Deck 13: Physical Properties of Solutions

Question 1

What is the percent CsCl by mass in a 0.711 M CsCl solution that has a density of 1.091 g/mL?

A)3.87 * 10^-4 %
B)3.87 * 10^-1 %
C)11.0 %
D)1.10 %
E)6.50 * 10^-2 %

Answer 1

11.0 %

Question 2

Heat of solution

A)is never positive ( $\Delta$ H°_soln $\le$ 0), because the solute-solvent attraction is never weaker than the combination of the solute-solute attraction and solvent-solvent attraction.
B)is always positive ( $\Delta$ H°_soln > 0), because the solute-solvent attraction is always weaker than the combination of the solute-solute attraction and solvent-solvent attraction.
C)is always zero ( $\Delta$ H°_soln = 0), because the solute-solvent attraction is defined as the average of the solute-solute attraction and solvent-solvent attraction.
D)is always negative ( $\Delta$ H°_soln < 0), because the solute-solvent attraction is always stronger than the combination of the solute-solute attraction and solvent-solvent attraction.
E)may be positive, zero, or negative, depending on the relative strength of the solute-solvent, solute-solute, and solvent-solvent attractive forces.

Answer 2

may be positive, zero, or negative, depending on the relative strength of the solute-solvent, solute-solute, and solvent-solvent attractive forces.

Question 3

Which of the following gives the molarity of a 17.0 % by mass solution of sodium acetate, CH₃COONa (molar mass = 82.0 g/mol)in water? The density of the solution is 1.09 g/mL.

A)2.26 * 10 ^{- 6} M
B)0.207 M
C)2.07 M
D)2.26 M
E)2.72 M

Answer 3

2.26 M

Question 4

Calculate the percent by mass of potassium nitrate in a solution made from 45.0 g KNO₃ and 295 mL of water. The density of water is 0.997 g/mL.

A)1.51 %
B)7.57 %
C)13.3 %
D)15.2 %
E)None of these

Question 5

Which response lists all the following pairs that are miscible liquids. Pair #1: octane (C₈H₁₈)and water
Pair #2: acetic acid (CH₃COOH)and water
Pair #3: octane (C₈H₁₈)and carbon tetrachloride (CCl₄)

A)1, 3
B)1, 2
C)3
D)2
E)2, 3

Question 6

Determine the mass percent HCl in a 1.2 M solution of hydrochloric acid with a density of 1.019 g/mL?

A)3.0 %
B)4.3 %
C)8.6 %
D)13%
E)30. %

Question 7

What is the percent CdSO₄ by mass in a 1.0 molal aqueous CdSO₄ solution?

A)1.00 * 10^-3 %
B)0.100 %
C)17.2 %
D)20.8 %
E)24.4 %

Question 8

A 20.0 % by mass solution of phosphoric acid (H₃PO₄)in water has a density of 1.114 g/mL at 20°C. What is the molarity of this solution?

A)0.0114 M
B)0.0568 M
C)0.114 M
D)2.27 M
E)11.4 M

Question 9

In which of the following solvents would you expect KBr to be most soluble?

A)C₆H₁₄ (hexane)
B)CH₃CH₂OH (ethanol)
C)C₆H₆ (benzene)
D)CCl₄ (carbon tetrachloride)
E)C₆H₁₂ (cyclohexane)

Question 10

What is the molarity of a solution of 10 % by mass cadmium sulfate, CdSO₄ (molar mass = 208.46 g/mol)by mass? The density of the solution is 1.10 g/mL.

A)0.528 M
B)0.436 M
C)0.479 M
D)0.048 M
E)22.9 M

Question 11

Which one of the following would be immiscible with water?

A)
B)
C)
D)
E)

Question 12

In how many grams of water should 25.31 g of potassium nitrate (KNO₃)be dissolved to prepare a 0.1982 m solution?

