum must find room for many top- ics. Hence, engineering curricula at more and more universities are shifting from the traditional year long general chemistry sequence to a single semester. And in most cases, these schools are offering a separate one-term course designed specifically for their engineering students. When schools—including our own—originally began offering these courses, there was no text on the market for them, so content from two- semester texts had to be heavily modified to fit the course. Although it is possible to do this, it is far from ideal. It became apparent that a book specifically geared for this shorter course was necessary. We have written this book to fill this need. Our goal is to instill an appreciation for the role of chemistry in many areas of en- gineering and technology and of the interplay between chemistry and engineering in a variety of modern technologies. For most engineering students, the chemistry course is primarily a prerequisite for courses involving materials properties. These courses usually take a phenomenological approach to materials rather than emphasizing the chemist’s molecular perspective. Thus one aim of this text is to provide knowledge of and appre- ciation for the chemical principles of structure and bonding that underpin materials sci- ence. This does not mean that we have written the book as a materials science text, but rather that the text is intended to prepare students for subsequent study in that area. The book also provides sufficient background in the science of chemistry for a technically educated professional. Engineering, after all, is the creative and practical application of a broad array of scientific principles, so its practitioners should have a broad base in the natural sciences. Content and Organization The full scope of the traditional general chemistry course cannot be taught meaning- fully in one semester or one or two quarters, so we have had to decide what content to include. There are basically two models used to condense the general chemistry cur- riculum. The first is to take the approach of an “essentials” book and reduce the depth of coverage and the number of examples but retain nearly all of the traditional topics. The second is to make more difficult and fundamental decisions as to what chemistry topics are proper and relevant to the audience, in this case future engineers. We chose the latter approach and built a 14-chapter book from the ground up to satisfy what we think are the goals of the course: Provide a concise but thorough introduction to the science of chemistry. Give students a firm foundation in the principles of structure and bonding as a foundation for further study of materials science. Show the connection between molecular behavior and observable physical properties. Show the connections between chemistry and the other subjects studied by engi- neering students, especially mathematics and physics. xix  Taken together, the 14 chapters in this book probably represent somewhat more ma- terial than can comfortably fit into a standard semester course. Thus departments or individual instructors will need to make some further choices as to the content that is most suitable for their own students. We suspect that many instructors will not choose to include all of the material on equilibrium in Chapter 12, for example. Similarly, we have included more topics in Chapter 8, on condensed phases, than we expect most faculty will include in their courses. Topic Coverage The coverage of topics in this text reflects the fact that chemists con- stantly use multiple concepts to understand their field, often using more than one model simultaneously. Thus the study of chemistry Courtesy of the U.S. Department of Energy’s we present here can be viewed from multiple perspectives: macro- scopic, microscopic, and symbolic. The latter two perspectives are emphasized in Chapters 2 and 3 on atoms, molecules, and reactions. In Chapters 4 and 5, we establish more of the connection between microscopic and macroscopic in our treatment of stoichiometry and Ames Laboratory gases. We return to the microscopic perspective to cover more details of atomic structure and chemical bonding in Chapters 6 through 8. The energetic aspects of chemistry, including important macroscopic consequences, are considered in Chapters 9 and 10, and kinetics and equilibrium are treated in Chapters 11 and 12, respectively. Chapter 13 deals with electrochemistry and corrosion, an important chemistry application for many engi- neering disciplines. Finally, we conclude with a discussion of nuclear chemistry. Specific Content Coverage We know that there are specific topics in general chemistry that are vital to future engineers. We’ve chosen to treat them in the following ways. Organic Chemistry: Organic chemistry is important in many areas of engineering, particularly as related to the properties of polymers. Rather than using a single or- ganic chapter, we integrate our organic chemistry coverage over the entire text, fo- cusing on polymers. We introduce organic polymers in Section 2.1 and use polymers and their monomers in many examples in this chapter. Chapter 2 also contains a rich discussion of organic line structures and functional groups and ends with a section on the synthesis, structure, and properties of polyethylene. Chapter 4 opens and ends with discussions of fuels, a topic to which we return in Chapter 9. Chapter 8 contains more on carbon and polymers, and the recycling of polymers provides the context for consideration of the second law of thermodynamics in Chapter 10. Acid–Base Chemistry: Acid–base reactions represent another important area of chemistry with applications in engineering, and again we have integrated our cover- age into appropriate areas of the text. Initially, we define acids and bases in