If the initial concentrations of A and B are 0M each, and the initial concentrations of C and D are 1.6M each, and Kc=4.7, what is the equilibrium concentration of A?

Explanation:

Hello,

In this case, for the reaction:

It is clear that the equilibrium expression is:

Nevertheless, since the initial concentrations of both A and B are 0 M and C and D 1.6 M, we should invert the reaction:

Thereby the equilibrium expression is also inverted:

Which can be written in terms of the reaction extent and initial concentrations as shown below:

Hence, solving for we obtain:

In such a way, the equilibrium concentration of A is:

Best regards.