One of the reaction that takes place in producing steel from iron ore is the reduction of iron(II) oxide by carbon monoxide to give iron metal and CO2.
FeO (s) + CO (g) ⇌ Fe (s) + CO2 (g); Kp = 0.265 atm at 1050K
What are the equilibrium partial pressures of CO and CO2 at 1050 K if the initial partial pressures are: 
= 1.4 atmand 
= 0.80 atm?
The given reaction is:
The reaction quotient (Qp) measures the partial pressures of products and reactants present during a reaction at a particular point in time. It also indicates the direction in which the reaction is going to proceed.
Here, 
And Kp=0.265
Since Qp>Kp, it indicates that the reaction will move in the backward direction to attain equilibrium. This means that the partial pressure of CO2 will decrease and the partial pressure of CO will increase by the same amounts. If the partial pressure of CO2 will decrease by p atm, the partial pressure of CO will increase by p atm.
Hence, 
and 
Equilibrium pressure constant (Kp) is defined as a number that expresses the relationship between the partial pressures of products and reactants present at equilibrium in a reversible chemical reaction at a given temperature.
Therefore, 
0.371 + 0.265p = 0.8 – p
1.265p = 0.429
p = 0.339 atm
