Chapter 11 Practice Questions

Chapter 11 Practice Questions Answers: 1. 181 g/mol 2. 0.0207 m 3. B 4. C 5. E 6. D 7. A 8. B 9. A 10. D 11. C 12. 80.2oC 13. A 14. B 15. E 16. B 1. A solution contains 650 g of solvent, 20.0 g of solute and is known to be 0.170 m. What is the molar mass of the solute in g/mol? 2. Calculate the concentration (in molal) of KBr in a solution prepared by dissolving 2.21 g of KBr in 897 g of water. ___ 3. Which intermolecular force is most important between a sodium ion and its neighbors in a dilute NaCl(aq) solution? a. ion-ion b. ion-dipole c. dipole-dipole d. London dispersion e. hydrogen bonding ___ 4. If glycerol and benzene (both liquids) are mixed together and then allowed to stand, the mixture separates into two liquid layers of pure glycerol and pure benzene. These two liquids are a. solvated b. anhydrous c. immiscible d. unsaturated e. dissociated ___ 5. The phrase “like dissolves like” refers to the fact that ____________. a. gases can only dissolve other gases b. solvents can only dissolve solutes of similar molar mass c. condensed phases can only dissolve other condensed phases d. polar solvents dissolve nonpolar solutes and vice versa e. polar solvents dissolve polar solutes and nonpolar solvents dissolve nonpolar solutes ___ 6. Which one of the following substances would be the most soluble in CCl4? a. CH3CH2OH b. H2O c. NH3 d. C10H22 e. NaCl ___ 7. A crystal is placed in a solution and it dissolves. The solution must have been a. unsaturated. b. saturated. c. supersaturated. d. dilute. e. concentrated. ___ 8. A crystal of potassium chloride added to a solution of potassium chloride does not dissolve and the solution remains unchanged. The solution is a. dilute. b. saturated. c. supersaturated. d. unsaturated. e. colloidal. ___ 9. Which of the following factors is important only for the solubility of gases in solvents? a. the pressure of the gas. b. the nature of the solute. c. the nature of the solvent. d. the temperature. e. the atmospheric pressure. ___ 10. Which factor does not affect the solubility of a solid electrolyte in a liquid solvent? a. temperature b. nature of the solvent c. common ion d. pressure e. nature of the solute ___ 11. Colligative properties are all similar in that they all a. were discovered in college laboratories. b. are due to solvent molecules linked together. c. depend on the concentration of particles in solution. d. have no harmful side effects. e. involve pressure. 12. 1.40 g of toluene (C7H8) is dissolved in 50.0 g of benzene. The boiling point of the solution is found to be 81.0C. Calculate the boiling point of pure benzene, in C. Kb = 2.61C/m for benzene. ___ 13. A biologist dilutes blood cells with water on a glass slide. As she watches under the microscope, the cells seem to explode. This is probably because she a. used distilled water. b. used very salty water. c. added the water too rapidly. d. used dead cells. e. exposed the cells to red light. ___ 14. The magnitudes of Kf and of Kb depend on the identity of the _______________. a. solute b. solvent c. solution d. temperature e. solute and solvent ___ 15. Adding solute to a solution decreases the ____________ of the solution. a. vapor pressure b. boiling point c. freezing point d. osmotic pressure e. freezing point and vapor pressure ___ 16. After swimming in the ocean for several hours, the swimmers noticed that their fingers appeared to be very wrinkled. This is an indication that seawater is ___ relative to the fluid in cells. a. isotonic b. hypertonic c. hypotonic d. supertonic e. none of these