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 reaction rate between 1.0 and 1.1 seconds?
    2. What is the reaction rate between 20.0 and 20.1 seconds?
    3. Assume that the reaction is first order and calculate the rate constant (k) for each of these times.
    4. Assume that the reaction is second order and calculate the rate constant (k) for each of these times.
    5. Based upon the above calculations what is the reaction order?
    6. Assume that the reaction is first order. Graph the data to show if this assumption is correct and if so use the graph to determine the rate constant.
    7. Assume that the reaction is second order. Graph the data to show if this assumption is correct and if so use the graph to determine the rate constant.

      time
      (seconds)      		 [N2O5]
      (mole*liter-1)
      0.0 1.500 x 10-3
      1.0 1.1837 x 10-3
      1.1 1.1560 x 10-3
      10.0 1.4043 x 10-4
      20.0 1.3147 x 10-5
      20.1 1.2839x10-5
      40.0 1.1522 x 10-7
      100.0 7.7575 x 10-14

  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 after 5 seconds at 10 C?
    2. What is the concentration of N2O5 after 10 seconds at 10 C?
    3. What is the concentration of NO2 after 5 seconds at 20 C?
    4. What is the concentration of N2O5 after 10 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