A)250.0 g
B)792.0 g
C)1,000. g
D)1,263 g
E)7,917 g

Question 13

A 15.00 % by mass solution of lactose (C₁₂H₂₂O₁₁, 342.30 g/mol)in water has a density of 1.0602 g/mL at 20°C. What is the molarity of this solution?

A)0.03097 M
B)0.4133 M
C)0.4646 M
D)1.590 M
E)3.097 M

Question 14

How many grams of water are needed to dissolve 27.8 g of ammonium nitrate NH₄NO₃ in order to prepare a 0.452 m solution?

A)769 g
B)36.2 g
C)100. g
D)0.157 g
E)157 g

Question 15

Which of the following liquids would make a good solvent for iodine, I₂?

A)HCl
B)H₂O
C)CH₃OH
D)NH₃
E)CS₂

Question 16

Calculate the molality of a solution containing 14.3 g of NaCl in 42.2 g of water.

A)2.45 * 10^-4 m
B)5.80 * 10^-4 m
C)2.45 * 10^-1 m
D)103 m
E)5.80 m

Question 17

What is the molarity of a solution that is 7.00 % by mass magnesium sulfate and has a density of 1.071 g/mL?

A)0.0890 M
B)0.496 M
C)0.543 M
D)0.623 M
E)1.32 M

Question 18

A 9.50 % by mass solution of acetone (C₃H₆O)in water has a density of 0.9849 g/mL at 20°C. What is the molarity of this solution?

A)0.621 M
B)1.61 M
C)1.66 M
D)1.71 M
E)16.9 M

Question 19

A saturated solution

A)contains more solute than solvent.
B)contains more solvent than solute.
C)contains equal moles of solute and solvent.
D)contains the maximum amount of solute that will dissolve in that solvent at that temperature.
E)contains a solvent with only sigma bonds and no pi bonds (i.e. only single bonds, with no double or triple bonds).

Question 20

Which of the following compounds should be soluble in CCl₄?

A)NaCl
B)H₂O
C)NaOH
D)C₈H₁₈
E)None of these

Question 21

The solubility of CO₂ gas in water

A)increases with increasing gas pressure.
B)increases with decreasing gas pressure.
C)decreases with increasing gas pressure.
D)is not dependent on pressure.

Question 22

Calculate the molality of a 15.0% by mass solution of MgCl₂ in H₂O. The density of this solution is 1.127 g/mL.

A)0.157 m
B)11.8 m
C)1.86 m
D)0.0134 m
E)1.58 m

Question 23

Oxygen gas makes up 21 % of the atmosphere by volume. What is the solubility of O₂(g)in water at 25°C if the atmospheric pressure is 741 mmHg? The Henry's law constant for oxygen gas at 25°C is 1.3 * 10^-3 mol/L·atm.

A)2.7 * 10^-4 M
B)1.3 * 10^-3 M
C)6.2 * 10^-3 M
D)9.6 * 10^-3 M
E)0.96 M

Question 24

The solubility of gases in water usually decreases with

A)increasing pressure.
B)increasing temperature.
C)decreasing temperature.

Question 25

The solubility of nitrogen gas at 25°C and a nitrogen pressure of 522 mmHg is 4.7 * 10 ^{- 4} mol/L. What is the value of the Henry's Law constant in mol/L·atm?

A)6.8 * 10^-4 mol/L·atm
B)4.7 * 10^-4 mol/L·atm
C)3.2 * 10^-4 mol/L·atm
D)9.0 * 10^-7 mol/L·atm
E)1.5 * 10³ mol/L·atm

Question 26

According to Raoult's law, which statement is false?

A)The vapor pressure of a solvent over a solution decreases as its mole fraction increases.
B)The solubility of a gas increases as the temperature decreases.
C)The vapor pressure of a solvent over a solution is less than that of pure solvent.
D)The greater the pressure of a gas over a solution the greater its solubility.
E)Ionic solutes dissociate in solution causing an enhancement of all colligative properties.

