Chemistry

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}

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

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

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