Question

What mass of Na2SO4is needed to make 2.5 L of 2.0 Msolution? (Na = 23 g; S = 32 g; O = 16 g)

Answer 1

Answer:

mass (g) needed = 710.2 grams Na₂SO₄(s)

Explanation:

Needed is 2.5 Liters of 2.0M Na₂SO₄; formula wt Na₂SO₄ = 142.04g/mol.

mass (grams) of Na₂SO₄(s) = Molarity needed x Volume needed in Liters x Formula Wt of solute

mass (grams) of Na₂SO₄(s) = (2.5L)(2.0M)(142.04g/mol) = 710.2 grams Na₂SO₄(s)

Mixing: Transfer 710.4 grams Na₂SO₄ into mixing vessel and add water-solvent up to but not to exceed 2.5 Liters total volume. Mix until dissolved.

Gives 2.5 Liters of 2.0M Na₂SO₄(aq) solution.