Answer:
Step-by-step explanation:
From the question given, we obtained the following:
Molarity = 45.0 micromoles per liter = 45x10^-6mol/L
Volume = 3L
Mole =?
Molarity = mole /Volume
Mole = Molarity x Volume
Mole = 45x10^-6 x 3
Mole = 1.35x10^-4 moles
Therefore, 1.35x10^-4 moles of magnesium sulfate is needed to make the solution.