Calculate the standard enthalpy of the reaction, \Delta {{H}^\circ}_{\rm rxn}, for the thermite reaction: \rm 2Al(s) + Fe_2O_3(s) \rightarrow 2Fe(s) + Al_2O_3(s) Elements in their standard state have an enthalpy of formation value of zero. The standard enthalpies of formation of \rm Fe_2O_3 and \rm Al_2O_3 are \matrix{\rm \Delta {\it H} ^\circ\!_f ~ of ~ Fe_2O_3(s) = -825.5~kJ/mol \cr \rm \Delta {\it H} ^\circ\!_f ~ of ~ Al_2O_3(s) = -1675~kJ/mol }