In: Chemistry
At a certain temperature, the Kp for the decompositon of H2S is 0.871. H2S(g) <----> H2(g) + S(g) Initally, only H2S is present at a pressure of 0.226 bar in a closed container. What is the total pressure in the container at equilibrium?
Solution
Write reaction and using ICE find final equilibrium pressures
H2S (g) ---- > H2 ( g) + S ( g)
I 0.226 0 0
C -x + x +x
E (0.226-x) x x
Kp = P (H2) P (S) / P(H2S)
0.871 = x2/ (0.226-x)
Lets solve quadratic equation.
(0.226-x) * 0.871 = x 2
x = 0.1862
Equilibrium pressure of H2S = 0.226 – x = 0.226 - 0.1862 = 0.0398 bar
Equilibrium pressure of H2 = x = 0.1862 bar
Equilibrium pressure of S = x = 0.1862 bar
Total pressure = 0.0398 + 0.1862 + 0.1862
= 0.412 bar
Total pressure is 0.412 bar