Chapter 14

Which one of the following statements about soaps and soap molecules is false? a. They have a polar end. b. They have a hydrophobic end. c. They are often sodium salts of long chain fatty acids. d. The hydrophilic end of a soap molecule is attracted by grease. e. They precipitate in water that contains Fe3+ ions.

d. The hydrophilic end of a soap molecule is attracted by grease.

Which of the following factors help determine whether or not a solution forms? a. The densities of the solute and solvent b. The polarities of the solute and solvent c. The energy of solvation (ΔHsolv) d. Two of the above e. All of the above

d. Two of the above

Calculate the heat of solution, ΔHsoln, if the lattice energy of the ionic solid is -155 kJ/mol and the heat of hydration is -130. kJ/mol. a. -25 kJ/mol b. +25 kJ/mol c. -130 kJ/mol d. -285 kJ/mol e. +285 kJ/mol

b. +25 kJ/mol

Which aqueous solution would have the lowest vapor pressure at 25°C? a. 1 M NaCl b. 1 M K3PO4 c. 1 M sucrose, C12H10O11 d. 1 M MgCl2 e. 1 M glucose, C6H12O6

b. 1 M K3PO4

Which of the following liquids would you predict to be the most soluble in water? a. CCl4 b. CH3OH c. CH3(CH2)4OH d. CH3(CH2)4NH2 e. CH3(CH2)4CH3

b. CH3OH

Calculate the osmotic pressure of a solution that contains 1.22 g of sucrose (C12H22O11) dissolved in 100. g of water at 25°C. (Assume the volume of the solution is 100. mL.) a. 6.32 torr b. 108 torr c. 249 torr d. 497 torr e. 663 torr

e. 663 torr

Which of the following correctly states the relationship between the solubility of a substance in water and the temperature of the solution? a. The solubility of a substance in water always increases as the temperature rises b. The solubility of a substance in water always decreases as the temperature rises c. The solubility of a solid substance in water cannot be accurately predicted as temperature rises d. The solubility of a gaseous substance in water decreases as the temperature decreases e. Two of the above are correct

C. The solubility of a solid substance in water cannot be accurately predicted as temperature rises

What would happen to the solubility of a gas in solution if the pressure above the solution is increased? a. solubility increases b. solubility decreases c. solubility remains the same d. it is impossible to predict what will happen to the solubility of a particular gas, since solubility varies from substance to substance

a. solubility increases

How many grams of nickel(II) sulfate, NiSO4 (molar mass = 154.8g/mol) must be dissolved in 288.0g of water to raise the boiling point by 0.350oC? (Kb = 0.51oC.kg/mol) a. 10.19g b. 15.3 g c. 19.2 g d. 30.6 g e. 36.9 g

b. 15.3 g

In a laboratory experiment, students synthesized a new compound and found that when 11.75g of the compound was dissolved to make 256.2mL of an ethanol solution, the osmotic pressure generated was 4.12atm at 25oC. Assuming the compound is nonvolatile and a non-electrolyte, what is the molar mass of the compound? a. 178.7 g/mol b. 272.2 g/mol c. 326.2 g/mol d. 14,570 g/mol e. 27,580 g/mol

b. 272.2 g/mol

When acetone is dissolved in water, the resulting solution becomes warm. Is this an endothermic or exothermic process? a. Endothermic b. Exothermic c. Cannot tell from the information provided

b. Exothermic

Water (H2O) and chloroform (CHCl3) a. Negative deviation b. Positive deviation c. Ideal d. More information is needed

b. Positive deviation

Which of the following would you predict to have the greatest solubility in water? a. hexanol b. propanol c. pentane d. ethyl methyl ketone e. cyclobutane

b. propanol

What would happen to the solubility of a gas in solution if the temperature is increased? a. solubility increases b. solubility decreases c. solubility remains the same d. it is impossible to predict what will happen to the solubility of a particular gas, since solubility varies from substance to substance

b. solubility decreases

Which of the following solutions would have the highest boiling point? a. 0.15m Zn(CH3COO)2 b. 0.16m BaI2 c. 0.10m Cr2(SO4)3 d. 0.35m CH4N2O e. pure water

c. 0.10m Cr2(SO4)3

Which of the following solutions would have the highest osmotic pressure? a. 0.15m Zn(CH3COO)2 b. 0.16m BaI2 c. 0.10m Cr2(SO4)3 d. 0.35m CH4N2O e. pure water

c. 0.10m Cr2(SO4)3

Hexane (C6H14) and octane (C8H18) a. Negative deviation b. Positive deviation c. Ideal d. More information is needed

c. Ideal

An aqueous solution is 22.0% by mass silver nitrate (AgNO3) and has a density of 1.22g/mL. What is the molality of this solution? a. 0.282m b. 1.06m c. 1.47m d. 1.66m e. 2.05m

d. 1.66m

Select the one best completion to the statement: Boiling point elevation ______. a. occurs only for molecular solutes. b. occurs only when ionic solids are present. c. is the change in boiling point observed when one goes to a higher elevation. d. results from a reduction in the vapor pressure of the solution. e. occurs only at sea level.

d. results from a reduction in the vapor pressure of the solution.

