Question

The chemicals A and B react to produce C and D:

A+B⇄C+D, K =[C][D]/[A][B]
The equilibrium constant K has a value of 0.3. Assume 0.2mol of A and 0.5mol of B are
dissolved in 1.00L, and the reaction proceeds. Calculate the concentrations of reactants and
products at equilibrium?

Answer 1

Let's denote the equilibrium concentrations of A, B, C, and D as [A], [B], [C], and [D] respectively.

Since A and B are reactants, their concentrations decrease by x, so [A] = 0.2 - x and [B] = 0.5 - x.

C and D are products, so their concentrations increase by x, so [C] = x and [D] = x.

We can plug these into the equilibrium expression, which is given as K = [C][D]/[A][B] = 0.3:

0.3 = (x)(x) / ((0.2 - x)(0.5 - x))

Solving this equation for x will give the change in concentration for each substance, and thus the equilibrium concentrations. However, this equation is a quadratic and may require the quadratic formula to solve.