Question

Calculate the standard enthalpy of formation of aluminum oxide from its elements given the following information:2 Al(s) + 3/2 O2(g) → Al2O3(s) ΔH°rxn = - 1675.7 kJ/molStandard enthalpy of formation of Al(s) = 0 kJ/molStandard enthalpy of formation of O2(g) = 0 kJ/mol

Answer 1

To calculate the standard enthalpy of formation of aluminum oxide  Al2O3 , we can use the given reaction and the standard enthalpies of formation of the elements involved.The balanced chemical equation is:2 Al s  + 3/2 O2 g   Al2O3 s The standard enthalpy change for this reaction  Hrxn  is given as -1675.7 kJ/mol.Since the standard enthalpy of formation  Hf  of Al s  and O2 g  are both 0 kJ/mol, we can directly use the Hrxn value as the standard enthalpy of formation for Al2O3 s .Therefore, the standard enthalpy of formation of aluminum oxide  Al2O3  is:Hf [Al2O3 s ] = -1675.7 kJ/mol