Determine the sign of G for the following reaction. Is the reaction spontaneous, nonspontaneous, or temperature dependent? (5 points) N2(g) + 2O2(g) + 16.2 kcal  2N2O(g)

Question

Determine the sign of G for the following reaction. Is the reaction spontaneous, nonspontaneous, or temperature dependent? (5 points)

N2(g) + 2O2(g) + 16.2 kcal  2N2O(g)

Answer 1

N₂(g) + 2O₂(g) + 16.2 kcal <==> 2N₂O(g)

First notice that heat (16.2 kcal) appears as a reactant. That tells you the reaction is ENDOTHERMIC (∆H is positive).

Next, notice that there are more moles of gas on the reactant side (3 moles) vs. the product side (2 moles). This suggests that ∆S is negative.

∆G = ∆H -T∆S

Since ∆H is positive and ∆S is negative, the reaction is non-spontaneous at all temperatures (not temperature dependent) and ∆G is positive.