Deck 12: Solutions

Question 1

Identify the major force between ethanol and water.

A) dipole-dipole
B) dispersion
C) hydrogen bonding
D) ion-ion
E) ion-dipole

Answer 1

hydrogen bonding

Question 2

Which of the following compounds will be most soluble in pentane (C₅H₁₂)?

A) pentanol (CH₃CH₂CH₂CH₂CH₂OH)
B) benzene (C₆H₆)
C) acetic acid (CH₃CO₂H)
D) ethyl methyl ketone (CH₃CH₂COCH₃)
E) None of these compounds should be soluble in pentane.

Answer 2

benzene (C₆H₆)

Question 3

Which of the following ions should have the most exothermic Δ_hydrationH?

A) Na⁺
B) Mg²⁺
C) Al³⁺
D) Ca²⁺
E) Sr²⁺

Answer 3

Al³⁺

Question 4

When AgNO₃ is dissolved in water, the solution becomes colder. Choose the situation below that best describes this change.

A) when >
B) when <
C) when is close to
D) when >
E) There isn't enough information to determine the answer.

Question 5

Identify the major force between acetone and chloroform.

A) dipole-dipole
B) dispersion
C) hydrogen bonding
D) ion-ion
E) ion-dipole

Question 6

A solution containing less solute than the equilibrium amount is called ________.

A) an unsaturated solution
B) a dilute solution
C) a supersaturated solution
D) a concentrated solution
E) a saturated solution

Question 7

Which of the following statements is generally TRUE?

A) The solubility of a solid is not dependent on either temperature or pressure.
B) The solubility of a solid is highly dependent on pressure.
C) The solubility of a solid is highly dependent on both pressure and temperature.
D) The solubility of a solid is highly dependent on temperature.
E) None of the above

Question 8

Based on general trends in solubility, which of the following compounds is least soluble in hexane (CH₃CH₂CH₂CH₂CH₂CH₂CH₃)?

A) methanol
B) ethanol
C) 1-propanol
D) 1-butanol
E) 1-pentanol

Question 9

Choose the statement below that is TRUE.

A) A solution will form between two substances if the solute-solvent interactions are of comparable strength to the solute-solute and solvent-solvent interactions.
B) A solution will form between two substances if the solute-solvent interactions are small enough to be overcome by the solute-solute and solvent-solvent interactions.
C) A solution will form between two substances if the solute-solute interactions are strong enough to overcome the solvent-solvent interactions.
D) A solution will form between two substances only if the solvent-solvent interactions are weak enough to overcome the solute-solvent interactions.
E) None of the above is true.

Question 10

Which of the following compounds will be most soluble in ethanol (CH₃CH₂OH)?

A) trimethylamine (N(CH₃)₃)
B) acetone (CH₃COCH₃)
C) ethylene glycol (HOCH₂CH₂OH)
D) hexane (CH₃CH₂CH₂CH₂CH₂CH₃)
E) None of these compounds should be soluble in ethanol.

Question 11

A solution containing more solute than the equilibrium amount is called ________.

A) an unsaturated solution
B) a dilute solution
C) a supersaturated solution
D) a concentrated solution
E) a saturated solution

Question 12

Which of the following defines dissolving?

A) rate of dissolution = rate of deposition
B) rate of dissolution < rate of deposition
C) rate of dissolution > rate of deposition
D) rate of bubbling > rate of dissolving
E) rate of evaporating > rate of condensing

Question 13

A solution is formed at room temperature by vigorously dissolving enough of the solid solute so that some solid remains at the bottom of the solution. Which statement below is TRUE?

A) The solution is considered unsaturated.
B) The solution is considered supersaturated.
C) The solution is considered saturated.
D) The solution would be considered unsaturated if it were cooled a bit to increase the solubility of the solid.
E) None of the above is true.

Question 14

Choose the situation below that would result in a Δ_solutionH near 0.

A) when >
B) when >
C) when <
D) when is close to
E) There isn't enough information to determine the answer.

Question 15

A solid can be purified through which technique?

A) recrystallization
B) dilution
C) dissolution
D) boiling
E) melting

Question 16

Choose the situation below that would result in an endothermic Δ_solutionH.

