Using the average bond energies in the table below

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

Problem

Using the average bond energies in the table below, estimate the enthalpy change

\Delta H

(in kJ mol⁻¹) for the elementary reaction

\text{H}_2+\text{Br}_2 \rightarrow 2\,\text{HBr}

. Average bond energies (kJ mol⁻¹): H–H 436 Br–Br 193 H–Br 366 (a)

\approx +100\,\text{kJ mol}^{-1}

(b)

\approx -300\,\text{kJ mol}^{-1}

(c)

\approx -100\,\text{kJ mol}^{-1}

(d)

\approx +300\,\text{kJ mol}^{-1}