Assessment Chapter Test A Chapter: Solutions In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question. 1. Agitation prevents settling in a(n) a. alloy. b. homogeneous mixture. c. suspension. d. gaseous mixture. 2. All of the following are heterogeneous mixtures except a. whole wheat bread. b. granite. c. tap water. d. an oil-water mixture. 3. What is the concentration of a 100. ml aqueous solution that contains 1.00 g KCl (molar mass 74.55 g/mol)? a. 1.34 M KCl b. 0.134 M KCl c. 0.0134 M KCl d. 0.001 34 M KCl 4. To determine the molarity of an HCl solution, you need to know the number of a. grams of HCl in 1 10 6 g of solution. b. moles of HCl dissolved in the total moles of solution. c. moles of HCl in 1 L of solution. d. moles of HCl dissolved in 1 kg of solvent. 5. What type of solute-solvent combination is carbon dioxide in water? a. gas-liquid b. liquid-gas c. liquid-liquid d. cannot be determined 6. What is the molarity of a solution that contains 0.202 mol KCl (molar mass 74.55 g/mol) in 7.98 L of solution? a. 0.0132 M KCl b. 0.0253 M KCl c. 0.459 M KCl d. 1.36 M KCl Modern Chemistry 104 Chapter Test
Use this figure to answer questions 7 and 8. Solubility (g per 100 g of water) 180 160 140 120 100 80 60 40 20 0 CsCl NaCH 3 COO SO 2 10 30 50 70 90 Temperature ( C) NaNO 3 RbCl LiCl NH 4 Cl KCl NaCl Li 2 SO 4 7. A solution containing 35 g of Li 2 SO 4 dissolved in 100 g of water is heated from 10 C to 90 C. According to information in the figure, this temperature change would result in a. an additional 5 g of Li 2 SO 4 in solution. b. an additional 30 g of Li 2 SO 4 in solution. c. 5 g of Li 2 SO 4 precipitate. d. no change in Li 2 SO 4 concentration. 8. According to saturation curves shown in the figure, which of the following solutions is supersaturated? a. 40 g of NaCH 3 COO in 100 g of water at 40 C b. 140 g of NaCH 3 COO in 100 g of water at 80 C c. 80 g of NaCH 3 COO in 100 g of water at 40 C d. 80 g of NaCH 3 COO in 200 g of water at 40 C 9. In 100 ml of cold water, 35 g of NaCl will dissolve, but 70 g will not. This observation implies that a. solubility depends on temperature. b. in order to dissolve more NaCl, you must increase the pressure. c. solubility depends on the amounts of solute and solvent present. d. NaCl is not easily hydrated. 10. What is the molarity of a solution that contains 125 g NaCl (molar mass 58.44 g/mol) in 4.00 L solution? a. 0.535 M NaCl b. 2.14 M NaCl c. 8.56 M NaCl d. 31.3 M NaCl Modern Chemistry 105 Chapter Test
11. Which of the following is soluble in water? a. potassium nitrate b. silver c. benzene d. carbon tetrachloride 12. In a solution at equilibrium, a. no dissolution occurs. b. the rate of dissolution is less than the rate of crystallization. c. the rate of dissolution is greater than the rate of crystallization. d. the rate of dissolution and the rate of crystallization are equal. 13. A dissolved solute that does not form ions is a. a nonelectrolyte. b. a weak electrolyte. c. a strong electrolyte. d. insoluble. 14. How many moles of HCl (molar mass 36.46 g/mol) are present in 0.70 L of a 0.33 M HCl solution? a. 0.23 mol b. 0.28 mol c. 0.38 mol d. 0.47 mol 15. If the temperature stays the same, the solubility of gases in liquids a. increases with increasing pressure. b. cannot reach equilibrium. c. decreases with increasing pressure. d. does not depend on pressure. 16. A NaOH solution contains 1.90 mol of NaOH (molar mass 40.00 g/mol), and its concentration is 0.555 M. What is its volume? a. 0.623 L b. 0.911 L c. 1.05 L d. 3.42 L 17. Which solution would be least likely to carry an electric current? a. NaCl b. HCl c. C 6 H 12 O 6 d. CsI Modern Chemistry 106 Chapter Test
18. Which type of mixture contains the smallest particles? a. emulsions b. solutions c. suspensions d. colloids 19. Which does not affect the rate at which a solid solute dissolves? a. the vapor pressure of the solvent b. the temperature of the solvent c. the surface area of the solid d. the speed at which the solution is stirred 20. Which pair of compounds is immiscible? a. water and alcohol b. water and toluene c. toluene and gasoline d. benzene and gasoline 21. Under which conditions is more CO 2 dissolved in a carbonated beverage? a. in a glass at room temperature b. in a bottle that has been left uncapped in the refrigerator c. in a glass with ice cubes d. in an unopened bottle in the refrigerator 22. A solid is dissolved in some water at 25 C in a beaker. The outside of the beaker feels cold to the touch. What does this tell you about this solution? a. The enthalpy of solution for the solid is negative. b. The solution has not come to equilibrium. c. The solution must be heated to continue the dissolving process. d. The enthalpy of solution for the solid is positive. 23. What is the molality of an aqueous NaOH solution made with 5.00 kg of water and 3.6 mol NaOH (molar mass 40.00 g/mol)? a. 3.6 m NaOH b. 1.4 m NaOH c. 0.72 m NaOH d. 0.090 m NaOH 24. How much methanol, CH 3 OH (molar mass 32.05 g/mol), is needed to make a 0.90 m solution in 250 g of water? a. 0.14 g CH 3 OH b. 7.2 g CH 3 OH c. 100 g CH 3 OH d. 220 g CH 3 OH Modern Chemistry 107 Chapter Test
