CHEM 14 PROBLEM SET 3 SS SY 2014-2015 !

Arrange the following substances in order of: 1. Increasing solubility in water A) NH3 B) I2 C) KNO3 D) CH3Cl !2. Decreasing solubility in water A) O2 (g) at 0oC and 1 atm B) O2 (g) at 40oC and 1 atm C) O2 (g) at 0oC and 4 atm !3. Increasing freezing point A) 0.30 m Ba(OH)2 B) 0.30 m CO(NH2)2 C) 0.30 m Fe(NO3)3 D) 0.30 m Al2(SO4)3 !4. Increasing boiling point A) 0.060 m NH4NO3 B) 0.040 m NiCl3 C) 0.080 m C6H12O6 D) 0.050 m Al2(SO4)3 !5. Increasing osmotic pressure A) 1.0 M CaCl2 B) 1.0 M CH3COOH C) 1.0 M HCl D) 1.0 M sucrose !!6. Increasing acidity A) H3PO3 B) H3AsO3 C) H3PO4 !Multiple Choice 1. 35.0 mL of 0.255 M nitric acid is added to 45.0 mL of 0.328 M Mg(NO3)2. What is the concentration of nitrate ion in the final solution? A) 0.481 M B) 0.296 M C) 0.854 M D) 1.10 M E) 0.0295 M !2. Which of the following pairs are NOT miscible? A) Pentane and hexane B) Ethyl alcohol and water C) Benzene and hexane D) Hexane and water E) Methyl alcohol and water !3. Arrange the acids HBr, H2Se, and H3As in order of increasing acid strength. A) HBr < H2Se < H3As B) HBr < H3As < H2Se C) H2Se < H3As < HBr D) H3As < H2Se < HBr E) H3As < HBr < H2Se !

4. Arrange the following acids, HOBr, HBrO3, and HBrO2 in order of increasing acid strength. A) HOBr < HBrO3 < HBrO2 B) HOBr < HBrO2 < HBrO3 C) HBrO2 < HOBr < HOBrO3 D) HBrO3 < HOBr < HBrO2 E) HBrO3 < HBrO2 < HOBr !5. Identify the ionic species present in an aqueous solution of Na2CO3. A) Na2+, CO32 D) Na+, C+, O2 B) Na2+, C2, O3 E) Na+, CO32 C) Na+, C4+, O32 !6. The distinguishing characteristic of all electrolyte solutions is that they A) contain molecules. D) always contain acids. B) conduct electricity. E) conduct heat. C) react with other solutions. !7. A saturated solution A) contains more solute than solvent. B) contains more solvent than solute. C) contains equal moles of solute and solvent. D) contains the maximum amount of solute that will dissolve in that solvent at that temperature. E) contains a solvent with only sigma bonds and no pi bonds (i.e. only single bonds, with no double or triple bonds) !8. Heat of solution A) is never positive, because the solute-solvent interaction is never weaker than the combination of the solute-solute attraction and solvent-solvent attraction. B) is always positive, because the solute-solvent attraction is always weaker than the combination of the solute-solute attraction and solvent-solvent attraction. C) is always zero, because the solute-solvent attraction is defined as the average of the solute-solute attraction and solvent-solvent attraction. D) is always negative, because the solute-solvent attraction is always stronger than the combination of the solute-solute attraction and solvent-solvent attraction. E) may be positive, zero, or negative, depending on the relative strength of the solute-solvent, solute-solute, and solvent-solvent attractive forces. !9. Which of the following pair/s are miscible? !Pair #1: octane (C8H18) and water Pair #2: acetic acid (CH3COOH) and water Pair #3: octane (C8H18) and carbon tetrachloride(CCl4) A) 1, 3 B) 1, 2 C) 3 D) 2 E) 2, 3 !10. What is the percent CdSO4 by mass in a 1.0 molal aqueous CdSO4 solution? A) 1.00 X 10-3% B) 0.100 % C) 17.2 % D) 20.8 % E) 24.4 % !11. What is the percent CsCl by mass in a 0.711 M CsCl solution that has a density of 1.091 g/mL? A) 3.87 X 10-4% B) 3.87 X 10-1% C) 11.0 % D) 1.10 % E) 6.50 X 10-2% !12. In how many grams of water should 25.31 g of potassium nitrate (KNO3) be dissolved to prepare a 0.1982 m solution? A) 250.0 g B) 792.0 g C) 1,000 g D) 1,263 g E) 7,917 g !13. The density of a 20.3 M CH3OH (methanol) solution is 0.858 g/mL. What is the molality of this solution? H2O is the solvent. A) 17.4 m B) 20.8 m C) 23.7 m D) 70.0 m E) 97.6 m

