Question 1

Predict the deviation from Raoult's law when two liquids are mixed and the heat of the solution is small.

Accepted Answer

A)  negative deviation 
B)  relatively ideal (small or zero deviation) 
C)  positive deviation 
A)  negative deviation 
B)  relatively ideal (small or zero deviation) 
C)  positive deviation

Question 2

You have a 10.40-g mixture of table sugar (C12H22O11) and table salt (NaCl). When this mixture is dissolved in 150. g of water, the freezing point is found to be -2.24°C. Calculate the percent by mass of sugar in the original mixture. (Assume that the NaCl is completely dissociated.)

Accepted Answer

A)  61.0% 
B)  53.8% 
C)  46.2% 
D)  39.0% 
E)  none of these 
A)  61.0% 
B)  53.8% 
C)  46.2% 
D)  39.0% 
E)  none of these

Question 3

Using the data below, calculate the vapor pressure of benzene over a chloroform-benzene solution at 25°C, which contains 50.0 g of CHCl3 and 50.0 g of C6H6. Assume that the solution behaves ideally.

Accepted Answer

A)  148 torr 
B)  68.0 torr 
C)  172 torr 
D)  125 torr 
E)  none of these 
A)  148 torr 
B)  68.0 torr 
C)  172 torr 
D)  125 torr 
E)  none of these

Question 4

You use 2.0 g of solid MX to prepare a saturated solution in 250. g of water. You find the freezing point to be -0.028°C. Calculate Ksp for the solid.

Accepted Answer

A)  2.2 × 10-4 
B)  5.6 × 10-5 
C)  1.4 × 10-5 
D)  3.5 × 10-6 
E)  none of these 
A)  2.2 × 10-4 
B)  5.6 × 10-5 
C)  1.4 × 10-5 
D)  3.5 × 10-6 
E)  none of these

Question 5

Consider a solution containing liquids A and B where the mole fraction of B is 0.60. Assuming ideality, calculate the mole fractions of A and B in the vapor at equilibrium with this solution at 25°C. (The vapor pressures of pure liquid A and pure liquid B at 25°C are 200. torr and 400. torr, respectively.)

Accepted Answer

P_total = X_aP°_a + X_bP°_b = (

Question 6

A liquid-liquid solution is called an ideal solution if
I. it obeys PV = nRT.
II. it obeys Raoult's law.
III. solute-solute, solvent-solvent, and solute-solvent interactions are very similar.
IV. solute-solute, solvent-solvent, and solute-solvent interactions are quite different.

Accepted Answer

A)  II, IV 
B)  II, III 
C)  I, II 
D)  I, II, III 
E)  I, II, IV 
A)  II, IV 
B)  II, III 
C)  I, II 
D)  I, II, III 
E)  I, II, IV

Question 7

Liquid A has vapor pressure x. Liquid B has vapor pressure y, and x > y. What is the mole fraction of A in the liquid mixture if the vapor above the solution is 50% A?

Accepted Answer

A)  y/(2x + 2y) 
B)  y/(x + y) 
C)  x/(2x + 2y) 
D)  x/(x + y) 
E)  none of these 
A)  y/(2x + 2y) 
B)  y/(x + y) 
C)  x/(2x + 2y) 
D)  x/(x + y) 
E)  none of these

Question 8

Acetone (mw = 58.08, P   =232 mmHg) and butanone (mw = 72.11, P  
=100 mmHg) have the indicated molar masses and vapor pressures. A container holds 1.00 kg of butanone. How much acetone must be added to the butanone to elevate the total vapor pressure over the mixture to 125 mmHg at 25°C?

Accepted Answer

A)  5.313 kg 
B)  290 g 
C)  188 g 
D)  More information needed 
E)  None of the above 
A)  5.313 kg 
B)  290 g 
C)  188 g 
D)  More information needed 
E)  None of the above

Question 9

A solution contains 1 mol of liquid A and 3 mol of liquid B. The vapor pressure of this solution is 314 torr at 25°C. At 25°C, the vapor pressure of liquid A is 265 torr and the vapor pressure of liquid B is 355 torr. Which of the following is true?

Accepted Answer

A)  This solution exhibits a positive deviation from Raoult's law. 
B)  This solution is ideal. 
C)  This solution exhibits a negative deviation from Raoult's law. 
A)  This solution exhibits a positive deviation from Raoult's law. 
B)  This solution is ideal. 
C)  This solution exhibits a negative deviation from Raoult's law.

