In: Chemistry
Hydrogen Sulfide decomposes according to the following reaction for which Kc= 9.30 x 10^-8 at 700 degrees C.
2H2S (g) makes 2H2 (g) + S2(g)
If .43 mol H2S is placed in a 3 L container what is the equilibrium concentration of H2 (g) at 700 degrees C?
moles of H2S = 0.43
volume = 3 L
concentration = moles / volume = 0.43 / 3
= 0.143 M
2H2S (g) ----------------> 2H2 (g) + S2(g)
0.143 0 0 ------------ initial
0.143 - 2x 2x x ------------ at equlibrium
Kc = [H2]^2[S2] / [H2S]^2
9.30 x 10^-8 = (2x)^2 (x) / (0.143 - 2x)
4x^3 + 1.86 x 10^-7x - 1.33 x 10^-8 = 0
by solving this equation we get
x = 1.482 x 10^-3
Equilibrium concentration of H2 = 2x = 2 x 1.482 x 10^-3
= 2.96 x 10^-3 M
Equilibrium concentration of [H2] = 2.96 x 10^-3 M