Question

At a certain temperature, the equilibrium constant for the reaction given below is 0.0400.

NO(g) + CO₂(g) → NO₂(g) + CO(g)

If 0.800 mol NO and 0.800 mol CO₂ are put into a 2.00 L container and allowed to react, what will be the concentration of NO at equilibrium?

a) 0.167 mol/L
d) 0.067 mol/L
c) 0.333 mol/L
b) 0.0400 mol/L
e) 0.667 mol/L

Answer 1

To find the concentration of NO at equilibrium, use the equilibrium constant expression and plug in the provided initial concentrations. Simplify the equation and solve for x to get the concentration of NO at equilibrium, which is 0.067 mol/L.

Step-by-step explanation:

To find the concentration of NO at equilibrium, we need to use the equilibrium constant expression:

Kc = [NO₂][CO] / [NO][CO₂]

Given that the equilibrium constant (Kc) is 0.0400, we can plug in the provided initial concentrations:

0.0400 = [NO₂][CO] / (0.800)(0.800)

Since we know the initial concentrations but not the concentration of NO at equilibrium, we can let 'x' represent the concentration of NO at equilibrium. So the expression becomes:

0.0400 = (0.016 + x)(0.800) / (0.800)(0.800)

Simplifying the equation:

0.0400 = (0.016 + x) / (0.800)

Solving for x, the concentration of NO at equilibrium:

x = 0.067 mol/L