Question

Calculate the standard reaction enthalpy for
the reaction
NO2(g) ! NO(g) + O(g)
Given:
O2(g) ! 2O(g)
H = +498.4 kJ/mol
NO(g) + O3(g) ! NO2(g) + O2(g)

H = −200 kJ/mol
3O2(g) ! 2O3(g)
H = +285.4 kJ/mol

Answer 1

The trick here is to add equations, as appropriate, (multiply and or reverse) to obtain the desired equation. Then follow suit with the delta H values.