For the reaction the enthalpy change is

CHEMISTRY · Single correct · A Level · Chemistry · Energetics · Energetics

Problem

For the reaction

\mathrm{H_2(g) + F_2(g) \rightarrow 2HF(g)}

the enthalpy change is

\Delta H_{\text{rxn}} = -542\,\text{kJ\,mol}^{-1}

. Given the average bond energies

D(\mathrm{H\! -\! H}) = 436\,\text{kJ\,mol}^{-1}

and

D(\mathrm{F\! -\! F}) = 158\,\text{kJ\,mol}^{-1}

, what is the average bond energy of the

\mathrm{H\! -\! F}

bond? (a)

560\,\text{kJ\,mol}^{-1}

(b)

654\,\text{kJ\,mol}^{-1}

(c)

568\,\text{kJ\,mol}^{-1}

(d)

594\,\text{kJ\,mol}^{-1}