Chemistry: A Molecular Approach 5th Edition

Book Preface

To the Student As you begin this course, I invite you to think about your reasons for enrolling in it. Why are you taking general chemistry? More generally, why are you pursuing a college education? If you are like most college students taking general chemistry, part of your answer is probably that this course is required for your major and that you are pursuing a college education so you can get a good job some day. Although these are good reasons, I would like to suggest a better one. I think the primary reason for your education is to prepare you to live a good life. You should understand chemistry—not for what it can get you—but for what it can do to you. Understanding chemistry, I believe, is an important source of happiness and fulfillment. Let me explain. Understanding chemistry helps you to live life to its fullest for two basic reasons. The first is intrinsic: through an understanding of chemistry, you gain a powerful appreciation for just how rich and extraordinary the world really is. The second reason is extrinsic: understanding chemistry makes you a more informed citizen—it allows you to engage with many of the issues of our day. In other words, understanding chemistry makes you a deeper and richer person and makes your country and the world a better place to live. These reasons have been the foundation of education from the very beginnings of civilization. How does chemistry help prepare you for a rich life and conscientious citizenship? Let me explain with two examples. My first one comes from the very first page of Chapter 1 of this book. There, I ask the following question: What is the most important idea in all of scientific knowledge? My answer to that question is this: the behavior of matter is determined by the properties of molecules and atoms. That simple statement is the reason I love chemistry. We humans have been able to study the substances that compose the world around us and explain their behavior by reference to particles so small that they can hardly be imagined. If you have never realized the remarkable dependence of the world we can see on the world we cannot, you have missed out on a fundamental truth about our universe. To have never encountered this truth is like never having read a play by Shakespeare or seen a sculpture by Michelangelo—or, for that matter, like never having discovered that the world is round. It robs you of an amazing and unforgettable experience of the world and the human ability to understand it. My second example demonstrates how science literacy helps you to be a better citizen. Although I am largely sympathetic to the environmental movement, a lack of science literacy within some sectors of that movement and the resulting anti-environmental backlash create confusion that impedes real progress and opens the door to what could be misinformed policies. For example, I have heard conservative pundits say that volcanoes emit more carbon dioxide—the most significant greenhouse gas—than does petroleum combustion. I have also heard a liberal environmentalist say that we have to stop using hair spray because it is causing holes in the ozone layer that will lead to global warming. Well, the claim about volcanoes emitting more carbon dioxide than petroleum combustion can be refuted by the basic tools you will learn to use in Chapter 4 of this book. We can easily show that volcanoes emit only 1/50th as much carbon dioxide as petroleum combustion. As for hair spray depleting the ozone layer and thereby leading to global warming, the chlorofluorocarbons that deplete ozone have been banned from hair spray since 1978, and ozone depletion has nothing to do with global warming anyway. People with special interests or axes to grind can conveniently distort the truth before an ill-informed public, which is why we all need to be knowledgeable. So this is why I think you should take this course. Not just to satisfy the requirement for your major and not just to get a good job some day, but to help you to lead a fuller life and to make the world a little better for everyone. I wish you the best as you embark on the journey to understanding the world around you at the molecular level. The rewards are well worth the effort. To the Professor First and foremost, thanks to all of you who adopted this book in its previous editions. You helped to make this book one of the most popular general chemistry textbooks in the world. I am grateful beyond words. Second, I have listened carefully to your feedback on the previous edition. The changes you see in this edition are the direct result of your input, as well as my own experience using the book in my general chemistry courses. If you have reviewed content or have contacted me directly, you will likely see your suggestions reflected in the changes I have made. Thank you. Higher education in science is changing. Foremost among those changes is a shift toward active learning. A flood of recent studies has demonstrated that General Chemistry students learn better when they are active in the learning process. However, implementing active learning can be a difficult and time-consuming process. One of my main goals in this revision is to give you, the professor, a range of tools to easily implement active learning in your class. My goal is simple: I want to make it easy for you to engage your students in active learning before class, during class, and after class.

■ BEFORE CLASS Although the term active learning has been applied mainly to in-class learning, the main idea—that we learn better when we are actively engaged— applies to all of learning. I have developed two main tools to help students prepare for class in an active way. The first tool is a complete library of 3– to 6–minute Key Concept Videos (KCVs) that, with this edition, span virtually all of the key concepts in a general chemistry course. The videos introduce a key concept and encourage active learning because they stop in the middle and pose a question that must be answered before the video continues playing. Each video also has an associated follow-up question that can be assigned using Mastering Chemistry. You can assign a video before each one of your classes to get your students thinking about the concepts for that day. A second tool for use before class is active reading. Each chapter in the book now contains 10–12 Conceptual Connection questions. These questions are live in the ebook, assignable in Mastering Chemistry, and contain wrong answer feedback. Instead of passively reading the assigned material with no accountability, you can now encourage your students to engage in active reading, in which they read a bit and then answer a question that probes their comprehension and gives them immediate feedback.

