# How can I calculate the activation energy of a reaction?

##### 1 Answer

You can calculate the activation energy of a reaction by measuring the rate constant k over a range of temperatures and then use the Arrhenius Equation to find

According to his theory molecules must acquire a certain critical energy

From BBC GCSE:

A is a constant termed the frequency factor

e is the base of natural logs

R is the gas constant = 8.31J/K/mol

T is the absolute temperature in degrees Kelvin.

If you take natural logs of both sides of the equation you get:

You then measure k over a range of temperatures, the method you use depends very much on the type of reaction you are studying.

You can then plot

So the gradient of the line is equal to

This is an example taken from Wikipedia relating to the decomposition of nitrogen (IV) oxide.