## Rate Law vs. Rate of reaction [ENDORSED]

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

Sophia Kim 1C
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### Rate Law vs. Rate of reaction

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.

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

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.