■ DURING CLASS By delivering some content through key concept videos and active reading before class, you can make room in your lecture to pose questions to your students that make the class experience active as well. This book features two main tools for in-class use. The first tool is Learning Catalytics, which allows you to pose many different types of questions to your students during class. Instead of passively listening to your lecture, students interact with the concepts you present through questions you pose. Your students can answer the questions individually, or you can pair them with a partner or small group. A second tool for in-class use is the Questions for Group Work. These questions appear in the endof-chapter material and are specifically designed to be answered in small groups.

■ AFTER CLASS Active learning can continue after class with two additional tools. The first is another library of 3– to 6–minute videos called Interactive Worked Examples (IWEs). Each IWE video walks a student through the solution to a chemistry problem. Like the KCVs, the IWE video stops in the middle and poses a question that must be answered before the video continues playing. Each video also has an associated follow-up problem that can be assigned using Mastering Chemistry. The second tool for after (or outside of) class active learning is Active Exam Preparation. Research studies suggest that students who take a pretest before an exam do better on the exam, especially if the pretest contains immediate feedback. Each chapter in this book contains a Self-Assessment Quiz that you can use to easily make a pretest for any of your exams. The Self-Assessment Quizzes are live in the ebook, assignable in Mastering Chemistry, and contain wrong answer feedback. Simply choose the questions that you want from each of the quizzes that span the chapters on your exam, and you can create an assignable pretest that students can use to actively prepare for your exams. Although we have added many active learning tools to this edition and made other changes as well, the book’s goal remains the same: to present a rigorous and accessible treatment of general chemistry in the context of relevance. Teaching general chemistry would be much easier if all of our students had exactly the same level of preparation and ability. But alas, that is not the case. My own courses are populated with students with a range of backgrounds and abilities in chemistry. The challenge of successful teaching, in my opinion, is figuring out how to instruct and challenge the best students while not losing those with lesser backgrounds and abilities. My strategy has always been to set the bar relatively high, while at the same time providing the motivation and support necessary to reach the high bar. That is exactly the philosophy of this book. We do not have to compromise rigor in order to make chemistry accessible to our students. In this book, I have worked hard to combine rigor with accessibility—to create a book that does not dilute the content and yet can be used and understood by any student willing to put in the necessary effort. Chemistry: A Molecular Approach is first and foremost a student-oriented book. My main goal is to motivate students and get them to achieve at the highest possible level. As we all know, many students take general chemistry because it is a requirement; they do not see the connection between chemistry and their lives or their intended careers. Chemistry: A Molecular Approach strives to make those connections consistently and effectively. Unlike other books, which often teach chemistry as something that happens only in the laboratory or in industry, this book teaches chemistry in the context of relevance. It shows students why chemistry is important to them, to their future careers, and to their world. Second, Chemistry: A Molecular Approach is a pedagogically driven book. In seeking to develop problemsolving skills, a consistent approach (Sort, Strategize, Solve, and Check) is applied, usually in a two- or three-column format. In the two-column format, the left column shows the student how to analyze the problem and devise a solution strategy. It also lists the steps of the solution, explaining the rationale for each one, while the right column shows the implementation of each step. In the three-column format, the left column outlines the general procedure for solving an important category of problems that is then applied to two side-by-side examples. This strategy allows students to see both the general pattern and the slightly different ways in which the procedure may be applied in differing contexts. The aim is to help students understand both the concept of the problem (through the formulation of an explicit conceptual plan for each problem) and the solution to the problem.

Brief Contents

1 Matter, Measurement, and Problem Solving 1 2 Atoms and Elements 48 3 Molecules and Compounds 90 4 Chemical Reactions and Chemical Quantities 138 5 Introduction to Solutions and Aqueous Reactions 166 6 Gases 210 7 Thermochemistry 262 8 The Quantum-Mechanical Model of the Atom 310 9 Periodic Properties of the Elements 350 10 Chemical Bonding I: The Lewis Model 392 11 Chemical Bonding II: Molecular Shapes, Valence Bond Theory, and Molecular Orbital Theory 436 12 Liquids, Solids, and Intermolecular Forces 494 13 Solids and Modern Materials 540 14 Solutions 578 15 Chemical Kinetics 630 16 Chemical Equilibrium 682 17 Acids and Bases 730 18 Aqueous Ionic Equilibrium 786 19 Free Energy and Thermodynamics 846 20 Electrochemistry 896 21 Radioactivity and Nuclear Chemistry 946 22 Organic Chemistry 988 23 Biochemistry 1036 24 Chemistry of the Nonmetals 1070 25 Metals and Metallurgy 1108 26 Transition Metals and Coordination Compounds 1134
Appendix I Common Mathematical Operations in Chemistry A-1 Appendix II Useful Data A-5 Appendix III Answers to Selected Exercises A-15 Appendix IV Answers to In-Chapter Practice Problems A-53 Glossary G-1 Photo and Text Credits C-1 Index I-1