write a chemical equation for the reaction corresponding to the standard enthalpy of formation of N2O5 (g) and determine its value from the following thermochemical data
2NO(g) + O2(g) ->2NO2(g) delta H=-1141 kJ
4NO2(g) + O2(g) -> 2N2O5 (g) delta H=-110.3 kJ
N2 (g) + O2 (g) ->2NO2(g) delta H=+180.5 kJ