A) when >
B) when <
C) when is close to
D) when >
E) There isn't enough information to determine the answer.

Question 17

Determine Δ_soluteH for KBr if the Δ_solutionH for KBr is +19.9 kJ mol^-1 and the Δ_hydrationH for KBr is -670. kJ mol^-1.

A) +650 kJ mol^-1
B) -650 kJ mol^-1
C) +690 kJ mol^-1
D) -710 kJ mol^-1
E) -690 kJ mol^-1

Question 18

When LiI is dissolved in water, the solution becomes hotter. Choose the situation below that best describes this change.

A) when >
B) when <
C) when is close to
D) when >
E) There isn't enough information to determine the answer.

Question 19

Choose the situation below that would result in an exothermic Δ_solutionH.

A) when >
B) when is close to
C) when <
D) when >
E) There isn't enough information to determine the answer.

Question 20

Which of the following defines dynamic equilibrium of a solution?

A) rate of dissolution = rate of deposition
B) rate of dissolution < rate of deposition
C) rate of dissolution > rate of deposition
D) rate of bubbling > rate of dissolving
E) rate of evaporating > rate of condensing

Question 21

Calculate the molality of a solution formed by dissolving 27.8 g of LiI in 500.0 mL of water.

A) 0.254 mol kg^-1
B) 0.394 mol kg^-1
C) 0.556 mol kg^-1
D) 0.241 mol kg^-1
E) 0.415 mol kg^-1

Question 22

What is the term for the amount of solute in moles per litre of solution?

A) molality
B) molarity
C) mole fraction
D) mole percent
E) mass percent

Question 23

Identify the compound whose solubility is least affected by temperature.

A) Na₂SO₄
B) K₂Cr₂O₇
C) KNO₃
D) KClO₃
E) NaCl

Question 24

Which of the following should have the largest Henry's law constant (k_H) in water?

A) Ar
B) CO
C) Xe
D) CH₃CH₃
E) CO₂

Question 25

Which of the following compounds is highly soluble at room temperature?

A) Na₂SO₄
B) K₂Cr₂O₇
C) KNO₃
D) KClO₃
E) NaCl

Question 26

Which of the following concentration units are temperature dependent?

A) mole fraction
B) molality
C) mass percent
D) molarity
E) None of the above

Question 27

Which of the following should have the smallest Henry's law constant (k_H) in water at 25 °C?

A) O₂
B) CO₂
C) N₂
D) He
E) NH₃

Question 28

Which of the following statements is TRUE?

A) In general, the solubility of a solid in water decreases with increasing temperature.
B) In general, the solubility of a gas in water decreases with increasing temperature.
C) The solubility of a gas in water usually increases with decreasing pressure.
D) The solubility of an ionic solid in water decreases with increasing temperature.
E) None of the above statements is true.

Question 29

Determine the solubility of CO₂ in soda water at 25 °C if the pressure of CO₂ is 5.2 bar. The Henry's law constant for carbon dioxide in water at this temperature is 3.4 × 10^-2 mol L^-1 bar^-1.

A) 0.15 mol L^-1
B) 0.57 mol L^-1
C) 0.65 mol L^-1
D) 0.18 mol L^-1
E) 0.29 mol L^-1

Question 30

Determine the partial pressure of oxygen necessary to form an aqueous solution that is 4.1 × 10^-4 mol L^-1 O₂ at 25 °C. The Henry's law constant for oxygen in water at 25 °C is 1.3 × 10^-3 mol L^-1 bar^-1.

A) 1.9 bar
B) 0.53 bar
C) 0.24 bar
D) 0.77 bar
E) 0.32 bar

Question 31

What mass (in g) of NH₃ must be dissolved in 475 g of methanol to make a 0.250 mol kg^-1 solution?

A) 2.02 g
B) 4.94 g
C) 1.19 g
D) 8.42 g
E) 1.90 g

Question 32

Which of the following statements is TRUE?

A) The solubility of a gas is not dependent on either temperature or pressure.
B) The solubility of a gas is highly dependent on pressure.
C) The solubility of a gas is highly dependent on both pressure and temperature.
D) The solubility of a gas is highly dependent on temperature.
E) None of the above.