Question 27

What is the mass percent CH₃OH of a 0.256 m CH₃OH(aq)solution?

A)0.814 %
B)0.992 %
C)1.23 %
D)1.29 %
E)1.51 %

Question 28

The density of a 20.3 M CH₃OH (methanol)solution is 0.858 g/mL. What is the molality of this solution? H₂O is the solvent.

A)17.4 m
B)20.8 m
C)23.7 m
D)70.0 m
E)97.6 m

Question 29

A solution of carbon tetrachloride in benzene, C₆H₆, at 20°C has a total vapor pressure of 78.50 mmHg. (Assume that this solution is ideal.)The vapor pressure of pure benzene at this temperature is 74.61 mmHg and its density is 0.87865 g/cm³; the vapor pressure of pure carbon tetrachloride is 91.32 mmHg and its density is 1.5940 g/cm³. What percentage of the volume of this solution is due to carbon tetrachloride? (Hint: assume that you have 1.000 L of solution.)

A)75.2%
B)76.7%
C)14.3%
D)24.8%
E)23.3%

Question 30

Consider a solution made from a nonvolatile solute and a volatile solvent. Which statement is true?

A)The vapor pressure of the solution is always greater than the vapor pressure of the pure solvent.
B)The boiling point of the solution is always greater than the boiling point of the pure solvent.
C)The freezing point of the solution is always greater than the freezing point of the pure solvent.

Question 31

Which of the following has the greater molal concentration (molality)?

A)1.0 m KNO₃
B)1.0 M KNO₃
C)Both have same molality.

Question 32

Calculate the molality of 6.0 M H₂SO₄ solution. The density of the solution is 1.34 g/mL.

A)4.48 m
B)7.98 m
C)8.10 m
D)8.43 m
E)10.2 m

Question 33

The vapor pressure of water at 20°C is 17.5 mmHg. What is the vapor pressure of water over a solution prepared from 2.00 * 10² g of sucrose (C₁₂H₂₂O₁₁)and 3.50 * 10² g water?

A)0.51 mmHg
B)16.0 mmHg
C)17.0 mmHg
D)18.0 mmHg
E)19.4 mmHg

Question 34

The solubility of oxygen in lakes high in the Rocky Mountains is affected by the altitude. If the solubility of O₂ from the air is 2.67 * 10^-4 M at sea level and 25°C, what is the solubility of O₂ at an elevation of 12,000 ft where the atmospheric pressure is 0.657 atm? Assume the temperature is 25°C, and that the mole fraction of O₂ in air is 0.209 at both 12,000 ft and at sea level.

A)1.75 * 10^-4 M
B)2.67 * 10^-4 M
C)3.66 * 10^-5 M
D)4.06 * 10^-4 M
E)None of the above.

Question 35

A solution of chloroform, CHCl₃, and acetone, (CH₃)₂CO, exhibits a negative deviation from Raoult's law. This result implies that

A)chloroform-chloroform interactions are stronger than chloroform-acetone interactions.
B)chloroform-chloroform interactions are weaker than chloroform-acetone interactions.
C)acetone-acetone interactions are stronger than chloroform-acetone interactions.
D)acetone-acetone interactions are weaker than chloroform-acetone interactions.
E)Both B and D.
F)Both A and C.

Question 36

What is the molality of a solution that is 3.68 % by mass calcium chloride?

A)0.0332 m
B)0.332 m
C)0.344 m
D)0.464 m
E)0.506 m

Question 37

The solubility of CO₂ gas in water

A)increases with increasing temperature.
B)decreases with decreasing temperature.
C)decreases with increasing temperature.
D)is not dependent on temperature.

Question 38

A solution is 40.0% by volume benzene (C₆H₆)in carbon tetrachloride at 20°C. The vapor pressure of pure benzene at this temperature is 74.61 mmHg and its density is 0.87865 g/cm³; the vapor pressure of pure carbon tetrachloride is 91.32 mmHg and its density is 1.5940 g/cm³. If this solution is ideal, its total vapor pressure at 20°C is

A)84.64 mmHg.
B)84.30 mmHg.
C)82.96 mmHg.
D)81.63 mmHg.
E)165.93 mmHg.

