The enthalpy change for the reaction H2(g) + F2(g) → 2HF(g) is -538 kJ/mol. If the enthalpy change for the reaction H2(g) → 2H(g) is 436 kJ/mol and the enthalpy change for the reaction F2(g) → 2F(g) is 155 kJ/mol, what is the enthalpy change for the reaction 2H(g) + 2F(g) → 2HF(g)?