The boiling point of ethanol, CH3CH2OH, is 78.500oC at 1atm. When 14.10g of an unknown, non-electrolyte compound was dissolved in 282.0g of ethanol, the solution was found to have a boiling point of 78.833oC. What is the molar mass of the unknown compound? (Kb for ethanol = 1.22 oC.kg/mol) a. 68.65 g/mol b. 84.40 g/mol c. 145.68 g/mol d. 174.46 g/mol e. 183.18 g/mol

e. 183.18 g/mol

An aqueous solution is 36.0% by mass potassium bromide, KBr, and has a density of 1.33g/mL. Calculate the molality of the solution: a. 2.27m b. 3.03m c. 3.50m d. 4.02m e. 4.73m

e. 4.73m

The vapor pressure of diethyl ether is 463.57 mmHg at 25oC. Calculate the vapor pressure of the solution that forms when 10.33g of aspirin, C9H8O4 (Molar Mass = 180.1g/mol) is dissolved in 242.1 g of diethyl ether, C4H10O (Molar Mass = 74.12 g/mol). a. 80.00 mmHg b. 386.1 mmHg c. 420.0 mmHg d. 444.6 mmHg e. 455.6 mmHg

e. 455.6 mmHg

Which of the following would have the highest freezing point? a. 0.14m Na2CO3 b. 0.13m MnBr2 c. 0.11m ZnI2 d. 0.36m C6H12O6 e. Pure water

e. Pure water

What is the mole fraction of ethanol, CH3CH2OH, in an aqueous solution that is 20.0% ethanol by mass? a. 0.150 b. 0.144 c. 0.0980 d. 0.0892 e. 0.208

d. 0.0892

Osmotic pressure ____. a. occurs only in ionic solutions. b. is lower with 1 M NaCl than 1 M sucrose. c. is created using detergents. d. is the hydrostatic pressure produced on the surface of a semi-permeable membrane by osmosis. e. is greater in the northern hemisphere than the southern hemisphere.

d. is the hydrostatic pressure produced on the surface of a semi-permeable membrane by osmosis.

All of the following statements apply to supersaturated solutions. Which one is false? a. Supersaturated solutions contain higher-than-saturated concentrations of solute. b. Supersaturated solutions are metastable. c. Supersaturated solutions produce crystals rapidly if disturbed. d. Crystals will precipitate from a supersaturated solution until the solution is saturated. e. Supersaturated solutions are created by reaching saturation, then heating the solution.

e. Supersaturated solutions are created by reaching saturation, then heating the solution.

Which of the following compounds is not produced by fractional distillation of crude oil? a. heating oil b. diesel c. kerosene d. gasoline e. ethanol

e. ethanol

Which of the following solutions would have the highest freezing point? a. 0.15m Zn(CH3COO)2 b. 0.16m BaI2 c. 0.10m Cr2(SO4)3 d. 0.35m CH4N2O e. pure water

e. pure water

Which of the following compounds is not miscible with CCl4, carbon tetrachloride? a. gasoline b. pentane, C5H12 c. H2O d. CH3CH2OCH2CH3 e. freon-12, CCl2F2

c. H2O

What is the mole fraction of ethanol, C2H5OH, in a solution of 47.5 g of C2H5OH in 850. g of water? a. 0.021 b. 0.18 c. 0.032 d. 0.98 e. 0.028

a. 0.021

Which of the following solutes in aqueous solution would be expected to exhibit the largest freezing-point lowering (assuming ideal behavior)? a. 0.1 m MgCl2 b. 0.1 m CH3COH c. 0.05 m Al2(SO4)3 d. 0.1 m KCl e. 0.25 m NH3

a. 0.1 m MgCl2

At 25°C a solution consists of 0.450 mole of pentane, C5H12, and 0.250 mole of cyclopentane, C5H10. What is the mole fraction of cyclopentane in the vapor that is in equilibrium with this solution? The vapor pressure of the pure liquids at 25°C are 451 torr for pentane and 321 torr for cyclopentane. Assume that the solution is an ideal solution. a. 0.284 b. 0.551 c. 0.716 d. 0.643 e. 0.357

