At 600C N2O4 is 50% dissociated. At this temperature and 1 atm the standard free energy change is :
Standard enthalpy and standard entropy for the oxidation of NH3 at 298 K are −382.64 kJ mol−1 and −145.6 J mol−1 K−1 respectively. Standard free energy change (in kJ mol−1) for the same reaction at 298 K is: