Question 1

Match the following.
-0.050 mol kg-1 NaCl

Accepted Answer

A) solution of ionic compound with highest freezing point. 
B) solution that is most strongly dependent upon pressure 
C) solution with ΔTb = 0.026 °C 
D) highest boiling point 
E) largest van't Hoff factor 
A) solution of ionic compound with highest freezing point. 
B) solution that is most strongly dependent upon pressure 
C) solution with ΔTb = 0.026 °C 
D) highest boiling point 
E) largest van't Hoff factor

Question 2

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

Accepted Answer

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

Question 3

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.

Accepted Answer

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

Question 4

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 5

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

Accepted Answer

A)  when   >   
B)  when      
E)  There isn't enough information to determine the answer. 
A)  when   >   
B)  when      
E)  There isn't enough information to determine the answer.

Question 6

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 7

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

Accepted Answer

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

Question 8

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

Accepted Answer

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

Question 9

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 10

Calculate the total solution volume required to produce an osmotic pressure of 6.39 mbar using 12.34 mg of a protein with a molar mass of 5309 g mol-1 at 25.0 °C.

Accepted Answer

A)  12.5 mL 
B)  11.8 mL 
C)  9.91 mL 
D)  8.37 mL 
E)  9.02 mL 
A)  12.5 mL 
B)  11.8 mL 
C)  9.91 mL 
D)  8.37 mL 
E)  9.02 mL

Question 11

What is the weight percent of vitamin C in a solution made by dissolving 6.50 g of vitamin C, C6H8O6, in 55.0 g of water?

Accepted Answer

A)  0. 547% 
B)  1.21% 
C)  10.6% 
D)  11.8% 
A)  0. 547% 
B)  1.21% 
C)  10.6% 
D)  11.8%

Question 12

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 13

Choose the aqueous solution that has the highest boiling point. These are all solutions of nonvolatile solutes and you should assume ideal van't Hoff factors where applicable.

Accepted Answer

A)  0.100 mol kg-1 NaNO3 
B)  0.100 mol kg-1 Li2SO4 
C)  0.200 mol kg-1 C3H8O3 
D)  0.060 mol kg-1 Na3PO4 
E)  They all have the same boiling point. 
A)  0.100 mol kg-1 NaNO3 
B)  0.100 mol kg-1 Li2SO4 
C)  0.200 mol kg-1 C3H8O3 
D)  0.060 mol kg-1 Na3PO4 
E)  They all have the same boiling point.

Question 14

Match the following.
-0.0050 mol kg-1 CO2

Accepted Answer

A) solution of ionic compound with highest freezing point. 
B) solution that is most strongly dependent upon pressure 
C) solution with ΔTb = 0.026 °C 
D) highest boiling point 
E) largest van't Hoff factor 
A) solution of ionic compound with highest freezing point. 
B) solution that is most strongly dependent upon pressure 
C) solution with ΔTb = 0.026 °C 
D) highest boiling point 
E) largest van't Hoff factor

Question 15

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 16

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.

Accepted Answer

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 
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 17

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 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

How much water must be added to 40.0 g of CaCl2 to produce a solution that is 35.0 wt% CaCl2?

Accepted Answer

A)  54.0 g 
B)  74.2 g 
C)  87.5 g 
D)  114 g 
A)  54.0 g 
B)  74.2 g 
C)  87.5 g 
D)  114 g

Question 20

How many grams of KBr are required to make 350. mL of a 0.115 mol L-1 KBr solution?

Accepted Answer

A)  0. 338 g 
B)  3.04 g 
C)  4.79 g 
D)  40.3 g 
A)  0. 338 g 
B)  3.04 g 
C)  4.79 g 
D)  40.3 g

Exam 12: Solutions

Match the following. -0.050 mol kg-1 NaCl

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

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 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.

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

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.

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

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

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.

Calculate the total solution volume required to produce an osmotic pressure of 6.39 mbar using 12.34 mg of a protein with a molar mass of 5309 g mol-1 at 25.0 °C.

What is the weight percent of vitamin C in a solution made by dissolving 6.50 g of vitamin C, C6H8O6, in 55.0 g of water?

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.

Choose the aqueous solution that has the highest boiling point. These are all solutions of nonvolatile solutes and you should assume ideal van't Hoff factors where applicable.

Match the following. -0.0050 mol kg-1 CO2

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

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.

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?

How much water must be added to 40.0 g of CaCl2 to produce a solution that is 35.0 wt% CaCl2?

How many grams of KBr are required to make 350. mL of a 0.115 mol L-1 KBr solution?

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Filters

Match the following. -0.050 mol kg^-1 NaCl

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

Determine the partial pressure of oxygen necessary to form an aqueous solution that is 4.1 × 10^-4mol 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.

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

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

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

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.

Calculate the total solution volume required to produce an osmotic pressure of 6.39 mbar using 12.34 mg of a protein with a molar mass of 5309 g mol^-1 at 25.0 °C.

What is the weight percent of vitamin C in a solution made by dissolving 6.50 g of vitamin C, C₆H₈O₆, in 55.0 g of water?

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.

Match the following. -0.0050 mol kg^-1 CO₂

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.

How much water must be added to 40.0 g of CaCl₂ to produce a solution that is 35.0 wt% CaCl₂?

How many grams of KBr are required to make 350. mL of a 0.115 mol L^-1 KBr solution?