A student mixed 300g of MgSO4 in water to a final volume of 6.00L. What is the molar concentration of the solution?

Answer 1

molar mass MgSO4 = 120.4 g/mol

Molarity (M) = moles solute / liter solution

moles solute = 300 g MgSO4 x 1 mol / 120.4 g = 2.49 moles

Liters of solution = 6.00 L

M = 2.49 moles / 6.00 L = 0.415 M (3 sig. figs; even though technically 300 g has only 1 sig. fig.)