Chemical Kinetics Query

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Discussion Overview

The discussion revolves around a query related to chemical kinetics, specifically the relationship between the fraction of activated molecules in a reaction and the probability factor in the Arrhenius Equation. The context includes theoretical aspects of first-order reactions and the calculation of half-life.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • Vivek questions whether the fraction of activated molecules (10^{-15}) corresponds to the probability factor (P) in the Arrhenius Equation.
  • One participant suggests that the fraction of activated molecules is actually represented by the exponential term in the Arrhenius Equation.
  • Another participant notes that A and P are related to collision rates and molecular geometries, indicating a more complex relationship.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between the fraction of activated molecules and the Arrhenius Equation, indicating that the discussion remains unresolved.

Contextual Notes

There is a lack of specific details regarding the problem that could clarify the assumptions involved, such as the exact constants provided and the context of the reaction.

Who May Find This Useful

Individuals interested in chemical kinetics, particularly those studying reaction rates and the Arrhenius Equation.

maverick280857
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HI

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
vivek
 
Last edited:
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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).
 
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).
 
Thanks Gokul, you were right about the exponential term.

Cheers
vivek
 

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