For the equilibrium CH₄ (g) +2 H₂ S(g) ⇆ CS₂ (g) +4 H₂ (g), the concentrations at equilibrium are [CH₄] = 0.3322 M, [H₂S] = 0.6644 M, [CS₂] =0.0678 M, and [H₂] =0.2712 M at 1400.0 K.Calculate K_c.

Question

Quizplus · Accepted Answer

The equilibrium constant $K_c$ is calculated using the equilibrium concentrations of the reactants and products raised to the power of their coefficients in the balanced chemical equation. For the given equilibrium:$$CH_4(g) + 2H_2S(g) \rightleftharpoons CS_2(g) + 4H_2(g)$$$$K_c = \frac{[CS_2][H_2]^4}{[CH_4][H_2S]^2}$$Plugging in the given concentrations:$$K_c = \frac{(0.0678)(0.2712)^4}{(0.3322)(0.6644)^2} = 2.50 \times 10^{-3}$$This matches choice B.

For the Equilibrium CH4 (G) +2 H2 S(g) ⇆ CS2

For the Equilibrium CH₄ (G) +2 H₂ S(g) ⇆ CS₂