conjunc- tion with the introduction to solutions in Chapter 3. Simple solution stoichiometry is presented in Chapter 4. Finally, a more detailed treatment of acid-base chemistry is presented in the context of equilibria in Chapter 12. Nuclear Chemistry: A chapter dealing with nuclear chemistry, previously available as a custom option, has been added to the standard book for this edition. Coverage in this chapter includes fundamentals of nuclear reactions, nuclear stability and radioac- tivity, decay kinetics, and the energetic consequences of nuclear processes. Mathematics: The math skills of students entering engineering majors generally are stronger than those in the student body at large, and most of the students taking a course of the type for which this book is intended will be concurrently enrolled in xx Preface an introductory calculus course. In light of this, we include references to the role of calculus where appropriate via our MathConnections boxes. These essays expand and review math concepts as they pertain to the particular topic being studied, and appear wherever the links between the topic at hand and mathematics seems espe- cially strong. These boxes are intended to be unobtrusive, so those students taking a precalculus math course will not be adversely affected. The point of including calculus is not to raise the level of material being presented, but rather to show the natural connections between the various subjects students are studying. Connections between Chemistry and Engineering Because this book is intended for courses designed for engineering majors, we strive to present chemistry in contexts that we feel will appeal to the interests of such students. Links between chemistry and engineering are central to the structure of the text. Each chapter begins and ends with a section called INSIGHT INTO... , which introduces a template or theme showing the interplay between chemistry and engineering. These sections are only the beginning Lawrence S. Brown of the connections, and the theme introduced in the initial Insight appears regularly throughout that chapter. We opt for currency in our engineering applications wherever possible, so throughout the book, we discuss recent key innova- tions in various fields. For example, Chapter 1 contains a brief discussion of OLEDs (organic light-emitting diodes), a new advance that appears likely to replace the liquid crystal screen in devices such as digital cameras and flat-panel computer monitors. OLEDs are revisited later in Chapter 6. In Chapter 2, we discuss the new polymer UHMWPE (ultra-high molecular weight polyethylene), which is stronger and lighter than Kevlar™ and is replacing Kevlar as filling in bulletproof vests. In Chapter 7, we describe mesoporous silicon nanoparticles, a front-line research topic that may have important applications in biomedical engineering in the future. Approach to Problem Solving Problem solving is a key part of college chemistry courses and is especially important as a broadly transferable skill for engineering students. Accordingly, this text includes worked problems throughout. All of our Example Problems include a Strategy section immediately following the problem statement, in which we emphasize the concepts and relationships that must be considered to work the problem. After the solution, we often include a section called Analyze Your Answer that is designed to help students learn to estimate whether or not the answer they have obtained is reasonable. In many examples, we also include Discussion sections that help explain the importance of a problem solving concept or point out common pitfalls to be avoided. Finally, each ex- ample closes with a Check Your Understanding problem or question to help the student to generalize or extend what’s been learned in the example problem. We believe that the general chemistry experience should help engineering stu- dents develop improved problem solving skills. Moreover, we feel that those skills should be transferable to other subjects in the engineering curriculum even though chemistry content may not be involved. Accordingly, we include a unique feature at the end of each chapter called FOCUS ON PROBLEM SOLVING. In these sections, the questions posed do not require a numerical answer, but rather ask the student to identify the strategy or reasoning to be used in the problem and often require them to Preface xxi  identify missing information for the problem. In most cases, it is not possible to arrive at a final numerical answer using the information provided, so students are forced to focus on developing a solution rather than just identifying and executing an algorithm. The end-of-chapter exercises include additional problems of this nature so the Focus on Problem Solving can be fully incorporated into the course. This feature grew out of an NSF-funded project on assessing problem solving in chemistry classes. Text Features We employ a number of features, some of which we referred to earlier, to help stu- dents see the utility of chemistry and understand the connections to engineering. INSIGHT INTO Sections Each chapter is built around a template called Insights Into.... These themes, which both open and close each chapter, have been chosen to showcase connections between engineering and chemistry. In addition to the chapter opening and closing sections, the template themes are woven throughout the chapter, frequently providing the context for points of discussion or example problems. This special Insight icon is used throughout the book to identify places where ideas pre- sented in the chapter opening section are revisited in the narrative. FOCUS ON PROBLEM SOLVING Sections Engineering faculties unanimously say that freshman engineering students need practice in solving problems. However, it is important to make a distinction here