Rate-determining slowest step


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Abigail Urbina 1K
Posts: 102
Joined: Thu Jul 27, 2017 3:01 am

Rate-determining slowest step

Postby Abigail Urbina 1K » Sun Mar 11, 2018 3:03 pm

When there are more than 1 elementary steps in a reaction mechanism, how do we determine which one is the slowest step?

Janet Nguyen 2H
Posts: 51
Joined: Fri Sep 29, 2017 7:05 am

Re: Rate-determining slowest step

Postby Janet Nguyen 2H » Sun Mar 11, 2018 3:20 pm

I think the problem will usually tell you which is slower on the side in parentheses or something. If not it will give you the experimental rate law and you can tell from which reactants are included in the rate law which step is the slow step

KayleeMcCord1F
Posts: 31
Joined: Fri Sep 29, 2017 7:05 am

Re: Rate-determining slowest step

Postby KayleeMcCord1F » Sun Mar 11, 2018 3:25 pm

I believe that the rates will be given along with the mechanism, and we can determine the slowest step from that.

RussellChin_3A
Posts: 42
Joined: Sat Jul 22, 2017 3:01 am

Re: Rate-determining slowest step

Postby RussellChin_3A » Sun Mar 11, 2018 9:58 pm

The slow step is usually given to you where there are different steps in a reaction mechanism. If not, the rate constant, k maybe given to you for you to identity the slow step. bottom line is, there is probably always going to be a way for you to determine the slow step of a reaction.

Annie Lieu-1H
Posts: 68
Joined: Fri Sep 29, 2017 7:04 am
Been upvoted: 1 time

Re: Rate-determining slowest step

Postby Annie Lieu-1H » Mon Mar 12, 2018 10:24 am

I believe that will always be given in the problem (whether explicitly states in directions, or derived from the rates given). Hope this helps :)

Ashley Garcia 2L
Posts: 33
Joined: Fri Sep 29, 2017 7:05 am

Re: Rate-determining slowest step

Postby Ashley Garcia 2L » Mon Mar 12, 2018 10:46 am

The rate determining step is the slowest step in the reaction mechanism. You can determine which of the elementary steps is the slow step by comparing their activation energies. The step with the largest activation energy is the rate determining/slow step because it requires the largest input of energy to overcome this energy barrier. If activation energies are not given, the slow step will be stated in the problem.


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