Question 1

Identify the major force between acetone and chloroform.

Accepted Answer

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

Question 2

What volume of a 0.716 mol L-1 KBr solution is needed to provide 30.5 g of KBr?

Accepted Answer

A) 21.8 mL 
B) 42.7 mL 
C) 184 mL 
D) 357 mL 
A) 21.8 mL 
B) 42.7 mL 
C) 184 mL 
D) 357 mL

Question 3

What is the expected freezing point of a 0.50 mol kg-1 solution of Li2SO4 in water? Kf for water is 1.86 °C m-1.

Accepted Answer

A) -0.93 °C 
B) -1.9 °C 
C) -2.8 °C 
D) -6.5 °C 
A) -0.93 °C 
B) -1.9 °C 
C) -2.8 °C 
D) -6.5 °C

Question 4

Calculate the osmotic pressure, in bar, of a solution containing 3.00 mg of a sugar (342 g mol-1)in 15.0 mL of water at 25 °C.

Accepted Answer

Question 5

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

Accepted Answer

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

Question 6

A mixture of pentane and hexane has a vapour pressure of 241 Torr. Calculate the mole fraction of pentane in the mixture. The vapour pressures of pure pentane and hexane are 425 Torr and 151 Torr, respectively. Assume ideal behaviour.

Accepted Answer

A) 0.620 
B) 0.672 
C) 0.380 
D) 0.328 
E) 0.500 
A) 0.620 
B) 0.672 
C) 0.380 
D) 0.328 
E) 0.500

Question 7

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.

Accepted Answer

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

Question 8

A solution of LiCl in water has XLiCl = 0.0900. What is the molality?

Accepted Answer

A) 4.46 mol kg-1 LiCl 
B) 5.00 mol kg-1 LiCl 
C) 5.49 mol kg-1 LiCl 
D) 9.89 mol kg-1 LiCl 
A) 4.46 mol kg-1 LiCl 
B) 5.00 mol kg-1 LiCl 
C) 5.49 mol kg-1 LiCl 
D) 9.89 mol kg-1 LiCl

Question 9

Choose the aqueous solution with the highest vapour pressure. These are all solutions of nonvolatile solutes and you should assume ideal van't Hoff factors where applicable.

Accepted Answer

A) 0.50 mol kg-1 C3H8O3 
B) 0.50 mol kg-1 C2H6O2 
C) 0.50 mol kg-1 C6H12O6 
D) 0.50 mol kg-1 C12H22O11 
E) They all have about the same vapour pressure. 
A) 0.50 mol kg-1 C3H8O3 
B) 0.50 mol kg-1 C2H6O2 
C) 0.50 mol kg-1 C6H12O6 
D) 0.50 mol kg-1 C12H22O11 
E) They all have about the same vapour pressure.

Question 10

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.

Accepted Answer

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

Question 11

At 20 °C, an aqueous solution that is 24.0% by mass in ammonium chloride has a density of 1.0674 g mL-1. What is the molarity of ammonium chloride in the solution? The formula weight of NH4Cl is 53.50 g mol-1.

Accepted Answer

A) 5.90 
B) 0.479 
C) 4.79 
D) 0.0445 
E) 22.5 
A) 5.90 
B) 0.479 
C) 4.79 
D) 0.0445 
E) 22.5

Question 12

Choose the statement below that is TRUE.

Accepted Answer

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. 
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 13

Calculate the freezing point of a solution containing 5.0 grams of KCl and 550.0 grams of water. The molal freezing point depression constant (Kf)for water is 1.86 °C m-1.

Accepted Answer

A) -0.45 °C 
B) +0.45 °C 
C) -0.23 °C 
D) +0.23 °C 
E) 1.23 °C 
A) -0.45 °C 
B) +0.45 °C 
C) -0.23 °C 
D) +0.23 °C 
E) 1.23 °C

Question 14

Define osmosis.

Accepted Answer

Osmosis is the flow of solvent

Question 15

What is the freezing point of a solution of 7.15 g MgCl2 in 100 g of water? Kf for water is 1.86 °C m-1.

Accepted Answer

A) -0.140 °C 
B) -1.40 °C 
C) -2.80 °C 
D) -4.18 °C 
A) -0.140 °C 
B) -1.40 °C 
C) -2.80 °C 
D) -4.18 °C

Question 16

Identify the colligative property.

