Is the Conversion of NO2 to HNO3 endo- or exothemic?

Question

Calculate the enthalpy and free energy change for the reaction
4NO2 + o2 + 2H2O-----> 4HNO3
in the aqueous phase.

Answer 1

Look up delta H formation and use
dHrxn = (n*dHf products) - (n*dHf reactants).
Do the same for dGo.