Hydrogen reacts with bromine to make hydrogen bromide.
H2+Br2→2HBr \mathrm{H_{2} + Br_{2} \rightarrow 2HBr} H2+Br2→2HBrThe energy change for the reaction is -103 kJ/mol.
| Bond | H−H\mathrm{H{-}H}H−H | Br−Br\mathrm{Br{-}Br}Br−Br |
|---|---|---|
| Bond energy (kJ/mol\mathrm{kJ/mol}kJ/mol) | 436 | 193 |
What is the bond energy of the H−Br\mathrm{H{-}Br}H−Br bond?
366 kJ/mol366\,\mathrm{kJ/mol}366kJ/mol
263 kJ/mol263\,\mathrm{kJ/mol}263kJ/mol
526 kJ/mol526\,\mathrm{kJ/mol}526kJ/mol
732 kJ/mol732\,\mathrm{kJ/mol}732kJ/mol
51 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.