Calculate the molality (m) of a 1820 g sample of a solution of the solute hexane dissolved in the solvent C6H6 if the sample contains 0.419 kg of hexane.

1 answer

Remember the definition of molality.
m = # moles solute/kg solvent.

Total g solution = 1820
mass hexane (C6H14) = 419
mass solvent (C6H6) = 1820-419 = 1401 g.

moles C6H14 = 419/molar mass.
kg solvent = 1.401
You do the math. Check my numbers.