To calculate the enthalpy change for the hydration of MgSO4, we need to find the enthalpy change for the following reaction:MgSO4 s + 7H2O l MgSO4 7H2O s We can do this by using Hess's Law, which states that the enthalpy change for a reaction is the same whether it occurs in one step or several steps. In this case, we have two steps with known enthalpy changes:1 MgSO4 s MgSO4 aq H1 = 44.5 kJ/mol2 MgSO4 aq + 7H2O l MgSO4 7H2O s H2 = -63.2 kJ/molTo find the enthalpy change for the overall reaction, we can simply add the enthalpy changes for these two steps:H_total = H1 + H2H_total = 44.5 kJ/mol + -63.2 kJ/mol H_total = -18.7 kJ/molSo the enthalpy change for the hydration of MgSO4 is -18.7 kJ/mol.