What is the molality of a solution produced by dissolving 14.40 g of LiCl (42.39 g/mol) in water to make 0.104 L of solution with a density of 1.102 g/mL?
A)0.340 m
B)3.39 m
C)3.27 m
D)3.74 m
E)2.96 m

Question

Quizplus · Accepted Answer

Molality (m) is defined as the number of moles of solute per kilogram of solvent. First, calculate the moles of LiCl: $ \frac{14.40 \, \text{g}}{42.39 \, \text{g/mol}} = 0.3396 \, \text{moles} $. The mass of the solution is $ 0.104 \, \text{L} \times 1.102 \, \text{g/mL} = 114.608 \, \text{g} $. Since the solution is mostly water, subtract the mass of LiCl to find the mass of the water (solvent): $ 114.608 \, \text{g} - 14.40 \, \text{g} = 100.208 \, \text{g} $, which is $ 0.100208 \, \text{kg} $. Finally, $ \frac{0.3396 \, \text{moles}}{0.100208 \, \text{kg}} = 3.39 \, \text{m} $.

What Is the Molality of a Solution Produced by Dissolving