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DON'T BE TRICKED BY YOUR INTEGRATED RATE PLOT!
Citation:
Urbansky*, E T. DON'T BE TRICKED BY YOUR INTEGRATED RATE PLOT! Moore, J.W. (ed.), JOURNAL OF CHEMICAL EDUCATION. American Chemical Society, Washington, DC, 78(7):921-923, (2001).
Description:
Reaction order can be determined from kinetic data in a variety of ways. Two methods commonly employed are comparison of initial rates (while varying reactant concentration) and plotting integrated rate expressions. Both of these are introduced in general and physical chemistry textbooks. However, the limitations of the integrated rate plot approach are generally not covered. For the integrated rate plot to be used to confirm first-order kinetics, at least 4-5 half-lives worth of data are required. Deviations from linearity between first- and second-order analyses of first-order data are not observed until the third half-life. Moreover, such deviation may be masked by indeterminate error. These points are demonstrated using simulated first-order kinetic data when conditions are idealized and when a randon error of up to +/- 10% is introduced into the concentation values.