(mk23835) kamalska HW02 Quigley (104001) This print-out should have 30 questions. Multiple-choice questions may continue on the next column or page nd all choices before answering. 001 10.0 points What is the maximum possible value of the vant Ho factor for a solution of the strong electrolyte FeCl3 that is so dilute that no ion association occur? 1. i = 2 2. i must be an odd number. 3. i = 0 4. i = 6 1. 90 torr 5. i = 4 2. 60 torr 002 (part 1 of 3) 10.0 points For the next three questions, consider the following pressure diagram for a binary liquid containing A and B. 90 torr 60 torr 3. 48 torr 4. 76 torr 5. 27 torr
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What is the corresponding vapor pressure of A? 1. 90 torr 2. 27 torr 3. 60 torr 4. 48 torr 5. 76 torr 004 (part 3 of 3) 10.0 points What is the corresponding total vapor pressure?
005 10.0 points Chemical processes, like dissolving solids, are favored by (decreased, increased) potential energy and (decreased, increased, unchanged) disorder. 1. increased; increased 2. decreased; decreased 3. increased; decreased
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xA
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If 1760 g of A (110 g/mol) and 1995 g of B (105 g/mol) are mixed, what is the vapor pressure of B? 1. 27 torr
4. decreased; increased 2. 48 torr 5. increased; unchanged 3. 76 torr 4. 90 torr 5. 60 torr 003 (part 2 of 3) 10.0 points 006 10.0 points A well-behaved (non-volatile, non-ionic) solute is dissolved in water to yield a solution that freezes at 0.930 C. At what temperature would this solution boil under 1.0000 atm pressure? Note that Kf = 1.86 C/m,
kamalska (mk23835) HW02 Quigley (104001) Kb = 0.512C/m. 1. 99.744C 2. 101.394C 3. 100.930C 4. 100.256C 5. 100.000C 6. 99.070C 007 10.0 points What is the eective molality of a solution containing 12.0 g of KI in 550 g water? Assume 100 percent ionic dissociation. 1. 0.13 molal 2. 0.072 molal 3. 0.59 molal 4. 0.42 molal 5. 0.066 molal 6. 0.26 molal 008 10.0 points Which of the following would likely dissolve in benzene? 1. Ca(HCO3 )2 2. Na2 CO3 3. C6 H12 O6 4. Cl2 CCCl2 5. NaCl 009 10.0 points Calculate the number of moles of oxygen that will dissolve in 45 L of water at 20 C if the partial pressure of oxygen is 0.21 atm. Henrys constant for oxygen is 0.0013 1. 0.00027 mol 2. 0.0062 mol 3. 0.0013 mol 4. 0.012 mol 5. 0.28 mol mol . L atm
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010 10.0 points The osmotic pressure of 1.00 g of a polymer dissolved in benzene to give 200 mL of solution is 1.50 kPa at 25 C. Estimate the average molar mass of the polymer. The gas law constant is 0.0821 Latmmol 1 K1 . 1. 1650 gmol1 2. 8260 gmol1 3. 62,000 gmol1 4. 41,300 gmol1 5. 693 gmol1 011 10.0 points Glycerol (a non-electrolyte that can be used as antifreeze in a car radiator) has a density of 1.261 g/mL and a molecular weight of 92 g. If 100 mL are mixed with 1 kg of water, what is a good estimate of the temperature at which this solution will freeze? (Kf water = 1.861C/m.) 1. 2.6 C 2. 12.4 C 3. 4.8 C 4. 0.23 C 5. 0.0 C
kamalska (mk23835) HW02 Quigley (104001) 012 10.0 points Which of the following statements is true regarding solubility? Assume the solute does not aect the solvent and we are dealing with dilute solutions. 1. We can expect substances with positive enthalpies of solution always to be soluble only if the entropy of solution is negative. 2. We can expect substances with positive enthalpies of solution always to be soluble. 3. All the statements are false because the solute always aects the solvent resulting in a negative entropy of solution. 4. We can expect substances with positive enthalpies of solution always to be soluble only if the entropy of solution is positive. 5. We can expect substances with negative enthalpies of solution always to be soluble. 013 10.0 points A decrease in temperature usually (increases, decreases, does not change) the solubility of common salts in water. 1. increases 2. decreases 3. does not change 014 10.0 points What is the percent ionization of a solution made by adding 6.00 grams of CH3 COOH to 100 g of water (Kb = 0.512C/m) if the boiling point of the solution is 100.712 C? Answer in units of %. 015 10.0 points Pure nitrobenzene boils at 210.88C and freezes at 5.70 C. It has a boiling point elevation constant of 5.24 and a freezing point depression constant of 7.00, both expressed in units of C and molality. A solution of an unknown solute dissolved in nitrobenzene boils
