Deck 14: Solutions and Their Behavior

Question 1

What is the molality of ethanol (C₂H₅OH) in an aqueous solution that is 39.8% ethanol by mass?

A) 1 m..
B) 0 m
C) 14 m
D) 1 m
E) 84.0 m

Answer 1

14 m

Question 2

What is the mass percent of an aqueous sodium hydroxide solution in which the mole fraction of NaOH is 0.0736?

A) 15.0%
B) 16%
C) 69%
D) 9%
E) 3%

Answer 2

15.0%

Question 3

What is the mass of H₂SO₄ in a 38.2-mL sample of concentrated sulfuric acid that has a density of 1.84 g/mL and consists of 98.3% H₂SO₄?

A) 37.6 g
B) 69.1 g
C) 4.73 g
D) 1.81 g
E) 20.4 g

Answer 3

69.1 g

Question 4

What is the definition of molality?

A) moles of solute per kg of solvent
B) grams of solute per kg of solution
C) grams of solute per liter of solution
D) moles of solute per liter of solvent
E) moles of solute per liter of solution

Question 5

A concentrated nitric acid solution has a density of 1.41 g/mL at 25°C and is 15.8 M. What is the percent by mass of HNO_{3 in the solution?}

A) 70.6% HNO_{3 by mass}
B) 1.12% HNO_{3 by mass}
C) 0.895% HNO_{3 by mass}
D) 1.77% HNO_{3 by mass}
E) 44.7% HNO_{3 by mass}

Question 6

What mass of an aqueous 18.8% glucose solution contains 85.5 g of water?

A) 105 g
B) 19.8 g
C) 14.5 g
D) 16.1 g
E) 85.5 g

Question 7

What volume of a 0.758 M solution of CaCl₂ contains 1.28 g of solute?

A) 65.7 mL
B) 15.2 mL
C) 1.69 mL
D) 8.74 mL
E) 84.8 mL

Question 8

Calculate the molarity of a solution of magnesium chloride with a concentration of 27.0 mg/mL.

A) 0.142 M
B) 3.53 M
C) 0.567 M
D) 0.452 M
E) 0.284 M

Question 9

What is the mole fraction of calcium chloride in 3.35 m CaCl₂(aq)? The molar mass of CaCl₂ is 111.0 g/mol and the molar mass of water is 18.02 g/mol.

A) 0.000866
B) 0.0569
C) 0.271
D) 37.2
E) 59.2

Question 10

What is the mass percent of an aqueous sodium hydroxide solution in which the molality of NaOH is 10.7 m?

A) 0%
B) 69%
C) 2%
D) 30.0%
E) 0%..

Question 11

If 11.7 g of naphthalene, C₁₀H₈, is dissolved in 104.2 g of chloroform, CHCl₃, what is the molality of the solution?

A) 0.0914 m
B) 13.4 m
C) 0.877 m
D) 0.101 m
E) 0.105 m

Question 12

A concentrated hydrochloric acid solution is 37.2% HCl by mass and has a density of 1.19 g/mL at 25°C. What is the molarity of HCl?

A) 12.1 M
B) 0.0434 M
C) 8.57 M
D) 11.7 M
E) 0.0857 M

Question 13

What is the mole fraction of urea, CH₄N₂O, in an aqueous solution that is 49% urea by mass?

A) 0.22
B) 0.78
C) 0.49
D) 0.42
E) 0.76

Question 14

What is the mole fraction of urea, CO(NH₂)₂, in a solution prepared by dissolving 4.8 g of urea in 30.3 g of methanol, CH₃OH?

A) 0.86
B) 0.14
C) 0.078
D) 0.92
E) 0.23

Question 15

The volume of a 32.4% (by mass) solution is 179.1 mL. The density of the solution is 1.296 g/mL. What is the mass of solute in this solution?

A) 232 g
B) 75.2 g
C) 716 g
D) 44.8 g
E) 157 g

Question 16

How many milliliters of 11.7 M H₂SO₄ are needed to prepare 600.0 mL of 0.10 M H₂SO₄?

