A student determined the energy released when propan-1-ol is burned. They used a copper calorimeter containing 100 cm3 of water and recorded a temperature rise of 30∘C30^{\circ}\text{C}30∘C.
The mass of propan-1-ol burned to achieve this temperature rise was higher than the theoretical value calculated using average bond energies.
Give one reason why the mass of propan-1-ol burned is higher than expected.
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.