Question 1

An ideal solution is formed from a mixture of the nonvolatile solute urea,CO(NH2)2,and methanol,CH3OH.The vapor pressure of pure methanol at 20°C is 89 mmHg.If 4.4 g of urea is mixed with 39.9 g of methanol,calculate the vapor pressure of the methanol solution.

Accepted Answer

A) 4.9 mmHg 
B) 80 mmHg 
C) 74 mmHg 
D) 15 mmHg 
E) 84 mmHg

Question 2

Calculate the mole fraction of NaCl in a solution prepared by dissolving 117 g NaCl in 1.15 kg H2O.

Accepted Answer

A) 9.90 $\times$ 10-1 
B) 1.11 $\times$ 10-2 
C) 6.08 $\times$10-2 
D) 1.52 $\times$10-2 
E) 3.04 $\times$ 10-2

Question 3

Determine the molarity of a solution containing 6.76 g BaCl2 in 750.0 mL of solution.

Accepted Answer

A) 3.25 $\times$ 10-2 M 
B) 2.44 $\times$ 10-2 M 
C) 9.01 $\times$ 10-3 M 
D) 4.33 $\times$ 10-2 M 
E) 9.01 M

Question 4

Solutions of benzene and toluene obey Raoult's law.The vapor pressures at 20°C are: benzene,76 torr;toluene,21 torr.
-What is the mole fraction of benzene in a benzene-toluene solution whose vapor pressure is 51 torr at 20°C?

Accepted Answer

A) 0.26 
B) 0.45 
C) 0.55 
D) 0.67 
E) 0.74

Question 5

All of the following are colligative properties except:

Accepted Answer

A) osmotic pressure 
B) boiling point elevation 
C) freezing point depression 
D) density elevation 
E) none of these

Question 6

At a given temperature,you have a mixture of benzene (vapor pressure of pure benzene = 745 torr)and toluene (vapor pressure of pure toluene = 290.torr).The mole fraction of benzene in the solution is 0.590.Assuming ideal behavior,calculate the mole fraction of toluene in the vapor above the solution.

Accepted Answer

A) 0.213 
B) 0.778 
C) 0.641 
D) 0.359 
E) 0.590

Question 7

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

Question 8

What volume of a 0.771 M solution of CaCl2 contains 1.28 g of solute?

Accepted Answer

A) 66.8 mL 
B) 15.0 mL 
C) 1.66 mL 
D) 8.89 mL 
E) 85.0 mL

Question 9

The observed van't Hoff factor for an electrolyte is less than the expected factor because of __________.

Accepted Answer

A) electrolytic repulsion 
B) complete dissociation 
C) coagulation 
D) ion pairing 
E) gelation

Question 10

The lattice energy of KF is 808 kJ/mol and its heat of solution is -17.7 kJ/mol.Calculate the hydration of energy of KF(s).

Accepted Answer

A) -35.4 kJ/mol 
B) -790.3 kJ/mol 
C) -825.7 kJ/mol 
D) 790.3 kJ/mol 
E) 825.7 kJ/mol

Question 11

Polyethylene is a synthetic polymer or plastic with many uses.1.36 g of a polyethylene sample was dissolved in enough benzene to make 100.mL of solution,and the osmotic pressure was found to be 1.86 torr at 25oC.What is the approximate molar mass of the polyethylene?

Accepted Answer

A) 179 g/mol 
B) 1.14 $\times$ 104 g/mol 
C) 7.35 $\times$ 103 g/mol 
D) 1.24 $\times$ 105 g/mol 
E) 1.36 $\times$ 105 g/mol

Question 12

If 2.00 g of helium gas and 3.82 g of oxygen gas are mixed together,what is the mole fraction of helium in the solution?

Accepted Answer

A) 0.344 
B) 0.193 
C) 0.807 
D) 0.119 
E) 1.24

Question 13

The vapor pressure of water at 90°C is 0.692 atm.What is the vapor pressure (in atm)of a solution made by dissolving 4.13 mole(s)of CsF(s)in 1.00 kg of water? Assume that Raoult's law applies.

Accepted Answer

A) 0.644 atm 
B) 0.795 atm 
C) 0.602 atm 
D) 0.692 atm 
E) none of these

Question 14

Which of the following correctly states the relationship between temperature and the solubility of a substance in water?

Accepted Answer

A) The solubility of a substance in water increases as the temperature rises,especially for gases. 
B) The solubility of a substance in water decreases as the temperature rises,especially for ionic solids. 
C) The solubility of a substance in water with temperature cannot be accurately predicted,especially for ionic solids. 
D) The solubility of a substance in water decreases as the temperature lowers,especially for gases. 
E) Both A and D are correct.

