Social Work homework help. Hello, I need help with the following chem question. A 15.0 mL sample of NaCl solution has a mass of 15.78% g. After the NaCl solution is evaporated to dryness, the dry salt residue has a mass of 3.26 g. Calculate the following concentrations for the NaCl solution.1. % (m/m)2. % (m/v)3. molarity (M)