A) 0.19 mL
B) 70 mL
C) 5.1 mL
D) 2.6 mL
E) 6.1 mL

Question 17

If the concentration of sodium carbonate in water is 12.8 ppm, what is the molarity of Na₂CO₃(aq)? The molar mass of Na₂CO₃ is 106.0 g/mol. Assume the density of the solution is 1.00 g/mL.

A) 8.28 × 10^-6 M
B) 1.21 × 10^-4 M
C) 1.36 × 10^-3 M
D) 0.136 M
E) 0.121 M

Question 18

What is the molality of a 19.4 M sodium hydroxide solution that has a density of 1.54 g/mL?

A) 12.6 m
B) 19.8 m
C) 25.4 m
D) 29.9 m
E) 50.4 m

Question 19

A 12.0% sucrose solution by mass has a density of 1.05 g/cm³. What mass of sucrose is present in a 53.0-mL sample of this solution?

A) 6.68 g
B) 6.06 g
C) 0.126 g
D) 464 g
E) 6.36 g

Question 20

If 27.9 g LiCl is dissolved in 175 g H₂O, what is the weight percent of LiCl in the solution?

A) 0.376%
B) 6.78%
C) 13.8%
D) 15.9%
E) 19.0%

Question 21

What partial pressure of oxygen gas is required in order for 0.00284 g of the gas to dissolve in 15.9 mL of pure water? The Henry's law constant for oxygen gas is 1.3 × 10^-3 M atm^-1.

A) 2.3 × 10^-7 atm
B) 4.3 × 10⁰ atm
C) 1.2 × 10^-7 atm
D) 2.3 × 10^-1 atm
E) 4.2 × 10^-2 atm

Question 22

Henry's Law constant is 0.0013 mol/kg?bar and 0.034 mol/kg?bar for O₂ and CO₂ respectively at 25°C. What pressure of CO₂ is required to achieve the same solubility as 0.711 bar of O₂?

A) 0.0 bar
B) 19.0 bar
C) $3.1 \times 10 ^ { - 5 }$ bar
D) $6.2 \times 10 ^ { - 5 }$ bar
E) 37.0 bar

Question 23

According to the National Institute of Standards webbook, the Henry's Law constant for O₂ gas is 0.0013 mol/kg?bar at 25°C What is the Henry's law constant in units of mol/kg?mmHg? (1 bar = 0.9869 atm; 1 atm = 760 mmHg)

A) $1.7 \times 10^ {- 6}$ mol/kg?mmHg
B) $1.3 \times 10 ^ { - 3 }$ mol/kg?mmHg
C) $9.9 \times 10 ^ { - 1 }$ mol/kg?mmHg
D) $5.8 \times 10 ^ { 5 }$ mol/kg?mmHg
E) $7.6 \times 10 ^ { 2 }$ mol/kg?mmHg

Question 24

The Henry's law constant for N₂ in water at 25 °C is 6.0 × 10^-4 mol/kg⋅bar. What is the equilibrium concentration of N₂ in water when the partial pressure of N₂ is 586 mm Hg? (760 mm Hg = 1 atm = 0.9869 bar)

A) 1.4 × 10^-9 M
B) 1.8 × 10^-5 M
C) 4.6 × 10^-4 M
D) 7.7 × 10^-4 M
E) 7.9 × 10^-4 M

Question 25

Which of the following liquids are miscible with water in any proportion?

A) Ethanol (CH3CH2OH) and carbon tetrachloride (CCl4)
B) Carbon tetrachloride (CCl4) and hexane (C6H14)
C) Ethanol (CH3CH2OH) and formic acid (HCO2H)
D) Ethanol (CH3CH2OH), carbon tetrachloride (CCl4), and hexane (C6H14)
E) Carbon tetrachloride (CCl4) and formic acid (HCO2H)

Question 26

Which of the following equations illustrates the formation of an aqueous solution of KF from its elements in their standard states?