Question 33

Which of the following should have the largest Henry's law constant (k_H) in water at 25 °C?

A) O₂
B) CO₂
C) N₂
D) He
E) NH₃

Question 34

Determine the Henry's law constant for ammonia in water at 25 °C if an ammonia pressure of 0.022 bar produces a solution with a concentration of 1.3 mol L^-1.

A) 59 mol L^-1 bar^-1
B) 0.017 mol L^-1 bar^-1
C) 0.029 mol L^-1 bar^-1
D) 35 mol L^-1 bar^-1
E) 0.038 mol L^-1 bar^-1

Question 35

Calculate the mass of oxygen (in mg) dissolved in a 5.00 L bucket of water exposed to a pressure of 1.13 bar of air. Assume the mole fraction of oxygen in air to be 0.21 and the Henry's law constant for oxygen in water at this temperature to be 1.3 × 10^-3 mol L^-1 bar^-1.

A) 49.4 mg
B) 23.5 mg
C) 9.87 mg
D) 27.3 mg
E) 13.7 mg

Question 36

Identify the gas that is dissolved in carbonated sodas.

A) carbon dioxide
B) oxygen
C) nitrogen
D) carbon monoxide
E) hydrogen

Question 37

Determine the solubility of N₂ in water exposed to air at 25 °C if the atmospheric pressure is 1.2 bar. Assume that the mole fraction of nitrogen is 0.78 in air and the Henry's law constant for nitrogen in water at this temperature is 6.1 × 10^-4 mol L^-1 bar^-1.

A) 1.5 × 10^-4 mol L^-1
B) 6.5 × 10^-4 mol L^-1
C) 5.7 × 10^-4 mol L^-1
D) 1.8 × 10^-4 mol L^-1
E) 3.6 × 10^-4 mol L^-1

Question 38

Identify the compound whose solubility decreases with increasing temperature.

A) Na₂SO₄
B) K₂Cr₂O₇
C) KNO₃
D) KClO₃
E) NaCl

Question 39

What is the term for the amount of solute in moles per kilogram of solvent?

A) molality
B) molarity
C) mole fraction
D) mole percent
E) mass percent

Question 40

Parts per billion requires a multiplication factor of ________.

A) 10^-6
B) 10^-3
C) 10³
D) 10⁶
E) 10⁹

Question 41

A solution is prepared by dissolving 38.6 g sucrose (C₁₂H₂₂O₁₁) in 495 g of water. Determine the mole fraction of sucrose if the final volume of the solution is 508 mL.

A) 4.09 × 10^-3
B) 7.80 × 10^-2
C) 1.28 × 10^-3
D) 7.23 × 10^-2
E) 2.45 × 10^-3

Question 42

A solution is prepared by dissolving 76.3 g NaI in 545 g of water. Determine the mole fraction of NaI if the final volume of the solution is 576 mL.

A) 6.04 × 10^-3
B) 1.65 × 10^-2
C) 1.40 × 10^-3
D) 1.32 × 10^-2
E) 8.84 × 10^-2

Question 43

Calculate the mole fraction of total ions in an aqueous solution prepared by dissolving 0.400 moles of MgCl₂ in 850.0 g of water.

A) 0.00841
B) 0.0270
C) 0.00900
D) 0.0248
E) 0.0167

Question 44

How many moles of KF are contained in 244 mL of 0.135 mol kg^-1 KF solution? The density of the solution is 1.22 g mL^-1.

A) 4.31 × 10^-2 mol KF
B) 4.02 × 10^-2 mol KF
C) 3.29 × 10^-2 mol KF
D) 2.32 × 10^-2 mol KF
E) 1.67 × 10^-2 mol KF

Question 45

What mass of NaCl is contained in 24.88 g of a 15.00% by mass solution of NaCl in water?

A) 20.00 g
B) 21.15 g
C) 3.73 g
D) 1.50 g
E) 12.44 g

Question 46

A solution is prepared by dissolving 98.6 g of NaCl in enough water to form 875 mL of solution. Calculate the mass % of the solution if the density of the solution is 1.06 g mL^-1.

