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Effect of Temperature on Chemical Equilibrium

  1. Feb 16, 2012 #1
    Hi guys I am a student of AP Chemistry. I am trying to understand the effect of temperature on equilibrium. I know that under the change of temperature, the equilibrium will shift to favor the endothermic process if heat is added and vice versa. But employing the Arrhenius Equation, I see a necessary concentration.

    Suppose that `⇌`(A, B);
    print(`output redirected...`); # input placeholder
    A ⇌ B
    According to the definition of rate laws,
    Rate*forward = k[A][A];
    Rate*reverse = k;

    k; is the rate constant
    [X]; is the respective concentration of substance X.


    Also, according to the Arrhenius Equation, for any reaction,
    k = A*exp(-E[a]/RT);where
    A; is a constant
    E[a]; is the activation energy
    R is the gas constant
    T is the temperature at which the reaction

    According to the definition of the equilibrium constant,

    K[c] = k[A]/k and k[A]/k = A[1]*exp(-E[a1]/RT)/(A[2]*exp(-E[a2]/RT)) and A[1]*exp(-E[a1]/RT)/(A[2]*exp(-E[a2]/RT)) = A[1]*exp(E[a2]-E[a1])/A[2];
    Therefore the K[c]; does not depend on T, which contradicts with Le Chatelier's Principle!
    How can I resolve this paradox, or what is the fault with my logic?

    Last edited: Feb 16, 2012
  2. jcsd
  3. Feb 16, 2012 #2


    User Avatar
    Homework Helper

    It's your maths, you are forgetting that eA/eB is eA-B not eA/B. :smile:
  4. Feb 16, 2012 #3
    What?? How were you able to read that?? I can't get LaTeX to work... I'm new to this sorry. I use Maple but don't know how to translate it to LaTeX.

    In any case, thank you SO MUCH FOR YOUR POST!!! IT FINALLY MAKES SENSE!


  5. Feb 17, 2012 #4


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    Staff: Mentor

    LatTeX here is used just for formulas, besides, what you wrote was not in LaTeX. See our LaTeX guide.
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