The average bond energies of some covalent bonds are shown in the table below.
Nitrogen gas reacts with hydrogen gas to produce ammonia gas according to the following equation:
N2(g)+3H2(g)→2NH3(g) \text{N}_2(\text{g}) + 3\text{H}_2(\text{g}) \rightarrow 2\text{NH}_3(\text{g}) N2(g)+3H2(g)→2NH3(g)| Bond | Bond energy in kJ mol−1\text{kJ mol}^{-1}kJ mol−1 |
|---|---|
| N≡N\text{N}\equiv\text{N}N≡N | 945 |
| H—H\text{H}—\text{H}H—H | 436 |
| N—H\text{N}—\text{H}N—H | 391 |
Calculate the overall energy change, in kJ mol−1\text{kJ mol}^{-1}kJ mol−1, for the reaction of 1 mol of nitrogen gas, N2\text{N}_2N2, with 3 mol of hydrogen gas, H2\text{H}_2H2, to form 2 mol of ammonia gas, NH3\text{NH}_3NH3.
