Question 1

Adding salt to water decreases the freezing point of the water since it lowers the vapor pressure of the ice.

Accepted Answer

A) True 
 B)False  False

Question 2

The term "proof" is defined as twice the percent by volume of pure ethanol in solution.Thus,a solution that is 95% (by volume)ethanol is 190 proof.What is the molarity of ethanol in a 92 proof ethanol/water solution? density of ethanol
= 0.80 g/cm3
Density of water
= 1.0 g/cm3
Mol.wt.of ethanol
= 46 g/mol

Accepted Answer

A) 0.46 M 
B) 0.80 M 
C) 0.92 M 
D) 8.0 M 
E) 17 M 
A) 0.46 M 
B) 0.80 M 
C) 0.92 M 
D) 8.0 M 
E) 17 M D

Question 3

A solution is made by adding 0.100 mole of ethyl ether to 0.491 mole of ethyl alcohol.If the vapor pressure of ethyl ether and ethyl alcohol at 20°C are 375 torr and 20.0 torr,respectively,the vapor pressure of the solution at 20°C (assuming ideal behavior)is:

Accepted Answer

A) 80.1 torr 
B) 315 torr 
C) 46.8 torr 
D) 395 torr 
E) none of these 
A) 80.1 torr 
B) 315 torr 
C) 46.8 torr 
D) 395 torr 
E) none of these A

Question 4

A solution consisting of 0.250 mol of methylbenzene,C6H5CH3,in 244 g of nitrobenzene,C6H5NO2,freezes at -1.2°C.Pure nitrobenzene freezes at 6.0°C.What is the freezing-point depression constant of nitrobenzene?

Accepted Answer

A) 4.8°C/m 
B) 3.5°C/m 
C) 29°C/m 
D) 7.0°C/m 
E) 14°C/m 
A) 4.8°C/m 
B) 3.5°C/m 
C) 29°C/m 
D) 7.0°C/m 
E) 14°C/m

Question 5

A 20.0-g sample of methyl alcohol (CH3OH,molar mass = 32.04 g/mol)was dissolved in 43.3 g of water.The mole fraction of CH3OH is:

Accepted Answer

A) 0.260 
B) 0.624 
C) 0.316 
D) 4.85 
E) 0.206 
A) 0.260 
B) 0.624 
C) 0.316 
D) 4.85 
E) 0.206

Question 6

The most likely reason for colloidal dispersion is __________.

Accepted Answer

A) the Tyndall effect 
B) coagulation 
C) precipitation 
D) emulsion formation 
E) electrostatic repulsion 
A) the Tyndall effect 
B) coagulation 
C) precipitation 
D) emulsion formation 
E) electrostatic repulsion

Question 7

When 92.0 g of a compound is dissolved in 1000.g of water,the freezing point of the solution is lowered to -3.72°C.Determine the molar mass of the compound.

Accepted Answer

46.0 g/mol
3.72°C = 1.86°C/m *

Question 8

What is the molarity of a HNO3 solution prepared by adding 255.4 mL of water to 350.0 mL of 12.3 M HNO3?

Accepted Answer

A) 16.9 M 
B) 7.45 M 
C) 7.11 M 
D) 2.61 M 
E) 3.14 M 
A) 16.9 M 
B) 7.45 M 
C) 7.11 M 
D) 2.61 M 
E) 3.14 M

Question 9

When solid Ca(CH3COO)2 is dissolved in a nearly saturated solution of Ca(CH3COO)2,the solution becomes warmer.This information indicates that if the temperature of a solution is decreased:

Accepted Answer

A) "$\Delta$H will become negative." 
B) "$\Delta$H will become zero." 
C) "The solubility of Ca(CH3COO)2 will decrease." 
D) "The solubility of Ca(CH3COO)2 will increase.' 
E) "The solubility of Ca(CH3COO)2 will not change." 
A) "$\Delta$H will become negative." 
B) "$\Delta$H will become zero." 
C) "The solubility of Ca(CH3COO)2 will decrease." 
D) "The solubility of Ca(CH3COO)2 will increase.' 
E) "The solubility of Ca(CH3COO)2 will not change."