a. 0.284

A solution contains 10.0 g pentane, C5H12, 10.0 g hexane, C6H14 and 10.0 g benzene, C6H6. What is the mole fraction of hexane? a. 0.303 b. 0.116 c. 0.333 d. 0.362 e. 0.335

a. 0.303

Calculate the molality of a solution prepared by dissolving 112. grams of copper (II) sulfate in 450. mL of water at 25°C. a. 1.56 m b. 1.97 m c. 0.00197 m d. 3.92 m e. 1.86 m

a. 1.56 m

A 1.0 g sample of a molecular compound having a molecular weight of 100,000 g/mol is dissolved in 100. g of water. Calculate the osmotic pressure of the solution in torr at a temperature of 27°C. (Assume the volume of the solution is 100. mL.) a. 1.9 torr b. 2.9 torr c. 3.9 torr d. 4.9 torr e. 5.9 torr

a. 1.9 torr

When 20.0 grams of an unknown compound are dissolved in 500. grams of benzene, the freezing point of the resulting solution is 3.77°C. The freezing point of pure benzene is 5.48°C, and Kf for benzene is 5.12°C/m. What is the molecular weight of the unknown? a. 120 g/mol b. 80.0 g/mol c. 100 g/mol d. 140 g/mol e. 160 g/mol

a. 120 g/mol

When 35.0 g of an unknown nonelectrolyte is dissolved in 220.0 g of benzene, the solution boils at 83.2°C. Calculate the molecular weight of the unknown nonelectrolyte. The Kb for benzene = 2.53°C/m. The boiling point of pure benzene is 80.1°C. a. 130 g/mol b. 20.3 g/mol c. 183 g/mol d. 156 g/mol e. 194 g/mol

a. 130 g/mol

For a dilute solution of NH4NO3, the van't Hoff factor (i) would be approximately a. 2. b. 3. c. 4. d. 1. e. 5.

a. 2.

A solution is made by mixing 52.1 g of propyl chloride, C3H7Cl, and 38.4 g of propyl bromide, C3H7Br. What is the vapor pressure of propyl chloride in the solution at 25°C? The vapor pressure of pure propyl chloride is 347 torr at 25°C and that of pure propyl bromide is 133 torr at 25°C. Assume that the solution is an ideal solution. a. 236 torr b. 128 torr c. 136 torr d. 147 torr e. 155 torr

a. 236 torr

What mass of a(n) 29.3% sucrose solution contains 62.8 g of water? a. 26.0 g b. 74.0 g c. 37.2 g d. 18.4 g e. 62.8 g

a. 26.0 g

Estimate the molecular weight of a biological macromolecule if a 0.100-gram sample dissolved in 50.0 mL of benzene has an osmotic pressure of 9.76 torr at 25.0°C. a. 3.8 × 103 g/mol b. 4.2 × 104 g/mol c. 5.6 × 104 g/mol d. 6.7 × 104 g/mol e. 8.3 × 103 g/mol

a. 3.8 × 103 g/mol

What is the mass percent of an aqueous sodium hydroxide solution in which the mole fraction of NaOH is 0.231? The density of the solution is 1.4339 g/mL. a. 40.0% b. 6.21% c. 68.9% d. 33.1% e. 6.44%

a. 40.0%

Calculate the vapor pressure of a solution prepared by dissolving 70.0 g of naphthalene, C10H8 (a nonvolatile nonelectrolyte), in 220.0 g of benzene, C6H6, at 20°C. Assume the solution is ideal. The vapor pressure of pure benzene is 74.6 torr at 20°C. a. 62.5 torr b. 14.5 torr c. 40.8 torr d. 60.1 torr e. 12.1 torr

a. 62.5 torr

How many grams of sucrose, C12H22O11, must be dissolved in 750. mL of water to prepare a 0.250 molal solution? a. 64.1 g b. 114 g c. 85.5 g d. 78.2 g e. 96.4 g

a. 64.1 g

A 0.0490 molal aqueous NaBr solution freezes at −0.173°C. What is its apparent percent dissociation in this solution? Kf = 1.86°C/m for water. NaBr → Na+ + Br− a. 89.8% b. 84.2% c. 96.4% d. 77.0% e. 68.9%

a. 89.8%

The boiling point of pure water in Winter Park, CO ( elev. 9000 ft), is 94°C. What is the boiling point of a solution containing 11.3 g of glucose (180 g/mol) in 55 mL of water in Winter Park? Kb for water = 0.512°C/m. a. 94.6°C b. 95.1°C c. 98.6°C d. 100°C e. 93.4°C

