what is the partial pressure of CO2(g) at equilibrium if initially 4.00 atm of CO(g) is in contact with graphite?

Question

Given that K_p = 1.5 x 10^-4 for the reaction 2 CO(g) <=> C(graphite) + CO₂(g), what is the partial pressure of CO₂(g) at equilibrium if initially 4.00 atm of CO(g) is in contact with graphite?

The correct answer is 0.0024 atm

Answer 1

2CO(g) < === > C(s) + CO₂(g)

4.00atm...............0............0..........Initial

-2x...................................+x..........Change

4-2x..................................x...........Equilibrium

Kp = (CO₂) / (CO)²

1.5x10^-4 = (x) / (4-2x)²

Solve for x and that will be the equilibrium partial pressure of CO₂