Question

For the following reaction, Kc = 255 at 1000 K .
CO (g) + Cl2 (g) ⇌ COCl2 (g)
A reaction mixture initially contains a CO concentration of 0.1470 M and a Cl2 concentration of 0.175 M at 1000 K

A:What is the equilibrium concentration of CO at 1000 K ? B:What is the equilibrium concentration of Cl2 at 1000 K ? C: What is the equilibrium concentration of COCl2 at 1000 K ?.

Answer 1

CO(g) + Cl2(g) <------> COCl2(g)

Kc = [COCl2]/[CO][Cl2] = 255

Initial concentration

[CO]= 0.1470M

[ Cl2 ] = 0.1750M

[ COCl2 ] = 0

Change in concentration

[CO] = -x

[ Cl2 ] = -x

[ COCl2 ] = +x

Equillibrium concentration

[ CO ] = 0.1470 - x

[ Cl2 ] = 0.1750 - x

[ COCl2] = x

Therefore,

x/(0.1470 -x)(0.1750 - x) = 255

x/ (0.025725 - 0.1470x - 0.1750x + x^2) = 255

x = 6.5598 - 37.485x - 44.625x + 255x^2

255x^2 - 83.11x + 6.5598 = 0

dividing by 255

x^2 - 0.326x + 0.026 = 0

x = 0.1391M

Therefore, at equillibrium

[ CO ] =0.1470 - 0.1391 =0.0079M

[ Cl2] = 0.1750 - 0.1391 = 0.0359M

[ COCl2 ] = 0.1391M