Set up a Hess Set up a HessSolution Since the product nitric

Solution

Since the product nitric acid (HNO3) appears in Eq.3, take this one as the starting point.

3NO2(g)+H2O(l)-------->2HNO3(aq) + NO(g) .... -137.3 kj/mol

Since the main reactant is NH3, take Eq.1 and add these equations.

4NH3(g)+5O2(g)------->4NO(g)+6H2O(l)..