Loading…
Loading…
GCSE Chemistry · key term
A reaction or change that takes in heat energy from the surroundings.
Used by Edexcel and OCR
Specification 7.12, 7.16 · Paper 2
Describes a change in which energy is transferred from the surroundings to the reacting particles.
Revise: Bond Breaking and MakingBond breaking is therefore endothermic.
Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
A reaction direction that takes in energy from the surroundings, usually as heat.
Revise: Equilibrium positionThe two directions of a reversible reaction have opposite energy changes: if the forward reaction is exothermic and releases heat, the reverse reaction is endothermic and takes in heat. Increasing temperature favours the endothermic direction, which takes in some of the added energy. Decreasing temperature favours the exothermic direction.
If asked about bonds, do not answer only by defining an endothermic or exothermic reaction. Relate the energy transfer directly to bond breaking and bond making.
Decide whether a profile is exothermic or endothermic by comparing the energy levels of the products and reactants—not by looking at the height of the peak.
Decide whether a reaction is exothermic or endothermic by comparing the product and reactant energy levels, rather than by looking only at the height of the peak.
Create a free account to read GCSE Chemistry revision notes for your exam board and track your progress.