## Rate Determining Step

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305113590
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### Rate Determining Step

How do we write a rate equation when there is a rate determining step along with several fast elementary steps?

Lexie Baughman 2C
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Joined: Sat Oct 06, 2018 12:16 am

### Re: Rate Determining Step

The rate-determining step is the slowest step in a reaction mechanism. Because it is the slowest, it determines the rate of the overall reaction. In a reaction with a slow initial step, the rate law will simply be determined by the stoichiometry of the reactants.

Michelle Nwufo 2G
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Joined: Fri May 18, 2018 3:00 am

### Re: Rate Determining Step

Lexie Baughman 2C wrote:The rate-determining step is the slowest step in a reaction mechanism. Because it is the slowest, it determines the rate of the overall reaction. In a reaction with a slow initial step, the rate law will simply be determined by the stoichiometry of the reactants.

How do you determine whether a step in a reaction mechanism is slow or not?

Anna O 2C
Posts: 98
Joined: Fri Sep 28, 2018 12:19 am

### Re: Rate Determining Step

A way that I think about the slow vs fast rates is with cooking. The entire length of the cooking session will be determined by the step that takes the longest and has the biggest overall effect on the time duration (example would be the baking in the oven compared to measuring the ingredients which takes seconds).

Lexie Baughman 2C
Posts: 30
Joined: Sat Oct 06, 2018 12:16 am

### Re: Rate Determining Step

As far as practice problems I've seen/done, they'll have to tell you the slow step in a mechanism, and depending whether the slow step involves an intermediate or not, you'll have to tailor your approach.

105169446
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### Re: Rate Determining Step

What happens if the slow step has an intermediate in it?

CristinaMorales1F
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Joined: Fri Feb 16, 2018 3:01 am

### Re: Rate Determining Step

can a slow step have an intermediate?

CristinaMorales1F
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Joined: Fri Feb 16, 2018 3:01 am

### Re: Rate Determining Step

How does a bottleneck work and how does this determine rate?

davidryan3f
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Joined: Fri Sep 28, 2018 12:23 am

### Re: Rate Determining Step

The slow step can't have intermediates. You substitute them using values in the other steps.

KHuang1L
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Joined: Fri Sep 28, 2018 12:19 am

### Re: Rate Determining Step

The rate law is determined by the rate determining step. If there are intermediates involved, then modify the rate law so that they are not included.

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