This key facts covers Key Facts: Exothermic Reactions 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 7 of 12 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
📌 Key Facts: Exothermic Reactions
- Temperature increases — the reaction mixture and surroundings get warmer
- Energy is released — transferred from reaction to surroundings
- ΔH is negative — enthalpy (energy change) is less than zero (e.g., ΔH = -400 kJ/mol)
- Energy profile dips down — products lower than reactants on diagram
- Everyday uses: Hand warmers, self-heating cans, heating pads
- Reversible exothermic — if reversed, the reaction is endothermic
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.
Quick recall flashcards
What does "exo" mean?
Outside/exit — energy exits to surroundings
What is an exothermic reaction?
A reaction that releases/transfers energy to the surroundings