Question 1

At 25°C, the vapor pressure of pure water is 25.756 mm Hg. What is the vapor pressure of water in a 0.500 m solution of sodium chloride?

Accepted Answer

A)  25.52 mm Hg 
B)  0.2301 mm Hg 
C)  0.4602 mm Hg 
D)  25.35 mm Hg 
E)  12.88 mm Hg 
A)  25.52 mm Hg 
B)  0.2301 mm Hg 
C)  0.4602 mm Hg 
D)  25.35 mm Hg 
E)  12.88 mm Hg

Question 2

Indicate which aqueous solution has the slowest evaporation rate.

Accepted Answer

A)  0.1 M KCl 
B)  0.2 M Na2CO3 
C)  0.2 M NaCl 
D)  0.1 M MgCl2 
E)  0.1 M NaBr 
A)  0.1 M KCl 
B)  0.2 M Na2CO3 
C)  0.2 M NaCl 
D)  0.1 M MgCl2 
E)  0.1 M NaBr

Question 3

Which of the solutions shown here will have the highest vapor pressure? White circles indicate solvent molecules; black circles indicate molecules of a nonvolatile solute.

Accepted Answer

A)    
B)    
C)    
D)    
A)    
B)    
C)    
D)

Question 4

Indicate which aqueous solution has the highest vapor pressure.

Accepted Answer

A)  0.1 M KCl 
B)  0.2 M Na2CO3 
C)  0.2 M NaCl 
D)  0.1 M MgCl2 
E)  0.2 M MgCl2 
A)  0.1 M KCl 
B)  0.2 M Na2CO3 
C)  0.2 M NaCl 
D)  0.1 M MgCl2 
E)  0.2 M MgCl2

Question 5

Which statement below regarding vapor pressure is not correct?

Accepted Answer

A)  Vapor pressure is an intensive property. 
B)  The substance with the stronger intermolecular forces has the lower vapor pressure. 
C)  Vapor pressure increases with increasing temperature. 
D)  Pure water has a higher vapor pressure at a given temperature than seawater. 
E)  A nonvolatile solute increases the vapor pressure of the solvent. 
A)  Vapor pressure is an intensive property. 
B)  The substance with the stronger intermolecular forces has the lower vapor pressure. 
C)  Vapor pressure increases with increasing temperature. 
D)  Pure water has a higher vapor pressure at a given temperature than seawater. 
E)  A nonvolatile solute increases the vapor pressure of the solvent.

Question 6

Which of the following gases do you expect to be most soluble in water?

Accepted Answer

A)  CO2 
B)  Ar 
C)  O2 
D)  N2 
E)  NH3 
A)  CO2 
B)  Ar 
C)  O2 
D)  N2 
E)  NH3

Question 7

The pressure of carbon dioxide in a beer bottle is about 2 atm. At this pressure about 0.15 g of carbon dioxide dissolves in 100 mL of beer. How much carbon dioxide remains dissolved in 100 mL after the bottle is opened? The partial pressure of carbon dioxide is 2.0 *10-4 atm.

Accepted Answer

A)  0.15 g 
B)  3.8 *10-3 g 
C)  6.0 * 10-5 g 
D)  3.0 * 10-4 g 
E)  1.5 * 10-5 g 
A)  0.15 g 
B)  3.8 *10-3 g 
C)  6.0 * 10-5 g 
D)  3.0 * 10-4 g 
E)  1.5 * 10-5 g

Question 8

What is the vapor pressure of an aqueous solution that has a solute mol fraction of   = 0.100? The vapor pressure of water is 25.756 mm Hg at 25°C.

Accepted Answer

A)  23.2 mm Hg 
B)  2.58 mm Hg 
C)  25.8 mm Hg 
D)  0.900 mm Hg 
E)  22.3 mm Hg 
A)  23.2 mm Hg 
B)  2.58 mm Hg 
C)  25.8 mm Hg 
D)  0.900 mm Hg 
E)  22.3 mm Hg

Question 9

Why would you expect or predict sodium fluoride to have the lowest solubility in water compared to the other sodium halide salts?

Accepted Answer

A)  Fluoride has the largest (most negative) enthalpy of hydration of all the halide ions. 
B)  Fluoride has the smallest (least negative) enthalpy of hydration of all the halide ions. 
C)  Sodium fluoride has the largest (most negative) lattice energy of all the sodium halides. 
D)  Sodium fluoride has the smallest molar mass of all the sodium halides. 
E)  Fluoride is the most basic of all the halide ions and forms HF in aqueous solution. 
A)  Fluoride has the largest (most negative) enthalpy of hydration of all the halide ions. 
B)  Fluoride has the smallest (least negative) enthalpy of hydration of all the halide ions. 
C)  Sodium fluoride has the largest (most negative) lattice energy of all the sodium halides. 
D)  Sodium fluoride has the smallest molar mass of all the sodium halides. 
E)  Fluoride is the most basic of all the halide ions and forms HF in aqueous solution.

