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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.
    [tex]

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


    where
    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?

    [/tex]
     
    Last edited: Feb 16, 2012
  2. jcsd
  3. Feb 16, 2012 #2

    epenguin

    User Avatar
    Homework Helper
    Gold Member



    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!

    Regards,

    BiP
     
  5. Feb 17, 2012 #4

    Borek

    User Avatar

    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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