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at 217.11 C. At what temperature in C, would this solution freeze? Assume that the solute is not volatile and does not ionize and does not associate in the solution. Answer in units of C. 016 10.0 points Many biological cells are killed if they are placed in pure water because 1. if nothing can pass through the cell wall, the greater pressure inside than outside causes the cell to burst open. 2. the in water the cells passes out through the cell wall causing the cell to shrivel and die. 3. vital cell constituents dissolved in the cell uid pass through the cell wall causing the cells to die. 4. if nothing can pass through the cell wall, the greater pressure outside than inside causes the cell to collapse. 5. more water passes in through the cell wall than passes out so the cells swell and burst. 017 10.0 points Which of the following molecules is most soluble in water? 1. CCl4 2. benzene (C6 H6 ) 3. CH3 CH2 CH2 CH2 CH2 CH3 4. CH3 CH2 OH 5. CH4 018 10.0 points Which of the following has the lowest freezing point and the highest boiling point? 1. 1.0 m sodium chloride 2. 1.5 m calcium chloride 3. 2.0 m potassium chloride
kamalska (mk23835) HW02 Quigley (104001) crease) in magnitude. 4. 1.5 m magnesium phosphate 1. increases; increases; increases 5. 1.5 m aluminum nitrate 2. increases; increases; decreases 019 10.0 points A 3.17 g sample of a molecular compound is dissolved in 99 g of tetrachloromethane (carbon tetrachloride). The normal boiling point of the solution is 61.51 C, the normal boiling point of CCl4 is 61.2 C. The boiling point constant for CCl4 is 4.95 K kg/mol. What is the molar mass of the compound? Answer in units of g/mol. 020 10.0 points The vapor pressure of pure CH2 Cl2 (with molecular weight 85 g/mol) is 133 torr at 0 C and the vapor pressure of pure CH2 Br2 (with molecular weight 174 g/mol) is 11 torr at the same temperature. What is the total vapor pressure at 0 C of a solution prepared from equal masses of these two substances? 1. 144 torr 2. 93 torr 3. 3.6 torr 4. 105 torr 2. False 5. 124 torr 6. 89 torr 7. 44 torr 8. 7.4 torr 9. 72 torr 021 10.0 points Consider a series of chloride salts (MCl2 ). As the charge-to-size ratio of M2+ (decreases, increases) the hydration energy of M2+ (decreases, increases, does not change) in magnitude and the crystal lattice energy of MCl2 (decreases, increases, may increase or de3. increases; decreases; decreases 4. decreases; increases; increases 5. decreases; decreases; increases 6. increases; decreases; increases
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7. increases; does not change; may increase or decrease 022 10.0 points 78 grams of Na2 SO4 (with MW 142.04 g/mol) is dissolved in 542 mL of water. What will be the freezing point of the solution? Assume complete dissociation of the salt and ideal behavior of the solution. Kf = 1.86 C/m. Answer in units of C. 023 10.0 points If you go to the top of a mountain, the amount of carbon dioxide that will dissolve in water should increase compared to sea level. 1. True
024 10.0 points In a closed vessel containing water the pressure is 18 torr. If we add more water to the vessel, the pressure 1. increases. 2. decreases. 3. remains the same. 025 10.0 points Which of the following statements about colligative properties of aqueous solutions is FALSE? 1. Colligative properties only depend on the
kamalska (mk23835) HW02 Quigley (104001) number of solute particles present in solution. 2. Osmosis is a colligative property. 3. The higher the concentration of solute in the solution, the higher the vapor pressure of the solvent. 4. For a given solution, the freezing point will be lowered more than the boiling point will be raised. 026 10.0 points Which of the following has the highest vapor pressure? 1. CH3 CH2 COOH 2. CH3 OH 3. CH3 CH2 OCH2 CH3 4. CH3 CH2 OH 5. H2 O 027 10.0 points Consider two solutes with the same lattice energy in kJ/mol; however, the particles of solute A are strongly solvated by water, while those of solute B are only weakly solvated. Which of the two dissolution processes is more exothermic, on a kJ/mol basis? 1. Cannot be answered without knowing the identities of the solutes. 2. Both processes are equally exothermic. 2. III, I, IV, II 3. dissolving A in water 3. IV, I, II, III 4. It depends on the molecular weights of the solutes. 5. dissolving B in water 028 10.0 points Which of the following solutes is likely to be most soluble in water? 4. II, IV, I, III 5. III, I, II, IV 1. CS2 2. Br2 3. ethanol (CH3 CH2 OH) 4. carbon tetrachloride (CCl4 )
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029 10.0 points The formation of tiny bubbles when a beaker of water is mildly heated indicates that 1. water is being decomposed into hydrogen and oxygen. 2. the lattice energy of water is large. 3. the liquid is at its boiling point. 4. air is less soluble in water at higher temperatures. 5. water is being extensively hydrogen bonded. 030 10.0 points Each of the following samples was placed in 1 liter of water. I) 0.6 mol NaOH II) 0.7 mol KCl III) 0.5 mol Na2 NO3 IV) 1 mol of sugar Rank the solutions that are made in terms of increasing order of boiling point elevation. (Remember your solubility rules.) 1. IV, II, I, III