Hydrogen sulfide decomposes according to the following reaction, for which Kc = 9.30 10-8 at 700°C.
2 H2S(g) 2 H2(g) + S2(g)
If 0.46 mol H2S is placed in a 4.6 L container, what is the equilibrium concentration of H2(g) at 700°C?
So I thought that by using ice H2 would be 0.46 mol and that it would be 0.1 M but that was not right.
(H2S) = mols/L = 0.46 mol/4.6L = 0.1M
............2H2S ==> 2H2 + S2
I............0.1......0.....0
C............-2x......2x....x
E..........0.1-2x.....2x....x
Substitute the E line into Kc expression and solve for x, then 2x = (H2)
To find the equilibrium concentration of H2(g), we need to use the stoichiometry of the balanced reaction and the given equilibrium constant (Kc) value.
First, let's determine the initial concentration of H2S. We are given that 0.46 mol of H2S is placed in a 4.6 L container, so we can calculate the initial concentration as follows:
Initial concentration of H2S = (0.46 mol) / (4.6 L) = 0.1 M
Now, let's set up an ICE (Initial, Change, Equilibrium) table to represent the reaction:
2 H2S(g) 2 H2(g) + S2(g)
---------------------------
I 0.1 M 0 M
C -2x M +2x M
E 0.1 M - 2x 2x M
To apply the ICE method, we assume that x moles of H2(g) react, resulting in the formation of 2x moles of H2(g) and S2(g). Thus, the equilibrium concentrations of H2(g) and S2(g) should be 2x M and x M, respectively.
The expression for the equilibrium constant (Kc) is given as the ratio of product concentrations to reactant concentrations, each raised to their respective stoichiometric coefficients:
Kc = [H2]^2 [S2] / [H2S]^2
Given that Kc = 9.30 * 10^-8 and the concentration of H2S is 0.1 M, we can substitute these values into the expression:
9.30 * 10^-8 = (2x)^2 * x / (0.1 - 2x)^2
Next, we need to solve this equation for x. The equation is quadratic, so we'll need to use the quadratic formula or other numerical methods to solve for x.
Once we have the value of x, we can calculate the equilibrium concentration of H2(g) using the equation:
[H2(g)] = 2x
This will give us the equilibrium concentration of H2(g) in M at 700°C.