To calculate the enthalpy change for the ionization of sulfuric acid, we need to add the enthalpy changes for the two steps involved in the process:1. H2SO4 l H+ aq + HSO4- aq with H1 = +1009 kJ/mol2. HSO4- aq H+ aq + SO4^2- aq with H2 = +513 kJ/molThe overall reaction is:H2SO4 l 2H+ aq + SO4^2- aq The enthalpy change for the overall reaction is the sum of the enthalpy changes for the two steps:H_total = H1 + H2H_total = +1009 kJ/mol + +513 kJ/mol H_total = +1522 kJ/molSo, the enthalpy change for the ionization of sulfuric acid is +1522 kJ/mol.