## Writing rate laws

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

Gavin Kellerman 1D
Posts: 17
Joined: Sat Jul 09, 2016 3:00 am

### Writing rate laws

When a reactant is first order is it necessary/proper to write the exponent of 1 in its rate law? For 0 order reactions, should the reactant be included in the rate law at all?

RohanGupta1G
Posts: 34
Joined: Sat Jul 22, 2017 3:00 am

### Re: Writing rate laws

When the reactant is first order, you do not need to include the exponent, when the reactant is 0 order, you do not need to write the reactant at all.

Sarah Rutzick 1L
Posts: 50
Joined: Tue Oct 10, 2017 7:13 am

### Re: Writing rate laws

Also, when you have a zero order reaction, the rate is equal to the equilibrium constant k, so you don't need to include the reactant.

Morgan Baxter 1E
Posts: 50
Joined: Thu Jul 27, 2017 3:00 am

### Re: Writing rate laws

If a reaction is zero order it should not be included in the rate law. If it was there, it would falsely report that concentration of the reactant influences the rate of reaction. It does not, so it should not be included.

Phillip Winters 2F
Posts: 50
Joined: Fri Sep 29, 2017 7:05 am

### Re: Writing rate laws

It's not necessary to write the 1 in first order reactions, the one is just implied if you write out the reactant with no exponent