A reaction has an overall energy change of +85 kJ mol−1+85\,\mathrm{kJ\,mol^{-1}}+85kJmol−1. It can be carried out with or without a catalyst.
Which pair of values could be the activation energies of this reaction without and with the catalyst?
without catalyst 130 kJ mol−1130\,\mathrm{kJ\,mol^{-1}}130kJmol−1; with catalyst 70 kJ mol−170\,\mathrm{kJ\,mol^{-1}}70kJmol−1
without catalyst 100 kJ mol−1100\,\mathrm{kJ\,mol^{-1}}100kJmol−1; with catalyst 130 kJ mol−1130\,\mathrm{kJ\,mol^{-1}}130kJmol−1
without catalyst 130 kJ mol−1130\,\mathrm{kJ\,mol^{-1}}130kJmol−1; with catalyst 100 kJ mol−1100\,\mathrm{kJ\,mol^{-1}}100kJmol−1
without catalyst 60 kJ mol−160\,\mathrm{kJ\,mol^{-1}}60kJmol−1; with catalyst 40 kJ mol−140\,\mathrm{kJ\,mol^{-1}}40kJmol−1
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.