Question 15

Solutions of benzene and toluene obey Raoult's law.The vapor pressures at 20°C are: benzene,76 torr;toluene,21 torr.
-If the mole fraction of benzene in a particular benzene-toluene solution is 0.64,what is the mole fraction of benzene in the vapor phase in equilibrium with that solution?

Accepted Answer

A) 0.24 
B) 0.50 
C) 0.64 
D) 0.78 
E) 0.87

Question 16

Benzene and toluene form an ideal solution.At 298 K,what is the mole fraction of benzene in the liquid that is in equilibrium with a vapor that has equal partial pressures of benzene and toluene? At 298 K,the vapor pressures of pure benzene and pure toluene are 95 and 28 torr,respectively.

Accepted Answer

A) 0.50 
B) 0.77 
C) 0.23 
D) 0.30 
E) none of these

Question 17

For each of the following solutions,describe the deviation with respect to Raoult's Law.
-hexane (C6H14)and chloroform (CHCl3)

Accepted Answer

A) relatively ideal 
B) positive deviation 
C) negative deviation 
D) more information needed 
E) none of these

Question 18

A 5.05-gram sample of a compound is dissolved in enough water to form 100.0 mL of solution.This solution has an osmotic pressure of 25.0 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) 9.88 $\times$ 101 g/mol 
B) 6.30 $\times$ 103 g/mol 
C) 3.75 $\times$ 103 g/mol 
D) 7.51 $\times$ 104 g/mol 
E) none of these

Question 19

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.

Accepted Answer

A) 39.0% 
B) 43.8% 
C) 53.9% 
D) 61.0% 
E) none of these

Question 20

A solution is prepared from 53.8 g of a nonvolatile,nondissociating solute and 85.0 g of water.The vapor pressure of the solution at 60°C is 132 torr.The vapor pressure of water at 60°C is 150.torr.What is the molar mass of the solute?

Accepted Answer

A) 61.1 g/mol 
B) 11.4 g/mol 
C) 34.6 g/mol 
D) 186 g/mol 
E) 83.6 g/mol

Exam 11: Properties of Solutions

An ideal solution is formed from a mixture of the nonvolatile solute urea,CO(NH₂) ₂,and methanol,CH₃OH.The vapor pressure of pure methanol at 20°C is 89 mmHg.If 4.4 g of urea is mixed with 39.9 g of methanol,calculate the vapor pressure of the methanol solution.

Calculate the mole fraction of NaCl in a solution prepared by dissolving 117 g NaCl in 1.15 kg H₂O.

Determine the molarity of a solution containing 6.76 g BaCl₂ in 750.0 mL of solution.

Solutions of benzene and toluene obey Raoult's law.The vapor pressures at 20°C are: benzene,76 torr;toluene,21 torr. -What is the mole fraction of benzene in a benzene-toluene solution whose vapor pressure is 51 torr at 20°C?

All of the following are colligative properties except:

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.

What volume of a 0.771 M solution of CaCl₂ contains 1.28 g of solute?

The observed van't Hoff factor for an electrolyte is less than the expected factor because of __________.

The lattice energy of KF is 808 kJ/mol and its heat of solution is -17.7 kJ/mol.Calculate the hydration of energy of KF(s) .

Polyethylene is a synthetic polymer or plastic with many uses.1.36 g of a polyethylene sample was dissolved in enough benzene to make 100.mL of solution,and the osmotic pressure was found to be 1.86 torr at 25^oC.What is the approximate molar mass of the polyethylene?

If 2.00 g of helium gas and 3.82 g of oxygen gas are mixed together,what is the mole fraction of helium in the solution?

The vapor pressure of water at 90°C is 0.692 atm.What is the vapor pressure (in atm) of a solution made by dissolving 4.13 mole(s) of CsF(s) in 1.00 kg of water? Assume that Raoult's law applies.

Which of the following correctly states the relationship between temperature and the solubility of a substance in water?

Solutions of benzene and toluene obey Raoult's law.The vapor pressures at 20°C are: benzene,76 torr;toluene,21 torr. -If the mole fraction of benzene in a particular benzene-toluene solution is 0.64,what is the mole fraction of benzene in the vapor phase in equilibrium with that solution?

Benzene and toluene form an ideal solution.At 298 K,what is the mole fraction of benzene in the liquid that is in equilibrium with a vapor that has equal partial pressures of benzene and toluene? At 298 K,the vapor pressures of pure benzene and pure toluene are 95 and 28 torr,respectively.

