Question

A mixture of 0.2000 mol of CO2 , 0.1000 mol of H2 , and 0.1600 mol of H2O is placed in a 2.000-L vessel. The following equilibrium is established at 500 K :
CO2(g)+H2(g)←−→CO(g)+H2O(g)

Calculate the initial partial pressure of CO2 .        

Calculate the initial partial pressure of H2 .

Calculate the initial partial pressure of H2O .

At equilibrium PH2O=3.51atm . Calculate the equilibrium partial pressure of CO2 .

Answer 1

total mol = 0.2000 + 0.1000 + 0.1600 = 0.4600 mol

1st find the total initial pressure

P*V = n*R*T

P*2.000 = 0.4600*0.0821*500

P = 9.4415 atm

P(CO2) = mol (CO2) * P total / total mol

= 0.2000 * 9.4415 / (0.4600)

= 4.105 atm

P(H2) = mol (H2) * P total / total mol

= 0.1000 * 9.4415 / (0.4600)

= 2.0525 atm

P(H2O) = mol (H2) * P total / total mol

= 0.1600 * 9.4415 / (0.4600)

= 3.2840 atm

CO2(g)+H2(g)←→CO(g)+H2O(g)

4.105 2.0525 3.2840

4.105-x 2.0525-x x 3.2840+x

Given

3.2840+x = 3.51

x = 0.226 atm

P(CO2) at equilibrium = 4.105 - x

= 4.105 - 0.226

= 3.879 atm