The equilibrium system shown below has a Ke = 8.3 x 10-2

Question

If [D] = 0.38 mol/L, what the [A]? 2A(g) + B(s) <=====> C(s) + 3D(g)

Answer 1

Given the chemical equation, the equilibrium expression is:

K_e = [D]³ /[A]² Substances B and C do NOT appear in the equilibrium expression. Recall that only gases and aqueous substances appear on the equilibrium expression as solids and liquids are presumed to have a constant concentration and so those values are incorporated in the equilibrium constant value given. The exponents of 3 and 2 come from the coefficients of substances D and A respectively.

Rearranging the above equation:

[A]² = [D]³ / K_e = (0.38)³ / (8.3 x 10^-2) = 0.661 To find [A], find the square root of 0.661

[A] = (0.661)^0.5 = 0.81 mol/L