Question 39

Calculate the molality of a 20.0% by mass ammonium sulfate (NH₄)₂SO₄ solution. The density of the solution is 1.117 g/mL.

A)0.150 m
B)1.51 m
C)1.70 m
D)1.89 m
E)2.10 m

Question 40

At 10°C one volume of water dissolves 3.10 volumes of chlorine gas at 1.00 atm pressure. What is the Henry's Law constant in mol/L·atm?

A)3.8
B)0.043
C)36.
D)3.1
E)0.13

Question 41

A solution that contains 55.0 g of ascorbic acid (VitaminC) in 250. g of water freezes at -2.34°C. Calculate the molar mass (in units of g/mol) of the solute. K_f of water is 1.86°C/m.

A) 1.26
B) 10.9
C) 43.6
D) 175
E) 277

Question 42

Which of the following aqueous solutions has the highest boiling point? K_b for water is 0.52°C/m.

A)0.2 m KCl
B)0.2 m Na₂SO₄
C)0.2 m Ca(NO₃)₂
D)A and B.
E)B and C.

Question 43

When 12.1 g of the sugar sucrose (a nonelectrolyte)are dissolved in exactly 800 g of water, the solution has a freezing point of -0.082°C. What is the molar mass of sucrose? K_f of water is 1.86°C/m.

A)426 g
B)99.2 g
C)178 g
D)266 g
E)343 g

Question 44

What volume of water should be added to 600. mL of ethanol in order to have a solution that boils at 95.0°C? (For ethanol, K_b = 1.22 °C/m, density = 0.789 g/cm³, boiling point = 78.4°C)

A)186 mL
B)245 mL
C)518 mL
D)116 mL
E)322 mL

Question 45

Which of the following aqueous solutions has the highest osmotic pressure at 25°C?

A)0.2 M KBr
B)0.2 M ethanol
C)0.2 M Na₂SO₄
D)0.2 M KCl

Question 46

What is the osmotic pressure of a 0.25 M solution of sucrose at 37°C? (R = 0.0821 L.atm/K.mol)

A)6.6 * 10^-5 atm
B)0.76 atm
C)6.4 atm
D)100 atm
E)940 atm

Question 47

Pure benzene, C₆H₆, freezes at 5.5° and boils at 80.1°C. What is the boiling point of a solution consisting of cyclohexane (C₆H₁₂)dissolved in benzene if the freezing point of this solution is 0.0°C? (For benzene, K_f = 5.12 °C/m, K_b = 2.53 °C/m; for cyclohexane, K_f = 20.0 °C/m, K_b = 2.79°C/m)

A)82.8°C
B)91.2°C
C)80.9°C
D)77.4°C
E)83.1°C

Question 48

What is the molar mass of toluene if 0.85 g of toluene depresses the freezing point of 100. g of benzene by 0.47°C? K_f of benzene is 5.12°C/m.

A)92.6 g/mol
B)78.0 g/mol
C)10.7 g/mol
D)81.8 g/mol
E)927 g/mol

Question 49

What is the osmotic pressure of a solution that contains 13.7 g of propyl alcohol (C₃H₇OH)dissolved in enough water to make 500. mL of solution at 27°C?

A)0.014 atm
B)0.037 atm
C)0.456 atm
D)0.01 atm
E)11.2 atm

Question 50

How many grams of sucrose (C₁₂H₂₂O₁₁, 342.3 g/mol)would be needed to make 2.5 L of a solution with an osmotic pressure of 14 atm at 25°C? (R = 0.0821 L.atm/K.mol)

A)0.57 g
B)6.8 g
C)2.0 * 10² g
D)4.9 * 10² g
E)5.8 * 10³ g

Question 51

What mass of ethanol, C₂H₅OH a nonelectrolyte, must be added to 10.0 L of water to give a solution that freezes at -10.0°C? Assume the density of water is 1.0 g/mL. K_f of water is 1.86°C/m.