Question 10

What is the expected boiling point of a solution prepared by dissolving 7.27 g of sodium iodide (NaI)in 68.6 g of water (H2O)? For water,Tb = 100.00oC and Kb = 0.512oC m-1.

Accepted Answer

A) 0.72oC 
B) 100.36oC 
C) 103.72oC 
D) 100.72oC 
E) 0.36oC 
A) 0.72oC 
B) 100.36oC 
C) 103.72oC 
D) 100.72oC 
E) 0.36oC

Question 11

Solid KF has a lattice energy of 804 kJ/mol and a heat of solution (in water)of -15 kJ/mol.RbF has a lattice energy of 768 kJ/mol and a heat of solution (in water)of -24 kJ/mol.Which salt forms stronger attractions with water?

Accepted Answer

A) KF,since it has a larger lattice energy. 
B) RbF,since it has a smaller lattice energy. 
C) KF,since it has a more negative heat of hydration. 
D) RbF,since it has a more negative heat of hydration 
E) They form equally strong attractions with water,since they both have negative heats of mixing. 
A) KF,since it has a larger lattice energy. 
B) RbF,since it has a smaller lattice energy. 
C) KF,since it has a more negative heat of hydration. 
D) RbF,since it has a more negative heat of hydration 
E) They form equally strong attractions with water,since they both have negative heats of mixing.

Question 12

What is the molality of a solution of 30.1 g of propanol (CH3CH2CH2OH)in 152 mL water,if the density of water is 1.00 g/mL?

Accepted Answer

A) 3.29 m 
B) 0.00330 m 
C) 0.303 m 
D) 0.501 m 
E) 5.01 m 
A) 3.29 m 
B) 0.00330 m 
C) 0.303 m 
D) 0.501 m 
E) 5.01 m

Question 13

The molar mass of a solid as determined by freezing point depression is 10% higher than the true molar mass.Which of the following experimental errors could not account for this discrepancy?

Accepted Answer

A) Not all the solid was dissolved. 
B) More than the recorded amount of solvent was pipetted into the solution. 
C) The solid dissociated slightly into two particles when it dissolved. 
D) Some solid was left on the weighing paper. 
E) Before the solution was prepared,the container was rinsed with solvent and not dried. 
A) Not all the solid was dissolved. 
B) More than the recorded amount of solvent was pipetted into the solution. 
C) The solid dissociated slightly into two particles when it dissolved. 
D) Some solid was left on the weighing paper. 
E) Before the solution was prepared,the container was rinsed with solvent and not dried.

Question 14

Calculate the osmotic pressure (in torr)of 6.00 L of an aqueous 0.958 M solution at 30.°C,if the solute concerned is totally ionized into three ions (e.g. ,it could be Na2SO4 or MgCl2).

Accepted Answer

A) 71.5 torr 
B) 5.43 $\times$ 104 torr 
C) 3.23 $\times$ 104 torr 
D) 1.81 $\times$ 104 torr 
E) 6.03 $\times$ 103 torr 
A) 71.5 torr 
B) 5.43 $\times$ 104 torr 
C) 3.23 $\times$ 104 torr 
D) 1.81 $\times$ 104 torr 
E) 6.03 $\times$ 103 torr

Question 15

A correct statement of Henry's law is:

Accepted Answer

A) The concentration of a gas in solution is inversely proportional to temperature. 
B) The concentration of a gas in solution is directly proportional to the mole fraction of solvent. 
C) The concentration of a gas in solution is independent of pressure. 
D) The concentration of a gas in a solution is inversely proportional to pressure. 
E) None of these. 
A) The concentration of a gas in solution is inversely proportional to temperature. 
B) The concentration of a gas in solution is directly proportional to the mole fraction of solvent. 
C) The concentration of a gas in solution is independent of pressure. 
D) The concentration of a gas in a solution is inversely proportional to pressure. 
E) None of these.

Question 16

What is the boiling point change for a solution containing 0.736 moles of naphthalene (a nonvolatile,nonionizing compound)in 250.g of liquid benzene? (Kb = 2.53°C/m for benzene)

Accepted Answer

A) 7.45 °C 
B) 0.859 °C 
C) 3.44 °C 
D) 1.86 °C 
E) 0.466 °C 
A) 7.45 °C 
B) 0.859 °C 
C) 3.44 °C 
D) 1.86 °C 
E) 0.466 °C

Question 17

Calculate the mole fraction of H2SO4 in 9.61 M H2SO4.The density of the solution is 1.520 g/mL.

