Sodium sulfate is slowly added to a solution containing 0.0500 M Ca 2 + ( aq ) and 0.0390 M Ag + ( aq ) . What will be the concentration of Ca 2 + ( aq ) when Ag 2 SO 4 ( s ) begins to precipitate?

The given question is incomplete. The complete question is as follows.

Sodium sulfate is slowly added to a solution containing 0.0500 M and 0.0390 M . What will be the concentration of (aq) when begins to precipitate? What percentage of the can be separated from the Ag(aq) by selective precipitation?

Explanation:

The given reaction is as follows.

= 0.0390 M

When precipitates then expression for will be as follows.

        = 0.00788 M

Now, equation for dissociation of calcium sulfate is as follows.

            = 0.00625 M

Now, we will calculate the percentage of remaining in the solution as follows.

                 = 12.5%

And, the percentage of that can be separated is as follows.

                     100 - 12.5

                     = 87.5%

Thus, we can conclude that 87.5% will be the concentration of when begins to precipitate.

the answer to this question is 3.

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)