Question

A 40.0 g of a solute is dissolved in 500. mL of a solvent to give a solution with a volume of 495 mL. The solvent has a density of 1.00 g/mL. Which statement about this solution is correct?
A. The molarity is the same as the molality.
B. The molarity is lower than the molality.
C. The molarity and molality cannot be compared without knowing the density of the solution as well.
D. The molality is greater than the molality.
E. The molarity and molality cannot be compared without knowing the solute.

Answer 1

Answer:

The molarity is greater than the Molality

Explanation:

Molality is the quantity of solute contained per Kg of solvent

While the molarity of the solution is the number of moles per dm^-3

Mass of solute = 40g

Volume of solvent = 500ml

Density of solvent = 1 g/ml

Hence 500ml = 500g

Molality = 40/0.5 = 80g/M/Kg

While the molarity 40/0.495 = 80.81/M/dm^3

80.81/M/dm^3 > 80g/M/Kg

The molarity is greater than the Molality