Suppose we carry out the precipitation of Ag₂CrO₄(s) described in Example 4-10. If we obtain 2.058 g of precipitate, we might conclude that it is nearly pure Ag₂CrO₄ but if we obtain 2.112 g, we can be quite sure that the precipitate is not pure. Explain this difference.

Example 4-10

A 25.00 mL pipetful of 0.250 M K₂CrO₄ is added to an excess of AgNO₃(aq). What mass of Ag₂CrO₄ will precipitate from the solution?

K₂CrO₄(aq) + 2 AgNO₃(aq)→Ag₂CrO₄(s) + 2 KNO₃(aq)