Solutions: Multiple Choice Review PSI AP Chemistry. 1. Which of the following would be FALSE regarding mixtures?

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1 Solutions: Multiple Choice Review PSI AP Chemistry Name Part A: Mixtures, Solubility, and Concentration 1. Which of the following would be FALSE regarding mixtures? (A) Mixtures do not obey the law of definite composition. (B) Mixtures are composed of only two pure substances. (C) Mixtures can be separated by physical methods. (D) Solutions, suspensions, and colloids are all considered mixtures. (E) None of these are false. 2. Identify the type of mixture of substances X, Y and Z based on the following data. Substance X Substance Y Substance Z Particle size 0.5nm 2000nm 500nm Settling of particles No Yes No Homogenous Yes No Yes Tyndall Effect No Yes Yes (A) X = suspension, Y= colloid, Z = solution (B) X = colloid, Y = solutions, Z = suspension (C) X = solution, Y = suspension, Z = colloid (D) X = colloid, Y = suspension, Z = solution 3. Which of the following physical methods is often employed to separate a solution? I. Distillation II. Filtration III. Evaporation (A) I only (B) II only (C) III only (D) I and II only (E) I and III only 4. Which of the following is FALSE regarding a suspension? (A) Suspensions have larger particles than solutions. (B) Solutions cannot be separated by filtration. (C) A sample of a suspension will not be uniform in composition. (D) Suspensions have smaller particles than colloids. (E) Solutions demonstrate the Tyndall effect.

2 5. A mixture of crystals of salt and sugar is added to water and stirred until all solids have dissolved. Which statement best describes the resulting mixture? (A) The mixture is homogeneous and can be separated by filtration. (B) The mixture is homogeneous and cannot be separated by filtration. (C) The mixture is heterogeneous and can be separated by filtration. (D) The mixture is heterogeneous and cannot be separated by filtration. 6. The phrase "like dissolves like" refers to the fact that. (A) gases can only dissolve other gases (B) polar solvents dissolve polar solutes and nonpolar solvents dissolve nonpolar solutes (C) solvents can only dissolve solutes of similar molar mass (D) condensed phases can only dissolve other condensed phases (E) polar solvents dissolve nonpolar solutes and vice versa 7. Ionic solids will most likely dissolve in (A) H2O(l), which is a polar solvent (B) H2O(l), which is a nonpolar solvent (C) CCl4(l), which is a polar solid (D) CCl4(l), which is a nonpolar solvent 8. Of the following, should be immiscible with carbon tetrachloride, CCl4. (A) C6H14 (B) Br2 (C) CH3CH2OH (D) C3H8 (E) I2 9. Which one of the following substances is more likely to dissolve in benzene (C6H6)? (A) CH3CH2OH (B) NH3 (C) NaCl (D) CCl4 (E) HBr 10. Which one of the following is most soluble in water? (A) CH3OH (B) CH3CH2CH2OH (C) CH3CH2OH (D) CH3CH2CH2CH2OH (E) CH3CH2CH2CH2CH2OH

3 11. Which one of the following is most soluble in hexane (C6H14)? (A) CH3OH (B) CH3CH2CH2OH (C) CH3CH2OH (D) CH3CH2CH2CH2OH (E) CH3CH2CH2CH2CH2OH 12. Which of the following substances is more likely to dissolve in water? O (A) CH 3 (CH 2 ) 9 CH (B) HOCH2CH2OH (C) CHCl3 (D) CH3(CH2)8CH2OH (E) CCl4 13. Which of the following is a water soluble substance whose solubility will increase with increasing temperature? (A) NH3(g) (B) LiOH(s) (C) CaCO3(s) (D) CBr4(l) (E) CO2(g) 14. Which of the following is a water soluble substance whose solubility will decrease with increasing temperature? (A) NH3(g) (B) LiOH(s) (C) CaCO3(s) (D) CBr4(l) (E) CO2(g) 15. A solution in a beaker has some un-dissolved solute lying on the bottom of the beaker. If the rate of crystallization is equal to the rate of dissolution of the excess solute, the solution is described as (A) dilute. (B) concentrated. (C) unsaturated. (D) saturated. (E) supersaturated.

