If the change of enthalpy of this reaction when proceeding left to right is +14 kcal, which chemical equation is correct?

n2o4 2 no2 + 14 kcal

n2o4 + 14 kcal 2 no2

N₂O₄ + 14 kcal ⇄ 2NO₂.

Explanation:

Since the sign of ΔH determines either the reaction is exothermic or endothermic:

+ve, the reaction is endothermic.

-ve, the reaction is exothermic.

∵ The change of enthalpy of this reaction when proceeding left to right is + 14 kcal (+ ve sign).

∴ The reaction is endothermic, the heat is a part of the reacatnts in the reaction.

So, the reaction is:

N₂O₄ + 14 kcal ⇄ 2NO₂.