## Distinguishing Different Types of Constants

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

Ava Harvey 2B
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Joined: Fri Sep 29, 2017 7:04 am

### Distinguishing Different Types of Constants

How can we distinguish between the different types of constants when using the pre-equilibrium approach? Because there's the equilibrium constant, K, the constant for the forward reaction, k, the constant for the reverse reaction, k', and the constant in the rate law. I'm not sure how to distinguish all of these when working through a reaction mechanism that has multiple steps, as the constants are all different values and could change the meaning of an answer. Also, just to clarify, is the constant for the forward reaction, k, the same value as the constant, k, that would be used in the rate law? Anything will help, thanks so much!

David Minasyan 1C
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Joined: Thu Jul 13, 2017 3:00 am

### Re: Distinguishing Different Types of Constants

As far as I know, yes the constant for the forward reaction, k, and the constant k used in the rate law are the same. And then for the others, the capital K is of course the concentration of products divided by concentration of reactants. And as you said, k' is the reverse rate law. So I guess the only to tell them apart is to look for capitalization, and an apostrophe.

Michelle Lu 1F
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Joined: Thu Jul 27, 2017 3:01 am
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### Re: Distinguishing Different Types of Constants

Hello, yes the k constant used for the forward reaction is the rate constant used in the forward reaction rate law. The way to differentiate this rate constant from k', the reverse rate constant, is the apostrophe. K on the other hand is the capital letter, which indicates that it is referring to the equilibrium constant which is the concentration of products over concentration of reactants, all put to their respective powers based on coefficients.

Angel R Morales Dis1G
Posts: 50
Joined: Sat Jul 22, 2017 3:01 am

### Re: Distinguishing Different Types of Constants

My T.A said that you can write small notations near the K's to distinguish them, for instance, the equilibrium constant can be written as K(eq) to help you distinguish from small k(fwd)/k(rev).
Also, if there are multiple steps, you can write a little 1 or 2 next to the k's to clear it up anymore.