Page 1 of 1

Rate Law vs. Rate of reaction

Posted: Wed Mar 07, 2018 1:52 am
by Sophia Kim 1C
I'm a bit confused on the difference between the rate of reaction, which is the change in the concentration of a species over change in time and rate law?
Rate law seems to be the same idea so i'm a bit confused.

Re: Rate Law vs. Rate of reaction  [ENDORSED]

Posted: Wed Mar 07, 2018 7:54 am
by Chem_Mod
The rate law and the rate of reaction are different. The rate of reaction (in terms of disappearance of reactant A) is -d[A]/dt.

The rate law relates the rate to an expression involving the rate constant k and the initial concentrations of reactants. The rate law for A + 2B --> C is:

rate = k[A][B]^2

assuming that A + 2B --> C is an elementary reaction. If it is not, the exponents will need to be determined experimentally.

The rate is usually the unique rate.