Hydrogen reacts with nitrogen to form ammonia (NH₃) according to the reaction 3H₂(g) + N₂(g) $\rightleftarrows$ 2NH₃(g)
The value of $\Delta$ H° is -92.38 kJ/mol, and that of $\Delta$ S° is -198.2 J/mol · K. Determine $\Delta$ G° at 25°C.

Question

Hydrogen reacts with nitrogen to form ammonia (NH₃) according to the reaction 3H₂(g) + N₂(g)

\rightleftarrows

2NH₃(g)
The value of

\Delta

H° is -92.38 kJ/mol, and that of

\Delta

S° is -198.2 J/mol · K. Determine

\Delta

G° at 25°C.

Quizplus · Accepted Answer

We can use the relationship between Gibbs free energy, enthalpy, and entropy:
F1F1F1S1F1F1F10G° = F1F1F1S1F1F1F10H° - T(F1F1F1S1F1F1F10S°)
Plugging in the given values:
F1F1F1S1F1F1F10G° = -92.38 kJ/mol - (298 K)(-0.1982 kJ/mol·K)
F1F1F1S1F1F1F10G° = -92.38 kJ/mol + 59.24 kJ/mol
F1F1F1S1F1F1F10G° = -33.14 kJ/mol
Thus, the answer is C.

Hydrogen Reacts with Nitrogen to Form Ammonia (NH3) According to the Reaction

Hydrogen Reacts with Nitrogen to Form Ammonia (NH₃) According to the Reaction