For each of the following solutions,describe the deviation with respect to Raoult's Law. -hexane (C₆H₁₄) and chloroform (CHCl₃)

A 5.05-gram sample of a compound is dissolved in enough water to form 100.0 mL of solution.This solution has an osmotic pressure of 25.0 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?

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.

A solution is prepared from 53.8 g of a nonvolatile,nondissociating solute and 85.0 g of water.The vapor pressure of the solution at 60°C is 132 torr.The vapor pressure of water at 60°C is 150.torr.What is the molar mass of the solute?

Exam 11: Properties of Solutions

An ideal solution is formed from a mixture of the nonvolatile solute urea,CO(NH2) 2,and methanol,CH3OH.The vapor pressure of pure methanol at 20°C is 89 mmHg.If 4.4 g of urea is mixed with 39.9 g of methanol,calculate the vapor pressure of the methanol solution.

Calculate the mole fraction of NaCl in a solution prepared by dissolving 117 g NaCl in 1.15 kg H2O.

Determine the molarity of a solution containing 6.76 g BaCl2 in 750.0 mL of solution.

Solutions of benzene and toluene obey Raoult's law.The vapor pressures at 20°C are: benzene,76 torr;toluene,21 torr. -What is the mole fraction of benzene in a benzene-toluene solution whose vapor pressure is 51 torr at 20°C?

All of the following are colligative properties except:

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.

What volume of a 0.771 M solution of CaCl2 contains 1.28 g of solute?

The observed van't Hoff factor for an electrolyte is less than the expected factor because of __________.

The lattice energy of KF is 808 kJ/mol and its heat of solution is -17.7 kJ/mol.Calculate the hydration of energy of KF(s) .

Polyethylene is a synthetic polymer or plastic with many uses.1.36 g of a polyethylene sample was dissolved in enough benzene to make 100.mL of solution,and the osmotic pressure was found to be 1.86 torr at 25oC.What is the approximate molar mass of the polyethylene?

If 2.00 g of helium gas and 3.82 g of oxygen gas are mixed together,what is the mole fraction of helium in the solution?

The vapor pressure of water at 90°C is 0.692 atm.What is the vapor pressure (in atm) of a solution made by dissolving 4.13 mole(s) of CsF(s) in 1.00 kg of water? Assume that Raoult's law applies.

Which of the following correctly states the relationship between temperature and the solubility of a substance in water?

Solutions of benzene and toluene obey Raoult's law.The vapor pressures at 20°C are: benzene,76 torr;toluene,21 torr. -If the mole fraction of benzene in a particular benzene-toluene solution is 0.64,what is the mole fraction of benzene in the vapor phase in equilibrium with that solution?

Benzene and toluene form an ideal solution.At 298 K,what is the mole fraction of benzene in the liquid that is in equilibrium with a vapor that has equal partial pressures of benzene and toluene? At 298 K,the vapor pressures of pure benzene and pure toluene are 95 and 28 torr,respectively.

For each of the following solutions,describe the deviation with respect to Raoult's Law. -hexane (C6H14) and chloroform (CHCl3)

A 5.05-gram sample of a compound is dissolved in enough water to form 100.0 mL of solution.This solution has an osmotic pressure of 25.0 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?

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.

A solution is prepared from 53.8 g of a nonvolatile,nondissociating solute and 85.0 g of water.The vapor pressure of the solution at 60°C is 132 torr.The vapor pressure of water at 60°C is 150.torr.What is the molar mass of the solute?

An ideal solution is formed from a mixture of the nonvolatile solute urea,CO(NH₂) ₂,and methanol,CH₃OH.The vapor pressure of pure methanol at 20°C is 89 mmHg.If 4.4 g of urea is mixed with 39.9 g of methanol,calculate the vapor pressure of the methanol solution.

Calculate the mole fraction of NaCl in a solution prepared by dissolving 117 g NaCl in 1.15 kg H₂O.

Determine the molarity of a solution containing 6.76 g BaCl₂ in 750.0 mL of solution.

What volume of a 0.771 M solution of CaCl₂ contains 1.28 g of solute?

Polyethylene is a synthetic polymer or plastic with many uses.1.36 g of a polyethylene sample was dissolved in enough benzene to make 100.mL of solution,and the osmotic pressure was found to be 1.86 torr at 25^oC.What is the approximate molar mass of the polyethylene?

For each of the following solutions,describe the deviation with respect to Raoult's Law. -hexane (C₆H₁₄) and chloroform (CHCl₃)

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.