Molecularity
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Molecularity
Does the molecularity of the slow elementary step always match that of the overall rate law?
Or can differ when intermediates are involved in the reactant side of the slow step?
Or can differ when intermediates are involved in the reactant side of the slow step?
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Re: Molecularity
Hi! I believe that the molecularity of the slow elementary step will always exactly match the rate law, as both the molecularity and rate law are only concerned with the species that affect the reaction in any given step. Therefore, I'm pretty sure intermediates would be ignored in both. Hope this helps!
Re: Molecularity
The molecularity is the number of species in an elementary step (i.e. the number of collisions) which has to agree with the order of the rate law. (Lecture 24)
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Re: Molecularity
Hello,
The molecularity will match/agree with the rate law. The kinetic order of any elementary reaction or reaction step is equal to its molecularity. Molecularity refers to the number of particles that collide in a specific step.
The molecularity will match/agree with the rate law. The kinetic order of any elementary reaction or reaction step is equal to its molecularity. Molecularity refers to the number of particles that collide in a specific step.
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Re: Molecularity
The Molecularity will always match the overall rate law. Molecularity is the number of particles in the elementary step.
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Re: Molecularity
Hello!
Because the overall reaction is limited by the slow step, the molecularity of the slow step will match the overall rate law.
Because the overall reaction is limited by the slow step, the molecularity of the slow step will match the overall rate law.
Re: Molecularity
Yun Su Choi 3G wrote:Does the molecularity of the slow elementary step always match that of the overall rate law?
Or can differ when intermediates are involved in the reactant side of the slow step?
yes and no
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Re: Molecularity
hi yun,
molecularity will always be the same as the slowest step, and this is the limit of the molecularity that matches the overall rate law as stated in lecture.
molecularity will always be the same as the slowest step, and this is the limit of the molecularity that matches the overall rate law as stated in lecture.
Re: Molecularity
the Molecularity of a slow step reaction will always match the overall molecularity of the chemical reaction. This is because the slowest step is always the rate determining step of a reaction and the kinetics and the rate of the reaction will always depend on that.
Re: Molecularity
To clarify, the slow rate order will be the overall rate order of the reaction mechanism?
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Re: Molecularity
the molecularity of the slow step will always match the overall order of the reaction, because the slow step determines the order
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Re: Molecularity
I believe molecularity of a reaction would have to agree with the slowest step. Molecularity reflects the number of species (reactants) involved in an elementary step, so while I think it is possible that each step might have different molecularity, the rate determining step will have the same species that are in the overall rate - as the slow step is the rate-limiting step - so they should be the same.
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Re: Molecularity
the overall resulting order of the reaction will match the molecularity of the slow step because the slow step determines the order of the reaction. intermediates cannot directly contribute to the overall rate law but they do indirectly contribute because if your rate law has an intermediate, replace the intermediate in the rate law with the reactants that made up the intermediate (which was a product) in the previous reaction
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Re: Molecularity
the overall resulting order of the reaction will match the molecularity of the slow step because the slow step determines the order of the reaction. intermediates cannot directly contribute to the overall rate law but they do indirectly contribute because if your rate law has an intermediate, replace the intermediate in the rate law with the reactants that made up the intermediate (which was a product) in the previous reaction
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