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Rate Equations



Rate Equations

AQA Content

Define the terms 'order of reaction' and 'rate constant'
Perform calculations using the rate equation
Explain the qualitative effect of changes in temperature on the rate constant k
Perform calculations using the equation k = Ae–Ea/RT
Understand that the equation k = Ae–Ea/RT can be rearranged into the form ln k = –Ea /RT + ln A and know how to use this rearranged equation with experimental data to plot a straight line graph with slope –Ea/R
These equations and the gas constant, R, will be given when required.

Specification Notes

The rate of a chemical reaction is related to the concentration of reactants by a rate equation of the form:

Rate = k[A]m [B]n

where m and n are the orders of reaction with respect to reactants A and B and k is the rate constant.

The orders m and n are restricted to the values 0, 1, and 2.
The rate constant k varies with temperature as shown by the equation:

k = Ae–Ea/RT

where A is a constant, known as the Arrhenius constant, Ea is the activation energy and T is the temperature in K.



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