In: Chemistry
The reaction 2H2S(g)⇌2H2(g)+S2(g) Kc=1.67×10−7 at 800∘C is carried out with the following initial concentrations: [H2S] = 0.150 M , [H2] =0.375 M , and [S2] = 0.00 M. Find the equilibrium concentration of [S2].
2H2S(g) <--------------------> 2H2(g) + S2(g)
0.150 0.375 0 ------------------------> initial
0.150-2x 0.375 +2x x -------------------> equilibrium
Kc = [H2]^2 [S2]/[H2S]^2
Kc = (0.375 +2x)^2 (x) / (0.150-2x )^2
1.67 x 10^-7 = (0.375 +2x)^2 (x) / (0.150-2x )^2
4x^3 - 6.68 x 10^-7 x^2 + 0.141x -9.64 x 10^-8 = 0
by solving this equation
x = 6.84 x 10^-7
[S2] = x = 6.84 x 10^-7 M
equilibrium concentration = 6.84 x 10^-7 M