Chapter 15 Study Questions
1. What is the mass percentage of KMnO4 in a solution containing 1.00 mole of KMnO4 and 158 g of water?
2. How many moles of KMnO4 are needed to prepare 335 g of a 22.0% solution?
3. How many moles of NaCl are in 275 mL of 0.500 M NaCl?
4. What mass of NaCl is needed to prepare 250. mL of a 2.00 M NaCl solution?
5. What volume of a 2.00 M NaCl solution is needed to make 125 mL of a 0.350 M NaCl solution?
6. What is the molarity of a solution made by dissolving 90.0 grams of glucose (C6H12O6; molar mass = 180. g/mole) in enough water to yield 200. mL of solution?
7. (Optional) What is the molarity of a 24.0% sucrose solution? The density of this solution is 1.10 g/cm3. (The molar mass of sucrose is 342 g/mole.)
8. When solutions of calcium chloride and silver nitrate are mixed, a silver chloride precipitate forms.
a) Write a balanced chemical equation for this reaction (include physical states).
b) What volume of 0.250 M calcium chloride is needed to form 1.72 grams of precipitate?
9. What volume of 0.400 M KOH is needed to neutralize 16.0 mL of 0.120 M HNO3?
10. List three properties of solutions that are colligative properties. List three properties of solutions that are not colligative properties.
11. Arrange the following solutions in order of decreasing boiling point:
a) pure water b) 1.0 M glucose (C6H12O6) c) 1.0 M Ca(NO3)2 d) 1.0 M MgSO4
12. Use the following equation to help you solve the problems below:
DTf = 1.86 °C x moles solute particles/kg water
a) What is the freezing point of a solution containing 0.11 moles of C6H12O6 in 55 g of H2O?
b) How many moles of a nonelectrolyte must be added to 200. grams of water to produce a solution with a freezing point of -2.79°C?
c) What is the freezing point of a solution containing 27.8 g of CaCl2 in 250 g of water? (Is CaCl2 an electrolyte or a nonelectrolyte and why is this important?)
Summary of Chapter 15: Solutions
molecular and ionic solutes
like dissolves like
nonpolar vs. polar solutes and solvents
Saturated, supersaturated and unsaturated solutions
solubility and temperature
dilution: V1 x M1 = V2 x M2
electrolytes and nonelectrolytes
volume x molarity = moles
how to prepare a solution from solid solute or by dilution
vapor pressure lowering
boiling point elevation
freezing point depression
calculate number of moles, concentration or molar mass from freezing point
DTf = 1.86 x moles solute/kg water