Question

For the following reaction, Kc = 255 at 1000 K.
CO (g) + Cl2 (g) ⇌ COCl2 (g)
A reaction mixture initially contains a COconcentration of 0.1550 M and a Cl2concentration of 0.178 M at 1000 K.

What is the equilibrium concentration of CO at 1000 K?

What is the equilibrium concentration of Cl2 at 1000 K?

What is the equilibrium concentration of COCl2 at 1000 K?

Answer 1

Given :

[CO]=0.1550 M and [Cl2] = 0.178 M         at T = 1000 K.

Kc = 255

Lets use ICE chart.

CO (g) +           Cl2 (g) ⇌ COCl2 (g)

I           0.1550                         0.178               0

C          -x                     -x                     +x

E          (0.1550-x)       (0.178-x)         x

Kc = [COCl2]/[CO][Cl2]

255 = x / ( 0.1550-x) ( 0.178-x)

255 = x/ (x² – 0.333x + 0.02759 )

255 x² – 84.915x + 7.035 = x

255 x² – 85.915x + 7.035 = 0

We use quadratic formula to solve this problem

By using quadratic formula we get

x = 0.14 = [COCl2] = 0.14 M

[CO]= 0.1550 – 0.140 = 0.015 M

[Cl2]= 0.178-0.140 = 0.038 M