Use the following data

CHEMISTRY · Subjective · A Level · Chemistry · Energetics · Energetics

Problem

Use the following data, obtained at 298 K and 1 bar, to determine the standard enthalpies of formation of SO

_2

(g) and SO

_3

(g). • S(s, rhombic) + O

_2

(g) → SO

_2

(g)

\Delta H^\circ = -296.8\,\text{kJ}

• 2 SO

_2

(g) + O

_2

(g) → 2 SO

_3

(g)

\Delta H^\circ = -198.0\,\text{kJ}

The standard enthalpies of formation of the elemental reactants are

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

. Report

\Delta H_{f}^{\circ}\bigl(\mathrm{SO_2}\bigr)

and

\Delta H_{f}^{\circ}\bigl(\mathrm{SO_3}\bigr)

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