Question 1

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

Question 2

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.

Accepted Answer

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

Question 3

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

Accepted Answer

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

Question 4

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.

Accepted Answer

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

Question 5

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

Accepted Answer

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

Question 6

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

Accepted Answer

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

Question 7

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.

Accepted Answer

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

Question 8

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.

Accepted Answer

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

Question 9

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.

Accepted Answer

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 10

A solution is prepared by dissolving 40.0 g of sucrose, C12H22O11, in 250. g of water at 25 °C. What is the vapour pressure of the solution if the vapour pressure of water at 25 °C is 23.76 mmHg?

Accepted Answer

A) 0.198 mmHg 
B) 20.5 mmHg 
C) 23.6 mmHg 
D) 24.0 mmHg

Question 11

A solid can be purified through which technique?

Accepted Answer

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

Question 12

Identify the solute with the lowest van't Hoff factor.

Accepted Answer

A) nonelectrolyte 
B) NaCl 
C) MgSO4 
D) MgCl2 
E) FeCl3

Question 13

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.

Accepted Answer

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

Question 14

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.

Accepted Answer

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 15

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.

Accepted Answer

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

Question 16

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

Accepted Answer

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

Question 17

A 150.0 mL sample of an aqueous solution at 25 °C contains 15.2 mg of an unknown nonelectrolyte compound. If the solution has an osmotic pressure of 8.44 Torr, what is the molar mass of the unknown compound?

Accepted Answer

A) 223 g mol-1 
B) 294 g mol-1 
C) 341 g mol-1 
D) 448 g mol-1 
E) 195 g mol-1

Question 18

At 20 °C, a 0.376 mol L-1 aqueous solution of ammonium chloride has a density of 1.0045 g mL-1. What is the mass % of ammonium chloride in the solution? The formula weight of NH4Cl is 53.50 g mol-1.

Accepted Answer

A) 0.381 
B) 0.705 
C) 0.374 
D) 2.68 
E) 2.00

Question 19

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.

Accepted Answer

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 20

What molality of pentane is obtained by dissolving 15 g pentane, C5H12, in 245.0 g hexane, C6H14?

Accepted Answer

A) 0.058 mol kg-1 
B) 0.068 mol kg-1  
C) 0.85 mol kg-1 
D) 61 mol kg-1

Exam 12: Solutions

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.

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.

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

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.

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.

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.

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.

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.

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^-1bar^-1.

A solution is prepared by dissolving 40.0 g of sucrose, C₁₂H₂₂O₁₁, in 250. g of water at 25 °C. What is the vapour pressure of the solution if the vapour pressure of water at 25 °C is 23.76 mmHg?

A solid can be purified through which technique?

Identify the solute with the lowest van't Hoff factor.

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 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.

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.

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

A 150.0 mL sample of an aqueous solution at 25 °C contains 15.2 mg of an unknown nonelectrolyte compound. If the solution has an osmotic pressure of 8.44 Torr, what is the molar mass of the unknown compound?

At 20 °C, a 0.376 mol L^-1 aqueous solution of ammonium chloride has a density of 1.0045 g mL^-1. What is the mass % of ammonium chloride in the solution? The formula weight of NH₄Cl is 53.50 g mol^-1.

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.

What molality of pentane is obtained by dissolving 15 g pentane, C₅H₁₂, in 245.0 g hexane, C₆H₁₄?

Exam 12: Solutions

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.

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.

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

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.

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

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

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.

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.

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 solution is prepared by dissolving 40.0 g of sucrose, C12H22O11, in 250. g of water at 25 °C. What is the vapour pressure of the solution if the vapour pressure of water at 25 °C is 23.76 mmHg?

A solid can be purified through which technique?

Identify the solute with the lowest van't Hoff factor.

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 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.

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.

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

A 150.0 mL sample of an aqueous solution at 25 °C contains 15.2 mg of an unknown nonelectrolyte compound. If the solution has an osmotic pressure of 8.44 Torr, what is the molar mass of the unknown compound?

At 20 °C, a 0.376 mol L-1 aqueous solution of ammonium chloride has a density of 1.0045 g mL-1. What is the mass % of ammonium chloride in the solution? The formula weight of NH4Cl is 53.50 g mol-1.

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.

What molality of pentane is obtained by dissolving 15 g pentane, C5H12, in 245.0 g hexane, C6H14?

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.

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.

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

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.

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.

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.

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.

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.

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^-1bar^-1.

A solution is prepared by dissolving 40.0 g of sucrose, C₁₂H₂₂O₁₁, in 250. g of water at 25 °C. What is the vapour pressure of the solution if the vapour pressure of water at 25 °C is 23.76 mmHg?

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.

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

At 20 °C, a 0.376 mol L^-1 aqueous solution of ammonium chloride has a density of 1.0045 g mL^-1. What is the mass % of ammonium chloride in the solution? The formula weight of NH₄Cl is 53.50 g mol^-1.

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.

What molality of pentane is obtained by dissolving 15 g pentane, C₅H₁₂, in 245.0 g hexane, C₆H₁₄?