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J. W. Hill, R. H. Petrucci, T. W. McCreary, & S. S. Perry General Chemistry, 4th edition.

Problem 13.34.

In the reaction, A products, with the initial concentration [A]0 = 1.512 M, [A] is found to be 1.496 M at t = 30 s. With the initial concentration [A]0 = 2.584 M, [A] is found to be 2.552 M at t = 1 min. What is the order of this reaction?






Answer:

First, find the rate of reaction in each experiment, being sure to be consistent in units. Then use the Method of Initial rates to find the order of reaction.

Experiment

[A]0 (M)

[A] (M) at t (s)

Rate (M s–1)

1

1.512

1.496 at 30 s

2

2.584

2.552 at 60 s

Since the rates are the same for both experiments, the reaction must be zero order. Mathematically:

, which can only be true for m = 0.