Please help me

Question

N2O5(g) + H2O(l) --> 2HNO3(l) delta H° = -76.2 kJ
H2O(l) --> H2(g) + 1/2O2(g) delta H° = 286.0 kJ
1/2N2(g) + 3/2O2(g) + 1/2H2(g) --> HNO3(l) delta H° = -174.0 kJ

Calculate delta H° for the reaction
2N2O5(g) --> 2N2(g) + 5O2(g)

Answer 1

See the post above.