A 2.0 L vessel is filled with 2.0 mol of SO2, 1.2 mol of O2 and 4.6 mol of SO3. After equilibrium of the formation reaction, there was 0.8 mol of SO2. Calculate Keq.
2SO2 (g) + O2 (g) ↔ 2SO3 (g)
To calculate Keq, we need to determine the concentrations of the reactants and products at equilibrium.
Initially, there are 2.0 mol of SO2, 1.2 mol of O2, and 4.6 mol of SO3 in a 2.0 L vessel. This means that the initial concentration of SO2 is 2.0 mol/2.0 L = 1.0 M, the initial concentration of O2 is 1.2 mol/2.0 L = 0.6 M, and the initial concentration of SO3 is 4.6 mol/2.0 L = 2.3 M.
At equilibrium, the concentration of SO2 is 0.8 mol/2.0 L = 0.4 M.
Using the stoichiometry of the reaction, we can determine that the change in concentration of SO3 is (2 * 0.4 M) = 0.8 M.
The equation for the reaction is:
2SO2 (g) + O2 (g) <--> 2SO3 (g)
From this equation, we can determine that the change in concentration of SO2 is (-2 * 0.4 M) = -0.8 M and the change in concentration of O2 is (-0.4 M).
Now, we substitute the changes in concentrations into the equilibrium expression:
Keq = ([SO3]^2) / ([SO2]^2 * [O2])
Keq = [(2.3 M - 0.8 M)^2] / [(0.4 M)^2 * (0.6 M)]
Keq = (1.5 M)^2 / (0.4 M)^2 * (0.6 M)
Keq = 2.25 M^2 / 0.16 M^3
Keq ≈ 14.06