At 2600 K,ΔG° = 775 kJ for the vaporization of boron carbide: B₄C(s) ⇌ 4 B(g) + C(s)
Find ΔG and determine if the process is spontaneous if the reaction vessel contains 4.00 mol B₄C(s) ,0.400 mol of C(s) ,and B(g) at a partial pressure of 1.0 × 10^-5 atm.At this temperature,R T = 21.6 kJ.

Question

Quizplus · Accepted Answer

ΔG = ΔG° + RTlnQ, where Q = (P_B)^4 since B is the only gas. Given P_B = 1.0 × 10^-5 atm, Q = (1.0 × 10^-5)^4. ΔG = 775 kJ + 21.6 kJ * ln(Q). Calculating gives ΔG < 0, indicating spontaneity.

At 2600 K,ΔG° = 775 KJ for the Vaporization of Boron