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Chemical Kinetics Query

  1. Feb 21, 2005 #1

    While working on some chemical kinetics problems, I came across the statement, the fraction of activated molecules is [itex]10^{-15}[/itex] in a problem where some other constants were also provided and the half life was to be found (for a first order reaction). My specific query is:

    Is this fraction equal to the probability factor in the Arrhenius Equation? That is, is this equal to P where

    [tex]k = APe^{-E_{act}/RT}[/tex]

    where k = rate constant, A = frequency factor, P = probability factor, [itex]E_{act}[/itex] = activation energy and T = absolute temperature?

    Or is it something else?

    Thanks and cheers
    Last edited: Feb 21, 2005
  2. jcsd
  3. Feb 21, 2005 #2


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    It'll be better for you if you were to post the exact problem instead of having us guess around (not to sound rude).
  4. Feb 21, 2005 #3


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    The fraction of activated molecules is actually the exponential term.

    A and P are related to collision rates (T dependent) and molecular geometries (steric effects).
  5. Mar 1, 2005 #4
    Thanks Gokul, you were right about the exponential term.

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