A student says that an exothermic reaction cannot need energy to start it, because the reaction releases energy. Which statement shows why the student is wrong?
The activation energy must be supplied before the reactant particles can react
The energy released forming bonds is always smaller than the activation energy
An exothermic reaction only releases energy once all the products have formed
Breaking the bonds in the reactants releases the energy that starts the reaction
39 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.