<Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (January 2017) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (January 2017) (Learn how and when to remove this template message) </Td> </Tr> <P> In chemistry, activation energy is the energy which must be available to a chemical system with potential reactants to result in a chemical reaction . Activation energy may also be defined as the minimum energy required to start a chemical reaction . The activation energy of a reaction is usually denoted by E and is expressed as kilojoules per mole (kJ / mol) or rarely kilocalories per mole (kcal / mol). </P>

What is an example of the use of activation energy