[mjgonzalez83]

My problem is:
1.00 mol of CO and 1.00 mol of Cl2 are introduced into an evacuated 1.75 L flask and the following equilibrium is established at 668 K:
CO (g) + Cl2 (g) ↔ COCl2 (g)
The reaction has a Kp = 22.5.  What is the total gas pressure at equilibrium?

I guess I am confused where to start. I've found other problems, but with different information, so I got confused. I know I am going to use the ideal gas law. But do I need to form some sort of ICE chart? I know the temp, R constant, and the moles, but where does the Kp come into play?

[sjb]

So, from your ICE table, what is the composition of the equilibrium mixture?

So how much gas do you have, and what is the value of p?

[mjgonzalez83]

Well in an ice chart. I need to have the initial concentration, which is one mol of Co and 1 mol of Cl2. I am not given p, just a constant Kp of 22.5.

[sjb]

One mole of Co, or one of CO, initially? (there's a difference)

Your numerical value for Kp is 22.5, what's the algebraic expression for it?

[mjgonzalez83]

I am assuming its the initial amount since it says they were introduced into the flack. I wasn't given an algebraic expression, just the CO(g) + Cl()g) <--> CoCl(g). Thats why I thought I might need to create the  ICE chart?

[sjb]

...I wasn't given an algebraic expression...

So you're not familiar with the concept of K = ^products/_reactants ?

[mjgonzalez83]

I think I'm familiar with it, but I am missing some connection. I feel like I have enough information to find the partial pressure using the ideal gas law, but I don't use the Kp value in the formula, so I feel like I'm am missing something really important.

[sjb]

What are the initial pressures of CO and Cl₂? How do they change over the course of the reaction? What are the equilibrium pressures of the individual gases in your system?

[mjgonzalez83]

So once I complete the ICE chart, what would be the next step. In other words what information do I take from the ICE chart to get to the next step?

[sjb]

Once you complete your ICE chart, you can calculate how much of each of the components you have at equilibrium (using the Kp). and so the total pressure.