A) K⁺(g) + F?(g) ? K⁺(aq) + F?(aq)
B) KF(s) ? KF(aq, 1 m)
C) K⁺(g) + F?(g) ? KF(s)
D) K(s) + $\frac { 1 } { 2 }$ F₂(g) ? KF(s)
E) K(s) + $\frac { 1 } { 2 }$ F₂(g) ? KF(aq, 1 m)

Question 27

The change in energy accompanying the equation below is the _____ of MX. MX(s) → M⁺(aq) + X−(aq)

A) enthalpy of hydration
B) enthalpy of solution
C) lattice energy
D) enthalpy of formation
E) electron attachment enthalpy

Question 28

The lattice enthalpy of LiCl is −834 kJ/mol and the enthalpy of solution of LiCl is -37 kJ/mol. Calculate the enthalpy of hydration of LiCl(s).

A) -797.0 kJ/mol
B) -74.0 kJ/mol
C) -871.0 kJ/mol
D) 797.0 kJ/mol
E) 871.0 kJ/mol

Question 29

What is the Henry's law constant for O2 if the solubility of O2 in water is 0.590 g/L at a pressure of 15.5 atm?

A) 3.81 × 10^-2 L·atm/mol
B) 8.41 × 10² L·atm/mol
C) 2.86 × 10^-1 L·atm/mol
D) 1.19 × 10^-3 L·atm/mol
E) None of these

Question 30

The Henry's law constant for O₂ in water at 25 °C is 1.3 × 10^-3 mol/kg⋅bar. What partial pressure of O₂ (in atm) is necessary to achieve an equilibrium concentration of 2.9 × 10^-3 mol/kg O₂? (1 atm = 0.9869 bar)

A) 0.44 atm
B) 0.45 atm
C) 2.1 atm
D) 2.3 atm
E) 3.8 atm

Question 31

The solubility of 1-pentanol in water is 2.7 g per 100 g of water at 25°C. What is the maximum amount of 1-pentanol that will dissolve in 2.1 g of water at 25°C?

A) 0.057 g
B) 1.3 g
C) 2.7 g
D) 5.7 g
E) 0.013 g

Question 32

If the solubility of O₂ at 0.300 bar and 25°C is 12.5 g/100 g H₂O, what is the solubility of O₂ at a pressure of 1.64 bar and 25°C?

A) 68 g/100 g H₂O
B) 25.4 g/100 g H₂O
C) 0.4 g/100 g H₂O
D) 0.0 g/100 g H₂O
E) 2.3 g/100 g H₂O

Question 33

What mass of Zn(NO₃)₂ must be diluted to a mass of 1.00 kg with H₂O to prepare 97 ppm Zn²⁺(aq)?

A) 7.8 × 10^-6 g
B) 7.8 × 10^-3 g
C) 3.3 × 10^-2 g
D) 1.3 × 10^-1 g
E) 2.8 × 10^-1 g

Question 34

Which of the following statements is INCORRECT?

A) The solubility of a gas in water decreases with increasing temperature.
B) The solubility of a gas in water is proportional to the partial pressure of the gas above the water.
C) The dissolution of a gas in water is usually an exothermic process.
D) The relationship between the solubility of a gas and its partial pressure is known as Henry's law.
E) The solubility of a gas in water is inversely proportional to the molar mass of the gas.

Question 35

What concentration of silver nitrate (in ppm) is present in 7.1 × 10^-7 M AgNO₃(aq)? For very dilute aqueous solutions, you can assume the solution's density is 1.0 g/mL. The molar mass of AgNO₃ is 169.9 g/mol.

A) 0.0071 ppm
B) 0.12 ppm
C) 0.71 ppm
D) 1.7 ppm
E) 8.3 ppm

Question 36

Two nonpolar solvents, such as hexane and carbon tetrachloride, may be miscible even though the enthalpy of mixing of these liquids might be small. A reason that mixing occurs is that mixtures have a greater dispersal of energy relative to pure solvents. The tendency toward greater dispersal of energy is a thermodynamic function called ____.

A) entropy
B) enthalpy
C) saturation
D) adhesion
E) cohesion

Question 37

Which of the following favor(s) the solubility of an ionic solid in a liquid solvent?

