Chemical Education Today
Spreadsheet Applications in Chemistry Using Microsoft Excel Dermot Diamond and Venita C. A. Hanratty. Wiley Interscience: New York, 1997. ISBN 0-471-14087-2. Paper, $34.95. Microsoft Excel is a spreadsheet program now in its seventh version. Originally designed for use primarily as a statistical database program for the business world, Excel has been updated in recent years to include several features that appeal to the scientific community. Among these features are improved graphing, nonlinear curve fitting, and a visual programming language. Excel is commonly used by undergraduate chemistry students (primarily in the laboratory) because it is easy to learn and readily available in campus computer labs. Spreadsheet Applications in Chemistry using Microsoft Excel provides chemistry instructors with an introduction to Excel and its applications in chemistry. For those with little or no spreadsheet experience, the first two chapters provide basics Excel uses, including graphing, functions, and statistical analysis. Experienced users will also find suggestions on customizing Excel in the later chapters. This book comes with a 3.5-inch diskette containing example spreadsheets that are discussed within. One example file mentioned in the book was missing from my diskette. Physical chemistry is a major topic of interest in the book. The authors demonstrate how to graph relevant functions in introductory quantum chemistry. By varying parameters such as the principal and orbital quantum numbers, one can quickly visualize changes in the radial distribution function of a hydrogen electron. Molecular orbital wave functions and densities are also easily graphed, demonstrating the difference between bonding and antibonding orbitals. Other programs such as Mathematica and Mathcad are also well suited to graphing wave functions, but Excel can be used in the absence of such software. Other physical chemistry topics discussed are activity coefficients, kinetics (Arrhenius plots and rate constants), and complex equilibria. The authors stress the importance of observing graphically the result of changing variables in the associated equations. Chemists of all varieties will be interested in the chapters on processing experimental data. The reader learns how to import many types of data files into Excel and to fit peaks. The ability to introduce any user-defined equation
is a necessity when fitting nonlinear data. Examples are worked involving chromatographic peaks, fluorescence decay processes, ion-selective electrodes, UV-vis absorption kinetic data at multiple wavelengths, and enzyme kinetics. Software packages are available to fit experimental data in black-box fashion, but with Excel the user (i.e., the student) is required to thoroughly understand the fitting process in order to implement the equations. One of the great strengths of Excel is the user’s ability to customize an entire spreadsheet, including graphs, with the use of dialog boxes. A dialog box allows one to select parameters for a problem, click a button, and immediately view the results. No entering of formulas or graphing is needed. To construct a dialog box, one must understand Excel’s Visual Basic symbolic language. Curiously, Visual Basic is first introduced in Chapter 3, but a full discussion is left until the end of the book, Chapter 8. The reader is led through several examples (titration curves, electrochemical kinetics) in which lengthy graphing problems are presented in a dialog box consisting of the key experimental variables. Instead of programming the spreadsheet by hand for each set of data, the user simply changes the settings in the box, and the graphical results are instantly updated. I recently saw an excellent application of Visual Basic at the ACS Meeting in San Francisco, presented by Professor Kim Cohn of California State University at Bakersfield. Students input molecular data into a dialog box (created from Visual Basic), and the rotation–vibration spectrum of a diatomic molecule is automatically graphed. The reader is warned in advance, however, that the prescribed method of learning Visual Basic is by experimenting with existing Visual Basic files and viewing their results. This method of learning requires an immersion of oneself into Excel and Visual Basic. Readers looking for a quick and easy way to learn this programming language should look elsewhere. However, for those willing to put forth the effort, one can transform Excel into a valuable classroom implement. This book is aimed at several audiences. For those who want to learn how to use Excel for chemistry applications, it is highly recommended. Less attention is paid to advanced applications such as peak fitting and customizing Excel with macros and dialog boxes, but the interested Excel user wishing to get started in this area will be put on the right track. Jeffery A. Greathouse Department of Chemistry University of the Incarnate Word San Antonio, TX 78209
Vol. 74 No. 11 November 1997 • Journal of Chemical Education
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