Given, Enthalpy of formation of CO(g)=−110kJmol−1 Enthalpy of formation of CO2(g)=−393kJmol−1 Enthalpy of formation of N2O(g)=81kJmol−1 Enthalpy of formation of N2O4(g)=9.7kJmol−1 N2O4(g)+3CO(g)→N2O(g)+3CO2(g) ∆rH=∆HProduct −∆HReactant =[(81)+3(−393)]−[(9.7)+3(−110)] =[81−1179]−[9.7−330] =(−1098)−(−320.3)=−777.7 ≈−778kJmol−1