4 16. A saturated solution. (A) contains as much solvent as it can hold (B) contains no double bonds (C) contains dissolved solute in equilibrium with undissolved solute (D) will rapidly precipitate if a seed crystal is added (E) cannot be attained 17. An unsaturated solution is one that. (A) has no double bonds (B) contains the maximum concentration of solute possible, and is in equilibrium with undissolved solute (C) has a concentration lower than the solubility (D) contains more dissolved solute than the solubility allows (E) contains no solute 18. Which procedure will increases the solubility of KCl in water? (A) stirring the solute and solvent mixture (B) increasing the surface area of the solute (C) raising the temperature of the solvent (D) increasing the pressure on the surface of the solvent 19. The curve to the right best represents the solubility curve for... (A) LiBr (B) C6H6 (C) NH3 (D) NaI (E) None of these 20. The bottler of a carbonated beverage dissolves carbon dioxide in water by placing carbon dioxide in contact with water at a pressure of 1 atm at room temperafure. The best way to increase the amount of dissolved CO2, would be to (A) increase the temperafure and increase the pressure of CO2. (B) decrease the temperature and decrease the pressure of CO2. (C) increase the temperature without changing the pressure of CO2. (D) decrease the temperature and increase the pressure of CO2. (E) increase the pressure of CO2 without changing the temperature.

5 21. How many moles of KNO3 would dissolve in a saturated solution containing 200 g of C. Assume the solubility of KNO3 is 40.0 g/100 g C. (A) mol (B) mol (C) 80.0 mol (D) 4.95 mol (E) 5.06 x 10 4 mol 22. Using the solubility data below, how many grams of solute could be recrystallized if the temperature is dropped from 43 o C to 32 o C? Temperature ( o C) Solubility of KNO3 (g/100g of H2O) (A) 10 grams (B) 15 grams (C) 20 grams (D) 30 grams (E) 40 grams

6 23. A sample of potassium nitrate (49.0 g) is dissolved in 101 g of water at 100 C, with precautions taken to avoid evaporation of any water. The solution is cooled to 30.0 C and no precipitate is observed. This solution is. (A) hydrated (B) placated (C) saturated (D) unsaturated (E) supersaturated 24. What is the molarity of an aqueos KNO3 25 o C assuming a solubility of 40 g KNO3/100 g H20. Assume a density of 1g/mL solution. (A) M (B) M (C) 3.96 M (D) M (E) 40.4 M 25. An aqueous solution of ethanol, C2H5OH, is 19.00% ethanol by mass and has a density of g/ml. Calculate the molality of the ethanol solution. (A) m (B) m (C) m (D) m (E) m 26. Consider a M Al(NO3)3 solution. This solution has a nitrate ion concentration of: (A) M (B) M (C) 2.70 M (D) 3.60 M (E) 8.10 M

7 27. How many moles of I - are present in L of a M solution of CoI2? (A) 2.00 (B) (C) (D) (E) How many ml of water must have evaporated from a 400 ml 0.2 M HCl solution to produce a 0.8 M solution of HCl? (A) 300 ml (B) 100 ml (C) 400 ml (D) 200 ml (E) 50 ml 29. Which of the following will change upon heating a solution assuming no evaporation has taken place? (A) Molality (B) Molarity (C) Mole fraction (D) Mass % 30. A solution is prepared by dissolving 17.0 g of NH3 in g of water. The mole fraction of NH3in the solution is. (A) (B) 0.05 (C) (D) 0.92 (E) A solution contains equal masses of glucose (molecular mass 180) and toluene (molecular mass 90). What is the mole fraction of glucose in the solution? (A) 1/4 (B) 1/3 (C) 1/2 (D) 2/3 (E) 3/4

8 32. What is the mole fraction of an aqueos 100 ml solution that is 0.10 M NaCl. Assume the density of the solution hnis 1.0 g/ml (A) 6.12 (B) (C) 5.12 (D) (E) 0.96 Part B: Formation and Properties 33. Which of the following is true regarding the soltution formation process. (A) Interolecular forces between the solute particles must weaken in which the enthalpy change is exothermic (-) (B) Intermolecular forces between the solvent molecules must weaken in which the enthalpy change is exothermic (-) (C) New coulombic attractions between the solute and solvent form in which the enthalpy change is (-) (D) Covalent bonds within the solute and solvent molecules must be broken (E) None of the above 34. Which of the following is NOT true regarding the heat of solution for a dissolution process? (A) The formation of hydrogen bonds between solutes and solvents release large amounts of energy when formed (B) Ideal solution have a heat of solution equal to zero (C) An endothermic dissolution process becomes more favorable as the temperature increases (D) An exothermic dissolution process becomes more favorable as the temperature increases (E) None of the above 35. In an aqueous solution of an ionic salt, the oxygen atom of the water molecule is attracted to the (A) negative ion of the salt, due to oxygen s partial positive charge (B) negative ion of the salt, due to oxygen s partial negative charge (C) positive ion of the salt, due to oxygen s partial positive charge (D) positive ion of the salt, due to oxygen s partial negative charge

