求NH3的燃烧热即为求下列反应的反应热:
NH3(g) + 7/ 4 O2(g) = NO2(g) + 3/2 H2O(l)
已知:
H2 + 1/2O2 = H2O (1) △ H = -241.8 kJ/mol
1/2N2 + O2 = NO2 (2) △H = 33.9 J/mol
1/2N2 + 3/2H2 = NH3 (3) △H= - 46 J/mol
3/2 (1) + (2) - (3)
= 3/2 *(-241.8) + 33.9 - (- 46 )
= -282.8 (kJ/mol)