A)85.7 kg
B)24.8 kg
C)5.38 kg
D)2.48 kg
E)1.17 kg

Question 52

What volume of ethanol (density = 0.7893 g/cm³)should be added to 450. mL of water in order to have a solution that freezes at -15.0°C? (For water, K_f = 1.86 °C/m.)

A)371 mL
B)470 mL
C)212 mL
D)132 mL
E)167 mL

Question 53

When 24.0 g of glucose (a nonelectrolyte)are dissolved in 500. g of water, the solution has a freezing point of -0.47°C. What is the molar mass of glucose? K_f of water is 1.86°C/m.

A)41.9 g
B)47.5 g
C)54.9 g
D)178 g
E)190. g

Question 54

Dissolving a solute such as KOH in a solvent such as water results in

A)an increase in the melting point of the liquid.
B)a decrease in the boiling point of the liquid.
C)a decrease in the vapor pressure of the liquid.
D)no change in the boiling point of the liquid.

Question 55

What is the freezing point of a solution that contains 10.0 g of glucose (C₆H₁₂O₆)in 100. g of H₂O? K_f for water is 1.86°C/m.

A)-0.186°C
B)+0.186°C
C)-0.10°C
D)+0.10°C
E)-1.03°C

Question 56

What is the boiling point of an aqueous solution of a nonelectrolyte that has an osmotic pressure of 10.50 atm at 25°C? K_b of water is 0.52°C/m. Assume the density of the solution is the same as that of pure water.

A)0.22°C
B)0.429°C
C)100.43°C
D)99.78°C
E)100.22°C

Question 57

What is the freezing point of an aqueous solution of a nonvolatile solute that has a boiling point of 102.5°C? For water K_f = 1.86°C/m and K_b = 0.52°C/m.

A)-8.94°C
B)-366°C
C)-0.99°C
D)0.99°C
E)8.94°C

Question 58

What is the freezing point of a solution prepared from 50.0 g ethylene glycol (C₂H₆O₂)and 85.0 g H₂O? K_f of water is 1.86°C/m.

A)17.6°C
B)-176°C
C)-1.50°C
D)1.50°C
E)-17.6°C

Question 59

During osmosis

A)pure solvent diffuses through a membrane but solutes do not.
B)pure solutes diffuse through a membrane but solvent does not.
C)pure solvent and a solution both diffuse at the same time through a membrane.
D)gases diffuse through a membrane into a solution and build up pressure.

Question 60

Calculate the freezing point of a solution made from 22.0 g of octane (C₈H₁₈)dissolved in 148.0 g of benzene. Benzene freezes at 5.50°C and its K_f value is 5.12°C/m.

A)-1.16°C
B)0.98°C
C)6.66°C
D)12.2°C
E)5.49°C

Question 61

An aqueous dextrose solution having a density of 1.04 g/cm³ freezes at -1.15°C. Find the osmotic pressure of this solution at 25°C. K_f of water is 1.86 °C/m; molecular mass of dextrose = 180.16 g/mol.

A)13.8 atm
B)14.1 atm
C)15.1 atm
D)12.9 atm
E)120 atm

Question 62

What is the osmotic pressure of a solution prepared from 13.7 g of the electrolyte HCl and enough water to make 0.500 L of solution at 18°C?

A)0.55 atm
B)1.10 atm
C)8.95 atm
D)17.9 atm
E)35.9 atm

Question 63

An aqueous fructose solution having a density of 1.049 g/cm³ is found to have an osmotic pressure of 17.0 atm at 25°C. Find the temperature at which this solution freezes. [Given: for water K_f = 1.86 °C/m; molecular mass of fructose = 180.16 g/mol]

A)-1.52°C
B)-1.30°C
C)-1.57°C
D)-1.69°C
E)-1.41°C

Question 64

A solution is prepared by adding 40.3 g of Mg(NO₃)₂ to 127 g of water. Calculate the mole fraction and molality of magnesium nitrate in this solution.

