A sports injury pack contains two chemicals stored apart. When the pack is squeezed, the chemicals mix and react, and the temperature of the pack falls from 21 °C to 5 °C.
Which conclusion can be made about the energy of the products compared with the energy of the reactants?
The products store less energy than the reactants, because the temperature of the pack went down
The products store less energy than the reactants, because energy was transferred to the surroundings
The products store more energy than the reactants, because energy was taken in from the surroundings
The products store the same energy as the reactants, because energy is conserved in the reaction
85 exam-style questions 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. Each one has a worked solution and a mark scheme showing where the marks go.