Calculate the molality of a solution containing 8.81 g glycerol (C3H8O3) dissolved in 63.50 g ethanol (C2H6O).

Answer 1

Glycerol

Molar mass glycerol = 92.095 g/mol

Mass: 8.81g

Mol: 8.81g x (1 mol / 92.095 g) = 0.0957 mol Glycerol

Ethanol

Molar mass ethanol = 46.069 g/mol (not needed here but would be needed if it was molarity)

Mass: 63.50 g or 0.06350 kg

Molality: moles of solute / kilogram of solvent

Moles of solute: 0.0957 mol Glycerol = 1.51 mol / kg

kg of solvent 0.06350 kg EtOH

Answer 2