A study of the system, H2(g) + I2(g) == 2 HI(g), was carried

Question

out. Kc = 54.9 at 699.0 K (Kelvin) for this reaction. A system was charged with 2.50 moles of HI in a 5.00 liter vessel as the only component initially. The system was brought up to 699.0 K and allowed to reach equilibrium. How many moles of H2 should there be in the container at that time?

I was going to set it up as
2.5HI (1/5.00) (1/127.91HI) but I am not sure if this is correct!

Chemistry(Please help, thank you!) - bobpursley, Wednesday, March 14, 2012 at 9:18pm
Hmmm. I don't see how it could be correct.

Do you do ICE tables?

I am familiar with how to do the ICE table but I am not sure how to set one up for this question with the 2.5 moles. I do not know what the initial values would be.