Which expression calculates reaction energy from mean bond energies?
Energy released forming product bonds minus energy to break reactant bonds
Sum of all product and reactant bond energies
Energy to break reactant bonds minus energy released forming product bonds
Activation energy minus product energy
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.