Hydrogen reacts with chlorine to produce hydrogen chloride.
H2(g)+Cl2(g)→2HCl(g) \text{H}_2(\text{g}) + \text{Cl}_2(\text{g}) \rightarrow 2\text{HCl}(\text{g}) H2(g)+Cl2(g)→2HCl(g)Table 1 shows the bond energies for the bonds involved in this reaction.
Table 1
| Bond | Bond energy in kJ/mol\text{kJ/mol}kJ/mol |
|---|---|
| H−H\text{H}-\text{H}H−H | 436 |
| Cl−Cl\text{Cl}-\text{Cl}Cl−Cl | 243 |
| H−Cl\text{H}-\text{Cl}H−Cl | 432 |
Calculate the overall energy change for this reaction.
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.