Question 10

How many milliliters of 11.8 M HNO3 are needed to prepare 386.2 mL of 0.18 M HNO3?

Accepted Answer

A)  2.5 × 101 mL 
B)  0.310 mL 
C)  0.030 mL 
D)  5.9 mL 
E)  40 mL 
A)  2.5 × 101 mL 
B)  0.310 mL 
C)  0.030 mL 
D)  5.9 mL 
E)  40 mL

Question 11

Diagram and label a vapor pressure diagram for an ideal solution of two volatile liquids. Indicate the deviation predicted by an endothermic heat of solution.

Accepted Answer

positive deviation;

Question 12

The freezing-point depression of a 3.00 × 10-3 M solution of a weak acid HA is 6.67 × 10-3 °C in water. Assuming that the molarity concentration and the molality concentration are the same and assuming ideal behavior, calculate Ka for the weak acid. Kf(H2O) = 1.86 °C kg/mol.

Accepted Answer

Question 13

The molal freezing-point depression constants for benzene and water are 5.12 and 1.86, respectively. When 4.6 g of formic acid (HCOOH) is dissolved in 1.0 kg of benzene, the freezing point is depressed by 0.26°C. When the same amount of formic acid is dissolved in 1.0 kg of water, the freezing point is lowered by 0.19°C. To explain these results, we must assume that

Accepted Answer

A)  formic acid is monomeric in benzene and associated in water. 
B)  formic acid is associated in benzene and monomeric in water. 
C)  formic acid is monomeric in benzene and dissociated in water. 
D)  formic acid is dissociated in benzene and monomeric in water. 
A)  formic acid is monomeric in benzene and associated in water. 
B)  formic acid is associated in benzene and monomeric in water. 
C)  formic acid is monomeric in benzene and dissociated in water. 
D)  formic acid is dissociated in benzene and monomeric in water.

Question 14

A solution is made of 175.0 g of methanol (CH3OH) in 169.0 g of water. What is the mole fraction of methanol?

Accepted Answer

A)  0.0159 
B)  0.509 
C)  0.632 
D)  ​0.591 
E)  ​0.368 
A)  0.0159 
B)  0.509 
C)  0.632 
D)  ​0.591 
E)  ​0.368

Question 15

A salt solution sits in an open beaker. Assuming constant temperature and pressure, the vapor pressure of the solution

Accepted Answer

A)  stays the same over time. 
B)  We need to know which salt is in the solution to answer this. 
C)  increases over time. 
D)  We need to know the temperature and pressure to answer this. 
E)  decreases over time. 
A)  stays the same over time. 
B)  We need to know which salt is in the solution to answer this. 
C)  increases over time. 
D)  We need to know the temperature and pressure to answer this. 
E)  decreases over time.

Question 16

A 5.00-g sample of a compound is dissolved in enough water to form 100.0 mL of solution. This solution has an osmotic pressure of 25 torr at 25°C. If it is assumed that each molecule of the solute dissociates into two particles (in this solvent), what is the molar mass of this solute?

Accepted Answer

A)  18,600 g/mol 
B)  37,200 g/mol 
C)  74,300 g/mol 
D)  1560 g/mol 
E)  none of these 
A)  18,600 g/mol 
B)  37,200 g/mol 
C)  74,300 g/mol 
D)  1560 g/mol 
E)  none of these

Question 17

Which of the following is an emulsion?

Accepted Answer

A)  fog 
B)  paint 
C)  whipped cream 
D)  smoke 
E)  milk 
A)  fog 
B)  paint 
C)  whipped cream 
D)  smoke 
E)  milk

Question 18

What is the molality of a solution of 31.8 g of ethanol (CH3CH2OH) in 405 mL of water if the density of water is 1.0 g/mL?

Accepted Answer

A)  78.5 m 
B)  1.58 m 
C)  1.70 m 
D)  0.0298 m 
E)  0.0307 m 
A)  78.5 m 
B)  1.58 m 
C)  1.70 m 
D)  0.0298 m 
E)  0.0307 m

Question 19

We can predict the solubility of a compound by looking at the sign of the enthalpy of solution.

Accepted Answer

A) True 
 B)False

Question 20

The osmotic pressure of a solution saturated with a salt M5X3 is 1.96 × 10-2 atm at 25° C. Calculate Ksp for M5X3, assuming ideal behavior.

Accepted Answer

Predict the deviation from Raoult's law when two liquids are mixed and the heat of the solution is small.

