Using this reversible reaction, answer:
N2O4 2NO2

If the change of enthalpy of this reaction when proceeding left to right is 14Kcal,
what is the correct chemical equation?


N2O4 = 2NO2 + 14 kcal
N2O2 = 2NO2, HR = +14 kcal
N2O4 + 14 kcal = 2NO2
N2O4 = 2NO2, HR = -14 kcal
.

I think it is the 4th one. Am I right?

The first equation is usually how it is written when heat is released, as in this case.