Question

A mixture of nitrogen gas, hydrogen gas and ammonia gas reacts by: N2(g) + 3H2(g) = 2NH3(g) If the total pressure in the reaction vessel is 50.0 atm ans the equilibrium mixture contains by volume: N2= 96.143% H2= 0.3506% NH3= 3.506% what is the equilibrium constant (Kp)?

Answer 1

I should point out that the total doesn't add up to 100% (almost but not quite) so you may want to check your problem vs your post.
%by volume = mole fraction or X.
Therefore, XN2 = 0.96143; XH2 = 0.003506; XNH3 = 0.03506

pN2 = XN2*Ptotal
pH2 = XH2*Ptotal
pNH3 = XNH3*Ptotal

Substitute the pressures into the Kp expression and solve for Kp. Post your work if you get stuck.

Answer 2

So I found the pressure of each one by foing 50.0 atm* 0.96 for N2 and got 48 atm. For PH2 I did 0.0035 * 50.0= 0.175 atm. For PNH3 0.03506* 50.0= 1.1753 atm, but I feel like I did something wrong because I don't know where to go from here

Answer 3

1. Since the values are given to more places that you have shown, I would recalculate and don't throw digits away. For example, pN2 you have only two places in your answer but more than that in the Ptotal and X. Same for H2 and NH3. Redo that.
2. Where do you go from here. As I posted, you substitute these values into the Kp expression and solve for Kp.
Kp = p^2NH3/pN2*p^3H2
Remember to check your post against your problem to make sure those numbers are right.