The bond energies of some covalent bonds are shown in the table.
Hydrogen gas reacts with fluorine gas to form hydrogen fluoride gas.
H2(g)+F2(g)→2HF(g) \text{H}_2(\text{g}) + \text{F}_2(\text{g}) \rightarrow 2\text{HF}(\text{g}) H2(g)+F2(g)→2HF(g)| Bond | Bond energy in kJ mol−1\text{kJ mol}^{-1}kJ mol−1 |
|---|---|
| H—H | 436 |
| F—F | 158 |
| H—F | 568 |
Calculate the overall energy change, in kJ mol−1\text{kJ mol}^{-1}kJ mol−1, for the reaction of 1 mol of hydrogen gas, H2\text{H}_2H2, with 1 mol of fluorine gas, F2\text{F}_2F2, to form 2 mol of hydrogen fluoride gas, HF\text{HF}HF.
