What is the molarity of sodium sulphate in a solution prepared by dissolving 15.5g in enough water to make 35ml of solution?

Molarity = moles of solute/volume of solution

Find moles NaCl

55 grams NaCl (1mol NaCl/58.44 grams) = 0.941 moles NaCl

Molarity = 0.941 moles NaCl/35 Liters

= 0.027 Molarity NaCl

( sounds reasonable as 55 grams is not much in 35 Liters of water, which would be about 17.5 2 liter sodas )