between problems and exercises. Exercises provide a chance to practice a narrow skill, whereas problems require multiple steps and thinking outside the context of the information given. Focus on Problem Solving offers students the chance to develop and practice true problem solving skills. These sections, which appear at the end of every chapter, include a mix of quantitative and qualitative questions that focus on the process of finding a solution to a problem, not the solution itself. We support these by including additional similar problems in the end-of-chapter material. MathConnections In our experience, one trait that distinguishes engineering stu- dents from other general chemistry students is a higher level of comfort with math- ematics. Typically most students who take a class of the sort for which this book has been written will also be taking a course in calculus. Thus it seems natural to us to point out the mathematical underpinnings of several of the chemistry concepts pre- sented in the text because this should help students forge mental connections between their courses. At the same time, we recognize that a student taking a precalculus math course should not be precluded from taking chemistry. To balance these concerns, we have placed any advanced mathematics into special MathConnections sections, which are set off from the body of the text. Our hope is that those students familiar with the mathematics involved will benefit from seeing the origin of things such as integrated rate laws, whereas those students with a less extensive background in math will still be able to read the text and master the chemistry presented. Example Problems Our examples are designed to illustrate good problem solving practices by first focusing on the reasoning behind the solution before moving into any needed calculations. We emphasize this “think first” approach by beginning with a Strategy section, which outlines a plan of attack for the problem. We find that many students are too quick to accept whatever answer their calculator might display. To combat this, we follow most solutions with an Analyze Your Answer section, which uses estimation and other strategies to walk students through a double check of their an- swers. Every example closes with a Check Your Understanding exercise to allow students to practice or extend the skill they have just learned. Answers to these additional exer- cises are included in Appendix J at the end of the book. End-of-Chapter Features Each chapter concludes with a chapter summary, outlin- ing the main points of the chapter, and a list of key terms, each of which includes the xxii Preface section number where the term first appeared. Definitions for all key terms appear in the Glossary. Problem Sets Each chapter includes roughly 100 problems and exercises, spanning a wide range of difficulty. Most of these exercises are identified with specific sec- tions to provide the practice that students need to master material from that section. Each chapter also includes a number of Additional Problems, which are not tied to any particular section and which may incorporate ideas from multiple sections. Focus on Problem Solving exercises follow, as described earlier. The problems for most chapters conclude with Cumulative Problems, which ask students to synthesize information from the current chapter with what they’ve learned from previous chapters to form answers. Answers for all odd-numbered problems appear at the end of the book in Appendix K. Margin Notes Margin notes in the text point out additional facts, further emphasize points, or point to related discussion either earlier or later in the book. New in this Edition There are several key changes in this second edition of the textbook. In addition to being able to catch and fix minor errors from the first edition, we were also able to find out which of the “Insight Into...” sections were the least successful at engag- ing student interest for that subject. Thus, we have introduced two new topics for the chapter-opening insights: Materials for Biomedical Engineering in Chapter 7 and Concrete Production and Weathering in Chapter 12. Both of these themes are more readily connected to engineering applications than those that they replaced from the first edition. The closing insight sections for Chapters 3 & 7 have also been rewritten to highlight topics with more current relevance. Because we realize that some instructors wish to include the topic in their courses, this edition includes a final chapter dealing with nuclear chemistry. We have also made significant changes to the end of chapter problems throughout the book. Approximately 25% of the problems in this edition are new, with most of the changes focused on two objectives. First, the new edition is integrated with the OWL electronic homework system, and a sizable majority of the new problems are available in OWL. This will make it significantly easier for instructors who would like to use OWL in their classes to achieve a strong correlation between problem assignments and the text. Second, we have worked to add a number of new problems that have a strong engineering focus. This addition is designed to provide more emphasis on the connections between the chemistry topics in this book and the engineering careers that the students who read it are pursuing. Many of these engineering problems are also available in OWL. Supplements for the Instructor Faculty Companion Website Accessible from www.cengage.com/chemistry/brown, this website provides WebCT and Blackboard versions of ExamView Computerized Testing. Instructor’s Resource CD-DVD Package ISBN-10: 1-439-04982-3 This collection of book-specific lecture and class tools is the fastest and easiest way to build powerful, customized, media-rich lectures. The CD includes chapter-specific PowerPoint