Kinetics Homework Problem Set

This problem set was developed by S.E. Van Bramer for Chemistry 146 at Widener University.

  1. The following experimental data was collected for the reaction at 298 K.

    2. 2 N2O5 ---> 4 NO2 + O2
    1. What is the average rate of N2O5 loss and the average rate of the reaction between 1.0 and 1.1 seconds? Assume the reaction is zero order and calculate the rate constant (k) using this value. Assume the reaction is first order and calculate the rate constant (k) using this value. Assume the reaction is second order and calculate the rate constant (k) using this value.
    2. What is the average rate of N2O5 loss and the average rate of the reaction between 5.0 and 5.1 seconds? Assume the reaction is zero order and calculate the rate constant (k) using this value. Assume the reaction is first order and calculate the rate constant (k) using this value. Assume the reaction is second order and calculate the rate constant (k) using this value.
    3. Based upon the above calculations what is the reaction order?
    4. Graphic analysis of rate consnstant. Graph the data to check if it is zero order, first order, and second order. Using these graphs determine the rate constant (k).

      time
      (seconds)      		 [N2O5]
      (mole*liter-1)
      0.0 1.500 x 10-3
      1.0 9.340 x 10-4
      1.1 8.908 x 10-4
      2.0 5.816 x 10-4
      5.0 1.404 x 10-4
      5.1 1.339 x 10-4
      10.0 1.315 x 10-5
      20.0 1.152 x 10-7

  2. The above experiment is repeated at several temperatures to obtain the following experimental data. Based upon this experimental data, determine the activation energy for this reaction and the preexponential factor.

    T (C) rate constant (sec-1)
    0 9.16 x 10-3
    20 0.12919
    40 1.2993
    50 3.7017
    70 25.017

  3. Using the constants determined above If the initial concentration of N2O5 is 3.0 x 10-4 M:

    1. What is the concentration of NO2 and N2O5 after 5 seconds at 10 C?
    2. What is the concentration of NO2 and N2O5 after 5 seconds at 20 C?
Please send comments or suggestions to svanbram@science.widener.edu

Scott Van Bramer
Department of Chemistry
Widener University
Chester, PA 19013

© copyright 1996, S.E. Van Bramer
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Last Updated: Saturday, May 18, 1996