Worksheets on AQA GCSE Chemistry 5.1 Exothermic and endothermic reactions, covering 5.1.1 Energy transfer during exothermic and endothermic reactions, 5.1.2 Reaction profiles, and 5.1.3 The energy change of reactions, with answers. Print them, or work through one on screen. Write your working straight onto the paper and Genie marks it question by question against the mark scheme.