Ethene reacts with bromine.
C2H4+Br2→C2H4Br2\mathrm{C_{2}H_{4} + Br_{2} \rightarrow C_{2}H_{4}Br_{2}}C2H4+Br2→C2H4Br2
| Bond | Bond energy in kJ mol−1\mathrm{kJ\,mol^{-1}}kJmol−1 |
|---|---|
| C=C | 612 |
| C–C | 348 |
| C–H | 412 |
| Br–Br | 193 |
| C–Br | 276 |
What is the energy change for this reaction?
−95 kJ mol−1-95\,\mathrm{kJ\,mol^{-1}}−95kJmol−1
+95 kJ mol−1+95\,\mathrm{kJ\,mol^{-1}}+95kJmol−1
+181 kJ mol−1+181\,\mathrm{kJ\,mol^{-1}}+181kJmol−1
+253 kJ mol−1+253\,\mathrm{kJ\,mol^{-1}}+253kJmol−1
36 exam-style questions on Edexcel GCSE Chemistry 10.2 Hydrocarbons, covering 10.2.1 Formulae and structures of the alkanes, 10.2.2 Alkenes and the C=C functional group, 10.2.3 Addition reactions of alkenes and testing for unsaturation, and 10.2.4 Combustion of alkanes and alkenes. Each one has a worked solution and a mark scheme showing where the marks go.