Question

Use the reaction I₂(s) I₂(g), h = 62.4 kj/mol, s = 0.145 kj/(molk), for question 10. which direction of the reaction is favored at 298 k (room temperature)? A. Toward I₂(g) production B. Both are equally favored C. It is impossible to tell D. Toward I₂(s) production

Answer 1

At 298 K, the reaction I₂(s) ⇌ I₂(g) is favored toward I₂(s) production, as the calculation of Gibbs free energy change (ΔG) using the provided enthalpy and entropy values results in a positive ΔG, indicating that the reaction is not spontaneous toward I₂(g) formation.

Step-by-step explanation:

The equilibrium direction of the reaction I₂(s) ⇌ I₂(g) at 298 K (room temperature) can be determined using Le Chatelier's principle, which says that a system at equilibrium will try to counteract changes. The reaction in question has an enthalpy change (ΔH) of 62.4 kJ/mol, which implies that the reaction is endothermic when proceeding towards I₂(g) formation since heat is absorbed. The equation ΔG = ΔH - TΔS can be used to determine Gibbs free energy change (ΔG) and predict the spontaneity of a reaction at a given temperature. In this case, we can calculate ΔG using the provided enthalpy (ΔH = 62.4 kJ/mol) and entropy (ΔS = 0.145 kJ/(mol·K)) values at 298 K.

ΔG = ΔH - TΔS = (62.4 kJ/mol) - (298 K)(0.145 kJ/(mol·K)) = 62.4 kJ/mol - 43.41 kJ/mol = 18.99 kJ/mol

Since ΔG is positive, the reaction is not spontaneous in the direction of I₂(g) formation at 298 K. Thus, the reaction is favored in the direction toward I₂(s) production (option D).