Propane burns completely in oxygen.
C3H8+5O2→3CO2+4H2O\mathrm{C_{3}H_{8} + 5O_{2} \rightarrow 3CO_{2} + 4H_{2}O}C3H8+5O2→3CO2+4H2O
| Bond | C−C\mathrm{C-C}C−C | C−H\mathrm{C-H}C−H | O=O\mathrm{O=O}O=O | C=O\mathrm{C=O}C=O | O−H\mathrm{O-H}O−H |
|---|---|---|---|---|---|
| Bond energy / kJ mol−1\mathrm{kJ\,mol^{-1}}kJmol−1 | 347 | 413 | 498 | 805 | 464 |
What is the energy change for this reaction?
+2054 kJ mol−1+2054\,\mathrm{kJ\,mol^{-1}}+2054kJmol−1
−2054 kJ mol−1-2054\,\mathrm{kJ\,mol^{-1}}−2054kJmol−1
−2401 kJ mol−1-2401\,\mathrm{kJ\,mol^{-1}}−2401kJmol−1
−198 kJ mol−1-198\,\mathrm{kJ\,mol^{-1}}−198kJmol−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.