If 500.0 ml of 0.10 m ca2+ is mixed with 500.0 ml of 0.10 m so42−, what mass of calcium sulfate will precipitate? ksp for caso4 is 2.40×10−5. express your answer to three significant figures and include the appropriate units.

Answer : The mass of calcium sulfate precipitate will be, 6.12 grams

Solution :

First we have to calculate the moles of and .

As, 0.05 moles of is mixed with 0.05 moles of  , it gives 0.05 moles of calcium sulfate.

Now we have to calculate the solubility of calcium sulfate.

The balanced equilibrium reaction will be,

The expression for solubility constant for this reaction will be,

Now put the value of in this expression, we get the solubility of calcium sulfate.

Now we have to calculate the moles of dissolved calcium sulfate in one liter solution.

Now we have to calculate the moles of calcium sulfate that precipitated.

Now we have to calculate the mass of calcium sulfate that precipitated.

Therefore, the mass of calcium sulfate precipitate will be, 6.12 grams