## Unique rate law

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

Mara Lockhart 3J
Posts: 53
Joined: Fri Sep 26, 2014 2:02 pm

### Unique rate law

In kinetics, what does a unique rate law mean?

Mara Lockhart 3J
Posts: 53
Joined: Fri Sep 26, 2014 2:02 pm

### Re: Unique rate law

I think I found the answer to my own question, but if anyone has additional comments, please add on!

To find the unique rate of a reaction, you take the rate (of any product or reactant) and divide by the stoichiometric coefficient of that chosen species. It does not matter what rate you choose, because there is only one average rate or unique rate of a reaction.

For example, if you have the rate of formation of H2O is 1.856 mol.L.s for the reaction H2 + 1/2O2 ----> H2O, the unique reaction rate would be (1.856mol.L.s)/(1) = 1.856 mol.L.s. So the unique retain rate is the average rate.

Neil DSilva 1L
Posts: 70
Joined: Fri Sep 26, 2014 2:02 pm

### Re: Unique rate law

You're referring to the unique average rate (not unique rate law), right? Other than that, everything else you said seems correct.

Mara Lockhart 3J
Posts: 53
Joined: Fri Sep 26, 2014 2:02 pm

### Re: Unique rate law

Whats the difference of the two? On question 14.5, the question just asked what is the unique rate of the reaction, so are they asking for the unique average rate or the unique rate law?

Kayla Denton 1A
Posts: 106
Joined: Fri Sep 26, 2014 2:02 pm

### Re: Unique rate law

If the question asks for the "rate" it just wants one number, not the rate law expression. So you'd just do the unique average rate (I guess they just omitted the word average because it was implied).

I don't think in the chapter they ever ask for the "unique rate law."

Neil DSilva 1L
Posts: 70
Joined: Fri Sep 26, 2014 2:02 pm

### Re: Unique rate law

Yeah, I didn't think the "unique rate law" was a thing, so I was just checking.