This deep dive covers Deep Dive: Where Does the Energy Go? 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 4 of 12 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
🔬 Deep Dive: Where Does the Energy Go?
In exothermic reactions, energy is transferred FROM the reacting chemicals TO the surroundings. This causes the temperature of the surroundings to increase.
Energy in Reactants > Energy in Products
The "extra" energy is released as heat
Common examples of exothermic reactions:
- Combustion — burning fuels (methane + oxygen → carbon dioxide + water + HEAT)
- Neutralisation — acid + alkali reactions always release heat
- Respiration — glucose + oxygen → CO₂ + water + energy (in cells)
- Oxidation — metals reacting with oxygen (rusting releases heat slowly)
- Displacement — reactive metal displacing less reactive one
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.