A) a small magnitude of the lattice energy of the solute
B) a large magnitude of the solvation energy of the ions
C) a large polarity of the solvent
D) all of the above
E) none of the above

Question 38

A 15 meter by 12 meter pool of water has a depth of 2.2 meters. What mass of silver ion is present in the reservoir if the concentration of silver ion is 0.14 ppm? (1 m³ = 1000 L; assume the density of the solution is 1.00 g/mL)

A) 5.5 × 10^-4 g
B) 5.5 × 10^-2 g
C) 0.55 g
D) 5.5 g
E) 55 g

Question 39

The standard enthalpy of formation of RbF(s) is -557.7kJ/mol and the standard enthalpy of formation of RbF(aq, 1 m) is -583.8 kJ/mol. Determine the enthalpy of solution of RbF and indicate whether the solution temperature will increase or decrease when RbF is dissolved in water.

A) -26.1 kJ/mol; increase
B) 26.1 kJ/mol; increase
C) -26.1 kJ/mol; decrease
D) +1141.5 kJ/mol; increase
E) -1141.5 kJ/mol; decrease

Question 40

Which of the following compounds is not miscible with water?

A) CH₃NH₂
B) CH₃COOH
C) CCl₄
D) CH₃CN
E) HOCH₂CH₂OH

Question 41

What is the equilibrium partial pressure of water vapor above a mixture of 37.5 g H₂O and 62.5 g HOCH₂CH₂OH at 55 °C. The partial pressure of pure water at 55.0 °C is 118.0 mm Hg. Assume ideal behavior for the solution.

A) 3.54 mm Hg
B) 31.7 mm Hg
C) 38.5 mm Hg
D) 79.5 mm Hg
E) 175 mm Hg

Question 42

Assuming ideal behavior, which of the following aqueous solutions would be expected to exhibit the smallest freezing-point lowering?

A) 0.1 m NaCl
B) 0.05 m CH₃COOH
C) 0.05 m Al₂(SO₄)₃
D) 0.1 m BaCl₂
E) 0.25 m C₆H₁₂O₆

Question 43

What is the freezing point of an aqueous 1.38 m NaCl solution? (K_fp for water is 1.858°C/m.) Assume no ion pairing occurs.

A) 5.1 °C
B) 2.6 °C
C) -5.1 °C
D) 0.0 °C
E) -2.6 °C

Question 44

What is the freezing point of a 0.29 m solution of glucose (C₆H₁₂O₆) in water? (K_fp for water is 1.858 °C/m.)

A) 0.27 °C
B) 0.54 °C
C) -0.54 °C
D) -0.27 °C
E) -1.08 °C

Question 45

A 0.20 M solution of MgSO₄ has an observed osmotic pressure of 7.7 atm at 25°C. Determine the observed van't Hoff factor for this experiment.

A) 2.0
B) 1.6
C) 0.31
D) 19
E) 1.8

Question 46

For the following gas-aqueous liquid equilibrium for a closed system at a constant temperature, N₂(g)
D
N₂(aq)
What is the effect on the equilibrium composition of the liquid when the partial pressure of N₂ gas above the liquid is decreased?

A) The amount of N₂ dissolved in the liquid decreases.
B) The amount of N₂ dissolved in the liquid increases.
C) The amount of N₂ dissolved in the liquid does not change.
D) Not enough information is provided to answer the question.
E) Either A or B is possible.

Question 47

If a 15.6-g sample of a nonelectrolyte is dissolved in 100.0 g of water, the resulting solution will freeze at -0.93°C. What is the molar mass of the nonelectrolyte? (K_fp for water is 1.858°C/m.)

A) 81 g/mol
B) 0.31 g/mol
C) 430 g/mol
D) 270 g/mol
E) 310 g/mol

Question 48

Ideally, colligative properties depend only on the:

A) relative number of solute and solvent particles in a solution.
B) molar masses of the solute particles in a solution.
C) density of a solution.
D) hydrated radii of the molecules or ions dissolved in a solution.
E) partial pressure of the gases above the surface of a solution.

Question 49

Which of the following solutions would have the highest osmotic pressure?

