Activation energy (Ea) is the minimum energy that colliding particles need to react. Even exothermic reactions need this initial energy input to break bonds in the reactants.
- Shown as the peak height above reactants on the energy profile
- Higher Ea = reaction is slower (fewer particles have enough energy)
- Lower Ea = reaction is faster
- Catalysts provide an alternative pathway with LOWER activation energy
This deep dive covers Deep Dive: Activation Energy within Reaction Profiles for GCSE Chemistry. Revise Reaction Profiles in Energy Changes for GCSE Chemistry with 28 exam-style questions and 15 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 5 of 13 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Reaction Profiles
What does activation energy represent on a reaction profile?
Explain how a catalyst affects the activation energy shown on a reaction profile. [2 marks]