A displacement reaction causes a temperature increase. Which statement is supported?
The overall reaction transfers energy to the surroundings
No activation energy is needed for the reaction to start
The products contain no chemical energy after reacting
Every individual bond change in the reaction is exothermic
94 exam-style questions on Edexcel GCSE Chemistry 8.2 Heat energy changes in chemical reactions, covering 8.2.1 Exothermic and endothermic changes, 8.2.2 Bond breaking, bond making and overall energy change, 8.2.3 Calculating energy change from bond energies, and 8.2.4 Activation energy and reaction profiles. Each one has a worked solution and a mark scheme showing where the marks go.