A) 0.2 M C₆H₁₂O₆, glucose
B) 0.15 M MgCl₂, magnesium chloride
C) 0.15 M KCl, potassium chloride
D) 0.2 M CH₃OH, methanol
E) 0.2 M C₁₂H₂₂O₁₁, sucrose

Question 50

What mass of ethylene glycol, when mixed with 225 g H₂O, will reduce the equilibrium vapor pressure of H₂O from 1.00 atm to 0.800 atm at 100 °C? The molar masses of water and ethylene glycol are 18.02 g/mol and 62.07 g/mol, respectively. Assume ideal behavior for the solution.

A) 15.6 g
B) 49.9 g
C) 194 g
D) 969 g
E) 3.10 × 10³ g

Question 51

Assuming ideal behavior, which of the following aqueous solutions should have the highest boiling point?

A) 1.00 m LiBr
B) 0.75 m K₂SO₄
C) 0.50 m Ca(NO₃)₂
D) 0.75 m NaCl
E) 1.25 m C₆H₁₂O₆

Question 52

For the following gas-liquid equilibrium for an aqueous system at a constant partial pressure of CO₂, CO₂(g)     D    CO₂(aq)
What is the effect on the equilibrium composition of the liquid when the temperature of the liquid is increased?

A) The amount of CO₂ dissolved in the liquid increases.
B) The amount of CO₂ dissolved in the liquid decreases.
C) The amount of CO₂ dissolved in the liquid does not change.
D) Not enough information is provided to answer the question.
E) Either A or B could occur.

Question 53

What is the boiling-point change for a solution containing 0.251 mol of naphthalene (a nonvolatile, nonionizing compound) in 250. g of liquid benzene? (K_bp = 2.53°C/m for benzene)

A) 2.54 °C
B) 10.08 °C
C) 0.159 °C
D) 2.52 °C
E) 0.635 °C

Question 54

What is the vapor pressure at 20°C of an ideal solution prepared by the addition of 4.50 g of the nonvolatile solute urea, CO(NH₂)₂, to 22.7 g of methanol, CH₃OH? The vapor pressure of pure methanol at 20°C is 89.0 mmHg.

A) 8.51 mmHg
B) 64.9 mmHg
C) 74.3 mmHg
D) 80.5 mmHg
E) 24.1 mmHg

Question 55

What is the freezing point of a solution containing 2.80 grams benzene (molar mass = 78.11 g/mol) dissolved in 43.0 grams paradichlorobenzene (molar mass = 147.0 g/mol)? The freezing point of pure paradichlorobenzene is 53.0 °C and the freezing point depression constant, K_fp, is -7.10 °C/m.

A) 46.7 °C
B) 47.1 °C
C) 58.9 °C
D) 52.6 °C
E) 58.9 °C..

Question 56

The vapor pressure of pure water at 15 °C is 12.8 mm Hg. What is the equilibrium vapor pressure of water above a mixture of 72.0 g ethanol (CH₃CH₂OH, molar mass = 46.07 g/mol) and 22.0 g water?

A) 2.84 mm Hg
B) 5.61 mm Hg
C) 7.19 mm Hg
D) 10.0 mm Hg
E) 12.8 mm Hg

Question 57

The vapor pressure of water at 90°C is 0.692 atm. What is the vapor pressure (in atm) of a solution made by dissolving 2.91 mole(s) of CsF(s) in 1.00 kg of water? Assume that Raoult's law applies.

A) 0.626 atm
B) 0.658 atm
C) 0.692 atm
D) 0.765 atm
E) none of these

Question 58

What mass of Na₂SO₄ must be dissolved in 100.0 grams of water to lower the freezing point by 2.50 °C? The freezing point depression constant, K_fp, of water is -1.86 °C/m. Assume the van't Hoff factor for Na₂SO₄ is 2.85.

A) 3.77 g
B) 6.36 g
C) 6.70 g
D) 11.3 g
E) 19.1 g

Question 59

A solution consisting of 0.278 mol of methylbenzene, C₆H₅CH₃, in 244 g of nitrobenzene, C₆H₅NO₂, freezes at -2.0°C. Pure nitrobenzene freezes at 6.0°C. What is the freezing-point depression constant of nitrobenzene?

