Question

A 0.100 mol sample of H2S is placed in a 10.0 L reaction vessel and heated to 1132°C. At equilibrium, 0.0285 mol H2 is present. What is the value of Kc at this temp?

2 H2S(g) 2 H2(g) + S2(g

After I do my calculations, I get

Kc= (0.0057)2 X (0.00285)/(0.0043)2

and get 5.03 X 10-3

the book says the answer is 2.3 X 10-4

What am I doing wrong?

Answer 1

I don't believe you are doing anything wrong although I obtained 5.01E-3 for Kc.
Everything looks ok to me. Just to make sure I started with 0.1mol/10L = 0.01M and set up 2H2S ==> 2H2 + S2
Kc = 5.01E-3 = (H2)^2(S2)/(H2S)^2 and solved the cubic equation. I obtained 0.00285M for x = (S2) so 5.01E-3 must be right.

Answer 2

Kc=5.01x10^-3,your answer is correct i dont know which book were you using