Calculate the enthalpy of the reaction 2no(g)+ o 2 (g)→2n o 2 (g) given the following reactions and enthalpies of formation: 1 2 n 2 (g)+ o 2 (g)→n o 2 (g), δ h ∘ a =33.2 kj 1 2 n 2 (g)+ 1 2 o 2 (g)→no(g), δ h ∘ b =90.2 kj