14. The solubility of gases in water usually decreases with A) increasing pressure B) increasing temperature C) decreasing temperature. !15. Oxygen gas makes up 21 % of the atmosphere by volume. What is the solubility of O2(g) in water at 25C if the atmospheric pressure is 741 mmHg? The Henrys Law constant for oxygen gas at 25 is 1.3 X 10-3 mol/L atm. A) 2.7 X 10-4 M B) 1.3 X 10-3 M C) 6.2 X 10-3 M D) 9.6 X 10-3 M E) 0.96 M !16. The solubility of oxygen in lakes high in the Rocky Mountains is affected by the altitude. If the solubility of O2 from the air is 0.96 M at sea level and 25C, what is the solubility of O2 at an elevation of 12,000 ft where the atmospheric pressure is 0.657 atm? Assume the temperature is 25C, and that the mole fraction of O2 in air is 0.209 at both 12,000 ft and at sea level. A) 1.75 X 10-4 M B) 2.67 X 10-4 M C) 3.66 X 10-5 M D) 4.06 X 10-4 M E) None of the above !17. At 10C, one volume of water dissolves 3.10 volumes of chlorine gas at 1.00 atmpressure. What is the Henrys Law constant in mol/Latm? A) 3.8 B) 0.043 C) 36 D) 3.1 E) 0.13 !18. Which of the following liquids will be a good solvent for iodine, I2? A) HCl B) H2O C) CH3OH D) NH3 E) CS2 !19. Consider a solution made from a nonvolatile solute and a volatile solvent. Which statement is true? A) The vapor pressure of the solution is always greater than the vapor pressure of the pure solvent. B) The boiling point of the solution is always greater than the boiling point of the pure solvent. C) The freezing point of the solution is always greater than the freezing point of the pure solvent. !20. The vapor pressure of water at 20C is 17.5 mmHg. What is the vapor pressure of water over a solution prepared from 2.00 X 102 g of sucrose (C12H22O11) and 3.50 X 102 g water? A) 0.51 mmHg B) 16.0 mmHg C) 17.0 mmHg D) 18.0 mmHg E) 19.4 mmHg !21. Dissolving a solute such as KOH in a solvent such as water results in A) an increase in the melting point of the liquid. B) a decrease in the boiling point of the liquid. C) a decrease in the vapor pressure of the liquid. D) no change in the boiling point of the liquid. !22. Which of the following aqueous solutions has the highest boiling point? Kb for water is 0.52C/m. A) 0.2 m KCl B) 0.2 m Na2SO4 C) 0.2 m Ca(NO3)2 D) A and B E) B and C !23. Which of the following aqueous solutions has the highest osmotic pressure at 25C? A) 0.2 M KBr B) 0.2 M ethanol C) 0.2 M Na2SO4 D) 0.2 M KCl !24. During osmosis A) pure solvent diffuses through a membrane but solutes do not. B) pure solutes diffuse through a membrane but solvent does not. C) pure solvent and a solution both diffuse at the same time through a membrane. D) gases diffuse through a membrane into a solution and build up pressure. !25. What mass of ethanol, C2H5OH a nonelectrolyte, must be added to 10.0 L of water to give a solution that freezes at 10.0C? Assume the density of water is 1.0 g/mL. Kf of water is 1.86C/m. A) 85.7 kg B) 24.8 kg C) 5.38 kg D) 2.48 kg E) 1.17 kg !!

