An equilibrium mixture of CO, O2, and CO2 at a certain temperature contains 0.0010 M CO2 and 0.0020 M O2. At this temperature, Kc equals 1.4 × 10^2 for the reaction: 2 CO(g) + O2(g) ⇌ 2 CO2(g). What is the equilibrium concentration of CO?

• A. 0.0050 M
• B. 0.0100 M
• C. 0.0025 M
• D. 0.0200 M

Answer: (A)

Verified step by step guidance

1. Write the balanced chemical equation for the reaction: 2 CO(g) + O2(g) ⇌ 2 CO2(g).
2. Express the equilibrium constant expression (Kc) for the reaction: Kc = ([CO2]^2) / ([CO]^2 * [O2]).
3. Substitute the known values into the Kc expression: Kc = 1.4 × 10^2, [CO2] = 0.0010 M, and [O2] = 0.0020 M.
4. Rearrange the Kc expression to solve for [CO]: [CO]^2 = ([CO2]^2) / (Kc * [O2]).
5. Calculate the equilibrium concentration of CO by taking the square root of the result from the previous step.