# Rate Equations

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• Created by: laraax123
• Created on: 27-09-15 12:51

Rate equations tell us how the rate is affected by concentrations of reactants. For the general equation A+B=C+D the rate tells us RATE= k(A)m(B)n. Square brackets indicate the concentration of whatevers inside them. The units of rate are mol dm-3 s-1. m and n are the orders of reaction and k is the rate constant. The bigger k is, the faster the reaction.

Reaction orders:

m and n are the orders of reaction with respect to reactant A and reactant B. They tell you how the concentration affects the rate.

-If (A) changes, the rate stays the same, the order of reaction with respect to A is 0.If (A) doubles or triples, the rate stays the same.

-If (A) changes and the rate changes then the order reaction with respect to A is 1.

-If the rate is proportional to (A)2, then the order of reaction with respect to A is 2. If A doubles, the rate will be (2)2= 4 times faster.

Writing rate equations:

eg: The chemical equation below