Nitrogen and hydrogen combine to form ammonia in the Haber process. Calculate (in kJ) the standard enthalpy change ?Hº for the reaction written below, using the bond energies given. N2(g) + 3H2(g) -› 2NH3(g) N=N (nitrogen-nitrogen triple bond) (945 kJ/mol) H-H (432 kJ/mol) N-H (391 kJ/mol)