Lecture presentations, a library of images from the text, the Instructor Solutions Manual, and sample chapters from the Student Solutions Manual and Study Guide. Also included are JoinIn™ questions for Response Systems, which let Preface xxiii  you transform your classroom and assess your students’ progress with instant in-class quizzes and polls. The Chemistry Multimedia Library DVD contains lecture-ready animations, simulations, and movies. ExamView® Computerized Testing CD-ROM ISBN-10: 0-538-73523-6 Featuring automatic grading, EXAMVIEW allows you to create, deliver, and custom- ize tests and study guides (both print and online) in minutes using the questions from the book’s test bank. See assessments onscreen exactly as they will print or display online. Build tests of up to 250 questions using up to 12 question types and enter an unlimited number of new questions or edit existing questions. Supplements for the Student Student Solutions Manual and Study Guide by Steve Rathbone of Blinn College ISBN-10: 1-439-04981-5 The STUDENT SOLUTIONS MANUAL AND STUDY GUIDE provides stu- dents with a comprehensive guide to working the solutions to the odd-numbered end-of-chapter problems in the text and also includes each chapter’s Study Goals and Chapter Objective quizzes. Because the best way for students to learn and un- derstand the concepts is to work multiple, relevant problems on a daily basis and to have reinforcement of important topics and concepts from the book, the STUDENT SOLUTIONS MANUAL gives students instant feedback by providing not only the answers to problems, but also detailed explanations of each problem’s solution. OWL for General Chemistry OWL Instant Access (1 Semester) ISBN-10: 0-495-05098-9 e-Book in OWL Instant Access (1 Semester) ISBN-10: 0-538-73313-6 Authored by Roberta Day and Beatrice Botch of the University of Massachusetts, Amherst, and William Vining of the State University of New York at Oneonta. OWL includes more assignable, gradable content (including end-of-chapter questions specific to this textbook), more reliability, and more flexibility than any other system. Developed by chemistry instructors for teaching chemistry, OWL makes homework management a breeze and has already helped hundreds of thousands of students master chemistry through tutorials, interactive simulations, and algorithmically generated homework questions that provide instant, answer-specific feedback. In addition, OWL users (instructors and students) experience service that goes far beyond the ordinary. OWL is continually enhanced with online learning tools to address the various learning styles of today’s students such as: e-Books, which offer a fully integrated electronic textbook correlated to OWL questions Go Chemistry® mini video lectures Quick Prep review courses that help students learn essential skills to succeed in General and Organic Chemistry Thinkwell Video Lessons that teach key concepts through video, audio, and white- board examples Jmol molecular visualization program for rotating molecules and measuring bond distances and angles Parameterized end-of-chapter questions designed specifically to match this text xxiv Preface Go Chemistry® for General Chemistry (27-module set) ISBN-10: 1-439-04700-6 GO CHEMISTRY® is a set of 27 exceptional mini video lectures on essential chem- istry topics that students can download to their video iPod, iPhone, or portable video player—ideal for the student on the go! Developed by award-winning chemists, these new electronic tools are designed to help students quickly review essential chemistry topics. Mini video lectures include animations and problems for a quick summary of key concepts. Selected modules include e-flashcards that briefly introduce key con- cepts and then test student understanding of the basics with a series of questions. GO CHEMISTRY also plays on QuickTime, iTunes, and Windows Media Player. For a complimentary look at the modules, visit www.cengage.com/go/chemistry where you can view and download two demo modules. Acknowledgments We are very excited to see this book move forward in this second edition, and we are grateful for the help and support we have enjoyed from a large and talented team of professionals. There are many people without whom we never could have done this. Foremost among them are our families, to whom this book is again dedicated. The origin of this text can be traced back many years, and a long list of people at Brooks/Cole played important roles. Jennifer Laugier first brought the two of us to- gether to work on a book for engineering students. Jay Campbell’s work as developmen- tal editor for the first edition was tremendous, and without his efforts the book might never have been published. When Jay became involved, the project had been languishing for some time, and the subsequent gains in momentum were clearly not coincidental. The editorial leadership team at that time, consisting of Michelle Julet, David Harris, and Lisa Lockwood, was also crucial in seeing this project come to fruition. The decision to launch a book in a market segment that has not really existed was clearly not an easy one, and we appreciate the confidence that everyone at Brooks/Cole placed in us. Like any modern business, the publishing industry seems to be one of constant change. Perhaps most obviously, our publisher is now known as Brooks/Cole Cengage Learning. And as we set out to work on this second edition, a number of changes had taken place in the Brooks/Cole team. Charlie Hartford and Lisa Lockwood supported us in the decision to go forward with this new edition and contributed valuable ideas leading to what we believe are substantial improvements. As our new developmental editor, Rebecca Heider has seen us through the entire revision process. When things were running behind schedule, she helped get us back