Question

A sample of air was passed through an electrical discharge causing the following reaction
N2(g) + O2(g)->2NO(g) .
Assuming that 1.00 mole of air (78% N2, 21% O2) was originally present at 1.00 atm, determine the partial pressure (in atm) of NO at equilibrium. Kp = 0.0123 at 4200 K (the temperature of the discharge).


I know Kp=[NO]^2/[N2][O2]. Also, I need to set up an ICE table, but do I use .78 for initial of N2 and .21 for Initial of O2? I'm confused.

Answer 1

Yes, that's what you do.

Answer 2

So would the ICE table look this this:
N2 O2 NO
.78 .21 0
-x -x 2x
.78-x .21-x 2x
(2x)^2/(.78-x)(.21-x)=Kp

Is that the correct set up? Thanks

Answer 3

You have it. Congrats!