This memory aid covers Memory Aids 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 10 of 13 in this topic. Use it for quick recall, then test yourself straight afterwards so the memory aid becomes usable in an answer.
🧠 Memory Aids
To draw the profile correctly: "Reactants UP to peak, then DOWN to products"
The curve always goes up first (activation energy required) then back down (either ending lower for exothermic or higher for endothermic).
For catalysts: "Same start, same end, lower middle"
A catalyst lowers the peak (the "middle" of the profile) but the start point (reactants) and end point (products) stay exactly the same. ΔH is unchanged.
Ea vs ΔH: "Ea is from the FLOOR, ΔH is from the START to FINISH"
Ea = from reactants level up to the peak. ΔH = from reactants level to products level. These are different measurements — do not confuse them.
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]