Accepted Answer

0.231
Assume 1 L (1000 mL)of solution.
m

Question 18

To calculate the freezing point of an ideal dilute solution of a single,nondissociating solute of a solvent,the minimum information one must know is:

Accepted Answer

A) the molality (of the solute) 
B) the molality (of the solute)and the freezing point depression constant of the solvent 
C) the same quantities as in B,plus the freezing point of the pure solvent 
D) all of the quantities in C,plus the molecular weight of the solute 
E) all of the quantities in C,plus the weight of the solvent 
A) the molality (of the solute) 
B) the molality (of the solute)and the freezing point depression constant of the solvent 
C) the same quantities as in B,plus the freezing point of the pure solvent 
D) all of the quantities in C,plus the molecular weight of the solute 
E) all of the quantities in C,plus the weight of the solvent

Question 19

Find the mass percent of CaCl2 in a solution whose molarity is 2.20 M and whose density is 1.18 g/mL.

Accepted Answer

A) 20.7% 
B) 26.1% 
C) 79.3% 
D) 24.4% 
E) none of these 
A) 20.7% 
B) 26.1% 
C) 79.3% 
D) 24.4% 
E) none of these

Question 20

What is reverse osmosis?

Accepted Answer

A) the application,to a concentrated solution,of a pressure that is greater than the osmotic pressure,such that solvent flows from the concentrated solution to the dilute solution 
B) the application,to a dilute solution,of a pressure that is greater than the osmotic pressure,such that solvent flows from the concentrated solution to the dilute solution 
C) the application,to a concentrated solution,of a pressure that is greater than the osmotic pressure,such that solute flows from the concentrated solution to the dilute solution 
D) the application,to a dilute solution,of a pressure that is greater than the osmotic pressure,such that solute flows from the concentrated solution to the dilute solution 
E) the application,to a concentrated solution,of a pressure that is greater than the osmotic pressure,such that solvent flows from the dilute solution to the concentrated solution 
A) the application,to a concentrated solution,of a pressure that is greater than the osmotic pressure,such that solvent flows from the concentrated solution to the dilute solution 
B) the application,to a dilute solution,of a pressure that is greater than the osmotic pressure,such that solvent flows from the concentrated solution to the dilute solution 
C) the application,to a concentrated solution,of a pressure that is greater than the osmotic pressure,such that solute flows from the concentrated solution to the dilute solution 
D) the application,to a dilute solution,of a pressure that is greater than the osmotic pressure,such that solute flows from the concentrated solution to the dilute solution 
E) the application,to a concentrated solution,of a pressure that is greater than the osmotic pressure,such that solvent flows from the dilute solution to the concentrated solution

Exam 11: Properties of Solutions

Adding salt to water decreases the freezing point of the water since it lowers the vapor pressure of the ice.

A solution is made by adding 0.100 mole of ethyl ether to 0.491 mole of ethyl alcohol.If the vapor pressure of ethyl ether and ethyl alcohol at 20°C are 375 torr and 20.0 torr,respectively,the vapor pressure of the solution at 20°C (assuming ideal behavior)is:

A solution consisting of 0.250 mol of methylbenzene,C6H5CH3,in 244 g of nitrobenzene,C6H5NO2,freezes at -1.2°C.Pure nitrobenzene freezes at 6.0°C.What is the freezing-point depression constant of nitrobenzene?

A 20.0-g sample of methyl alcohol (CH3OH,molar mass = 32.04 g/mol)was dissolved in 43.3 g of water.The mole fraction of CH3OH is:

The most likely reason for colloidal dispersion is __________.

When 92.0 g of a compound is dissolved in 1000.g of water,the freezing point of the solution is lowered to -3.72°C.Determine the molar mass of the compound.

What is the molarity of a HNO3 solution prepared by adding 255.4 mL of water to 350.0 mL of 12.3 M HNO3?