on track. Lisa Weber has coor- dinated the integration of our text with the OWL homework system, this integration being one of the major undertakings of this revision. Teresa Trego managed the actual production process, and most of the production work was done by Pre-Press PMG under the leadership of Patrick Franzen. Within Pre-Press, a talented team of indi- viduals has handled all aspects of production, including copyediting, illustration, photo research, and page layout. Allen Apblett has again served as an accuracy checker during the page proof stage of production. Jon Olafsson has overseen revisions to ancillary materials. The book in your hands truly reflects the best efforts of many hard working professionals, and we are grateful to all of them for their roles in this project. In preparing the new material for this edition, we have also been helped by colleagues with expertise in specific areas. Conversations with Victor Lin and Klaus Schmidt-Rohr of Iowa State University led to the development of the new insight sections involving biomaterials and concrete. Sherry Yennello of Texas A&M University provided much needed advice and assistance with the nuclear chemistry chapter. It has been nearly four years since the first edition was published, and over that time we have received useful feedback from numerous students and colleagues. Much of that feedback was informal, including e-mail from students or faculty members Preface xxv  pointing out errors they have found or letting us know about sections they really liked. Although there is no way to list all of the people who have contributed in this way, we do sincerely thank you all. Faculty members from a wide variety of institutions also provided more formal comments on the text at various stages of its development. We thank the following reviewers for their contributions to the current revision. Paul A. DiMilla, Northeastern University Walter England, University of Wisconsin–Milwaukee Mary Hadley, Minnesota State University, Mankato Andy Jorgensen, University of Toledo Karen Knaus, University of Colorado–Denver Pamela Wolff, Carleton University Grigoriy Yablonsky, Saint Louis University We also thank the following reviewers for their contributions to the development of the first edition of the book. Robert Angelici, Iowa State University Allen Apblett, Oklahoma State University Jeffrey R. Appling, Clemson University Rosemary Bartoszek-Loza, The Ohio State University Danny Bedgood, Charles Sturt University James D. Carr, University of Nebraska Victoria Castells, University of Miami Paul Charlesworth, Michigan Technological University Richard Chung, San Jose State University Charles Cornett, University of Wisconsin—Platteville Robert Cozzens, George Mason University Ronald Evilia, University of New Orleans John Falconer, University of Colorado Sandra Greer, University of Maryland Benjamin S. Hsaio, State University of New York at Stony Brook Gerald Korenowski, Rensselaer Polytechnic Institute Yinfa Ma, University of Missouri—Rolla Gerald Ray Miller, University of Maryland Linda Mona, Montgomery College Michael Mueller, Rose-Hulman Institute of Technology Kristen Murphy, University of Wisconsin—Milwaukee Thomas J. Murphy, University of Maryland Richard Nafshun, Oregon State University Scott Oliver, State University of New York at Binghamton The late Robert Paine, Rochester Institute of Technology Steve Rathbone, Blinn College Jesse Reinstein, University of Wisconsin—Platteville Don Seo, Arizona State University Mike Shaw, Southern Illinois University—Edwardsville Joyce Solochek, Milwaukee School of Engineering Jack Tossell, University of Maryland Peter T Wolczanski, Cornell University Larry Brown Tom Holme October, 2009 xxvi Preface Student Introduction Chemistry and Engineering As you begin this chemistry course, odds are that you may be wondering “Why do I have to take chemistry anyway? I’ll never really need to know any of this to be an engi- neer.” So we’d like to begin by offering just a few examples of the many links between our chosen field of chemistry and the various branches of engineering. The most ob- vious examples, of course, might come from chemical engineering. Many chemical engineers are involved with the design or optimization of processes in the chemical industry, so it is clear that they would be dealing with concepts from chemistry on a daily basis. Similarly, civil or environmental engineers working on environmental pro- tection or remediation might spend a lot of time thinking about chemical reactions taking place in the water supply or the air. But what about other engineering fields? Much of modern electrical engineering relies on solid-state devices whose proper- ties can be tailored by carefully controlling their chemical compositions. And although most electrical engineers do not regularly make their own chips, an understanding of how those chips operate on an atomic scale is certainly helpful. As the push for ever smaller circuit components continues, the ties between chemistry and electrical en- gineering will grow tighter. From organic light-emitting diodes (OLEDs) to single molecule transistors, new developments will continue to move out of the chemistry lab and into working devices at an impressive pace. Some applications of chemistry in engineering are much less obvious. At 1483 feet, the Petronas Towers in Kuala Lumpur, Malaysia, were the tallest buildings in the world when they were completed in 1998. Steel was in short supply in Malaysia, so the towers’ architects decided to build the structures out of something the country had an abundance of and local engineers were familiar with: concrete. But the impressive height of the towers required exceptionally strong concrete. The engineers eventually settled on a material that has come to be known as high strength concrete, in which chemical