There are many good sources of quantitative problems in chemistry, but conceptual problems are much harder to find. A few recent textbooks, such as the second edition of The Chemical World, by Moore, et. al., include some conceptual problems at the end of each chapter. Dan H. Barouch's 1997 book, Voyages in Conceptual Chemistry, contains 150 interesting conceptual problems for general and inorganic chemistry, but there is little more. Consequently, this new book from England should become a valuable resource for chemistry instructors who want to provide students with guided practice in conceptual thinking.

A Question of Chemistry contains five kinds of conceptual problems from all areas of chemistry. The problems are not organized by subdiscipline, reflecting the authors' opinion that such divisions are arbitrary and the fact that a number of the problems were difficult, or impossible, to neatly classify in this way. There is, however, sufficient diversity that every chemistry instructor should be able to find at least a few useful problems in each category.

The problems are designed to help students develop particular thinking and research skills. Chapter 2, for example, is entitled "Understanding an Argument". Each problem in this chapter presents a particular line of reasoning followed by a question about the argument, such as "Which one of the following is the best statement of the underlying assumption in the argument?" or "Which one of the following statements best represents the flaw in the argument?" Four or five possible statements are given, most of which are true but usually irrelevant to the analysis of the argument. In my own teaching I have found that most general chemistry students, and far too many students in upper-division courses, do not understand how to evaluate a scientific argument, so I am eager to use problems of this type in my courses to see whether they will help students improve. I suspect that these problems will work best in a cooperative-learning situation, but I may also use them in other ways.

Chapter 3 goes a step further and provides guided practice in constructing arguments. Here students are given three statements and asked to order them into a logical argument. Chapter 4, "Critical Reading", presents short reading passages followed by one or more questions. In some cases the questions have several suggested answers; in others they are more open ended. Chapter 5, "Making Judgments", contains questions that do not have a single right answer. These problems are designed to stimulate discussion of such matters as the best interpretation of a set of data, the precise meaning of a scientific term, or the best way to make a certain measurement. Chapter 6 contains problems that require students to go to the chemical literature for answers. A reference is given as part of each question, but students may have to consult additional papers cited in that article. The final chapter contains commentaries on the odd-numbered problems, which give both the preferred answer, where possible, and a discussion of the reasoning that the authors would use in answering the question.

A Question of Chemistry is a valuable addition to the chemical education literature, particularly the chapters on evaluating and constructing arguments, two essential thinking skills that are difficult to teach. The questions in these chapters should work well. The multiple-choice format provides students with enough structure to get started, though the problems are so well constructed that the correct answer is not obvious, stimulating students to think deeply. The problems in "Making Judgments" are also very interesting because they require students to make assumptions, interpret the meaning of terms, and make order-of-magnitude estimates.

There is an increasing awareness that chemistry teachers need a larger array of methods and materials to help students develop process skills. Not only will the problems in A Question of Chemistry be useful as written, they also provide models to help instructors construct even more problems of the same type.