Answer:
21 kJ/mol
Explanation:
Step 1: Given and required data
- Temperature (T): 25 °C (298 K)
- Equilibrium constant (Kc): 2.1 × 10⁻⁴
- Ideal gas constant (R): 8.314 J/K.mol
Step 2: Write the balanced equation at equilibrium
CO(g) + 2 H₂(g) ⇄ CH₃OH(g)
Step 3: Calculate the standard Gibbs free energy of the reaction (ΔG°)
We will use the following expression.
ΔG° = - R × T × ln Kc
ΔG° = - (8.314 J/K.mol) × 298 K × ln 2.1 × 10⁻⁴ = 2.1 × 10⁴ J/mol = 21 kJ/mol