When solid Ca(CH3COO)2 is dissolved in a nearly saturated solution of Ca(CH3COO)2,the solution becomes warmer.This information indicates that if the temperature of a solution is decreased:

What is the expected boiling point of a solution prepared by dissolving 7.27 g of sodium iodide (NaI)in 68.6 g of water (H2O)? For water,Tb = 100.00oC and Kb = 0.512oC m-1.

Solid KF has a lattice energy of 804 kJ/mol and a heat of solution (in water)of -15 kJ/mol.RbF has a lattice energy of 768 kJ/mol and a heat of solution (in water)of -24 kJ/mol.Which salt forms stronger attractions with water?

What is the molality of a solution of 30.1 g of propanol (CH3CH2CH2OH)in 152 mL water,if the density of water is 1.00 g/mL?

The molar mass of a solid as determined by freezing point depression is 10% higher than the true molar mass.Which of the following experimental errors could not account for this discrepancy?

Calculate the osmotic pressure (in torr)of 6.00 L of an aqueous 0.958 M solution at 30.°C,if the solute concerned is totally ionized into three ions (e.g. ,it could be Na2SO4 or MgCl2).

A correct statement of Henry's law is:

What is the boiling point change for a solution containing 0.736 moles of naphthalene (a nonvolatile,nonionizing compound)in 250.g of liquid benzene? (Kb = 2.53°C/m for benzene)

Calculate the mole fraction of H2SO4 in 9.61 M H2SO4.The density of the solution is 1.520 g/mL.

To calculate the freezing point of an ideal dilute solution of a single,nondissociating solute of a solvent,the minimum information one must know is:

Find the mass percent of CaCl2 in a solution whose molarity is 2.20 M and whose density is 1.18 g/mL.

What is reverse osmosis?

Chemical Foundations

Atoms, molecules, and Ions

Stoichiometry

Chemical Reactions and Solutions Stoichiometry

Gases

Thermochemistry

Atomic Structure and Periodicity

Bonding: General Concepts

Covalent Bonding: Orbitals

Liquids and Solids

Chemical Kinetics

Chemical Equilibrium

Acids and Bases

Acid-Base Equilibria

Solubility and Complex Ion Equilibria

Spontaneity, entropy, and Free Energy

Electrochemistry

The Nucleus: a Chemists View

The Representative Elements

Transition Metals and Coordination Chemistry

Organic and Biological Molecules

Filters

A solution consisting of 0.250 mol of methylbenzene,C₆H₅CH₃,in 244 g of nitrobenzene,C₆H₅NO₂,freezes at -1.2°C.Pure nitrobenzene freezes at 6.0°C.What is the freezing-point depression constant of nitrobenzene?

A 20.0-g sample of methyl alcohol (CH₃OH,molar mass = 32.04 g/mol)was dissolved in 43.3 g of water.The mole fraction of CH₃OH is:

What is the molarity of a HNO₃ solution prepared by adding 255.4 mL of water to 350.0 mL of 12.3 M HNO₃?

When solid Ca(CH₃COO)₂ is dissolved in a nearly saturated solution of Ca(CH₃COO)₂,the solution becomes warmer.This information indicates that if the temperature of a solution is decreased:

What is the expected boiling point of a solution prepared by dissolving 7.27 g of sodium iodide (NaI)in 68.6 g of water (H₂O)? For water,T_b = 100.00^oC and K_b = 0.512^oC m^-¹.

What is the molality of a solution of 30.1 g of propanol (CH₃CH₂CH₂OH)in 152 mL water,if the density of water is 1.00 g/mL?

Calculate the osmotic pressure (in torr)of 6.00 L of an aqueous 0.958 M solution at 30.°C,if the solute concerned is totally ionized into three ions (e.g. ,it could be Na₂SO₄ or MgCl₂).

What is the boiling point change for a solution containing 0.736 moles of naphthalene (a nonvolatile,nonionizing compound)in 250.g of liquid benzene? (K_b = 2.53°C/m for benzene)

Calculate the mole fraction of H₂SO₄ in 9.61 M H₂SO₄.The density of the solution is 1.520 g/mL.

Find the mass percent of CaCl₂ in a solution whose molarity is 2.20 M and whose density is 1.18 g/mL.