9 36. In aqueous solution, a chloride ion is attracted to which end of the water molecule? (A) the hydrogen end, which is the partial positive pole (B) the hydrogen end, which is the partial negative pole (C) the oxygen end, which is the partial positive pole (D) the oxygen end, which is the partial negative pole 37. A sample of 10.6 g of KNO3 was dissolved in g of water at 25 o C. The final temperature of the solution was 21.5 o C. What is the molar heat of solution of KNO3? Assume the specific heat of the solution is 4.2 J/. (A) kj/mole (B) kj/mole (C) kj/mole (D) kj/mole (E) kj/mol 38. The ΔH for the solution process when solid sodium hydroxide dissolves in water is 44.4 kj/mol. When a 10.1-g sample of NaOH dissolves in g of water in a coffeecup calorimeter, the temperature increases from 23.0 C to C. Assume that the solution has the same specific heat as liquid water, i.e., 4.18 J/g-K. (A) 33.3 (B) 35.2 (C) 24.0 (D) 33.7 (E) Which of the following is not a strong electrolyte? (A) KNO3 (B) NaClO4 (C) CH3CO2H (D) KCl (E) MgSO4 40. A m solution of which one of the following solutes will have the greatest conductivity? (A) KClO 4 (B) Ca(ClO 4 ) 2 (C) pure water (D) CH2CO2H (E) NaCl

10 41. Which of the following pairs of liquids would form the most ideal solution? (A) C3H8(l) and H2O(l) (B) CH3CH2OH(l) and H2O(l) (C) CH3CH2OH(l) and C8H18(l) (D) C9H20(l) and C10H22(l) (E) HNO3(l) and H2O(l) 42. As the concentration of a solute in a solution increases, the freezing point of the solution, the boiling point, and the vapor pressure of the solution. (A) increases, increases, decreases (B) increases, decreases, decreases (C) decreases, increases, decreases (D) decreases, decreases, dcreases (E) increases, increases, increases 43. A M solution of which one of the following solutes will have the highest vapor pressure? (A) NaClO4 (B) Mg(ClO4)2 (C) AlCl3 (D) C6H12O6 (E) KCl 44. The vapor pressure of pure water at 25 C is 23.8 torr. What is the vapor pressure (torr) of water above a solution prepared by dissolving 18.0 g of glucose (a nonelectrolyte, MW = g/mol) in 95.0g of water? (A) 24.3 (B) 23.4 (C) (D) (E) Which liquid will have the lowest freezing point? (A) pure H2O (B) aq M glucose (C) aq M sucrose (D) aq M FeI3 (E) aq M KF

11 46. Which of the following aqueous solutions will have the highest boiling point? (A) 0.10 m Na2SO4 (B) 0.20 m glucose (C) 0.25 m sucrose (D) 0.10 m NaCl (E) 0.10 m SrSO4 47. What would be the freezing point of a 120 ml solution of 0.60 M Ca(NO3)2? Assume a Kb of C/m for water and a density of the solution of 1.01 g/ml. The molal freezing point depression constant for water is C/m. (A) (B) (C) 3.32 (D) 1.11 (E) What is the boiling point change for a solution containing moles of naphthalene (a nonvolatile, non-ionizing compound) in 250. g of liquid benzene? (Kb= 2.53 C/m for benzene) (A) 3.32 C (B) 1.93 C (C) 7.41 C (D) 4.31 C (E) o C 49. What is the boiling point of a 2 m solution of NaCl in water? (The boiling point elevation constant, kb, for water is 0.51 o C/m) (A) 100 o C (B) 101 o C (C) 102 o C (D) 103 o C (E) 104 o C 50. A solution, which was made by dissolving g of a nonelectrolyte in 500 g of water, exhibits a freezing point of C. What is the molecular weight of this nonelectrolyte compound? For water, Kf is 1.86 C/ m and Kb is 0.51 C /m. (A) 57.7 g mol-1 (B) 124 g mol-1 (C) g mol-1 (D) 115 g mol-1 (E) 231 g mol-1

12 51. The osmotic pressure of a solution formed by dissolving g of aspirin (C9H8O4) in L of water at 25 C is atm. (A) 13.6 (B) (C) (D) 2.45 (E) 1.38

13 1. B 2. C 3. E 4. B 5. B 6. B 7. A 8. C 9. D 10. A 11. E 12. B 13. B 14. A 15. D 16. C 17. C 18. C 19. C 20. D 21. A 22. C 23. D 24. C 25. D 26. C 27. C 28. A 29. B 30. B 31. B 32. E 33. C 34. D Answers 35. D 36. A 37. B 38. A 39. C 40. B 41. D 42. C 43. D 44. B 45. E 46. A 47. A 48. A 49. C 50. B 51. C

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