## Unique Rate [ENDORSED]

$aR \to bP, Rate = -\frac{1}{a} \frac{d[R]}{dt} = \frac{1}{b}\frac{d[P]}{dt}$

104922499 1F
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Joined: Fri Sep 29, 2017 7:04 am

### Unique Rate

Can someone clarify what unique rate laws are? I did not understand what Lavelle said during class about this. Thanks!

Sabrina Dunbar 1I
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### Re: Unique Rate

The unique rate is the instantaneous rate of change at any time t during the reaction. Unlike the average rate, which takes into account all of the times at which the reaction proceeds and averages it, the instantaneous rate is specific to a time and therefore it generates a different k value. The general equation used for the unique rate can be written as rate=d[R]/dt while the average rate is rate=∆concentration/∆t. Unique rate laws are specific to each reaction and are confined to a specific time.

Alvin Tran 2E
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Joined: Fri Sep 29, 2017 7:06 am

### Re: Unique Rate

In addition, when you calculate the unique rate, it is the same for all the reactants and products involved in the reaction.

Angela G 2K
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### Re: Unique Rate  [ENDORSED]

For a reaction aA + bB -> cC + dD, where the lowercase letters are the stoichiometric coefficients and the uppercase letters are chemical species, the unique rate law is
$-\frac{1}{a}\frac{d[A]}{dt} = -\frac{1}{b}\frac{d[B]}{dt} = \frac{1}{c}\frac{d[C]}{dt} = \frac{1}{d}\frac{d[D]}{dt}$

This rate law is unique to the reaction and the same for all reactants and products in this reaction.

104922499 1F
Posts: 53
Joined: Fri Sep 29, 2017 7:04 am

### Re: Unique Rate

thanks!

Connie2I
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Joined: Fri Sep 29, 2017 7:07 am

### Re: Unique Rate

Is there a way to know when exactly we should be using unique rate?