Flashcards for AQA GCSE Chemistry Energy transfer during exothermic and endothermic reactions, covering the key terms, definitions and equations you need to recall for Paper 1 and Paper 2. 21 cards, matched to the AQA GCSE Chemistry (8462) specification. Recall questions account for roughly 40% of marks at GCSE Chemistry, so these target the marks you can secure before the paper starts.