26. What volume of water should be added to 600 mL of ethanol in order to have a solution that boils at 95.0C? (For ethanol, Kb = 1.22 C/m, density = 0.789 g/cm3, boiling point = 78.4C) A) 186 mL B) 245 mL C) 518 mL D) 116 mL E) 322 mL !27. Which of the following aqueous solutions would be expected to have the highest boiling point? A) 0.100 m CaCl2 B) 0.200 m NaOH C) 0.050 m K2SO4 D) 0.050 m Al2(SO4)3 E) 0.200 m CH3OH !28. What is the boiling point of an aqueous solution of a nonelectrolyte that has an osmotic pressure of 10.50 atm at 25C? Kb of water is 0.52C/m. Assume the density of the solution is the same as that of pure water. A) 0.22C B) 0.429C C) 100.43C D) 99.78C E) 100.22C !29. An aqueous dextrose solution having a density of 1.04 g/cm3 freezes at 1.15C. Find the osmotic pressure of this solution at 25C. Kf of water is 1.86 C/m; molecular mass of dextrose = 180.16 g/mol. A) 13.8 atm B) 14.1 atm C) 15.1 atm D) 12.9 atm E) 120 atm !30. What is the osmotic pressure of a solution prepared from 13.7 g of the electrolyte HCl and enough water to make 0.500 L of solution at 18C? A) 0.55 atm B) 1.10 atm C) 8.95 atm D) 17.9 atm E) 35.9 atm !31. Arrange the following aqueous solutions in order of increasing boiling points: 0.050 m Mg(NO3)2; 0.100 m ethanol; 0.090 m NaCl. A) Mg(NO3)2 < NaCl < ethanol D) NaCl < ethanol < Mg(NO3)2 B) ethanol < Mg(NO3)2 < NaCl E) Mg(NO3)2 < ethanol < NaCl C) ethanol < NaCl < Mg(NO3)2 !32. The osmotic pressure of a 0.010 M MgSO4 solution at 25C is 0.318 atm. Calculate i, the van't Hoff factor, for this MgSO4 solution. A) 0.013 B) 1.3 C) 1.5 D) 2.0 E) 76.8 !33. In the reaction HSO4(aq) + OH(aq) SO42(aq) + H2O(l), the conjugate acid-base pairs are : pair 1 pair 2 A) HSO4 and SO42 ; H2O and OH B) HSO4 and H3O+ ; SO42 and OH C) HSO4 and OH ; SO42 and H2O D) HSO4 and H2O ; OH and SO42 E) HSO4 and OH ; SO42 and H3O+ !34. Which one of these statements about strong acids is true? A) All strong acids have H atoms bonded to electronegative oxygen atoms. B) Strong acids are 100% ionized in water. C) The conjugate base of a strong acid is itself a strong base. D) Strong acids are very concentrated acids. E) Strong acids produce solutions with a higher pH than weak acids. !35. The pH of coffee is approximately 5.0. How many times greater is the [H3O+] in coffee than in tap water having a pH of 8.0? A) 0.62 B) 1.6 C) 30 D) 1000 E) 1.00 X 104 !36. Acid strength increases in the series: HCN < HF < HSO4. Which of these species is the strongest base? A) H2SO4 B) SO42 C) F D) CN E) HSO4 !37. Which of these acids is the strongest? A) H2SO3 B) H2SeO3 C) H2TeO3 !

38. Arrange the acids H2Se, H2Te, and H2S in order of increasing acid strength. A) H2S < H2Se < H2Te D) H2Se < H2S < H2Te B) H2S < H2Te < H2Se E) H2Se < H2Te < H2S C) H2Te < H2S < H2Se 39. Consider a solution made from a non-volatile solute and a volatile solvent. Which of the following statements is TRUE? A) The vapor pressure of the solution is always greater than the vapor pressure of the pure solvent B) The boiling point of the solution is always greater than the boiling point of the pure solvent C) The freezing point of the solution is always greater than the freezing point of the pure solvent !40. In the reaction CaO(s) + SO2(g) CaSO3(s), A) O2 acts as a Lewis base, and SO2 acts as a Lewis acid. B) Ca2+ acts as a Lewis base, and SO42 acts as a Lewis acid. C) SO42 acts as a Lewis base, and SO2 acts as a Lewis acid. D) SO2 acts as a Lewis base, and O2 acts as a Lewis acid. E) SO2 acts as a Lewis base, and Ca2+ acts as a Lewis acid. !41. The dissolution of a gas in a liquid is generally an exothermic process. Which of the following can explain this observation? A) IFA between gas molecules is much weaker than IFA between gas and solvent molecules B) IFA between gas and solvent molecules is much weaker than IFA between gas molecules C) IFA between solvent molecules is much weaker than IFA between gas and solvent molecules D) IFA between gas and solvent molecules is much weaker than IFA between solvent molecules !42. The solubility of valine is 9.62 g in 100 g H2O at 50. What will be observed when 10.0 g valine is mixed with 100 g H2O at 50? A) The mixture will form a solution. B) A heterogeneous mixture of a solution and an undetermined quantity of undissolved valine will be observed. C) A heterogenous mixture of 9.62 g valine solid and a solution will be obtained. D) A heterogeneous mixture of 0.38 g solid valine and a solution will be obtained. !43. Given the following solubilities: !Temperature, (50) Solubility of KCl (g/100 g H2O) 43 g Solubility of NH4Cl (g/100 g H2O) 52 g !If 50 g each of KCl and NH4Cl are mixed with 100 g H2O at 50, what type of solution will you obtain? A) Saturated with both salts B) Saturated with KCl, unsaturated with NH4Cl C) Saturated with NH4Cl, unsaturated with KCl D) Unsaturated with both salts !44. Which of the following preparations will yield 18.0% aqueous KCl solution by mass? A) Dissolve 18.0 g of KCl in 100 g of water. B) Dissolve 18.0 g of KCl in 100 mL of solution. C) Dissolve 18.0 g of KCl in 82 g of solution. D) Dissolve 18.0 g of KCl in 82 mL of water. !45. Which of the following solutions has a lead (II) concentration of 5.0 ppm? A) 5.0 mg of lead (II) in 1 mL of solution B) 5.0 g of lead (II) in 1 mL of solution C) 5.0 ng of lead (II) in 1 mL of solution D) 5.0 g of lead (II) in 1 mL of solution !

