1. Which of the following aqueous solutions has the highest boiling point at 1.0 atm?

2. A 0.2-M solution of K2CO3 is a better conductor of electricity than a 0.2-M solution of KBr. Which of the following best explains this observation?

3. Suppose a sample of a homogenous solution contains 10 percent hexane (molar mass 86 g mol−1) by mass. Which of the following statements is true regarding the minimum information needed to calculate the molarity of hexane in this solution?

4. What volume of distilled water should be added to 20 mL of 5 M HCl(aq) to prepare a 0.8-M solution?

5. What is the final concentration of Pb2+ ions when a 100 mL 0.20 M Pb(NO3)2 solution is mixed with a 100 mL 0.30 M NaCl solution?

6. A sample of 60 mL of 0.4 M NaOH is added to 40 mL of 0.6 M Ba(OH)2. What is the hydroxide concentration [OH–] of the final solution?

7. Salts containing which of the following ions are insoluble in cold water?

8. Sodium chloride is least soluble in which of the following liquids?

9. Which of the following pairs of liquids forms the most ideal solution when mixed in equal volumes at 25°C?

10. Ethanol, CH3CH2OH(l), and water, H2O(l), are mixed in equal volumes at 25°C and 1 atm. Mixing different proportions of ethanol and water produce different enthalpy values. At low concentrations of water or ethanol, solvation is exothermic, but for mixing equal amounts, it is endothermic. Which of the following is a logical interpretation of this observation?

11. What is the molality of a solution that has 29 g NaCl dissolved in 200 g of water?

12. An aqueous solution that is 66 percent C2H4O (44 g mol−1) by mass has a mole fraction of ethanol closest to:

13. A dilute hydrochloric acid solution was added to a sample of an unknown solution in a lab. A white precipitate was formed, filtered from the solution, washed with hot water, and then dissolved in a solution of NH3. A few drops of K2SO4 were added to the filtrate and another white precipitate formed. What two ions were precipitated out of solution?

14. A 360-mg sample of glucose, C6H12O6 (molar mass 180 g mol−1), is dissolved in enough water to produce a 200-mL solution. What is the molarity of a 10-mL sample of this solution?

15. What is the vapor pressure of a solution in which 2.00-mol propylene glycol, a nonvolatile compound, is mixed with 8.00-mol water? Assume the solution behaves ideally and is at the temperature where the vapor pressure of water is 20.0 mmHg.

16. A solution contains 144 g H2O and 92 g of ethanol (CH3CH2OH, molar mass 46 g mol−1). The mole fraction of ethanol is closest to:

17. A solution of NaCl is heated from 25°C to 75°C. True statements regarding this solution include which of the following? I. The molality of the solution did not change. II. The molarity of the solution did not change. III. The density of the solution did not change.

18. Ethanol, CH3CH2OH(l), and water, H2O(l), are mixed in equal volumes at 25°C and 1 atm. What is the mole fraction of ethanol in the solution? (The density of ethanol and water at 25°C are 0.79 g mL−1 and 1.0 g mL−1, respectively.)

19. A solution is prepared by dissolving a nonvolatile solute in a pure solvent. Compared to the pure solvent, the solution

20. BaF2 is sparingly soluble in water. The addition of dilute HF to a saturated BaF2 solution at equilibrium is expected to

21. A student mixes equal volumes of 1.0-M solutions of copper (II) chloride and magnesium sulfate, and no precipitate is observed. When the student mixes equal volumes of 1.0-M solutions of aluminum sulfate and copper (II) fluoride, a precipitate is observed. Which of the following is the formula of the precipitate?

22. Ethanol, CH3CH2OH(l), and water, H2O(l), are mixed in equal volumes at 25°C and 1 atm. The intermolecular forces between ethanol and water include: I. Hydrogen bonding II. Dipole–dipole attraction III. London dispersion forces

23. Which of the following compounds is the least soluble in water?

24. A 1.0-L solution contains 0.1 mol KCl, 0.1 mol CaCl2, and 0.1 mol AlCl3. What is the minimum number of moles of Pb(NO3)2 that must be added to precipitate all of the Cl− ions as PbCl2?

25. Ethanol, CH3CH2OH(l), and water, H2O(l), are mixed in equal volumes at 25°C and 1 atm. Which of the following include endothermic processes regarding the preparation of the solution? I. Ethanol molecules move away from other ethanol molecules as they move into solution. II. Water molecules move away from other water molecules as they move into solution. III. Ethanol molecules form hydrogen bonds with water molecules as they move into solution.