a. 94.6°C

Which one of the following solutes is most likely to have low water solubility due to the dissolution process being highly endothermic? a. AlF3 b. RbF c. CaF2 d. AgCl e. FeCl2

a. AlF3

Which of the following solutions would not be expected to exist? a. MgCl2 in CCl4 b. NaCl in water c. Pentane, C5H12, in CCl4 d. methanol, CH3OH, in water e. Vegetable oil in mineral oil

a. MgCl2 in CCl4

Which of the following is not considered to occur if metallic sodium is placed in water? a. Sodium would dissolve. b. Sodium would react. c. Hydrogen gas would be produced. d. If evaporated to dryness, solid sodium hydroxide would be obtained. e. An oxidation state change would occur.

a. Sodium would dissolve.

Which of the following statements about soaps and detergents is false? a. The polar end is attracted to grease and oil. b. They have a polar and a nonpolar end. c. They are emulsifiers for grease and oil. d. Phosphate detergents can produce pollution problems. e. They can be described as surfactants.

a. The polar end is attracted to grease and oil.

Consider the dissolution of KCl in water, an endothermic process. Which of the following is true? a. The solubility of KCl increases as temperature increases. b. The solubility of KCl does not depend on temperature. c. The solubility of KCl increases as temperature increases, but only if pressure also increases. d. The solubility of KCl increases if pressure increases. e. None of these is true.

a. The solubility of KCl increases as temperature increases.

Select the most appropriate explanation of the following observation on solubility: "Hydrogen chloride, HCl, is very soluble in water." a. Water is a polar solvent, and it promotes the ionization of many polar molecules. b. Opposites attract, that is, polar solutes dissolve in non-polar solvents and vice-versa. c. Water promotes the dissociation of many ionic solids. d. Gases that interact only slightly with solvents dissolve freely. e. Relatively light molecules are generally more soluble in water than heavier molecules.

a. Water is a polar solvent, and it promotes the ionization of many polar molecules.

The process of ____ involves adhesion of species onto the surface of colloid particles. a. adsorption b. absorption c. dispersion d. precipitation e. suspension

a. adsorption

Which of the following terms is not generally used in describing the dissolution of solids and gases in liquids? a. miscibility b. saturation c. molality d. molarity e. % solute by mass

a. miscibility

Physical properties that depend on the ____ but not the ____ of solute particles in a given amount of solvent are called colligative properties. a. number; kind b. polarity; number c. number; polarity d. kind; number e. polarity; concentration

a. number; kind

Which of the following solutions has the lowest osmotic pressure? a. 0.10 M Al(NO3)3 b. 0.20 M NH3 c. 0.15 M Ba(NO2)2 d. 0.10 M MgCl2 e. 0.15 M NaCl

b. 0.20 M NH3

If 8.32 grams of methanol, CH3OH, are dissolved in 10.3 grams of water, what is the mole fraction of methanol in the solution? a. 0.61 b. 0.31 c. 0.11 d. 0.43 e. 0.36

b. 0.31

Calculate the molality of a solution that contains 51.2 g of naphthalene, C10H8, in 500. mL of carbon tetrachloride. The density of CCl4 is 1.60 g/mL. a. 0.250 m b. 0.500 m c. 0.750 m d. 0.840 m e. 1.69 m

b. 0.500 m

Calculate the mole fraction of ethanol, C2H5OH, in a solution that contains 230. grams of C2H5OH and 312 grams of benzene, C6H6. a. 0.44 b. 0.56 c. 0.57 d. 1.8 e. 2.3

b. 0.56

If 4.27 grams of sucrose, C12H22O11, are dissolved in 15.2 grams of water, what will be the boiling point of the resulting solution? Kb for water = 0.512°C/m. a. 101.64°C b. 100.42°C c. 99.626°C d. 100.73°C e. 101.42°C

b. 100.42°C

What is the molality of a solution prepared by dissolving 10.0 grams of methylamine, CH3NH2, in 50.0 mL of ethanol, C2H5OH? The specific gravity of ethanol is 0.789. a. 6.30 m b. 8.18 m c. 4.26 m d. 5.16 m e. 3.87 m

b. 8.18 m

Trimellitic acid is an organic acid that has a composition of 51.44% C, 2.88% H, and 45.68% O by mass. A 8.55-g sample of trimellitic acid dissolved in 20 g of acetone, CH3COCH3, has a boiling point of 59.68°C. What is the molecular formula of trimellitic acid? (Kb for acetone is 1.71°C/m, and pure acetone has a boiling point of 56.20°C.) a. CH2O b. C9H6O6 c. C3HO2 d. C18HO16 e. C6H2O4

b. C9H6O6

Which of the following statements about gas solubility in liquids is false? a. Most gases that are soluble in water are polar or react with water. b. Gas, liquid dissolutions are always endothermic. c. Gases are more soluble under high pressure than under low pressure. d. Gas solubility decreases with increasing temperature. e. A carbonated beverage will go flat more slowly in the refrigerator.

b. Gas, liquid dissolutions are always endothermic.

