At 400K, an equilibrium mixture of H2, I2, and HI consists of 0.054 mol H2, 0.019 mol I2, and 0.059 mol HI in a 1L flask. What is the value of KP for the following equilibrium? 2HI(g) H2(g) + I2 (g) I understand you convert to Molarity from moles first, then plug that into the Kc equation, but then I keep making a mistake at about that point. Thanks!

Question

At 400K,  an equilibrium mixture of H2, I2, and HI consists of 0.054 mol H2, 0.019 mol I2, and 0.059 mol HI in a 1L flask. What is the value of KP for the following equilibrium?
2HI(g) <-->  H2(g) + I2 (g)

I understand you convert to Molarity from moles first, then plug that into the Kc equation, but then I keep making a mistake at about that point. Thanks!

chmvijay · Answer

just write the Kp for the following and put in that equation and solve

anonymous · Answer

Right, I did that but still got the wrong answer. \: I think I'm not converting something correctly or something.

chmvijay · Answer

Kp  =   Kc (RT)∆n   
did u do this

anonymous · Answer

Yes, I think the moles are screwing me up though. I got 0 change in moles, is this correct?

chmvijay · Answer

yaa its correct delta n =0

anonymous · Answer

Hmm well, wouldn't to the ^0 power make it = 1 then? That's where I am confused. It says the correct answer was the value I got for Kc. (0.29)

anonymous · Answer

OH  NO, I just realized I multiplied all of it together! I did ((0.29)(0.0821)(400))^0. Oops! Thank you!! (:

chmvijay · Answer

you are confusing me to LOL

anonymous · Answer

Hahaha thank you for sticking it out with me anyways, I have a final tomorrow & you're helping tons (:

chmvijay · Answer

:)