A) 11.3%
B) 12.7%
C) 9.4%
D) 10.6%
E) 11.9%

Question 47

Calculate the molality of a solution that is prepared by mixing 25.5 mL of CH₃OH (d = 0.792 g mL^-1) and 387 mL of CH₃CH₂CH₂OH (d = 0.811 g mL^-1).

A) 0.630 mol kg^-1
B) 0.812 mol kg^-1
C) 1.57 mol kg^-1
D) 2.01 mol kg^-1
E) 4.98 mol kg^-1

Question 48

Calculate the mole fraction of MgCl₂ in an aqueous solution prepared by dissolving 0.400 moles of MgCl₂ in 850.0 g of water.

A) 0.00841
B) 0.0270
C) 0.00900
D) 0.0252
E) 0.0167

Question 49

A 4.55 L sample of water contains 0.115 g of sodium ions. Determine the concentration of sodium ions in ppm if the density of the solution is 1.00 g mL^-1.

A) 52.3 ppm
B) 13.2 ppm
C) 12.7 ppm
D) 25.3 ppm
E) 36.5 ppm

Question 50

A solution is prepared by dissolving 49.3 g of KBr in enough water to form 473 mL of solution. Calculate the mass % of KBr in the solution if the density is 1.12 g mL^-1.

A) 10.4%
B) 8.57%
C) 10.1%
D) 11.7%
E) 9.31%

Question 51

How many moles of KF are contained in 347 g of water in a 0.175 mol kg^-1 KF solution?

A) 1.65 × 10^-2 mol KF
B) 5.04 × 10^-2 mol KF
C) 6.07 × 10^-2 mol KF
D) 3.22 × 10^-2 mol KF
E) 1.98 × 10^-2 mol KF

Question 52

Determine the molality of a solution prepared by dissolving 0.500 moles of CaF₂ in 11.5 moles H₂O.

A) 1.88 mol kg^-1
B) 4.35 mol kg^-1
C) 5.31 mol kg^-1
D) 4.14 mol kg^-1
E) 2.41 mol kg^-1

Question 53

Determine the molality of an aqueous solution prepared by dissolving 0.112 moles of LiCl in 13.7 moles of H₂O.

A) 0.454 mol kg^-1
B) 0.220 mol kg^-1
C) 0.818 mol kg^-1
D) 0.122 mol kg^-1
E) 0.153 mol kg^-1

Question 54

What mass of ethane (CH₃CH₃) is contained in 50.0 mL of a 13.9% by mass solution of ethane in hexane? The density of the solution is 0.611 g mL^-1.

A) 2.35 g
B) 8.49 g
C) 11.8 g
D) 6.95 g
E) 4.25 g

Question 55

What mass of CuCl₂ is contained in 75.85 g of a 22.4% by mass solution of CuCl₂ in water?

A) 17.0 g
B) 5.89 g
C) 29.5 g
D) 33.9 g
E) 11.2 g

Question 56

A 1.00 L sample of water contains 0.0036 g of Cl⁻ ions. Determine the concentration of chloride ions in ppm if the density of the solution is 1.00 g mL^-1.

A) 2.8 ppm
B) 7.2 ppm
C) 3.6 ppm
D) 1.8 ppm
E) 5.4 ppm

Question 57

An aqueous solution is 0.387 mol L^-1 in HCl. What is the molality of the solution if the density is 1.23 g mL^-1?

A) 0.115 mol kg^-1
B) 0.387 mol kg^-1
C) 0.315 mol kg^-1
D) 0.411 mol kg^-1
E) 0.318 mol kg^-1

Question 58

Commercial grade HCl solutions are typically 39.0% (by mass) HCl in water. Determine the molality of the HCl if the solution has a density of 1.20 g mL^-1.

A) 39.0 mol kg^-1
B) 17.5 mol kg^-1
C) 6.39 mol kg^-1
D) 10.7 mol kg^-1
E) 9.44 mol kg^-1

Question 59

Commercial grade HCl solutions are typically 39.0% (by mass) HCl in water. Determine the molarity of the HCl if the solution has a density of 1.20 g mL^-1.

A) 7.79 mol L^-1
B) 10.7 mol L^-1
C) 12.8 mol L^-1
D) 9.35 mol L^-1
E) 13.9 mol L^-1

Question 60

A solution is 0.0433 mol kg^-1 LiF. What is the molarity of the solution if the density is 1.10 g mL^-1?

