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CHEM 121 Studioby Learn4Less · UBC CHEM 121

CHEM 121 glossary

Activation energy

The minimum energy that reacting particles must have for a reaction to occur: the height of the energy barrier between reactants and products. The lower the activation energy, the faster the reaction at a given temperature.

Energy profile with and without a catalystEnergy against reaction progress. Reactants start higher than products. The uncatalysed path climbs a tall barrier; the catalysed path climbs a lower one (smaller activation energy) between the same reactants and products, so the reaction goes faster but releases the same overall energy.reaction progressenergyreactantsproductshigher Eₐlower Eₐuncatalysedcatalysed

EaE_a is the climb from the reactants to the top of the barrier.

Example

A catalyst lowers the activation energy without changing the energies of the reactants or products, so the reaction runs faster at the same temperature.

See alsoCatalyst