Question 65

What is the molarity and molality of a solution that is 10.00 % by mass potassium hydrogen carbonate (KHCO₃, 100.11 g/mol)and has a density of 1.0650 g/mL?

Question 66

Arrange the following aqueous solutions in order of increasing boiling points: 0.050 m Mg(NO₃)₂; 0.100 m ethanol; 0.090 m NaCl.

A)Mg(NO₃)₂ < NaCl < ethanol
B)ethanol < Mg(NO₃)₂ < NaCl
C)ethanol < NaCl < Mg(NO₃)₂
D)NaCl < ethanol < Mg(NO₃)₂
E)Mg(NO₃)₂ < ethanol < NaCl

Question 67

What is the percent by mass of sodium phosphate in a 0.142 M Na₃PO₄(aq)solution that has a density of 1.015 g/mL?

Question 68

Calculate the approximate freezing point of a solution made from 21.0 g NaCl and 1.00 * 10² g of H₂O. [K_f of water is 1.86°C/m.]

A)3.59°C
B)6.68°C
C)-13.4°C
D)-6.68°C
E)-3.59°C

Question 69

What is the concentration of O₂(g)in water at 25°C exposed to a partial pressure of oxygen of 325 mmHg? The Henry's law constant for oxygen gas at 25°C is 1.3 * 10^-3 mol/L·atm.

Question 70

What is the mole fraction of sodium phosphate in a 0.142 M Na₃PO₄(aq)solution that has a density of 1.015 g/mL?

Question 71

What is the approximate Na⁺ ion concentration in a 0.75 M Na₂CO₃ solution?

A)0.375 M
B)0.75 M
C)1.25 M
D)1.50 M
E)2.25 M

Question 72

A solution is prepared by adding 6.24 g of benzene (C₆H₆, 78.11 g/mol)to 80.74 g of cyclohexane (C₆H₁₂, 84.16 g/mol). Calculate the mole fraction and molality of benzene in this solution.

Question 73

Consider a 0.90 M Al(NO₃)₃ solution. This solution has a nitrate ion concentration of

A)0.30 M.
B)0.90 M.
C)0.0 M.
D)8.1 M.
E)2.7 M.

Question 74

Which of the following aqueous solutions has the lowest freezing point?

A)0.18 m KCl
B)0.15 m Na₂SO₄
C)0.12 m Ca(NO₃)₂
D)pure water
E)0.20 m C₂H₆O₂ (ethylene glycol)

Question 75

How many grams of propanol (C₃H₇OH, 60.10 g/mol)would be needed to make 750 mL of a solution with an osmotic pressure of 25 atm at 25°C? (R = 0.0821 L.atm/K.mol)

Question 76

Which of the following concentration units will not change with temperature: molarity, percent mass, mole fraction, and molality?

Question 77

What is the molarity of a solution that is 5.50 % by mass oxalic acid (C₂H₂O₄)and has a density of 1.0244 g/mL?

Question 78

The concentration of nitrogen in water at 25°C was determined to be 7.2 * 10^-6 M. Calculate the partial pressure of nitrogen at the surface of the water in mmHg. The Henry's law constant for nitrogen gas at 25°C is 6.8 * 10^-4 mol/L·atm?

Question 79

What is the molality of a 0.142 M Na₃PO₄(aq)solution that has a density of 1.015 g/mL?

Question 80

The osmotic pressure of a 0.010 M MgSO₄ solution at 25°C is 0.318 atm. Calculate i, the van't Hoff factor, for this MgSO₄ solution.

A)0.013
B)1.3
C)1.5
D)2.0
E)76.8