You have a 10.40-g mixture of table sugar (C₁₂H₂₂O₁₁) and table salt (NaCl). When this mixture is dissolved in 150. g of water, the freezing point is found to be -2.24°C. Calculate the percent by mass of sugar in the original mixture. (Assume that the NaCl is completely dissociated.)

Using the data below, calculate the vapor pressure of benzene over a chloroform-benzene solution at 25°C, which contains 50.0 g of CHCl₃ and 50.0 g of C₆H₆. Assume that the solution behaves ideally.

You use 2.0 g of solid MX to prepare a saturated solution in 250. g of water. You find the freezing point to be -0.028°C. Calculate K_sp for the solid.

A liquid-liquid solution is called an ideal solution if I. it obeys PV = nRT. II. it obeys Raoult's law. III. solute-solute, solvent-solvent, and solute-solvent interactions are very similar. IV. solute-solute, solvent-solvent, and solute-solvent interactions are quite different.

Liquid A has vapor pressure x. Liquid B has vapor pressure y, and x > y. What is the mole fraction of A in the liquid mixture if the vapor above the solution is 50% A?

Acetone (mw = 58.08, P =232 mmHg) and butanone (mw = 72.11, P =100 mmHg) have the indicated molar masses and vapor pressures. A container holds 1.00 kg of butanone. How much acetone must be added to the butanone to elevate the total vapor pressure over the mixture to 125 mmHg at 25°C?

A solution contains 1 mol of liquid A and 3 mol of liquid B. The vapor pressure of this solution is 314 torr at 25°C. At 25°C, the vapor pressure of liquid A is 265 torr and the vapor pressure of liquid B is 355 torr. Which of the following is true?

How many milliliters of 11.8 M HNO₃ are needed to prepare 386.2 mL of 0.18 M HNO₃?

Diagram and label a vapor pressure diagram for an ideal solution of two volatile liquids. Indicate the deviation predicted by an endothermic heat of solution.

The freezing-point depression of a 3.00 × 10^-3 M solution of a weak acid HA is 6.67 × 10^-3 °C in water. Assuming that the molarity concentration and the molality concentration are the same and assuming ideal behavior, calculate K_a for the weak acid. K_f(H₂O) = 1.86 °C kg/mol.

A solution is made of 175.0 g of methanol (CH₃OH) in 169.0 g of water. What is the mole fraction of methanol?

A salt solution sits in an open beaker. Assuming constant temperature and pressure, the vapor pressure of the solution

A 5.00-g sample of a compound is dissolved in enough water to form 100.0 mL of solution. This solution has an osmotic pressure of 25 torr at 25°C. If it is assumed that each molecule of the solute dissociates into two particles (in this solvent), what is the molar mass of this solute?

Which of the following is an emulsion?

What is the molality of a solution of 31.8 g of ethanol (CH₃CH₂OH) in 405 mL of water if the density of water is 1.0 g/mL?

We can predict the solubility of a compound by looking at the sign of the enthalpy of solution.

The osmotic pressure of a solution saturated with a salt M₅X₃ is 1.96 × 10^-2 atm at 25° C. Calculate K_sp for M₅X₃, assuming ideal behavior.

Atoms, Molecules, and Ions

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Types of Chemical Reactions and Solution Stoichiometry

Gases

Chemical Equilibrium

Acids and Bases

Applications of Aqueous Equilibria

Energy, Enthalpy, and Thermochemistry

Spontaneity, Entropy, and Free Energy

Electrochemistry

Quantum Mechanics and Atomic Theory

Bonding: General Concepts

Covalent Bonding: Orbitals

Chemical Kinetics

Liquids and Solids

The Representative Elements

Transition Metals and Coordination Chemistry

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Exam 17: Properties of Solutions

Predict the deviation from Raoult's law when two liquids are mixed and the heat of the solution is small.

You have a 10.40-g mixture of table sugar (C12H22O11) and table salt (NaCl). When this mixture is dissolved in 150. g of water, the freezing point is found to be -2.24°C. Calculate the percent by mass of sugar in the original mixture. (Assume that the NaCl is completely dissociated.)

Using the data below, calculate the vapor pressure of benzene over a chloroform-benzene solution at 25°C, which contains 50.0 g of CHCl3 and 50.0 g of C6H6. Assume that the solution behaves ideally.

You use 2.0 g of solid MX to prepare a saturated solution in 250. g of water. You find the freezing point to be -0.028°C. Calculate Ksp for the solid.