Accepted Answer

A) vapour pressure lowering 
B) freezing point depression 
C) boiling point elevation 
D) osmotic pressure 
E) All of the above 
A) vapour pressure lowering 
B) freezing point depression 
C) boiling point elevation 
D) osmotic pressure 
E) All of the above

Question 17

A solution is prepared by dissolving 7.00 g of glycerin (C3H8O3)in 201 g of ethanol (C2H5OH). The freezing point of the solution is ________°C. The freezing point of pure ethanol is -114.6 °C. The molal freezing point depression constant (Kf)for ethanol is 1.99 °C m-1. The molar masses of glycerin and of ethanol are 92.1 g mol-1 and 46.1 g mol-1, respectively.

Accepted Answer

A) -121.3 
B) 0.752 
C) -107.9 
D) -113.8 
E) -115.4 
A) -121.3 
B) 0.752 
C) -107.9 
D) -113.8 
E) -115.4

Question 18

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?

Accepted Answer

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. 
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 19

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.

Accepted Answer

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 
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 20

Calculate the total solution volume required to produce an osmotic pressure of 4.87 mbar using 8.21 mg of a protein with a molar mass of 4450 g mol-1 at 25.0 °C.

Accepted Answer

A) 10.6 mL 
B) 4.79 mL 
C) 12.3 mL 
D) 9.39 mL 
E) 8.00 mL 
A) 10.6 mL 
B) 4.79 mL 
C) 12.3 mL 
D) 9.39 mL 
E) 8.00 mL

Exam 12: Solutions

Identify the major force between acetone and chloroform.

What volume of a 0.716 mol L-1 KBr solution is needed to provide 30.5 g of KBr?

What is the expected freezing point of a 0.50 mol kg-1 solution of Li2SO4 in water? Kf for water is 1.86 °C m-1.

Calculate the osmotic pressure, in bar, of a solution containing 3.00 mg of a sugar (342 g mol-1)in 15.0 mL of water at 25 °C.

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

A mixture of pentane and hexane has a vapour pressure of 241 Torr. Calculate the mole fraction of pentane in the mixture. The vapour pressures of pure pentane and hexane are 425 Torr and 151 Torr, respectively. Assume ideal behaviour.

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 solution of LiCl in water has XLiCl = 0.0900. What is the molality?

Choose the aqueous solution with the highest vapour pressure. These are all solutions of nonvolatile solutes and you should assume ideal van't Hoff factors where applicable.

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.

At 20 °C, an aqueous solution that is 24.0% by mass in ammonium chloride has a density of 1.0674 g mL-1. What is the molarity of ammonium chloride in the solution? The formula weight of NH4Cl is 53.50 g mol-1.

Choose the statement below that is TRUE.

Calculate the freezing point of a solution containing 5.0 grams of KCl and 550.0 grams of water. The molal freezing point depression constant (Kf)for water is 1.86 °C m-1.

Define osmosis.

What is the freezing point of a solution of 7.15 g MgCl2 in 100 g of water? Kf for water is 1.86 °C m-1.

Identify the colligative property.

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?

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.

Calculate the total solution volume required to produce an osmotic pressure of 4.87 mbar using 8.21 mg of a protein with a molar mass of 4450 g mol-1 at 25.0 °C.

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Filters

What volume of a 0.716 mol L^-1 KBr solution is needed to provide 30.5 g of KBr?

What is the expected freezing point of a 0.50 mol kg^-1 solution of Li₂SO₄ in water? K_f for water is 1.86 °C m^-1.

Calculate the osmotic pressure, in bar, of a solution containing 3.00 mg of a sugar (342 g mol^-1)in 15.0 mL of water at 25 °C.

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 solution of LiCl in water has X_LiCl = 0.0900. What is the molality?

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.

At 20 °C, an aqueous solution that is 24.0% by mass in ammonium chloride has a density of 1.0674 g mL^-1. What is the molarity of ammonium chloride in the solution? The formula weight of NH₄Cl is 53.50 g mol^-1.

Calculate the freezing point of a solution containing 5.0 grams of KCl and 550.0 grams of water. The molal freezing point depression constant (K_f)for water is 1.86 °C m^-1.

What is the freezing point of a solution of 7.15 g MgCl₂ in 100 g of water? K_f for water is 1.86 °C m^-1.

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.

Calculate the total solution volume required to produce an osmotic pressure of 4.87 mbar using 8.21 mg of a protein with a molar mass of 4450 g mol^-1 at 25.0 °C.