For the gas phase decomposition of dinitrogen pentoxide at 335 K

2 N2O5 > 4 NO2 + O2

the average rate of disappearance of N2O5 over the time period from t = 0 s to t = 111 s is found to be 8.5610-4 M s-1.

The average rate of formation of NO2 over the same time period is M s-1.