A solution is prepared by dissolving 10.00g sucrose (mol wt=343g) in 50g water. The volume of resulting solution is 50mL. Calculate the following.

Question

A. Morality

B. Molality

C. Mole fraction

D. Mass%

E. Density of the solution

Answer 1

Molarity = moles sucrose / liter of solution

moles = 10.00 g x 1 mol / 343 g = 0.02915 moles

volume = 50 ml x 1 L / 1000 ml = 0.050 L

Molarity = 0.02915 moles / 0.050 L = 0.58 M (2 sig. figs.)

Molality = moles sucrose / kg water

Molality = 0.02915 moles / 0.05 kg = 0.58 m (2 sig. figs.)

Mole fraction = moles of sucrose / total moles = moles sucrose / moles sucrose + moles H2O

moles sucrose = 0.02915 moles

moles H2O = 50 g H2O x 1 mol H2O / 18 g = 2.78 moles H2O

Total moles = 2.78 + 0.02915 = 2.807 moles

Mole fraction of sucrose = 0.02915 mol / 2.807 mol = 0.010 (2 sig. figs.)

Density of solution = grams / ml

total grams = 50 g H2O + 10.0 g sucrose = 60.0 g

mls = 50 mls

density = 60 g / 50 mls = 1.2 g/ml (2 sig. figs.)