Consider the following pairs of liquids. Which numbered response contains all the pairs that are miscible and none that are immiscible? I. benzene, C6H6, and hexane, C6H14 II. water, H2O, and methanol, CH3OH III. water, H2O, and hexane, C6H14 a. I b. I and II c. II and III d. II e. I, II, and III

b. I and II

Which response contains only true statements about hydrophobic colloids? I. They cannot exist in water without an emulsifier. II. Milk and Mayonnaise are examples. III. Grease and oil are attracted to the hydrophilic end of soap molecules. a. II, III b. I, II c. II d. III e. I, II, III

b. I, II

Which of the following statements regarding a 1 M sucrose solution is not correct? a. The boiling point is greater than 100°C. b. The freezing point is lower than that of a 1 M NaCl solution. c. The freezing point is less than 0.0°C. d. The boiling point is lower than that of a 1 M NaCl solution. e. The vapor pressure at 100°C is less than 760 torr.

b. The freezing point is lower than that of a 1 M NaCl solution.

Which one of the following statements is false? a. The effects of lattice energies and hydration energies oppose each other in the dissolution of solids in liquids. b. The solvation process usually absorbs heat. c. Nonpolar solids do not dissolve appreciably in polar solvents. d. The solubility of a gas that does not react with the solvent decreases as temperature increases. e. The separation of solute particles from a crystal requires energy.

b. The solvation process usually absorbs heat.

Crude oil is a complex solution of liquids, and some gases and solids. The components are commonly separated from each other by utilizing a technique called fractional distillation. A physical property of the components upon which this technique is not dependent is ____. a. condensation point b. density c. volatility d. boiling point e. vapor pressure

b. density

Which of the following is not a colligative property? a. osmotic pressure b. vapor pressure raising c. boiling point elevation d. freezing point depression e. All of these are colligative properties

b. vapor pressure raising

A 0.1000 m aqueous solution of a weak acid, HA, is 1.5% ionized. At what temperature does it freeze? Kf for water = 1.86°C/m. a. −0.0764°C b. −0.189°C c. −0.372°C d. −0.564°C e. −0.721°C

b. −0.189°C

What is the freezing point of a 0.24 m solution of glucose, C6H12O6, in water? (Kf for water is 1.858°C/m.) a. 0.22°C b. 0.45°C c. -0.45°C d. -0.22°C e. -0.89°C

c. -0.45°C

Which of these aqueous solutions would be expected to have the highest boiling point? a. 0.100 m KCl b. 0.100 m NaOH c. 0.075 m K2SO4 d. 0.050 m Al2(SO4)3 e. 0.200 m CH3OH

c. 0.075 m K2SO4

If 41.6 g of acetic acid, CH3COOH, are dissolved in 65.0 g of water, what is the mole fraction of acetic acid? a. 0.200 b. 0.275 c. 0.161 d. 0.192 e. 0.840

c. 0.161

Sucrose is a nonvolatile, nonionizing solute in water. Determine the vapor pressure lowering, at 27°C, of a solution of 75.0 grams of sucrose, C12H22O11, dissolved in 180. g of water. The vapor pressure of pure water at 27°C is 26.7 torr. Assume the solution is ideal. a. 0.585 torr b. 0.058 torr c. 0.571 torr d. 5.62 torr e. 0.548 torr

c. 0.571 torr

Calculate the molality of a 10.0% H3PO4 solution in water. a. 0.380 m b. 0.760 m c. 1.13 m d. 1.51 m e. 1.89 m

c. 1.13 m

If the mole fraction of CH3OH in a solution with only water is 0.0250, what is the molality of the CH3OH? a. 12.4 m b. 3.82 m c. 1.42 m d. 5.76 m e. 0.0256 m