A) 0.0441 mol L^-1
B) 0.0390 mol L^-1
C) 0.0519 mol L^-1
D) 0.0476 mol L^-1
E) 0.0417 mol L^-1

Question 61

Place the following aqueous solutions of nonvolatile, nonionic compounds in order of decreasing osmotic pressure. I. 0.011 mol L^-1 sucrose II. 0.00095 mol L^-1 glucose III. 0.0060 mol L^-1 glycerin

A) I > III > II
B) I > II > III
C) II > III > I
D) III > I > II
E) II > I > III

Question 62

Calculate the boiling point of a solution of 500.0 g of ethylene glycol (C₂H₆O₂) dissolved in 500.0 g of water. K_f = 1.86 °C m^-1 and K_b = 0.512 °C m^-1. Use 100 °C as the boiling point of water.

A) 108 °C
B) 92 °C
C) 130 °C
D) 70 °C
E) 8.3 °C

Question 63

The boiling point elevation of an aqueous sucrose solution is found to be 0.39 °C. What mass of sucrose (molar mass = 342.30 g mol^-1) would be needed to dissolve in 500.0 g of water? K_b (water) = 0.512 °C m^-1.

A) 261 g sucrose
B) 528 g sucrose
C) 762 g sucrose
D) 223 g sucrose
E) 130. g sucrose

Question 64

An unknown nonelectrolyte and nonvolatile compound is dissolved in enough pure water to make 348 mL of solution. The vapour pressure above the solution drops from 198.7 mbar to 196.7 mbar when 100.0 g of the compound is dissolved at constant temperature. Determine the molar mass of the unknown compound. Assume no change in volume occurs upon dissolution.

A) 689 g mol^-1
B) 342 g mol^-1
C) 180 g mol^-1
D) 509 g mol^-1
E) 243 g mol^-1

Question 65

Calculate the volume of solution that has a vapour pressure of 25.8 mbar and contains 200.3 g of galactose, C₆H₁₂O₆, at a temperature of 22.0 °C. The vapour pressure of pure water at 22 °C is 26.40 mbar, the density of water is 1.00 g mL^-1, and assume no change in volume occurs upon dissolution.

A) 200 mL
B) 91.3 mL
C) 769 mL
D) 862 mL
E) 981 mL

Question 66

Calculate the mass of lactose, C₁₂H₂₂O₁₁, contained in 500.0 mL of solution if the measured vapour pressure of the solution is 121.2 mbar at 50 °C. The vapour pressure of pure water at 50 °C is 123.3 mbar; assume no change in volume occurs upon dissolution.

A) 118 g
B) 165 g
C) 239 g
D) 94.6 g
E) 280 g

Question 67

Determine the freezing point of a solution that contains 78.8 g of naphthalene (C₁₀H₈, molar mass = 128.16 g mol^-1) dissolved in 722 mL of benzene (d = 0.877 g mL^-1). Pure benzene has a melting point of 5.50 °C and a freezing point depression constant of 4.90 °C m^-1.

A) 4.76 °C
B) 4.17 °C
C) 0.74 °C
D) 1.33 °C
E) 1.68 °C

Question 68

Determine the vapour pressure of a solution at 55 °C that contains 34.2 g NaCl in 375 mL of water. The vapour pressure of pure water at 55 °C is 0.1574 bar.

A) 0.153 bar
B) 0.127 bar
C) 0.0967 bar
D) 0.108 bar
E) 0.0907 bar

Question 69

Give the reason that antifreeze is added to a car radiator.

A) The freezing point is lowered and the boiling point is elevated.
B) The freezing point is elevated and the boiling point is lowered.
C) The freezing point and the boiling point are elevated.
D) The freezing point and the boiling point are lowered.
E) None of the above.

Question 70

Calculate the vapour pressure of pure water at 85 °C if a 285 mL solution containing 173.0 g of mannose, C₆H₁₂O₆, has a vapour pressure of 545.0 mbar.

