This memory aid covers Memory Aids within Exothermic Reactions for GCSE Chemistry. Revise Exothermic Reactions in Energy Changes for GCSE Chemistry with 20 exam-style questions and 14 flashcards. This topic shows up very often in GCSE exams, so students should be able to explain it clearly, not just recognise the term. It is section 9 of 12 in this topic. Use it for quick recall, then test yourself straight afterwards so the memory aid becomes usable in an answer.
🧠 Memory Aids
EXO = EXIT = energy EXITS to surroundings = temperature goes UP
The "exo" prefix means "outside" or "exit". Energy exits the chemical system and goes into the surroundings, warming them up. Hand warmers, fires, and explosions all release heat — they all EXOT energy OUT.
ΔH sign rule: EXO = EXtra (negative) — you gain extra heat in the surroundings
Exothermic → ΔH is NEGATIVE (the system loses energy, so the change is negative)
On the energy profile: "EXothermic EXits — the products EXIT below the reactants on the diagram."
Practice questions for Exothermic Reactions
In an exothermic reaction, energy is transferred:
Explain, in terms of bond breaking and bond making, why combustion is an exothermic reaction.