what-is-the-standard-enthalpy-change-chemistry-homework-help-

Given the standard enthalpy changes for the following two reactions:

(1)N₂(g) + 2O₂(g)N₂O₄(g)…… Î”H° = 9.2 kJ

(2)2N₂O(g)2N₂(g) + O₂(g)……ΔH° = -164.2 kJ

what is the standard enthalpy change for the reaction:

(3)2N₂O(g) + 3O₂(g)2N₂O₄(g)……ΔH° = ?

 kJ