## Making one reactant concentration small

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

Petrina Kan 2I
Posts: 102
Joined: Fri Aug 30, 2019 12:17 am

### Making one reactant concentration small

In reactions with more than one reactant, why are we allowed to make one reactant small and the other ones large in order to find the rate law?

Jasleen Kahlon
Posts: 52
Joined: Wed Nov 21, 2018 12:19 am

### Re: Making one reactant concentration small

I think that this is done to isolate one of the reactants in order to see the change

Rafsan Rana 1A
Posts: 55
Joined: Sat Aug 24, 2019 12:16 am

### Re: Making one reactant concentration small

I think making of the reaction concentration smaller conceptually simulates the reactant not having as much of an affect on reaction rate allowing us to see kind of affect the other reactant has.

Kevin Xu 4F
Posts: 50
Joined: Fri Aug 09, 2019 12:16 am

### Re: Making one reactant concentration small

By making all but one of the reactants very large, we can isolate the change in the concentration of one specific compound so that the rate law can be experimentally determined as opposed to testing all different trials and keeping different concentration of species the same. Since the concentration is so large, any change in it is negligible and thus can be ommitted in the rate law. The rate reactions produced by this are called psuedo rate laws.