A liquid-liquid solution is called an ideal solution if I. it obeys PV = nRT. II. it obeys Raoult's law. III. solute-solute, solvent-solvent, and solute-solvent interactions are very similar. IV. solute-solute, solvent-solvent, and solute-solvent interactions are quite different.

Liquid A has vapor pressure x. Liquid B has vapor pressure y, and x > y. What is the mole fraction of A in the liquid mixture if the vapor above the solution is 50% A?

Acetone (mw = 58.08, P =232 mmHg) and butanone (mw = 72.11, P =100 mmHg) have the indicated molar masses and vapor pressures. A container holds 1.00 kg of butanone. How much acetone must be added to the butanone to elevate the total vapor pressure over the mixture to 125 mmHg at 25°C?

A solution contains 1 mol of liquid A and 3 mol of liquid B. The vapor pressure of this solution is 314 torr at 25°C. At 25°C, the vapor pressure of liquid A is 265 torr and the vapor pressure of liquid B is 355 torr. Which of the following is true?

How many milliliters of 11.8 M HNO3 are needed to prepare 386.2 mL of 0.18 M HNO3?

Diagram and label a vapor pressure diagram for an ideal solution of two volatile liquids. Indicate the deviation predicted by an endothermic heat of solution.

The freezing-point depression of a 3.00 × 10-3 M solution of a weak acid HA is 6.67 × 10-3 °C in water. Assuming that the molarity concentration and the molality concentration are the same and assuming ideal behavior, calculate Ka for the weak acid. Kf(H2O) = 1.86 °C kg/mol.

A solution is made of 175.0 g of methanol (CH3OH) in 169.0 g of water. What is the mole fraction of methanol?

A salt solution sits in an open beaker. Assuming constant temperature and pressure, the vapor pressure of the solution

A 5.00-g sample of a compound is dissolved in enough water to form 100.0 mL of solution. This solution has an osmotic pressure of 25 torr at 25°C. If it is assumed that each molecule of the solute dissociates into two particles (in this solvent), what is the molar mass of this solute?

Which of the following is an emulsion?

What is the molality of a solution of 31.8 g of ethanol (CH3CH2OH) in 405 mL of water if the density of water is 1.0 g/mL?

We can predict the solubility of a compound by looking at the sign of the enthalpy of solution.

The osmotic pressure of a solution saturated with a salt M5X3 is 1.96 × 10-2 atm at 25° C. Calculate Ksp for M5X3, assuming ideal behavior.

Atoms, Molecules, and Ions

Stoichiometry

Types of Chemical Reactions and Solution Stoichiometry

Gases

Chemical Equilibrium

Acids and Bases

Applications of Aqueous Equilibria

Energy, Enthalpy, and Thermochemistry

Spontaneity, Entropy, and Free Energy

Electrochemistry

Quantum Mechanics and Atomic Theory

Bonding: General Concepts

Covalent Bonding: Orbitals

Chemical Kinetics

Liquids and Solids

The Representative Elements

Transition Metals and Coordination Chemistry

The Nucleus: a Chemists View

Organic and Biochemical Molecules

Filters

You have a 10.40-g mixture of table sugar (C₁₂H₂₂O₁₁) and table salt (NaCl). When this mixture is dissolved in 150. g of water, the freezing point is found to be -2.24°C. Calculate the percent by mass of sugar in the original mixture. (Assume that the NaCl is completely dissociated.)

Using the data below, calculate the vapor pressure of benzene over a chloroform-benzene solution at 25°C, which contains 50.0 g of CHCl₃ and 50.0 g of C₆H₆. Assume that the solution behaves ideally.

You use 2.0 g of solid MX to prepare a saturated solution in 250. g of water. You find the freezing point to be -0.028°C. Calculate K_sp for the solid.

How many milliliters of 11.8 M HNO₃ are needed to prepare 386.2 mL of 0.18 M HNO₃?

The freezing-point depression of a 3.00 × 10^-3 M solution of a weak acid HA is 6.67 × 10^-3 °C in water. Assuming that the molarity concentration and the molality concentration are the same and assuming ideal behavior, calculate K_a for the weak acid. K_f(H₂O) = 1.86 °C kg/mol.

A solution is made of 175.0 g of methanol (CH₃OH) in 169.0 g of water. What is the mole fraction of methanol?

What is the molality of a solution of 31.8 g of ethanol (CH₃CH₂OH) in 405 mL of water if the density of water is 1.0 g/mL?

The osmotic pressure of a solution saturated with a salt M₅X₃ is 1.96 × 10^-2 atm at 25° C. Calculate K_sp for M₅X₃, assuming ideal behavior.