In: Chemistry
or the
following reaction, Kc = 255 at 1000 K. CO (g) + Cl2 (g) ⇌ COCl2 (g) You may want to reference (Pages 693 - 702)Section 15.8 while completing this problem. |
Part A If a reaction mixture initially contains a CO concentration of 0.1470 and a Cl2 concentration of 0.180 at 1000K. What is the equilibrium concentration of CO at 1000 K? Express your answer in molarity to three significant figures.
SubmitRequest Answer Part B What is the equilibrium concentration of Cl2 at 1000 K? Express your answer in molarity to three significant figures.
SubmitRequest Answer Part C What is the equilibrium concentration of COCl2 at 1000 K? Express your answer in molarity to three significant figures.
|
ICE Table:
[CO] [Cl2] [COCl2]
initial 0.147 0.18 0
change -1x -1x +1x
equilibrium 0.147-1x 0.18-1x +1x
Equilibrium constant expression is
kc = [COCl2]/[CO]*[Cl2]
255.0 = (1*x)/((0.147-1*x)(0.18-1*x))
255.0 = (1*x)/(2.646*10^-2-0.327*x + 1*x^2)
6.747-83.38*x + 2.55*10^2*x^2 = 1*x
6.747-84.38*x + 2.55*10^2*x^2 = 0
This is quadratic equation (ax^2+bx+c=0)
a = 2.55*10^2
b = -84.38
c = 6.747
Roots can be found by
x = {-b + sqrt(b^2-4*a*c)}/2a
x = {-b - sqrt(b^2-4*a*c)}/2a
b^2-4*a*c = 2.386*10^2
roots are :
x = 0.1957 and x = 0.1352
x can't be 0.1957 as this will make the concentration negative.so,
x = 0.1352
At equilibrium:
[CO] = 0.147-1x = 0.147-1*0.13517 = 0.01183 M
[Cl2] = 0.18-1x = 0.18-1*0.13517 = 0.04483 M
[COCl2] = +1x = +1*0.13517 = 0.13517 M
A) 0.0118 M
B) 0.0448 M
C) 0.135 M