The formula for Epsom salts is MgSO4*7H2O. If 1.250g of the compound is dissolved in water, calculatenthe number of milliliters of 0.200M Ba(NO3)2 that would be required to just precipitate all of the sulfate as barium sulfate.

25 mL

Explanation:

From the balanced equation of reaction:

1 mole of the epsom salt requires 1 mole of to precipitate barium sulfate.

mole of epsom salt = mass/molar mass

                              =  1.250/246.4746 = 0.0051 mole

Hence, 0.0051 mole of epsom salt will also require 0.0051 mole of for sulafe's precipitation.

Molarity of = mole/volume = 0.200 M

Volume = mole/molarity

                 = 0.0051/0.200

                      = 0.025 Liter

0.025 Liter = 25 milliliters.

25 milliliters of 0.200 M would be required to precipitate all the sulfate as barium sulfate.