For the reaction of HNO3 is this the reaction? Is the water liquid?
2HNO3(s)> 2NO2(g)+H2O(l)+ 1/2O2(g)
What are you reacting HNO3 with? Normally it doesn't decompose by itself although the gas phase shows decomposition into NO2 and NO3 (see this link--(Broken Link Removed) .
N2O5 is the anhydride of HNO3.