46. Alcoholic proof is a measure of how much alcohol (i.e., ethanol) is contained in an alcoholic beverage. Its use is now mostly historical, and alcohol is sold labelled with its alcohol content measured as a percentage of alcohol by volume. Which of the following is TRUE? A) Vodka, which is 50 proof, contains 50% alcohol. B) Tequila Rose, which is 30 proof, is labeled 60% alcohol. C) A 100 mL red wine sample, which is 20 proof, contains 40 mL of alcohol. D) Beer, which is 10 proof contains 10 mL of alcohol in a 200 mL solution. !47. Compound AB partially dissociates in aqueous solution to form A+ and B-. Compound CD, on the other hand, completely dissociates in aqueous solution to form C+ and D-. If a solution of AB has the same concentration as that of a separate solution of CD, which of the following statements is TRUE? A) The concentrations of A+ and C+ are the same. B) The concentration of B- is greater than the concentration of D-. C) The concentrations of all the ions are same. D) The sum of the concentrations of C+ and D- are greater than the sum of the concentrations of A+ and B- !48. Which of the following properties is possessed ONLY by a strong electrolyte? A) Produces ions when dissolved in water B) Conducts electricity C) Ionizes completely in water D) Produces a solution that has a higher boiling point than that of the pure solvent !49. Which of the following observations is NOT an application of colligative properties? A) Boiling water takes a longer time in Manila than in Baguio. B) Addition of glycerol as a coolant in automobile radiator. C) Shrinking of red blood cells when blood is mixed with a saturated NaCl solution. D) High volatility of pure alcohol than an aqueous solution of the same alcohol. !50. What is the degree of dissociation for a 0.01 M aqueous solution of a diprotic acid whose osmotic pressure is 0.685 atm at 25C. (R = 0.0821 L atm/mol K) A) 0.6 B) 0.9 C) 0.8 D) 0.5 E) 0.4 !PROBLEM SOLVING !1.Common commercial acids and bases are aqueous solutions with the following properties: !Acid Density of solution(g/mL) Mass percent Hydrochloric Acid 1.19 38 Nitric Acid 1.42 70 Sulfuric Acid 1.84 95 Acetic Acid 1.05 99 Ammonia 0.90 28 !Calculate the concentration in molarity, molality, mole fraction, and ppm for each of the reagents above. !2. Potassium hydrogen phthalate, KHC8H4O4 (FW = 204.22), acts as a monoprotic acid. When 0.625 g of pure potassium hydrogen phthalate was titrated with barium hydroxide solution, 13.6 mL of the base was required to reach the equivalence point. Calculate the molarity of the Ba(OH)2 solution. !3. 100 mg of a salt (FW = 128) was completely dissolved in 25.0 mL of water resulting in a solution that freezes at -0.105C. From this information, show that the solute is an electrolyte. Estimate the degree (%) ionization of the salt in water. !

4. Calculate the osmotic pressure at 20C of a saturated AgCN solution (FWAgCN = 133.9; AgCN solubility: 2.3 x 10-5g/100 mL water). In the saturated solution, what is the concentration of AgCN in ppm units? ! 5. An aqueous solution contains 10% (by weight) ethylene glycol (MW = 62), a non-electrolytic, non volatile solute. Density of the solution is 1.49 g/mL . a. Calculate the boiling point of the solution. b. Calculate the point of the solution. c. Calculate the osmotic pressure at 27C. d. Calculate the vapor pressure lowering at 27C (Vapor pressure of pure water at 27C is 26.7 torr) !6. At a certain temperature, the vapor pressure of pure benzene is 0.930 atm. A solution was prepared by dissolving 10.0 g of a non-volatile, non-volatile solute in 78.11 g of benzene at that temperature. The vapor pressure of the solution was found to be 0.900 atm. Calculate the molar mass of the solute. !!