Bond enthalpies are given in the table below:
| Bond | Bond enthalpy / 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 |
What is the enthalpy change, in kJ mol−1\text{kJ mol}^{-1}kJ mol−1, for the reaction below?
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)−1080 kJ mol−1-1080\text{ kJ mol}^{-1}−1080 kJ mol−1
−93 kJ mol−1-93\text{ kJ mol}^{-1}−93 kJ mol−1
+93 kJ mol−1+93\text{ kJ mol}^{-1}+93 kJ mol−1
−186 kJ mol−1-186\text{ kJ mol}^{-1}−186 kJ mol−1
