This key facts covers Key Facts: Catalysts and 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 7 of 13 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
📌 Key Facts: Catalysts and Activation Energy
- Catalysts speed up reactions without being used up
- They provide an alternative reaction pathway
- The alternative pathway has lower activation energy
- More particles now have enough energy to react
- Catalysts are unchanged at the end — can be reused
- Catalysts don't change ΔH — same energy released/absorbed overall
- On the diagram: catalyst curve has a lower peak but same start and end points
Quick Check: On a reaction profile, where is the activation energy measured from and to?
Activation energy is measured from the energy level of the REACTANTS up to the PEAK of the curve. It is NOT measured from the x-axis or from the products. The activation energy represents the minimum energy that colliding particles must have in order for the reaction to proceed.
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]