Question

3. Find the molarity of a solution made from 734 g of Li2SO4 and 2.5 L of water

Answer 1

mol wt of Li2SO4 = 109.9g/mole
So, you have 734/109.9 = 6.68 moles

6.68moles/2.5L = 2.67M solution

assuming the addition of the solute does not materially affect the volume of the solution.