A) 7.1°C/m
B) 29°C/m
C) 14.0°C/m
D) 3.5°C/m
E) 7.0°C/m

Question 60

For a dilute solution of (NH₄)₂SO₄, the van't Hoff factor (i) would be approximately ___.

A) 1
B) 2
C) 3
D) 4
E) 5

Question 61

Aqueous colloidal solutions can be classified as ________ (water-fearing), or hydrophilic (water-loving).

Question 62

If an egg's shell is carefully dissolved using an acid, the egg white and yolk will remain intact inside a membrane. If the egg is then placed in distilled water, it will slowly expand until it bursts. Why?

Question 63

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.

Question 64

Because ________ particles are relatively large (say, 1000 nm in diameter) they scatter visible light, making the mixtures containing these particles appear cloudy. This scattering is known as the Tyndall effect.

Question 65

A solution is prepared by dissolving 5.88 g of an unknown nonelectrolyte in enough water to make 0.355 L of solution. The osmotic pressure of the solution is 1.21 atm at 27 °C. What is the molar mass of the solute? (R = 0.08206 L⋅atm/mol⋅K)

A) 0.00297 g/mol
B) 30.3 g/mol
C) 42.5 g/mol
D) 175 g/mol
E) 337 g/mol

Question 66

What is the osmotic pressure of an aqueous solution that is 0.46% NaCl by weight at 36°C. Assume the density of the solution is 1.0 g/mL. Assume no ion pairing. (R = 0.0821 L · atm/K·mol)

A) 0.20 atm
B) 2.0 atm
C) 2.3 × 10² atm
D) 4.0 atm
E) 0.47 atm

Question 67

_____ are colloidal dispersions of one liquid in another.

Question 68

A solution in which there is more dissolved solute than in a saturated solution is known as a(n) ________ solution.

Question 69

A surfactant used for cleaning is called a(n) ________.

Question 70

What type of colloid is formed when a liquid is dispersed in a gas?

A) Aerosol
B) Foam
C) Gel
D) Sol
E) Emulsion

Question 71

The osmotic pressure of blood is 7.65 atm at 37 °C. What mass of glucose (C₆H₁₂O₆, molar mass = 180.2 g/mol) is needed to prepare 2.25 L of solution for intravenous injection? The osmotic pressure of the glucose solution must equal the osmotic pressure of blood. (R = 0.08206 L⋅atm/mol⋅K)

A) 0.676 g
B) 0.698 g
C) 5.67 g
D) 122 g
E) 1.02 × 10³ g

Question 72

All of the following are colloidal dispersions EXCEPT ____.

A) marshmallow
B) white wine
C) milk
D) whipped cream
E) cheese

Question 73

Which of the following solutions has the lowest osmotic pressure?

A) 0.10 M Al(NO₃)₃
B) 0.20 M C_6.0H₁₂O₆
C) 0.15 M Ba(NO₃)₂
D) 0.10 M CaBr₂
E) 0.15 M Na_2Cl

Question 74

Henry's law states that the solubility of a gas in a liquid is directly proportional to its pressure above the liquid. This law holds Right for gases such as nitrogen and oxygen. However, Henry's law does not hold Right for hydrogen chloride gas. Why?

Question 75

What is the concentration unit used in the calculation of osmotic pressure of a dilute solution?

A) Molality
B) Weight percent
C) Mass fraction
D) Mole fraction
E) Molarity

Question 76

Which of the following is a colligative property?

A) Vapor pressure addition
B) Boiling point depression
C) Freezing point depression
D) Osmotic pressure
E) Melting point elevation

Question 77

The following equation is known as ________ law: .

Question 78

A 3.0 g sample of a small protein having a molecular weight of 42,000 g/mol is dissolved in 52.8 mL of water at 21°C. What is the osmotic pressure of the solution? (R = 0.0821 L · atm/K·mol, 1 atm = 760 mmHg)

A) 25 mmHg
B) 1900 mmHg
C) 1.8 mmHg
D) 23,000 mmHg
E) 0.033 mmHg

Question 79

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.
E) They can be described as surfactants.

Question 80

If one of the factors determining the equilibrium of a system is changed, the system adjusts to counteract that change. This is known as ________ principle.