reactions between silica fume and portland cement produce a stronger ma- terial, more resistant to compression. This example illustrates the relevance of chem- istry even to very traditional fields of engineering, and we will discuss some aspects of the chemistry of concrete in Chapter 12. About This Text Both of us have taught general chemistry for many years, and we are familiar with the difficulties that students may encounter with the subject. Perhaps more importantly, for the past several years, we’ve each been teaching engineering students in the type of one semester course for which this text is designed. The approach to subjects pre- sented in this text draws from both levels of experience. We’ve worked hard to make this text as readable and student friendly as possible. One feature that makes this book different from any other text you could have used for this course is that we incorporate connections between chemistry and engineer- ing as a fundamental component of each chapter. You will notice that each chapter begins and ends with a section called INSIGHT INTO.... These sections are only the beginning of the connections, and the theme introduced in the initial insight ap- pears regularly throughout that chapter. This special icon identifies material that is closely related to the theme of the chapter opening Insight section. We’ve heard many xxvii  students complain that they don’t see what chemistry has to do with their chosen fields, and we hope that this approach might help you to see some of the connections. Engineering students tend to take a fairly standard set of courses during their first year of college, so it’s likely that you might be taking calculus and physics courses along with chemistry. We’ve tried to point out places where strong connections be- tween these subjects exist, and at the same time to do this in a way that does not dis- advantage a student who might be taking a precalculus math class. Thus we may refer to similarities between equations you see here and those you might find in a physics text, but we do not presume that you are already familiar with those equations. In the case of math, we use special sections called MathConnections to discuss the use of math, and especially calculus, in chemistry. If you are familiar with calculus or are taking it concurrently with this class, these sections will help you to see how some of the equations used in chemistry emerge from calculus. But if you are not yet taking calculus, you can simply skip over these sections and still be able to work with the needed equations. Although our primary intent is to help you learn chemistry, we also believe that this text and the course for which you are using it can help you to develop a broad set of skills that you will use throughout your studies and your career. Foremost among them is problem solving. Much of the work done by practicing engineers can be characterized as solving problems. The problems you will confront in your chemistry class clearly will be different from those you will see in engineering, physics, or math. But taken together, all of these subjects will help you formulate a consistent approach that can be used to attack virtually any problem. Many of our students tend to “jump right in” and start writing equations when facing a problem. But it is usually a better idea to think about a plan of attack before doing that, especially if the problem is diffi- cult or unfamiliar. Thus all of our worked examples include a Strategy section in which we outline the path to a solution before starting to calculate anything. The Solution section then puts that strategy into action. For most numerical examples, we follow the solution with a section we call Analyze Your Answer, in which we use estimation or comparison to known values to confirm that our result makes sense. We’ve seen many students who believe that whatever their calculator shows must be the right answer, even when it should be easy to see that a mistake has been made. Many examples also include a Discussion section in which we might talk about common pitfalls that you should avoid or how the problem we’ve just done relates to other ideas we’ve already explored. Finally, each example problem closes with a Check Your Understanding ques- tion or problem, which gives you a chance to practice the skills illustrated in the ex- ample or to extend them slightly. Answers to these Check Your Understanding questions appear in Appendix J. While we are thinking about the example problems, a few words about rounding and significant figures are in order. In solving the example problems, we have used atomic weights with the full number of significant figures shown in the Periodic Table inside the back cover. We have also used as many significant figures as available for constants such as the speed of light or the universal gas constant. Where intermediate results are shown in the text, we have tried to write them with the appropriate number of significant figures. But when those same intermediate results are used in a subse- quent calculation, we have not rounded the values. Instead we retain the full calcula- tor result. Only the final answer has actually been rounded. If you follow this same procedure, you should be able to duplicate our answers. (The same process has been used to generate the answers to numerical problems appearing in Appendix K.) For problems that involve finding the slope or intercept of a line, the values shown have been obtained by linear regression using the algorithms built into either a spreadsheet or a graphing calculator. A unique feature of this text is the inclusion of a Focus on Problem Solving ques- tion at the end of each chapter. These questions are designed to force you to think about the process of solving the problem rather than just getting an answer. In many