Answer:
Equilibrium concentration of [S₂] is 1.67x10⁻⁷M
Explanation:
Based in the reaction:
2H₂S(g ) ⇌ 2H₂(g) + S₂(g)
Kc = 1.67x10⁻⁷ = [S₂] [H₂]² / [H₂S]²
The reaction is in equilibrium when [S₂] [H₂]² / [H₂S]² = Kc
With initial concentrations, the equilibrium concentrations must be:
[H₂S] = 0.100M - 2X
[S₂] = X
[H₂] = 0.100M + 2X
Replacing these values in Kc:
1.67x10⁻⁷ = [X] [0.100M + 2X]² / [0.100M - 2X]²
1.67x10⁻⁷ = 4X³ + 0.4X² + 0.01X / 4X² - 0.4X + 0.01
6.68x10⁻⁷X² - 6.68x10⁻⁸X + 1.67x10⁻⁹ = 4X³ + 0.4X² + 0.01X
0 = 4X³ + 0.4X² + 0.01X - 1.67x10⁻⁹
Solving for X:
X = 1.67x10⁻⁷M
As [S₂] = X, equilibrium concentration of [S₂] is 1.67x10⁻⁷M