The Cover: Chemical Dynamics

Cover artist Betsy True has superimposed two graphics from our Viewpoints paper, Anatomy of Elementary Chemical Reactions, by Alexander and Zare (page 1105).

One is an atomic-scale diagram showing several types of collisions of a chlorine atom with a methane molecule, and the other is a color-coded contour plot for the potential-energy surface of a collinear, triatomic system. The level of detail at which collisions of atoms, molecules, and ions can be understood is phenomenal and has changed tremendously during the fifty-year period covered by Viewpoints. Alexander and Zare capture the excitement of these developments in their paper.

Computers in Chemical Education

This year ACS's George C. Pimentel Award in Chemical Education went to Stanley G. Smith of the University of Illinois. Smith's award address chronicled the development of computers as a tool for helping students learn chemistry. An article based on the address begins on page 1080*. It is a must-read paper for anyone interested in the subject.

Students will find that most of the instruments they encounter after graduation have computers built in. Viswanathan and Horowitz (page 1124), Smith, Thorne, and Nadler (page 1129), and Williams (page 1133) describe creative and useful laboratory applications of computers. Iannone (page 1188) describes how the Solver function of Excel can help students analyze data from the infrared spectrum of HCl. Bowen (page 1172) gives advice for those who would like to explore the many new opportunities offered by computer-based testing.

This month JCE Online+ is inaugurating a new feature, Mathcad in the Chemistry Curriculum, edited by Theresa Julia Zielinski.
The column's mission statement and abstracts of its first five peer-reviewed contributions begin on page 1189. Mathcad software enables teachers of mathematics-intensive courses to prepare interactive documents with which students can explore and develop models of chemical systems.

Judd's News from Online column (page 1073*) this month is aimed at those who would like to put course materials on the Web, and Wink's continuing series on the NSF Web site (page 1078*) details the primary information on science and engineering available there. In our book review section, Goldsmith (page 1091) describes Galactic Data Viewer, a freeware product that displays a wide range of data conveniently.

Chemical Kinetics

This issue contains a wealth of information about chemical kinetics in addition to our Viewpoints article. Arce, Betancourt, Rivera, and Pijem (page 1142*) have developed a simple kinetics experiment involving food coloring that allows introductory students to observe a color change at the same time they are collecting kinetic data with a spectrophotometer. The blue-bottle reaction, a fascinating illustration of kinetics at work, can be made even more interesting in a number of ways, some of which are contained in a letter and an author's reply on page 1067*. Enzyme kinetics and the meaning of K_m and V/K, an important topic in biochemistry, is addressed by Northrop beginning on page 1153.

Hodgson, Ngeh, Orbell, and Bigger (page 1150) describe a kinetics experiment in which students determine an activation energy from non-isothermal absorbance-time data. Another take on the Arrhenius equation begins on page 1186 where Carroll shows why typical kinetics studies are invariably in the region where rates increase rapidly with temperature. An experiment in which students use a dye laser to measure excited-state lifetimes of iodine vapor is described by Henderson, Tennis, and Ramsey beginning on page 1139. Drok, Ritchie, and Power (page 1145) have addressed students' lack of experience with heterogeneous reaction kinetics by developing an experiment based on a rotating-disk electrode.

Mathematical equations encountered in kinetics are often intractable, and therefore approximation methods are common. One of these, the quasi-steady-state approximation, is validated by Bond, Martincigh, Mika, Simoyi (page 1158) by comparing results with those obtained by numerical integration. Viossat and Ben-Aim deal with the same approximation, applying it to a reaction system of three components and deriving the conditions under which it is valid (page 1165). Those interested in the theory of unimolecular reactions will want to turn to the review of a new book on the subject on page 1098.

ACS Presidential Election

Each year the ACS elects a president. Both of the candidates in this year's election are members of the Division of Chemical Education, and we expect that their views on chemical education will be of interest to all readers. Daryle Busch's statement is on page 1070 and Glenn Crosby's is on page 1071.

* designates articles of special interest
to high school teachers.