cases, these problems do not include sufficient information to allow you to reach a xxviii Student Introduction final solution. Although we know from experience that many beginning engineering students might find this frustrating, we feel it is a good approximation to the kind of problems that a working engineer might confront. Seldom would a client sit down and provide every piece of information that you need to solve the problem at hand. One of the most common questions we hear from students is “How should I study for chemistry?” Sadly, that question is most often asked after the student has done poorly on one or more exams. Because different people learn best in different ways, there isn’t a single magic formula to ensure that everyone does well in chem- istry. But there are some common strategies and practices that we can recommend. First and foremost, we suggest that you avoid getting behind in any of your classes. Learning takes time, and very few people can master three chapters of chemistry (or physics, or math, or engineering) the night before a big exam. Getting behind in one class inevitably leads to letting things slide in others, so you should strive to keep up from the outset. Most professors urge students to read the relevant textbook material before it is presented in class. We agree that this is the best approach, because even a general familiarity with the ideas being presented will help you to get a lot more out of your class time. In studying for exams, you should try to make a realistic assessment of what you do and don’t understand. Although it can be discomforting to focus on the problems that you don’t seem to be able to get right, spending more time studying things that you have already mastered will probably have less impact on your grade. Engineering students tend to focus much of their attention on numerical problems. Although such calculations are likely to be very important in your chemistry class, we also encourage you to try to master the chemical concepts behind them. Odds are that your professor will test you on qualitative or conceptual material, too. Finally, we note that this textbook is information rich. It includes many of the topics that normally appear in a full year college chemistry course, but it is designed for a course that takes only one semester. To manage the task of paring down the volume of materials, we’ve left out some topics and shortened the discussion of oth- ers. Having the Internet available means that you can always find more information if what you have read sparks your interest. We are excited that this book has made it into your hands. We hope you en- joy your semester of learning chemistry and that this book is a positive part of your experience. Larry Brown Tom Holme October, 2009 Student Introduction xxix This page intentionally left blank Introduction Chapter Titleto 2 1 Chemistry OUTLINE 1.1 INSIGHT INTO Aluminum 1.2 The Study of Chemistry 1.3 The Science of Chemistry: Observations and Models 1.4 Numbers and Measurements in Chemistry 1.5 Problem Solving in Chemistry and Engineering 1.6 INSIGHT INTO Material Selection and Bicycle Frames Scientists from Lawrence Berkeley National Laboratory and the University of California at Berkeley developed this nanoscale “conveyor belt.” Individual metal atoms are transported along a carbon nanotube from one metal droplet to another. This research offers a pos- sible means for the atomic scale construction of optical, electronic, and mechanical devices. Courtesy of Zettl Research Group, Lawrence Berkeley National Laboratory, and the University of California at Berkeley I n the not too distant future, engineers may design and assemble miniature mechanical or electronic devices, gears, and other parts fabricated on an atomic scale. Their decisions will be guided by knowledge of the sizes and properties of the atoms of different elements. Such devices might be built up atom by atom: each atom would be specified based on relevant design criteria and maneuvered into posi- tion using techniques such as the “conveyor belt” shown above. These nanomachines Nanoscience deals with objects whose will be held together not by screws or rivets but by the forces of attraction between sizes are similar to those of atoms the different atoms—by chemical bonds. Clearly, these futuristic engineers will need and molecules. Try a web search for “nanoscience” or “molecular machines” to understand atoms and the forces that bind them together. In other words, they will to learn more. need to understand chemistry. At least for now, though, this atomic level engineering remains in the future. But what about today’s practicing engineers? How do their decisions depend on knowl- Online homework for this Online chapterhomework for this may be assigned edge of chemistry? And from your own perspective as an engineering student, why are chapter may be assigned in OWL you required to take chemistry? in OWL. 1  The Accreditation Board for Engineering and Technology, or ABET, is a profes- sional organization that oversees engineering education. According to ABET’s defini- tion, “Engineering is the profession in which a knowledge of the mathematical and natural sciences gained by study, experience, and practice is applied with judgment to develop ways to utilize, economically, the materials and forces of nature for the ben- efit of mankind.” So as one of the sciences, chemistry is clearly included in the realm of knowledge at the disposal of an engineer. Yet engineering students do not always recognize the role of chemistry in their chosen profession. One of the main goals of this textbook is to instill an appreciation of the role of chemistry in many areas of engineering and technology and in the interplay between chemistry and engineering in a variety of modern technologies. The study of chemistry involves