At high temperatures,boron carbide vaporizes according to B₄C(s) ⇌ 4 B(g) + C(s)
At 2500 K,the equilibrium pressure of B(g) is 0.0342 mm Hg over a mixture of 0.300 mol B₄C(s) and 0.500 mol C(s) .Calculate ΔG° for this process.

Question

Quizplus · Accepted Answer

The equation for calculating ΔG° is: ΔG°=-RTlnK where R is the universal gas constant, T is the temperature in Kelvin, and K is the equilibrium constant for the reaction. To calculate K, we use the equilibrium pressure of B(g) and the stoichiometric coefficients of the balanced chemical equation: K = (P_B)^4 / (P_B₄C × P_C) Substituting the given values: K = (0.0342 mm Hg)^4 / (0.300 mol × 0.500 mol) = 6.20 × 10^-10 Thus, ΔG° = - (8.314 J/K mol) × (2500 K) × ln(6.20 × 10^-10) = 832 kJ Therefore, the correct answer is choice A (832 kJ).

At High Temperatures,boron Carbide Vaporizes According to B4C(s)⇌ 4 B(g)

At High Temperatures,boron Carbide Vaporizes According to B₄C(s)⇌ 4 B(g)