Iron powder reacts with oxygen in an exothermic reaction. In its reaction profile, the reactants are at energy level X, the products are at lower energy level Y and the peak is at energy level Z.
Which statement must be true about the reverse reaction?
Its activation energy is Z − Y, and its products are at energy level X.
Its activation energy is Z − X, and its products are at energy level X.
Its activation energy is Z − X, and its products are at energy level Y.
Its activation energy is Z − Y, and its products are at energy level Y.
106 exam-style questions on OCR GCSE Chemistry 3.2 Energetics, covering 3.2.1 Exothermic and endothermic reactions and reaction profiles and 3.2.2 Calculating energy change from bond energies. Each one has a worked solution and a mark scheme showing where the marks go.