c. 1.42 m

A solution is made by mixing 52.1 g of propyl chloride, C3H7Cl, and 38.4 g of propyl bromide, C3H7Br. What is the lowering of the vapor pressure of propyl chloride at 25°C in this solution? The vapor pressure of pure propyl chloride is 347 torr at 25°C and that of pure propyl bromide is 133 torr at 25°C. Assume that the solution is an ideal solution. a. 192 torr b. 200 torr c. 111 torr d. 219 torr e. 171 torr

c. 111 torr

At 25°C a solution consists of 0.450 mole of pentane, C5H12, and 0.250 mole of cyclopentane, C5H10. What is the lowering of the vapor pressure of pentane in this solution? The vapor pressure of the pure liquids at 25°C are 451 torr for pentane and 321 torr for cyclopentane. Assume that the solution is an ideal solution. a. 115 torr b. 138 torr c. 161 torr d. 187 torr e. 206 torr

c. 161 torr

What is the vapor pressure of a aqueous solution containing 10 %(by weight) ethylene glycol (62 g/mol) at 25°C. PH2O = 24.3 torr at 25°C. a. 25.1 torr b. 21.9 torr c. 23.5 torr d. 18.9 torr e. 0.761 torr

c. 23.5 torr

The freezing point of an aqueous solution containing 15 g of a nonelectrolyte in 150 mL water is −5.4°C. What is the molecular weight of the compound? Kf = 1.86°C/m for water. a. 121 g/mol b. 2.78 g/mol c. 34.4 g/mol d. 41.2 g/mol e. 53.8 g/mol

c. 34.4 g/mol

The compound X2Y is only partially dissociated in water solution to form X+ and Y2− ions. A 0.0100 m solution is found to freeze at −0.040°C. Calculate the apparent percent dissociation of X2Y. Kf for water = 1.86°C/m. a. 42% b. 56% c. 58% d. 79% e. 85%

c. 58%

Calculate the molality of a solution that contains 25 g of H2SO4 dissolved in 40. g of H2O. a. 3.2 m b. 4.4 m c. 6.4 m d. 13 m e. 14 m

c. 6.4 m

Which of the following compounds is not miscible with water? a. (CH3CH2)2NH b. CH3COOH c. CCl4 d. CH3CN e. HOCH2CH2OH

c. CCl4

All of the following describe detergents except: a. Detergents may contain sulfonate. b. Detergents do precipitate the ions of hard water. c. Detergents contain carboxylate groups. d. Detergents don't leave bathtub ring. e. Detergents can be used as soap substitutes.

c. Detergents contain carboxylate groups.

Colloids are described by all of the following except: a. The particles in a colloid are so small that settling is negligible. b. The mixture appears cloudy. c. Only combinations of liquids and gases can form colloids. d. Colloids are not suspensions or homogeneous mixtures. e. Mayonnaise, whipped cream and fog are all examples of colloids.

c. Only combinations of liquids and gases can form colloids.

The change in energy accompanying the process below is the ____ of MX. M+(g) + X−(g) → MX(s) a. heat of hydration b. heat of solution c. crystal lattice energy of MX d. heat of ionization e. heat of dissociation

c. crystal lattice energy of MX

Which one of the following combinations must be a colloid? dispersed phase / dispersing medium a. solid / solid b. liquid / gas c. gas / gas d. gas / liquid e. liquid / liquid

c. gas / gas

Which of the following is not a colligative property? a. boiling-point elevation b. osmotic pressure c. lattice energy d. freezing-point lowering e. vapor-pressure lowering

c. lattice energy

Which one of the following is an example of an emulsion? a. shaving cream b. fog c. mayonnaise d. styrofoam e. white gold (an alloy)

c. mayonnaise

At 25°C, 100 g of water will be saturated with 35.7 g of NaCl. Which word below describes the solution of 1.55 mol of NaCl dissolved in 250 mL of water? a. saturated b. unsaturated c. supersaturated d. metasaturated e. none of these apply

c. supersaturated

The molality of a solution is a. the mass of solute divided by the kilograms of solvent. b. the moles of solute divided by the liters of solvent. c. the moles of solute divided by the kilograms of solvent. d. the mass of solute divided by the moles of solution. e. the moles of solute divided by the liters of solution.

c. the moles of solute divided by the kilograms of solvent.

