Answer to Question #140225 in Inorganic Chemistry for Christine

Question

4. Given the following thermochemical equations
2H2(g) + O2(g) → 2H2O(l) ∆H = -571.6 KJ
N2O5(g) + H2O(i) → 2HNO3(l) ∆H = -73.7 KJ
½ N2(g) + 3/2 O2(g) + ½ H2(g) → HNO3(l) ∆H = -174.1 KJ
Calculate ∆H for the formation of one mole of dinitrogen pentoxide from its elements in their stable state at 25oC and 1 atm.

Answer 1

∆H=∆H2-∆H1 = -174.1 - (-571.6) = 397,5