The enthalpies of formation of ${\mathrm{Al}}_2{\mathrm{O}}_3\left(\mathrm{s}\right)$ and ${\mathrm{Fe}}_2{\mathrm{O}}_3\left(\mathrm{s}\right)$ are $-1670 \mathrm{kJ} {\mathrm{mol}}^{-1}$ and $-834 \mathrm{kJ} {\mathrm{mol}}^{-1}$respectively. The enthalpy change of the reaction ${\mathrm{Fe}}_2{\mathrm{O}}_3\left(\mathrm{s}\right)+\mathrm{Al}\left(\mathrm{s}\right)⟶{\mathrm{Al}}_2{\mathrm{O}}_3\left(\mathrm{s}\right)+2\mathrm{Fe}\left(\mathrm{s}\right)$ would be