If the van't Hoff factor for NaCl is 1.88, what is the freezing point of a 0.50 molal NaCl solution in water? Kf = 1.86°C/m for water. a. −0.93°C b. 1.86°C c. −1.75°C d. 1.75°C e. −1.86°C

c. −1.75°C

At 40°C, the vapor pressure of heptane is 92 torr. If a solution is made of naphthalene in heptane and has a vapor pressure of 82 torr, what is the mole fraction of naphthalene? Assume ideal solution behavior. a. 0.891 b. 0.435 c. 0.487 d. 0.109 e. 1.109

d. 0.109

If the mole fraction of methanol in a solution (with only water) is 0.28, what is the mole fraction of the water? a. 0.28 b. 1.28 c. 0.62 d. 0.72 e. 0.36

d. 0.72

What is the molality of an aqueous solution that is 10.0% ethanol, C2H5OH, by mass? a. 1.38 m b. 1.77 m c. 2.17 m d. 2.42 m e. 2.66 m

d. 2.42 m

A solution consists of 0.450 mole of pentane, C5H12, and 0.250 mole of cyclopentane, C5H10. What is the vapor pressure of pentane in this solution at 25°C? The vapor pressure of the pure liquids at 25°C are 451 torr for pentane and 321 torr for cyclopentane. Assume that the solution is an ideal solution. a. 80.2 torr b. 188 torr c. 203 torr d. 290 torr e. 306 torr

d. 290 torr

If the concentration of CO2 is 2.90 g of CO2 per 1.00 L of soft drink when bottled under 2.0 atm of CO2 pressure, what will be the concentration of the CO2 in the drink after it has been opened and left to come to equilibrium with the atmosphere which has a CO2 partial pressure of 3.0 × 10−4 atm? a. 2.2 × 10−3 g CO2/L b. 2.0 × 10−4 g CO2/L c. 1.0 × 10−4 g CO2/L d. 4.4 × 10−4 g CO2/L e. 4.6 × 10−2 g CO2/L

d. 4.4 × 10−4 g CO2/L

What is the mass percent of an aqueous sodium hydroxide solution in which the molality of NaOH is 25.0 m? The density of the solution is 1.5290 g/mL. a. 0.0612% b. 68.9% c. 1.76% d. 50.0% e. 0.654%

d. 50.0%

What mass of water must be used to dissolve 20.0 grams of ethanol, C2H5OH, to prepare a 0.0500 molal solution of ethanol? a. 3.76 kg b. 4.00 kg c. 8.70 kg d. 6.35 kg e. 7.18 kg

d. 6.35 kg

A 4.305-gram sample of a nonelectrolyte is dissolved in 105 grams of water. The solution freezes at −1.23°C. Calculate the molecular weight of the solute. Kf for water = 1.86°C/m. a. 39.7 g/mol b. 58.4 g/mol c. 46.2 g/mol d. 62.0 g/mol e. 74.2 g/mol

d. 62.0 g/mol

What is the vapor pressure at 20°C of an ideal solution prepared by the addition of 4.60 g of the nonvolatile solute urea, CO(NH2)2, to 50.2 g of methanol, CH3OH? The vapor pressure of pure methanol at 20°C is 89.0 mmHg. a. 4.15 mmHg b. 76.0 mmHg c. 81.5 mmHg d. 84.9 mmHg e. 13.0 mmHg

d. 84.9 mmHg

Calculate the boiling point of a solution prepared by dissolving 70.0 g of naphthalene, C10H8 (a nonvolatile nonelectrolyte), in 220.0 g of benzene, C6H6. The Kb for benzene = 2.53°C/m. The boiling point of pure benzene is 80.1°C. a. 87.8°C b. 73.8°C c. 83.2°C d. 86.4°C e. 106.3°C

d. 86.4°C

When 1.150 grams of an unknown nonelectrolyte dissolves in 10.0 grams of water, the solution freezes at −2.16°C. What is the molecular weight of the unknown compound? Kf for water = 1.86°C/m. a. 88.6 g/mol b. 116 g/mol c. 74.2 g/mol d. 99.1 g/mol e. 132 g/mol

d. 99.1 g/mol

Which one of the following statements is false? a. Carbon tetrachloride, CCl4, is more miscible with hexane, C6H14, than it is with a polar solvent like methanol, CH3OH. b. Gases are generally more soluble in water under high pressures than under low pressures. c. The solubilities of solids in liquids may either increase or decrease as temperature increases. d. Apparent percentage ionization of a polar covalent solute in water increases as concentration of the solute increases. e. A supersaturated solution can be described as being metastable.

d. Apparent percentage ionization of a polar covalent solute in water increases as concentration of the solute increases.

Which one of the following statements is false? a. All ions are hydrated in aqueous solution. b. All cations are hydrated in aqueous solution. c. All anions are hydrated in aqueous solution. d. Hydration is generally highly endothermic for ionic compounds. e. The heats of hydration of cations increases as their charge-to-radius ratios increase.

d. Hydration is generally highly endothermic for ionic compounds.

