Two Step Reactions

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Uisa_Manumaleuna_3E
Posts: 25
Joined: Wed Sep 21, 2016 2:56 pm

Two Step Reactions

Postby Uisa_Manumaleuna_3E » Wed Mar 15, 2017 6:19 pm

small question on finding out which step of a reaction is the rate determining step.

The rate determining step IS the slowest step. Does that mean that this step takes more energy to be carried out in comparison to the faster step?

Miya McLaughlin 2B
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Re: Two Step Reactions

Postby Miya McLaughlin 2B » Wed Mar 15, 2017 7:39 pm

Yes, it will take more energy for the slow step to be carried out compared the fast step because there is a higher energy barrier that the atoms must overcome. (ie higher activation energy)
A higher activation energy means not as many molecules will be able to get over the energy barrier as often. So higher activation energy will lead to a slower step, thereby making it the rate determining step.

vannahyazon 1L
Posts: 11
Joined: Wed Nov 18, 2015 3:00 am

Re: Two Step Reactions

Postby vannahyazon 1L » Thu Mar 16, 2017 9:50 am

Yes, the slow step takes more energy to be carried out than the fast step.

If you think about the 2 step free energy diagram that we did on Quiz 3, if k1 > k2 this means that the rate is faster for k1. If the rate is faster, the activation energy is lower (deltaGdoubledagger1). But k2 is slower, so the activation energy is higher (deltaGdoubledagger2).

Aliya Habib 1L
Posts: 20
Joined: Fri Sep 25, 2015 3:00 am

Re: Two Step Reactions

Postby Aliya Habib 1L » Fri Mar 17, 2017 7:44 pm

vannahyazon 1L wrote:Yes, the slow step takes more energy to be carried out than the fast step.

If you think about the 2 step free energy diagram that we did on Quiz 3, if k1 > k2 this means that the rate is faster for k1. If the rate is faster, the activation energy is lower (deltaGdoubledagger1). But k2 is slower, so the activation energy is higher (deltaGdoubledagger2).

Good explanation!
Can you explain how to write the rate law for the information given?


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