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Differential method for the determination of the order of reaction and the rate constants
Author(s) -
Ross S. D.
Publication year - 1982
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550140510
Subject(s) - chemistry , reaction rate constant , order (exchange) , constant (computer programming) , first order , rate equation , thermodynamics , degree (music) , homogeneous , order of reaction , reaction rate , analytical chemistry (journal) , mathematical analysis , kinetics , mathematics , chromatography , physics , quantum mechanics , acoustics , economics , programming language , biochemistry , catalysis , finance , computer science
A method is proposed whereby the orders and rate constants for processes obeying the rate law − dA / dt = kA n may be determined. The method is illustrated in two ways. First, simulated data for processes of various orders are treated, and the treatment is shown to be capable of reproducing orders and rate constants to a high degree of accuracy. The factors affecting the accuracy with which n and k can be determined are considered. These are inaccuracy in the determination of concentration values, irregularity of the time intevals between concentration determinations, and the length of those time intervals. It is shown that if concentrations are determined at times that are close together, the effect of the other two factors is small, but if the time intervals are made longer, the errors due to the other two factors affect the calculated values of n and k much more seriously. Second, the method was applied to two homogeneous reactions, of which one was first‐order and one was second order, and three heterogeneous reactions, of which one was found by the original workers to be first order, one to be zero order, and one to vary between zero and first order, depending on the initial pressure. The present method gives results in agreement with these conclusions and reproduces the rate constants to within ±5% in all cases.