1. A solution contains 25.0 g of NaCl in 83.0 mL of solution. a) What is the %(w/v) concentration of the NaCl solution? b) What is the molarity of the NaCl solution?

Answer 1

%(w/v) means grams solute per 100 mls solution.

g solute = 25.0 g

vol solution = 83.0 ml

%(w/v) = 25.0/83.0 (x100) = 30.1% w/v

molarity = mols solute per liter soln

mols = 25.0 g NaCl x 1 mol/58.4 g = 0.428 mols

liters of soln = 83.0 mls x 1 L/1000 ml = 0.083 L

molarity (M) = 0.428 mol / 0.083 L = 5.16 M