Calulate initial pressure (in ATM)

Question

Consider the formation of phosgene: CO(g) + Cl₂(g) ⇌ COCl₂(g) Into a sealed 1.50 L flask, chemist placed 3.00 × 10⁻² mol of phosgene gas (COCl₂) and heated it to 800.0 K. After the system reached equilibrium, the pressure of CO was found to be 0.497 atm. Calculate the equilibrium constant Kp for this reaction. Calculate the initial pressure (in atm) of the phosgene gas. R = 0.08206 L･atm/mol･K.

Answer 1

Initial pressure of phosgene :

PV = nRT

P = nRT/V

P = (3.00 × 10⁻² mol)(0.0821)(800)/1.5)

P = 0.876 atm

COCl₂ <==> CO + Cl₂

0.876…………0……0…….Initial

-x……………+x…….+x…..,Change

0.876-x…..0.497…0.497….Equilibrium

So pressure of COCl₂= 0.876-0.497 = 0.379 atm

Kp = (CO)(Cl₂) / (COCl2)

Ko = (0.497)(0.497) / 0.379

Kp = 0.652