Chemistry Chapter 12 Solutions Part 4

1. Identify the CORRECT statement concerning the solubility of various solutes: a) NaCl would be soluble in the hydrocarbon solvent hexane. b) CaCl2 would be soluble in water. c) KCl would be soluble in the hydrocarbon solvent benzene. d) Hexane and benzene would be immiscible. e) Alcohols and water are generally immiscible. 2. Under what conditions are the molality and molarity of a solution nearly the same? a) For all solutions where water is the solvent. b) For all solutions which are very dilute. c) For all dilute solutions in which the solvent has a density near 1.0 g/mL. d) For all solutions in which the solvent has a density near 1.0 g/mL. 3. What is the molarity of a solution in which 50.0 mL of chloroform, CHCl3, are placed in a 100.0 mL volumetric flask and the flask is filled to the mark with acetone? The density of pure CHCl3 is 1.483 g/mL. a) 6.21 M b) 0.500 M c) 5.00 M d) 4.188 M e) 0.006 M 4. What is the molality of a urea solution in which 10.0 grams of urea, (NH2)2CO are added to 300.0 mL of water at STP? a) 0.166 m b) 5.55 x 10-4 m c) 33.3 m d) 3.33 x 10-2 m e) 0.555 m 5. What is the mole fraction of sulfuric acid in an aqueous solution which is 4.00 M sulfuric acid? The density of the solution is 1.250 g/mL. a) 0.941 b) 0.0672 c) 0.0625 d) 0.0774 6. A solution has a mole fraction of the nonvolatile solute sucrose of 0.125. The vapor pressure of the pure solvent is 26.0 torr at 25°C. What is the vapor pressure of the solution? a) 3.25 torr b) 22.75 torr c) 26.0 torr d) 760 torr 7. What would be the freezing point of a 3.00 m aqueous solution of a nonvolatile, nonelectrolyte material? The cryoscopic constant of water is Kf = 1.86 °C/molal. a) 5.6° C b) -5.6 °C c) -3 ° C d) -1.86 °C 8. A solution was made by dissolving 4.50 grams of a nonvolatile solute in 100.0 grams of acetone. The solution boiled at 56.12 °C. The boiling point of pure acetone is 55.95°C and its Kb = 1.71°C/molal. What is the molecular weight of the unknown solute? a) 453 g/mol b) 492 g/mol c) 2.23 x 105 g/mol d) 223.5 g/mol 9. Colloids can be distinguished from true solutions by: a) the dispersing medium. b) the hydrophobic nature of the solute. c) the sizes of the dispersed particles. d) the fact that no settling out occurs in the colloidal dispersion. 10. A colloidal suspension in which a liquid mist is suspended in a gaseous dispersing medium would be called: a) a gel b) a foam c) an emulsion d) an aerosol 11. Identify the INCORRECT statement below concerning the formation of solutions. a) The large crystal lattice energy of ionic solids is generally favorable to their solution formation. b) The entropy change upon mixing generally is a favorable factor for the formation of a solution. c) An exothermic heat of solution would favor the formation of a solution relative to an endothermic one. d) The exothermic hydration of ions in water is generally a favorable factor to solution formation. e) One may generally say that "like dissolves like." 12. Identify the INCORRECT statement below: a) An endothermic heat of solution for NaCl(aq) implies that its solubility would increase as T increases. b) Henry's Law relates the pressure of a gas above a liquid to the concentration of dissolved gas. c) The solubility of a substance always increases when the temperature of solution is increased. d) Raoult's Law relates the vapor pressure of a liquid to its mole fraction in the solution phase. e) A colligative property is a physical property of a solution that depends on the number of solute particles, and not their identity. 13. Another name for a true solution is: a) heterogeneous mixture b) homogeneous mixture c) suspension d) colloid 14. Which factor below would generally favor solution formation? a) nonpolar solvents b) endothermic heat of solution c) large crystal lattice energy of solute d) entropy of mixing 15. Which substance would have the highest solubility in hexane, C6H14? a) NaCl b) H2O c) S8 d) NH3 16. A 10.0% aqueous solution of glucose C6H12O6 by mass used in intravenous feeding would have what molality? a) 0.617 mol/kg b) 0.555 mol/kg c) 0.100 mol/kg d) 0.111 mol/kg 17. What additional piece of information would be required to calculate the molarity of the solution in Problem #16? a) mole fraction of the solute b) molecular weight of solvent c) mass density of the solution d) heat capacity of the solution 18. A colloidal suspension in which tiny droplets of oil are suspended in soapy water (when doing dishes, etc.) is called: a) a gel b) an aerosol c) a foam d) an emulsion 19. Oil is solubilized in soapy water by the: a) formation of micelles b) Tyndall effect c) reverse osmosis process d) eutrophication process 20. Suppose 3.6 grams of an unknown solute is dissolved in 100 grams of liquid benzene and the freezing point of the liquid is lowered by 2.56° C. Which of the following substances is this unknown substance most likely to be? The cryoscopic constant of benzene is 5.12° C/molal. a) C6H14 b) C5H12 c) H2O d) NaCl 21. Identify the INCORRECT statement below: a) Henry's Law relates the pressure of a gas above a liquid to the concentration of dissolved gas. b) The solubility of a substance generally increases when the temperature of solution is increased. c) A colligative property is a physical property of a solution that depends on the number of solute particles, and not their identity. d) An endothermic heat of solution for NaCl(aq) implies that its solubility would increase as T increases. e) Raoult's Law relates the vapor pressure of a liquid to its mole fraction in the solution phase. 22. Colloids can be distinguished from true solutions by: a) the hydrophobic nature of the solute b) the dispersing medium c) the fact that no settling out occurs in the colloidal dispersion d) the sizes of the dispersed particles KEY 1)b 2)c 3)a 4)e 5)d 6)b 7)b 8)a 9)c 10)d 11)a 12)c 13)b 14)d 15)c 16)a 17)c 18)d 19)a 20)b 21)b 22)d .