How to Calculate Kp for a Sealed Vessel at Equilibrium?

[veitch]

Homework Statement

Given a sealed vessel at 2000K, initially contains I2 (g) + Cl2 (g) <- -> 2 ICl (g) with partial pressures .3 atm, .3 atm and .5 atm respectively. At equilibrium the partial pressure of ICl has increased by 52.8% (so .764 atm)... calculate Kp. But that is one part that confuses me. Does only one pressure change?

Anyway.. I just did a Kp calculation for a previous question with no change and got the proper answer (it's given)... but using an ICE table in that question allowed me to solve for x to figure out the diffferent pressures... I tried to do that here but Got:

I2 Cl2 ICl
(.3-x) (.3-x) (.5+2x)

but if I add them together and equal to the total pressure (1.1 atm) ... everything cancels out. I admit I don't have a great understanding of pressures yet... any help would be greatly appreciated.

 

[Borek]

All partial pressures change in this case.