Given the following reactions,
2 PCl₃(g) ⇌ 2 P(g) + 3 Cl₂(g) K_c = 0.0667
PCl₃(g) + Cl₂(g) ⇌ PCl₅(g) K_c = 4.0
Calculate K_c for the reaction below.
2 P(g) + 5 Cl₂(g) ⇌ 2 PCl₅(g)

Question

Given the following reactions, 2 PCl₃(g)⇌ 2 P(g)+ 3 Cl₂(g)K_c = 0.0667 PCl₃(g)+ Cl₂(g)⇌ PCl₅(g)K_c = 4.0 Calculate K_c for the reaction below. 2 P(g)+ 5 Cl₂(g)⇌ 2 PCl₅(g)

Quizplus · Accepted Answer

To find the $K_c$ for the target reaction, we can manipulate the given reactions and their equilibrium constants. The target reaction is the sum of the first reaction reversed and the second reaction multiplied by 2. When reversing a reaction, the equilibrium constant becomes the reciprocal of the original. When multiplying a reaction, the equilibrium constant is raised to the power of the multiplier. Therefore, for the first reaction reversed, $K_c = \frac{1}{0.0667}$, and for the second reaction doubled, $K_c = (4.0)^2$. Multiplying these gives the $K_c$ for the target reaction: $\frac{1}{0.0667} \times 16 = 240$.

Given the Following Reactions