Question 10

Which of the following compounds has the largest melting point?

Accepted Answer

A)  NaF 
B)  KCl 
C)  RbCl 
D)  BeF2 
E)  NaCl 
A)  NaF 
B)  KCl 
C)  RbCl 
D)  BeF2 
E)  NaCl

Question 11

You are working as an intern in a biochemistry lab. Your advisor just isolated an enzyme and asks you to determine its molar mass using osmosis. You dissolve 1.0 g of the enzyme in water to make 250 mL of solution. You measure the osmotic pressure and find it to be 3.5 torr at 298 K. You report that the molar mass is ________ g/mol.

Accepted Answer

A)  between 0 and 1,000 
B)  between 1,000 and 5,000 
C)  between 5,000 and 10,000 
D)  between 10,000 and 20,000 
E)  between 20,000 and 50,000 
A)  between 0 and 1,000 
B)  between 1,000 and 5,000 
C)  between 5,000 and 10,000 
D)  between 10,000 and 20,000 
E)  between 20,000 and 50,000

Question 12

Determine the molal concentration of a sugar solution in water that has a freezing point of -2.1°C. Kf = 1.86°C/m for water.

Accepted Answer

A)  1.13 m 
B)  -1.13 m 
C)  3.91 m 
D)  -3.91 m 
E)  0.113 m 
A)  1.13 m 
B)  -1.13 m 
C)  3.91 m 
D)  -3.91 m 
E)  0.113 m

Question 13

Which intermolecular interactions are likely to result in the lowest vapor pressure of a substance?

Accepted Answer

A)  dispersion interactions 
B)  dipole-dipole interactions 
C)  hydrogen bonds 
D)  ion-dipole interactions 
E)  ion-ion interactions 
A)  dispersion interactions 
B)  dipole-dipole interactions 
C)  hydrogen bonds 
D)  ion-dipole interactions 
E)  ion-ion interactions

Question 14

The freezing point of a 0.0925 m solution of ammonium chloride was found to be -0.325°C. What is the actual van 't Hoff factor for this salt at this concentration compared to the ideal one of 2?
Kf (water) = 1.86°C/m

Accepted Answer

A)  1.89 
B)  1.95 
C)  1.90 
D)  1.80 
E)  1.97 
A)  1.89 
B)  1.95 
C)  1.90 
D)  1.80 
E)  1.97

Question 15

Which intermolecular interactions are likely to result in the highest vapor pressure of a substance?

Accepted Answer

A)  dispersion interactions 
B)  dipole-dipole interactions 
C)  hydrogen bonds 
D)  ion-dipole interactions 
E)  ion-ion interactions 
A)  dispersion interactions 
B)  dipole-dipole interactions 
C)  hydrogen bonds 
D)  ion-dipole interactions 
E)  ion-ion interactions

Question 16

Which statement about the vapor pressure of a liquid is not correct?

Accepted Answer

A)  The vapor pressure increases with increasing temperature because more molecules have sufficient energy to overcome the attractive forces that hold them in the liquid. 
B)  The vapor pressure increases with increasing strength of intermolecular interactions because molecules are better able to pull each other into the gas phase. 
C)  The pressure at which the rate of molecules evaporating equals the rate of molecules condensing is called the vapor pressure. 
D)  Adding a nonvolatile solute to a liquid decreases the vapor pressure. 
E)  The enthalpy of vaporization determines how sensitive the vapor pressure of a substance is to a change in temperature. 
A)  The vapor pressure increases with increasing temperature because more molecules have sufficient energy to overcome the attractive forces that hold them in the liquid. 
B)  The vapor pressure increases with increasing strength of intermolecular interactions because molecules are better able to pull each other into the gas phase. 
C)  The pressure at which the rate of molecules evaporating equals the rate of molecules condensing is called the vapor pressure. 
D)  Adding a nonvolatile solute to a liquid decreases the vapor pressure. 
E)  The enthalpy of vaporization determines how sensitive the vapor pressure of a substance is to a change in temperature.

Question 17

A 300 mg sample of caffeine was dissolved in 10.0 g of camphor (Kf = 39.7°C/m), decreasing the freezing point of camphor by 3.07°C. What is the molar mass of caffeine?

Accepted Answer

A)  47.0 g/mol 
B)  194 g/mol 
C)  388 g/mol 
D)  94.0 g/mol 
E)  97.0 g/mol 
A)  47.0 g/mol 
B)  194 g/mol 
C)  388 g/mol 
D)  94.0 g/mol 
E)  97.0 g/mol

Question 18

What is the molality of a solution produced by dissolving 14.40 g of LiCl (42.39 g/mol) in water to make 0.104 L of solution with a density of 1.102 g/mL?

Accepted Answer

A)  0.340 m 
B)  3.39 m 
C)  3.27 m 
D)  3.74 m 
E)  2.96 m 
A)  0.340 m 
B)  3.39 m 
C)  3.27 m 
D)  3.74 m 
E)  2.96 m

Question 19

What information is provided by the van 't Hoff factor?