a vast number of concepts and skills. The phi- losophy of this book is to present those basic ideas and also to apply them to aspects of engineering where chemistry is important. Each chapter will begin with an exam- ple of chemistry related to engineering. Some of these examples, such as the burning of fuels, will involve fairly clear applications of chemical principles and reactions. In other cases, the role of chemistry may be less immediately apparent. In Chapter 6, we will consider how evolving knowledge of chemical properties has driven the design of different light sources, from the simple incandescent bulb through modern lasers and organic light emitting diodes (OLEDs). Other themes will involve the design and se- lection of materials for various uses and the importance of chemistry in environmen- tal engineering problems. All of these chapter-opening sections have titles that begin with “Insight into... ,” and the questions that are raised in them will guide our explo- ration of the relevant fundamentals of chemistry presented throughout that chapter. Our first case considers the production of aluminum and the history of aluminum as a structural material. Chapter Objectives After mastering this chapter, you should be able to ❚ describe how chemistry and engineering helped transform aluminum from a pre- cious metal into an inexpensive structural material. ❚ explain the usefulness of the macroscopic, microscopic, and symbolic perspectives in understanding chemical systems. ❚ draw pictures to illustrate simple chemical phenomena (like the differences among solids, liquids, and gases) on the molecular scale. ❚ explain the difference between inductive and deductive reasoning in your own words. ❚ use appropriate ratios to convert measurements from one unit to another. ❚ express the results of calculations using the correct number of significant figures. INSIGHT INTO 1.1 Aluminum If you are thirsty, you might ask yourself several questions about what to drink. But you probably wouldn’t ask, “Where did the can that holds this soda come from, and Each year, more than 100 billion why is it made of aluminum?” The aluminum can has become so common that it’s aluminum cans are produced in the easy to take for granted. What makes aluminum an attractive material for this type of United States. application, and how did it become such a familiar part of life? 2 Chapter 1 Introduction to Chemistry  You probably can identify a few properties of aluminum that make it suitable for use in a soda can. Compared with most other metals, aluminum is light but fairly strong. So a typical aluminum can is much lighter than a comparable tin or steel can. This means that the can does not add much weight compared to the soda itself, so the cans are easier to handle and cheaper to ship. A soda can made of lead certainly would be less convenient. The fact that aluminum does not readily undergo chemical reac- tions that might degrade it as the cans are transported and stored is also important. But although all of those features of the aluminum can are nice, they wouldn’t be of much practical use if aluminum were not readily available and reasonably inexpensive. The widespread availability of aluminum results from an impressive collaboration between the basic science of chemistry and the applied sciences of engineering. In the 19th century, aluminum was a rare and precious material. In Europe, Napoleon was emperor of a sizable portion of the continent, and he would impress guests by using extravagant aluminum tableware. In the United States, when architects wanted a suit- ably impressive material for the capstone at the top of the Washington Monument, a tribute to the “father of our country,” they chose aluminum. Weighing in at 100 ounces, the capstone of the monument was the largest single piece of pure aluminum ever cast at that time. Yet today, sheets of aluminum weighing more than 100 pounds are regularly found in many metal shops. Why was aluminum so expensive then, and what changed to make it so affordable now? Initial discussion of this question can be framed in terms of Figure 1.1, which looks rather broadly at the interactions of human society with the earth. Society, represented by the globe, has needs for goods and materials. Currently, and for the foreseeable future, the raw materials needed to make these goods must somehow be extracted from the earth. When the goods are used up, the leftovers become waste that must be disposed of, completing the cycle by returning the exhausted materials to the ecosys- tem. Ultimately, the role of engineering in this cycle is to maximize the efficiency with which materials are extracted and minimize the amount of waste that is returned. Figure 1.1 ❚ The interactions of human society with the earth can be thought of largely in terms of the conversion of matter from raw materials into waste. Much of engineering consists of efforts to optimize the processes used in these conversions. And as the science of matter, chemistry is an important element of the knowledge exploited in engineering those processes. Matter flows from the ecosphere into the human economy as raw materials. Human society Matter flows from the human economy Ecosphere into the ecosphere as waste. 1.1 Aluminum 3  Let’s think about aluminum in this context. Pure aluminum is never found in The aluminum in bauxite is typically nature. Instead, the metal occurs in an ore, called bauxite, that is composed of both found in one of three minerals: gibbsite, useless rock and aluminum in combination with oxygen. So before aluminum can be bohmite, and diaspore. used in our soda can, it must first be extracted or “won” from its ore and purified. Because aluminum combines very readily with oxygen, this presents some serious challenges. Some of these challenges are chemical and will be revisited in Chapt