Question

1. The thermochemical equation for the production of nitrogen monoxide is N2 (g) + O2 (g) ↔ 2NO (g) – 180.9 kJ. The heat of formation of nitrogen monoxide is (in kJ/mole)

Answer 1

I believe you have written the chemical equation and the -180.9 kJ is then + 180.9 kJ = dH reaction.
I believe that the THERMOCHEMICAL equation is for 1 mol of the material so since this is for two moles I would rewrite it as
1/2 N2 + 1/2 O2 ==> NO - 90.4 kJ/mol
This is clearly an endothermic reaction so the dH NO/mol = +90.4 kJ/mol.