Accepted Answer

The van 't Hoff factor gives t

Question 20

Which of the following is not typically needed to calculate the lattice energy of an ionic compound?

Accepted Answer

A)  enthalpy of vaporization 
B)  bond enthalpy 
C)  enthalpy of solution 
D)  electron affinity 
E)  ionization energy 
A)  enthalpy of vaporization 
B)  bond enthalpy 
C)  enthalpy of solution 
D)  electron affinity 
E)  ionization energy

Exam 11: Solutions: Properties and Behavior

At 25°C, the vapor pressure of pure water is 25.756 mm Hg. What is the vapor pressure of water in a 0.500 m solution of sodium chloride?

Indicate which aqueous solution has the slowest evaporation rate.

Which of the solutions shown here will have the highest vapor pressure? White circles indicate solvent molecules; black circles indicate molecules of a nonvolatile solute.

Indicate which aqueous solution has the highest vapor pressure.

Which statement below regarding vapor pressure is not correct?

Which of the following gases do you expect to be most soluble in water?

The pressure of carbon dioxide in a beer bottle is about 2 atm. At this pressure about 0.15 g of carbon dioxide dissolves in 100 mL of beer. How much carbon dioxide remains dissolved in 100 mL after the bottle is opened? The partial pressure of carbon dioxide is 2.0 *10-4 atm.

What is the vapor pressure of an aqueous solution that has a solute mol fraction of = 0.100? The vapor pressure of water is 25.756 mm Hg at 25°C.

Why would you expect or predict sodium fluoride to have the lowest solubility in water compared to the other sodium halide salts?

Which of the following compounds has the largest melting point?

Determine the molal concentration of a sugar solution in water that has a freezing point of -2.1°C. Kf = 1.86°C/m for water.

Which intermolecular interactions are likely to result in the lowest vapor pressure of a substance?

The freezing point of a 0.0925 m solution of ammonium chloride was found to be -0.325°C. What is the actual van 't Hoff factor for this salt at this concentration compared to the ideal one of 2? Kf (water) = 1.86°C/m

Which intermolecular interactions are likely to result in the highest vapor pressure of a substance?

Which statement about the vapor pressure of a liquid is not correct?

A 300 mg sample of caffeine was dissolved in 10.0 g of camphor (Kf = 39.7°C/m), decreasing the freezing point of camphor by 3.07°C. What is the molar mass of caffeine?

What is the molality of a solution produced by dissolving 14.40 g of LiCl (42.39 g/mol) in water to make 0.104 L of solution with a density of 1.102 g/mL?

What information is provided by the van 't Hoff factor?

Which of the following is not typically needed to calculate the lattice energy of an ionic compound?

Matter and Energy: The Origin of the Universe

Atoms, Ions, and Molecules: Matter Starts Here

Stoichiometry: Mass, Formulas, and Reactions

Solution Chemistry: The Hydrosphere

Thermochemistry: Energy Changes in Reactions

Properties of Gases: the Air We Breathe

A Quantum Model of Atoms: Waves and Particles

Chemical Bonds: What Makes a Gas a Greenhouse Gas

Molecular Geometry: Shape Determines Function

Intermolecular Forces: The Uniqueness of Water

Solids: Structures and Applications

Organic Chemistry: Fuels, Pharmaceuticals, Materials, and Life

Chemical Kinetics: Reactions in the Air We Breathe

Chemical Equilibrium: How Much Product Does a Reaction Really Make

Acid-Base and Solubility Equilibria: Reactions in Soil and Water

Metal Ions: Colorful and Essential

Thermodynamics: Spontaneous and Nonspontaneous Reactions and Processes

Electrochemistry: the Quest for Clean Energy

Biochemistry: the Compounds of Life

Nuclear Chemistry: Applications to Energy and Medicine

Life and the Periodic Table

Filters

The pressure of carbon dioxide in a beer bottle is about 2 atm. At this pressure about 0.15 g of carbon dioxide dissolves in 100 mL of beer. How much carbon dioxide remains dissolved in 100 mL after the bottle is opened? The partial pressure of carbon dioxide is 2.0 *10^-⁴ atm.

What is the vapor pressure of an aqueous solution that has a solute mol fraction of $What is the vapor pressure of an aqueous solution that has a solute mol fraction of = 0.100? The vapor pressure of water is 25.756 mm Hg at 25°C.$ = 0.100? The vapor pressure of water is 25.756 mm Hg at 25°C.

Determine the molal concentration of a sugar solution in water that has a freezing point of -2.1°C. K_f = 1.86°C/m for water.

The freezing point of a 0.0925 m solution of ammonium chloride was found to be -0.325°C. What is the actual van 't Hoff factor for this salt at this concentration compared to the ideal one of 2? K_f(water) = 1.86°C/m

A 300 mg sample of caffeine was dissolved in 10.0 g of camphor (K_f = 39.7°C/m), decreasing the freezing point of camphor by 3.07°C. What is the molar mass of caffeine?