Which of the following pairs are not miscible? a. pentane, C5H12, and hexane, C6H14 b. ethanol, CH3CH2OH, and water c. benzene, C6H6, and hexane, C6H14 d. hexane, C6H14, and water e. methanol, CH3OH, and water

d. hexane, C6H14, and water

The use of detergents containing ____ is now discouraged because they can cause eutrophication. a. phosphites b. sulfites c. nitrates d. phosphates e. sulfates

d. phosphates

The Tyndall effect describes ____. a. precipitation of colloidal particles using electrically charged plates b. the adsorption of positive ions onto the surface of a hydrophilic solid c. hydrophobic interactions between nonpolar molecules d. the scattering of light by colloidal particles e. the bending of light by particles dissolved in solution

d. the scattering of light by colloidal particles

Calculate the freezing point of a solution that contains 8.0 g of sucrose (C12H22O11) in 100. g of H2O. Kf for H2O = 1.86°C/m. a. −0.044°C b. −0.22°C c. −0.39°C d. −0.44°C e. 0.04°C

d. −0.44°C

What is the mole fraction of CH3OH in a 3.50 m aqueous solution of CH3OH? a. 0.0630 b. 0.0679 c. 0.650 d. 0.350 e. 0.0592

e. 0.0592

What is the mass % solute of a 2.00 molal H2SO4 solution in water? a. 1.1 % b. 9.8 % c. 19.6 % d. 2.0 % e. 16.4 %

e. 16.4 %

What is the molecular weight of a polymer if 1.55 g of it dissolved in 100 mL of water generates osmotic pressure equal to 15.2 torr at 25°C? a. 24,100 g/mol b. 24.3 g/mol c. 624 g/mol d. 19.0 g/mol e. 19,000 g/mol

e. 19,000 g/mol

Calculate the osmotic pressure associated with 50.0 g of an enzyme of molecular weight 98,000 g/mol dissolved in 2600. mL of benzene at 30.0°C. a. 0.484 torr b. 1.68 torr c. 1.96 torr d. 2.48 torr e. 3.71 torr

e. 3.71 torr

Estimate the molecular weight of a polymer if a 100.-mL solution of 6.5 g of the polymer in toluene has an osmotic pressure of 0.044 atm at 27°C. a. 62,000 b. 45,000 c. 22,000 d. 5500 e. 36,000

e. 36,000

The freezing point of a solution of 1.048 g of an unknown nonelectrolyte dissolved in 36.21 g of benzene is 1.39°C. Pure benzene freezes at 5.48°C and its Kf value is 5.12°C/m. What is the molecular weight of the compound? a. 59.2 g/mol b. 54.0 g/mol c. 61.4 g/mol d. 42.4 g/mol e. 36.3 g/mol

e. 36.3 g/mol

Consider the three statements below. Which numbered response contains all the statements that are true and no false statements? I. Hydration is a special case of solvation in which the solvent is water. II. The oxygen end of water molecules is attracted toward Ca2+ ions. III. The hydrogen end of water molecules is attracted toward Cl− ions. a. I b. II c. III d. I and II e. I, II, and III

e. I, II, and III

Which numbered response lists all of the following statements that are true, and no false statements? I. Many solids that dissolve in endothermic processes have solubilities that increase as temperature increases. II. The solubility in water of a gas that does not react with water increases as the partial pressure of that gas above the surface of the solution increases. III. Most gases that are reasonably soluble in water are polar or else they react with water or ionize in water.

e. I, II, and III

The dissolution process is exothermic if the amount of energy released in bringing about ____ interactions exceeds the sum of the amounts of energy absorbed in overcoming ____ and ____ interactions. a. solute-solute; solvent-solvent; solvent-solute b. solvent-solvent; solute-solute; solvent-solute c. solvent-solute; solute-solute; crystal lattice d. solute-solute; crystal lattice; solvent-solvent e. solvent-solute; solute-solute; solvent-solvent

e. solvent-solute; solute-solute; solvent-solvent

Calculate the freezing point of a solution that contains 68.4 g of sucrose (table sugar) in 300. g of water. One mole of sucrose is 342 g. Kf for H2O = 1.86°C/m. a. −0.186°C b. −0.372°C c. −0.558°C d. −0.744°C e. −1.24°C

e. −1.24°C

Calculate the freezing point of a solution that contains 30.0 g of urea, CH4N2O, in 200. g of water. Urea is a nonvolatile nonelectrolyte. Kf for H2O = 1.86°C/m. a. −1.86°C b. −2.79°C c. −3.72°C d. −4.23°C e. −4.65°C

e. −4.65°C