25. What mass of NaCl (molar mass 58.44 g/mol) is needed to make a 1.50 m solution using 300. g of solvent? a. 26.3 g NaCl b. 11.7 g NaCl c. 1.50 g NaCl d. 0.0877 g NaCl Modern Chemistry 108 Chapter Test
TEACHER RESOURCE PAGE 26. According to the kinetic-molecular theory, the particles in a liquid can change relative positions but still are influenced by attractive forces. Their ability to move about explains the fluidity of liquids and their ability to diffuse. As some particles at the surface of a liquid gain energy, they overcome the attractive force and vaporize. 27. In ionic crystals, monatomic or polyatomic positive and negative ions are arranged in a regular pattern. In metallic crystals, metal atoms are surrounded by a sea of valence electrons. The electrons are donated by the metal atoms and belong to the crystal as a whole. 28. a. 10.7 kj b. 28.9 kj 29. 9.83 kj 30. 0.766 kj Equilibrium vapor pressure is the pressure exerted by a vapor in equilibrium with its corresponding liquid at a given temperature. a. A liquid boils when its equilibrium vapor pressure is equal to atmospheric pressure. At high elevations, there is lowered atmospheric pressure. This means that the equilibrium vapor pressure will equal the lowered atmospheric pressure at a lower temperature. b. Increasing the temperature of a liquid increases its average kinetic energy. That in turn increases the number of molecules that have enough energy to escape from the liquid phase into the vapor phase. This increased evaporation rate increases the concentration of molecules in the vapor phase, which increases the equilibrium vapor pressure. 11 Gases, pp. 93 103 TEST A 1. b 2. c 3. b 4. d 5. d 6. a 7. a 8. a 9. a 10. b 11. b 12. b 13. d 14. a 15. d 16. c 17. c 18. a 19. a 20. d 21. c 22. a 23. c 24. a 25. c TEST B 1. c 2. b 3. c 4. b 5. b 6. b 7. a 8. Avogadro s law 9. temperature 10. pressure 11. temperature 12. 760 mm 13. V P VP 14. effusion 15. pressure 16. newton 17. barometer 18. partial pressure 19. decrease 20. absolute zero 21. c 22. d 23. i 24. j 25. a 26. e 27. h 28. k 29. b 30. 5.7 10 2 mm Hg 31. 40. atm 32. 150. C 33. 459 mm Hg 34. 236 L 35. 16 g/mol 36. 2.05 g/l 37. 0.77 L 38. 22.3 g 39. 2.051 12 Solutions, pp. 104 113 TEST A 1. c 2. c 3. b 4. c 5. a 6. b 7. c 8. c 9. c 10. a Modern Chemistry 228 Answer Key
TEACHER RESOURCE PAGE 11. a 12. d 13. a 14. a 15. a 16. d 17. c 18. b 19. a 20. b 21. d 22. d 23. c 24. b 25. a TEST B 1. b 2. c 3. a 4. a 5. b 6. d 7. d 8. c 9. decreases 10. solute 11. colloid 12. equilibrium 13. nonpolar 14. ions 15. supersaturated solution 16. particle size 17. solution 18. exothermic 19. hydration 20. immiscible 21. solvated 22. hydrate 23. increase 24. alloy 25. Like dissolves like means that you can make a general prediction that polar solvents will dissolve polar solutes, and nonpolar solvents will dissolve nonpolar solutes. 26. Both terms are ways of expressing the concentration of a solution. Molarity is the number of moles of solute per liter of solution. Molality is the number of moles of solute per kilogram of solvent. 27. Solutions are homogeneous mixtures. Suspensions and colloids are heterogeneous mixtures. Solutions have the smallest particle size, followed by the size of colloid particles and suspension particles. Solutions and colloids do not settle out on standing, but suspensions do. Solutions and colloids cannot be separated by filtration, but suspensions can be. Solutions do not scatter light. Colloids scatter light. Suspensions may scatter light, but they are not transparent. 28. Ethanol must be polar, since it dissolves in water, which is a polar substance. Carbon tetrachloride must be nonpolar, since it does not dissolve in water. 29. 10.0 g/100 g H 2 O 30. 6.07 kg H 2 O 31. 12.0 g 32. 0.122 g MgCl 2 33. 24.4 g I 2 34. 0.0846 M 35. 1.67 L NaCl 36. 0.799 m C 12 H 22 O 11 13 Ions in Aqueous Solutions and Colligative Properties, pp. 114 124 TEST A 1. b 2. d 3. c 4. a 5. c 6. b 7. d 8. d 9. a 10. d 11. c 12. a 13. c 14. b 15. a 16. a 17. b 18. b 19. c 20. d 21. a 22. d 23. d 24. d 25. d TEST B 1. a 2. d 3. c 4. c 5. b 6. b 7. d 8. a 9. precipitation 10. semi-permeable membrane 11. electrolyte 12. spectator ion 13. three 14. osmotic pressure 15. H 3 O 16. Ca(NO 3 ) 2 17. greater 18. lower 19. 2K (aq) S 2 (aq) 20. Dissociation is the separation of ions that occurs when an ionic compound Modern Chemistry 229 Answer Key