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Homework Help: Activation energy problem

  1. Feb 26, 2008 #1
    [SOLVED] Activation energy

    The reaction, 2NOCI (g) = 2NO (g) + Cl[tex]^{}_2{}[/tex](g) , has rate constant values for the reaction of NOCl of 9.3 x 10^-6 Is at 350 K and 6.9 x 10^-4 Is at 400 K. Calculate the activation energy for the reaction. What is the rate constant at 425 K?

    I am unsure how to solve this. Can someone help me and show me how to do it.
  2. jcsd
  3. Feb 26, 2008 #2
    SCREAMS arrhenius equation.
  4. Feb 26, 2008 #3
    Excuse me, why the rude behavior? This is suppose to be a help forum. It might be obvious to you, but I'm not sure if im using the equation right.
  5. Feb 27, 2008 #4
    The Arrhenius equation is ln(k) = ln(A) - E/(RT). You are given values of k at two different temperatures T. R is the gas constant, A and E are empirical constants, E being the activation energy. So just plug the corresponding values (k,T) into this equation to generate two equations in two unknowns. After you know A and E, use the equation to get k at any other T. Does this help?
  6. Feb 27, 2008 #5
    Yes thank you. I already figured this out on my own. That is exactly what I did. Ea=100,232, A=8.47x10^9, and with T=425 I got 4.06x10^-3 for k.

    I hope i did the math right but it looks right.
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