Use the free energies of formation given below to calculate the equilibrium constant (K) for the following reaction at 298 K. 2 HNO₃(aq) + NO(g) → 3 NO₂(g) + H₂O(l) K= ?
ΔG°_f (kJ/mol) -110.9 87.6 51.3 -237.1

Question

Quizplus · Accepted Answer

The equilibrium constant can be calculated using Gibbs Free Energy change (ΔG) at 298 K, where ΔG = -RTlnK.

First, we need to calculate the ΔG for the given reaction using the free energy of formation values:

ΔG = (3 * (-51.3 kJ/mol) + 237.1 kJ/mol) - (2 * (-110.9 kJ/mol)) - 87.6 kJ/mol
ΔG = -379.4 kJ/mol

Substituting the values in the equation, we have:

-379.4 kJ/mol = -(8.314 J/mol*K) * (298 K) * lnK

Solving for K, we get:

K = 1.15 × 10^-9

Therefore, the best choice is C.

Use the Free Energies of Formation Given Below to Calculate