In: Chemistry
At a particular temperature the equilibrium constant for the reaction: H2(g) + F2(g) ⇔ 2HF(g) is K = 25.0. A reaction mixture in a 10.00-L flask contains 0.33 moles each of hydrogen and fluorine gases plus 0.30 moles of HF. What will be the concentration of H2 when this mixture reaches equilibrium?
H2(g) + F2(g) <===> 2HF(g)
initial 0.33/10 = 0.033 M 0.033 M 0.03 M
change x x 2x
equil 0.033-x 0.033 - x 0.03+2x
Reaction quotient(Q) = [HF]^2/[H2][F2]
= 0.03^2/(0.033^2)
= 0.826
K = 25
Q<K .so that froward reaction is favourable.
at equilibrium
K = [HF]^2/[H2][F2]
25 = (0.03+2x)^2/(0.033-x)^2
x = 0.02
concentration of H2 at equil = 0.033 - x
= 0.033- 0.02 = 0.013 M