A) 531 mbar
B) 578 mbar
C) 508 mbar
D) 599 mbar
E) 520 mbar

Question 71

Determine the vapour pressure of a solution at 28 °C that contains 62.5 g of fructose (C₆H₁₂O₆) in 325.0 mL of water. The vapour pressure of pure water at 28 °C is 28.3 Torr.

A) 27.8 Torr
B) 16.9 Torr
C) 28.8 Torr
D) 36.9 Torr
E) 24.9 Torr

Question 72

Calculate the vapour pressure of pure water at 65 °C if a 465 mL solution containing 123.0 g of ribose, C₅H₁₀O₅, has a vapour pressure of 247.54 mbar. Assume no change in volume occurs upon dissolution.

A) 264 mbar
B) 239 mbar
C) 309 mbar
D) 363 mbar
E) 255 mbar

Question 73

Determine the boiling point of a solution that contains 78.8 g of naphthalene (C₁₀H₈, molar mass = 128.16 g mol^-1) dissolved in 722 mL of benzene (d = 0.877 g mL^-1). Pure benzene has a boiling point of 80.1 °C and a boiling point elevation constant of 2.53 °C m^-1.

A) 2.2 °C
B) 2.5 °C
C) 82.3 °C
D) 80.4 °C
E) 82.6 °C

Question 74

An unknown nonelectrolyte and nonvolatile compound is dissolved in enough pure water to make 229 mL of solution. The vapour pressure above the solution drops from 233.7 Torr to 229.1 Torr when 82.3 g of the compound is dissolved at constant temperature. Determine the molar mass of the unknown compound. Assume no change in volume occurs upon dissolution.

A) 323 g mol^-1
B) 480 g mol^-1
C) 414 g mol^-1
D) 459 g mol^-1
E) 508 g mol^-1

Question 75

Choose the solvent below that would show the greatest boiling point elevation when used to make a 0.10 mol kg^-1 nonelectrolyte solution.

A) CCl₄, K_b = 29.9 °C m^-1
B) C₆H₆, K_b = 5.12 °C m^-1
C) CH₃CH₂OCH₂CH₃, K_b = 1.79 °C m^-1
D) CH₃CH₂OH, K_b = 1.99 °C m^-1
E) CHCl₃, K_b = 4.70 °C m^-1

Question 76

Calculate the freezing point of a solution of 500.0 g of ethylene glycol (C₂H₆O₂) dissolved in 500.0 g of water. K_f = 1.86 °C m^-1 and K_b = 0.512 °C m^-1.

A) 30.0 °C
B) -30.0 °C
C) 8.32 °C
D) -8.32 °C
E) 70.2 °C

Question 77

Calculate the volume of solution that has a vapour pressure of 31.27 mbar and contains 84.3 g of sucrose, C₁₂H₂₂O₁₁, at a temperature of 25.0 °C. The vapour pressure of pure water at 25 °C is 31.7 mbar, the density of water is 1.00 g mL^-1, and assume no change in volume occurs upon dissolution.

A) 204 mL
B) 31.8 mL
C) 286 mL
D) 323 mL
E) 516 mL

Question 78

Determine the vapour pressure of a solution at 25 °C that contains 76.6 g of glucose (C₆H₁₂O₆) in 250.0 mL of water. The vapour pressure of pure water at 25 °C is 0.03173 bar.

A) 0.360 bar
B) 0.318 bar
C) 0.0308 bar
D) 0.0387 bar
E) 0.00567 bar

Question 79

Calculate the mass of maltose, C₁₂H₂₂O₁₁, contained in 725.0 mL of solution if the measured vapour pressure of the solution is 41.6 mbar at 30 °C. The vapour pressure of pure water at 30 °C is 42.40 mbar; assume no change in volume occurs upon dissolution.

A) 482 g
B) 329 g
C) 265 g
D) 163 g
E) 94.1 g

Question 80

Determine the freezing point depression of a solution that contains 30.7 g glycerin (C₃H₈O₃, molar mass = 92.09 g mol^-1) in 376 mL of water. Some possibly useful constants for water are K_f = 1.86 °C m^-1 and K_b = 0.512 °C m^-1.

A) 0.887 °C
B) 1.65 °C
C) 2.54 °C
D) 3.33 °C
E) 0.654 °C