Chemistry Chapter 12 Solutions Part 3

1. Which of the following is not a colligative property? a) freezing point depression b) boiling point elevation c) solubility d) vapor pressure lowering 2. Which of the following has the least effect on the solubility of a solid in a liquid solvent? a) temperature b) nature of the solvent c) pressure d) nature of the solute 3. "The amount of a gas dissolved in a solution is directly proportional to the pressure of the gas above the solution" is: a) Raoult's law b) Henry's law c) an example of osmotic pressure d) van't Hoff's method 4. The ability of one liquid to dissolve in another is called: a) hydrophilicity b) miscibility c) an expanded solvent d) the solvation energy 5. The dissolution of salt (NaCl) in water is an unfavorable endothermic process. Dissolution occurs anyway because: a) the system becomes more ordered. b) the vapor pressure of the solution decreases. c) salt is a nonpolar solute, water is a nonpolar solvent. d) the randomness or entropy of the system increases greatly. 6. Which of the following concentration measures may change in value as the temperature of a solution changes? a) molality b) molarity 7. An aqueous solution contains 64.0 g of ethanol (C2H5OH) in 122.0 g of total solution. The mole fraction of ethanol is: a) 0.301 b) 0.432 c) 0.698 d) 0.205 e) none of these 8. A 10.0 g sample of sucrose (C12H22O11) was dissolved in 200.0 g of water. What is the vapor pressure of this solution at 100° C? (the vapor pressure of pure water at 100° C is 760 torr) a) 760 torr b) 758 torr c) 111 torr d) 688 torr e) none of these 9. Calculate the change in vapor pressure (P) of a solution prepared by dissolving 25.5 g of napthalene (C10H8), which is a nonvolatile solute, in 150.0 g of benzene (C6H6). The vapor pressure of benzene at 20° C is 74.6 torr. a) 70 torr b) 7.0 torr c) 67.4 torr d) 0.09 torr 10. What mass of ethylene glycol (M.W. = 62.l g/mol) antifreeze must be added to 10.0 liters of water to produce a solution that freezes at -23.3 C degrees. Density of water is lg/ml and Kf = l.86° C/m. a) 7.8 g b) 3.4 g c) 7.8 kg d) 0.78 kg e) 78 kg 11. What is the boiling point in C° of a solution of a 2.15 m aqueous solution of glycerol ? (Kb = 0.512° C/m) a) 101.1 b) 100.2 c) 100 d) 1.1 12. A solution was made by dissolving 3.75 g of a solute in 108.7 g of acetone . The solution boiled at 56.58° C. The boiling point of pure acetone is 55.95° C, and the Kb =1.71° C/m. What is the molecular weight of the solute? a) 143 b) 105 c) 12.7 d) 93.6 13. At 25° C, benzoic acid is much more soluble in benzene (C6H6) than it is in water. In this situation benzoic acid could be considered to be: a) hydrophilic b) colloidal c) nonpolar d) polar 14. Hydrophobic colloids do need a surfactant or an ernulsitying agent to become soluble in water, whereas hydrophilic colloids don't need such an agent to be soluble in water. a) true b) false 15. Soaps, unlike Detergents, react with "hard water" containing Mg and Ca ions to form "scum. " a) true b) false 16. A solution has a lower vapor pressure than the pure solvent under the same conditions. a) true b) false 17. Which of these would be least soluble in water? a) butanol (CH3CH2CH2CH2-OH) b) pentanol (CH3CH2CH2CH2CH2- OH) c) hexanol (CH3CH2CH2CH2CH2CH 2-OH) d) octanol (CH3CH2CH2CH2CH2CH 2CH2CH2-OH) 18. Which of the following aqueous solutions would have the lowest vapor pressure at 25° C? (Hint: Which solute in aqueous solution produces the greatest number of particles?) a) 0.01 m CaCl2 b) 0.01 m NaCl c) 0.02 m NaCl d) 0.015 m CaCI2 KEY 1)c 2)c 3)b 4)b 5)d 6)b 7)a 8)b 9)b 10)c 11)a 12)d 13)c 14)a 15)a 16)a 17)d 18)d