Rate Law: Write and Apply

Question

The reaction of ICl with hydrogen

2 ICl + H₂I₂ + 2 HCl

is first order in ICl and second order in H₂.

Complete the rate law for this reaction in the box below.

Use the form k[A]^m[B]ⁿ... , where '1' is understood for m, n ... (don't enter 1) and concentrations taken to the zero power do not appear.

Rate =

In an experiment to determine the rate law, the rate of the reaction was determined to be 1.06×10^-2 Ms^-1 when [ICl] = 9.70×10^-2 M and [H₂] = 0.215 M. From this experiment, the rate constant is_______ M^-2s^-1.

Answer 1

Rate = k[ICI]^m[H₂]ⁿ

Rate = k[ICI][H₂]²

To solve for k, the rate constant, set up the above equation and substitute the given values. Pay careful attention to units so that your answer for k has the correct units:

1.06x10^-2 Ms^-1 = k[9.70x10^-2 M][0.215 M]²

1.06x10^-2 Ms^-1 = 4.48x10^-3 M³ k

k = 2.37 M^-2s^-1