8.已知 C(s) + 0.5O2(g) → CO(g) ∆H= -26 kcal/mol，C(s) + O2(g) → CO2(g) ∆H= -94 kcal/mol，則 CO(g) + 0.5O2(g) → CO2(g) 之∆H 為______
kcal/mol。