A New Way to Learn Chemistry

Chemistry: A Project of the American Chemical Society, by Jerry Bell et al., W. H. Freeman & Co., 2005, 820 pages plus appendices and index, suggested retail price $122.95 (ISBN 0-7167-3126-6)

Over the past decade, there have been important advances in chemical education, stimulated in part by the five-year chemistry curriculum reform projects funded by the National Science Foundation. The broad theme was the development of methods and materials to actively engage undergraduate students in learning--to move from classrooms where students passively receive information from a lecturer to classrooms where students construct a deep conceptual understanding of chemistry. The various innovations developed in projects like these have begun to change the teaching of chemistry in colleges and universities.

But chemistry education has always been largely textbook-driven, so those faculty interested in innovative approaches have had to rely on traditional textbooks that, until recently, have done little to reinforce the active approach to learning. After several years of development and field-testing, the GenChem Editorial-Writing Team assembled by the American Chemical Society has produced a new general chemistry textbook that is built on an active learning foundation. This is a bold effort to provide chemistry instructors with the foundation for an inquiry-based course that will engage students and provide them with a solid background in chemistry.            

What is different about this book? First, it is much shorter than the typical first-year text. Almost all general chemistry textbooks contain more than 1,000 pages; this one is 20% shorter. Second, rather than the usual 20 to 25 tightly focused chapters, "Chemistry" is organized into 11 discursive chapters, each of which develops a broad concept in detail. Third, and most important, this is not a book that you can read in bed without a pencil.

It is a teaching textbook, one filled with carefully posed queries that send the student to the lab to do a simple experiment, to a kit to build a three-dimensional model of a molecule, to a cooperative learning group to discuss a question, to various references to look up data, or to pencil and paper to solve a problem. These activities--"Investigate This," "Consider This," and "Check This"--are an integral part of the book; the subsequent discussion builds on what the students have learned. Also inserted at appropriate intervals within each chapter are sections entitled "Reflection" and "Projection" that review what has been learned and introduce the questions to be considered next. These sections show students how to read a book thoughtfully.

Beyond the superficial differences in form and the inclusion of active learning activities, "Chemistry" approaches the subject differently from any introductory book that I have ever seen. Rather than beginning with the usual boring chapter about the nature of chemistry and units, this book starts by looking at the unusual properties of water--a real scientific problem.

I liked the approach instantly because of my positive memories of high school chemistry. I remember my teacher, Harold Wik, turning on the faucet and dramatically asking the question, "What holds water together?" Since then, water and chemistry have been connected in my mind. By page 12, the students are drawing Lewis structures and constructing molecular models to try to understand water.

The first pages set the tone for the book: Engage students in a real problem, and use it to develop the fundamentals. By the end of Chapter 1, the students have learned about molecular structure, polarity, and hydrogen bonding and have seen the importance of hydrogen bonding in both nucleic acids and proteins. They have also learned about two bulk properties, density and heat capacity, and how they are affected by intermolecular forces. Any student who is not excited about chemistry at this point is just not paying attention.

One of the major challenges in teaching general chemistry is how to help students develop a conceptual understanding of the subject. Many students are algorithmic learners who learn problem-solving patterns and get through the course by using those memorized patterns to solve the numerical problems that are the core of most exams. "Chemistry" focuses on building students' chemical intuition before introducing the quantitative aspects.

Chapter 6, "Chemical Reactions," is a brilliant example. Beginning with a series of activities that investigate some of the important aspects of chemical reactions, students are guided through a sophisticated analysis of the effects of electronegativity, resonance, and charge delocalization on the strengths of Lewis and Brønsted acids and bases. With this understanding in hand, the text moves to coordination complexes as examples of Lewis acid-base reactions, and then to electrophiles and nucleophiles as illustrated by simple organic reactions as well as condensation polymerization. Formal charge is introduced as a way of evaluating charge separation.            

It is then natural to introduce oxidation numbers because formal charge and oxidation number represent the two different ways of assigning the bonding electrons in a Lewis structure to the individual atoms. The oxidation numbers are used to balance and analyze redox reactions, including some important biochemical examples.

By the end of this chapter, the students have learned a set of powerful conceptual tools to analyze and understand chemical reactions, tools they will continue to use throughout their study of the subject. Subsequent chapters introduce the equilibrium constant and the Nernst equation so that students learn how to perform the quantitative calculations that are an essential part of every general chemistry course.

Just picking up the book and looking at the chapter titles, one might ask, "What have they left out?" There is no chapter on the gas laws, for example. But overall, the answer is, "Very little." All the topics in a standard first-year course are discussed, but they are discussed in context. The ideal gas equation is introduced in Chapter 7 in the context of the difference between internal energy and enthalpy and pressure-volume work.

It is true that the usual one-page discussion of Graham's law of effusion has been left out, as have the individual historical gas-law relationships, Boyle's law and Charles's law. The writing team has made some difficult decisions to eliminate things that are part of the traditional general chemistry course, and instructors using this book may well find one of their favorite small topics left out. But the core material of any good course is all there.

Most general chemistry textbooks have some built-in flexibility in that the order in which chapters and sections are covered can often be changed without significant disruption of the flow. "Chemistry," however, is so tightly integrated that the instructor must use it in the way it is written. It is also a book that requires an active-learning, inquiry-based approach. It will not work unless the students do the exercises. In the large lecture sections that are standard in large universities, it will require planning and organization to use this book effectively, but it can be done.

To help teachers prepare, the editorial-writing team has prepared a "Faculty Resource and Organizational Guide" (http://bcs.whfreeman.com/acsgenchem). ACS is also offering workshops to acquaint faculty with both the content and pedagogy of the book and to offer suggestions on how to use it. Certainly, this book is easier to use in small classes, but creative, motivated instructors can overcome almost any physical constraint.

This is an interesting and innovative book that should be seriously considered by faculty and departments that want to improve their first-year courses. It is designed both to stimulate interest in chemistry and to improve student learning. After reading the book, I am convinced that it will succeed in both objectives, and the experiences of the faculty who field-tested the preliminary versions corroborate this conclusion. But it is not a panacea. Because of the diversity of institutions and courses, many different kinds of inquiry-based, active-learning curricula must be developed; other textbooks must be written.

The past decade has seen much progress, but a large fraction of chemistry students are still being taught through lectures in courses based on traditional textbooks. "Chemistry" provides an example of how chemistry should be taught. Our goal for the next decade should be to bring all chemistry courses up to the standard it sets.

Jeffrey Kovac is professor of chemistry at the University of Tennessee, Knoxville, where he has taught general chemistry, among other courses, since 1976. He is the author of "Writing across the Chemistry Curriculum: An Instructor's Handbook" (with Donna W. Sherwood) and "The Ethical Chemist: Professionalism and Ethics in Science," both published by Prentice Hall.