1. Calculate the vapor pressure at 25 °C for a solution prepared by dissolving 166.6 g of common table sugar (sucrose, molar mass = 342.3 g/mol) in 686.2 mL of water (molar mass = 18.01 g/mol). At 25 °C, the density of water is 0.9971 g/mL and its vapor pressure is 23.76 torr.
Enter your answer in 4 significant figures.
2. A solvent has a molar mass of 64.9 g/mol and a normal boiling point of 139.6 oC. The boiling point elevation constant, K b , for this solvent is 1.73 oC/m. If 11.9 g of a nonelectrolyte having a molar mass of 30.5 g/mol are mixed with 200.0 g of the solvent, what is the boiling point of the solution?
3. An aqueous solution prepared by dissolving 1.62 g of anhydrous AlCl3 in 50.0 g of water has a freezing point of -1.74 °C. Calculate the boiling point of this solution. Kf and Kb for water are 1.86°C/m and 0.512 °C/m, respectively. Assume the boiling point of water is 100.000 °C.
4. 0.110 m aqueous solution of a weak acid, HA, is 1.80% ionized. At what temperature does it freeze? Kf for water = 1.86o C/m
5. Given the following information about the general compound represented by the symbol AB dissolving in water, choose the correct responses from below.
AB(s) → A+(aq) + B-(aq)
If the heat of solvation for this compound is -30.8 kJ/mol and the crystal lattice energy is -62.2 kJ/mol, the ΔHsolution for this compound is _______________
The dissolution of compound AB in water is an _______________
If the water’s temperature is increased, the solubility of compound AB in water will _______
If the pressure of compound AB is increased, the solubility of compound AB in water will ____
6. 33.8 g of a nonelectrolyte compound is dissolved in 160.0 g of a solvent that has a normal freezing point of 27.7 oC. The resulting solution freezes at 26.5 oC. What is the molar mass of the nonelectrolyte compound? Kf for the solvent is 1.74 o C/m.
7. Three enclosed flasks with different volumes contain 50 mL of water at 40oC.
Flask 1 has a volume of 500. mL Flask 2 has a volume of 100. mL
Flask 3 has a volume of 250. mL
Which flask has the greatest vapor pressure of water? Which flask has the smallest amount of water vapor?
8. A solvent has a molar mass of 68.2 g/mol and a normal freezing point of 31.9 oC. The freezing point depression constant, K f, for this solvent is 3.39 oC/m. If 18.0 g of a nonelectrolyte (molar mass = 44.2 g/mol) are mixed with 110.0 g of the solvent, what is the freezing point of the solution?