Question

In which direction will the net reaction proceed.
X(g) + Y(g) <==> Z(g) .. Kp = 1.00 at 300k
for each of these sets of initial conditions?
1) [X] = [Y] = [Z] = 1.0 M
a] net reaction goes to the left [this one?]
b] net reaction goes to the right
c] reaction is at equilibrium

b] Px = Pz = 1.0 atm, Py = 0.50 atm
a] net reaction goes to the left
b] net reaction goes to the right
c] reaction is at equilibrium

I chose a because i converted KP to KC for part A.. is this correct so far?: KC = Kp(RT)^-∆n
KC = 1.00[(0.0821)(300k)]^-1 = 0.04060089 < 1.0 M? I don't even know if that approach was right and i honestly have no idea about part B.. please help!

Answer 1

I converted Kp to Kc also but didn't arrive at the same answer.
I think your Kc = Kp(RT)^-delta n is correct. But delta n is 1-2 = -1 so
Kc = Kp(RT)^(-)(-1). and that makes Kc about 25. Check me out on that.
(Z)/(X)(Y) and Q = 1 which is too small so the reaction will shift to the right to make Z larger and X and Y smaller to make 1 turn to 25. As for this being the approach, I think it is the only approach because the concns are given in molarity.

For part b I would look at it this way. Qp = pZ/pX*pY = 2
Compare with Kp = 1. Qp is larger so the reaction will shift to the left.

Answer 2

thank you!