Question 1

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).

Accepted Answer

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 
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 2

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.

Accepted Answer

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

Question 3

A nonelectrolyte compound with a molar mass of 648 g mol-1 was dissolved in enough water to make 250 mL of solution at 25 °C and produced an osmotic pressure of 27.4 mbar. Calculate the mass of the compound, in g, used to make this solution.

Accepted Answer

A) 0.267 g 
B) 0.179 g 
C) 0.106 g 
D) 0.0873 g 
E) 0.236 g 
A) 0.267 g 
B) 0.179 g 
C) 0.106 g 
D) 0.0873 g 
E) 0.236 g

Question 4

Identify the compound whose solubility is least affected by temperature.

Accepted Answer

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

Question 5

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

Accepted Answer

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

Question 6

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.

Accepted Answer

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

Question 7

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.

Accepted Answer

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 
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 8

Which of the following defines dynamic equilibrium of a solution?

Accepted Answer

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

Question 9

A solution of LiCl in water is 20.0 wt% LiCl. What is the mole fraction of LiCl? Assume the density of the solution is 1.00 g mL-1.

Accepted Answer

A) 0.0960 
B) 0.106 
C) 0.472 
D) 4.44 
A) 0.0960 
B) 0.106 
C) 0.472 
D) 4.44

Question 10

Which of the following solutions will have the lowest freezing point?

Accepted Answer

A) 0.010 mol kg-1 K Br 
B) 0.010 mol kg-1 Na2CO3 
C) 0.035 mol kg-1 CH3CH2OH  
D) 0.015 mol kg-1 BaCl2 
A) 0.010 mol kg-1 K Br 
B) 0.010 mol kg-1 Na2CO3 
C) 0.035 mol kg-1 CH3CH2OH  
D) 0.015 mol kg-1 BaCl2

Question 11

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

Accepted Answer

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

Question 12

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

Accepted Answer

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

Question 13

Choose the aqueous solution below with the lowest freezing point. These are all solutions of nonvolatile solutes and you should assume ideal van't Hoff factors where applicable.

Accepted Answer

A) 0.075 mol kg-1 NaI 
B) 0.075 mol kg-1 (NH4)3PO4 
C) 0.075 mol kg-1 NaBrO4 
D) 0.075 mol kg-1 LiCN 
E) 0.075 mol kg-1 KNO2 
A) 0.075 mol kg-1 NaI 
B) 0.075 mol kg-1 (NH4)3PO4 
C) 0.075 mol kg-1 NaBrO4 
D) 0.075 mol kg-1 LiCN 
E) 0.075 mol kg-1 KNO2

Question 14

What volume of 3.00 mol L-1 CH3OH solution is needed to provide 0.220 mol of CH3OH?

Accepted Answer

A) 1.52 mL 
B) 13.6 mL 
C) 73.3 mL 
D) 660 mL 
A) 1.52 mL 
B) 13.6 mL 
C) 73.3 mL 
D) 660 mL

Question 15

Determine ΔsoluteH for KBr if the ΔsolutionH for KBr is +19.9 kJ mol-1 and the ΔhydrationH for KBr is -670. kJ mol-1.

Accepted Answer

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 
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 16

What is the weight percent of a caffeine solution made by dissolving 8.35 g of caffeine, C8H10N4O2, in 75 g of benzene, C6H6?

Accepted Answer

A) 0.010% 
B) 0.011% 
C) 10% 
D) 11% 
A) 0.010% 
B) 0.011% 
C) 10% 
D) 11%

Question 17

A solution of methanol and water has a vapour pressure of 213 Torr. What would you predict as the mole fractions of each component, assuming ideal behaviour? The vapour pressures of methanol and water are 256 Torr and 55.3 Torr, respectively.

Accepted Answer

A)    = 0.214,   = 0.786   
B)    = 0.786,   = 0.214 
C)    = 0.885,   = 0.115 
D)    = 0.900,   = 0.100 
E)    = 0.115,   = 0.885 
A)    = 0.214,   = 0.786   
B)    = 0.786,   = 0.214 
C)    = 0.885,   = 0.115 
D)    = 0.900,   = 0.100 
E)    = 0.115,   = 0.885

Question 18

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.

Accepted Answer

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 
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 19

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

Accepted Answer

A) 0.120 mol kg-1 C2H6O2 
B) 0.040 mol kg-1 (NH4)2SO4 
C) 0.060 mol kg-1 K2CO3 
D) 0.030 mol kg-1 LiC2H3O2 
E) They all have the same vapour pressure. 
A) 0.120 mol kg-1 C2H6O2 
B) 0.040 mol kg-1 (NH4)2SO4 
C) 0.060 mol kg-1 K2CO3 
D) 0.030 mol kg-1 LiC2H3O2 
E) They all have the same vapour pressure.

Question 20

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? Kb (water)= 0.512 °C m-1.

Accepted Answer

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

Exam 12: Solutions

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 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 nonelectrolyte compound with a molar mass of 648 g mol-1 was dissolved in enough water to make 250 mL of solution at 25 °C and produced an osmotic pressure of 27.4 mbar. Calculate the mass of the compound, in g, used to make this solution.

Identify the compound whose solubility is least affected by temperature.

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 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.

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.

Which of the following defines dynamic equilibrium of a solution?

A solution of LiCl in water is 20.0 wt% LiCl. What is the mole fraction of LiCl? Assume the density of the solution is 1.00 g mL-1.

Which of the following solutions will have the lowest freezing point?

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

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

Choose the aqueous solution below with the lowest freezing point. These are all solutions of nonvolatile solutes and you should assume ideal van't Hoff factors where applicable.

What volume of 3.00 mol L-1 CH3OH solution is needed to provide 0.220 mol of CH3OH?

Determine ΔsoluteH for KBr if the ΔsolutionH for KBr is +19.9 kJ mol-1 and the ΔhydrationH for KBr is -670. kJ mol-1.

What is the weight percent of a caffeine solution made by dissolving 8.35 g of caffeine, C8H10N4O2, in 75 g of benzene, C6H6?

A solution of methanol and water has a vapour pressure of 213 Torr. What would you predict as the mole fractions of each component, assuming ideal behaviour? The vapour pressures of methanol and water are 256 Torr and 55.3 Torr, respectively.

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.

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

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? Kb (water)= 0.512 °C m-1.

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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 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 nonelectrolyte compound with a molar mass of 648 g mol^-1 was dissolved in enough water to make 250 mL of solution at 25 °C and produced an osmotic pressure of 27.4 mbar. Calculate the mass of the compound, in g, used to make this solution.

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 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.

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 solution of LiCl in water is 20.0 wt% LiCl. What is the mole fraction of LiCl? Assume the density of the solution is 1.00 g mL^-1.

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

What volume of 3.00 mol L^-1 CH₃OH solution is needed to provide 0.220 mol of CH₃OH?

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

What is the weight percent of a caffeine solution made by dissolving 8.35 g of caffeine, C₈H₁₀N₄O₂, in 75 g of benzene, C₆H₆?

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.

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.