Ethene reacts with bromine to form 1,2-dibromoethane.
The equation shows the structural formulas of the reactants and products involved in this reaction:
HH\/C=C/\HH+Br−Br→HH∣∣H−C−C−H∣∣BrBr \begin{array}{c} \text{H} \quad \text{H} \\ \backslash \quad / \\ \text{C}=\text{C} \\ / \quad \backslash \\ \text{H} \quad \text{H} \end{array} + \quad \text{Br}-\text{Br} \quad \rightarrow \quad \begin{array}{c} \text{H} \quad \text{H} \\ | | \\ \text{H}-\text{C}-\text{C}-\text{H} \\ | | \\ \text{Br} \quad \text{Br} \end{array} HH\/C=C/\HH+Br−Br→HH∣∣H−C−C−H∣∣BrBrUse the bond energy data in the table below to calculate the energy change, in kJ mol−1\text{kJ mol}^{-1}kJ mol−1, for this reaction.
| Bond | Bond energy in kJ mol−1\text{kJ mol}^{-1}kJ mol−1 |
|---|---|
| C=C | 614 |
| C—H | 413 |
| Br—Br | 193 |
| C—C | 348 |
| C—Br | 276 |
