Calculating equilibrium pressure. Just need someone to check my math.

[wayoftheyetigirl]

I've done all the work, I just keep coming up wrong on my math. I'm not sure what I'm missing.

 

The equilibrium constant, Kp, for the following reaction is 0.636 at 600 K:

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

Calculate the equilibrium partial pressures of all species when COCl2(g) is introduced into an evacuated flask at a pressure of 1.73 atm at 600 K.

PCOCl2=
PCO=
PCl2=

setting up ICE, I know that Kp=x/(1.73-x)=.636

(.636)[1.73-x]^2=x
(.636)[1.73^2-2(1.73)x + x^2]=x
(.636)x^2-[2(1.73)(.636)+1]x + (.636)(1.73)^2

x^2-[2(1.73)+1/(.636)]x + 1.73^2= 0

a=1
b= -[2(1.73)+1/(.636)]= -5.032
c= (1.73)^2= 2.993

quadratic equation such that:
[(-5.032)^2-4(2.993)]^1/2 = [13.349]^1/2= 3.654

x=(-(-5.032)+-3.654)/2
x=4.343 or .689

Go with .689 since the other value of x is greater than the initial pressure of 1.73.
PCO=PCL2=(1.73-x)=(1.73-.689)=1.041
PCOCL2=x=.689

[studiot]

Before answering this I am interested to learn what course is teaching the chemical dynamics of carbonyl chloride or phosgene, considering its deployment is outlawed under international treaty?

[Fuzzwood]

Your equation for the equilibrium is wrong. You square the part for the starting materials while this does not have a stoiciometric coefficient.

[studiot]

I think the equation is simply missing the equals sign (or the right arrow if you prefer those)

 

It says that the dissociation is carbonyl chloride to carbon monoxide plus chlorine.

[John Cuthber]

Before answering this I am interested to learn what course is teaching the chemical dynamics of carbonyl chloride or phosgene, considering its deployment is outlawed under international treaty?

No course is teaching about phosgene.

The course is teaching about equilibrium constants; it happens to be using phosgene as an example because the chemistry is reasonably well documented.

 

I'd like to know what course taught you that the only thing you can do with phosgene is to poison people?

It's an important industrial chemical.and, according to Wiki "World production of this compound was estimated to be 2.74 million tonnes in 1989."

 

from

https://en.wikipedia.org/wiki/Phosgene#Production

[studiot]

No course is teaching about phosgene.

The course is teaching about equilibrium constants; it happens to be using phosgene as an example because the chemistry is reasonably well documented.

 

I'd like to know what course taught you that the only thing you can do with phosgene is to poison people?

It's an important industrial chemical.and, according to Wiki "World production of this compound was estimated to be 2.74 million tonnes in 1989."

 

from

https://en.wikipedia.org/wiki/Phosgene#Production

 

So go ahead and answer the OP's question.

[John Cuthber]

 

So go ahead and answer the OP's question.

I guess it would be nitpicking to ask why you didn't do that, rather tan leaping to a conclusion about war gases.

 

I suspect Fuzzword already answered the actual question.

The OP's problem is that they have squared something for no good reason.

(Technically, there are other problems too- the = sign or --> or whatever is missing and there are no units for the eqm constant,but essentially the real problem is already nailed.)

Edited December 7, 2015 by John Cuthber