## Units for rate laws

Posts: 91
Joined: Fri Sep 28, 2018 12:16 am

### Units for rate laws

Should the convention of rate laws always include moles vs mmol? The textbook often gives mmol when giving concentration, but should we convert this to moles to stay in SI conventions?

Grace Kim 1J
Posts: 60
Joined: Fri Sep 28, 2018 12:18 am
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### Re: Units for rate laws

The reaction rate units is usually in the form mol L^-1 s^-1 (the time unit varies - s, min, hr, etc). However, the rate constant, k, is determined by the using the rate law for the order of reaction and the unit of rates and concentration. For example, the first order reaction has rate=k[A], or k=rate/[A], so the units would be the unit of rate divided by the unit of concentration, which is (mol/L.s)/(mol/L)=s-1

Yvonne Du
Posts: 64
Joined: Fri Sep 28, 2018 12:23 am

### Re: Units for rate laws

It is not necessary, but make sure to keep the units constant.