Question 1

Explain why water does not dissolve in gasoline.

Accepted Answer

Water is polar and gasoline is

Question 2

The Dirty Dozen refer to twelve chemicals that are harmful for the environment.Identify the compound that was not used as an insecticide.

Accepted Answer

A)  Chlordane 
B)  DDT 
C)  Aldrin 
D)  polychlorinated biphenyl 
E)  Heptachlor 
A)  Chlordane 
B)  DDT 
C)  Aldrin 
D)  polychlorinated biphenyl 
E)  Heptachlor

Question 3

Identify the classification of opal.

Accepted Answer

A)  aerosol 
B)  solid aerosol 
C)  foam 
D)  emulsion 
E)  solid emulsion 
A)  aerosol 
B)  solid aerosol 
C)  foam 
D)  emulsion 
E)  solid emulsion

Question 4

Calculate the freezing point of a solution containing 5.0 grams of KCl and 550.0 grams of water.The molal-freezing-point-depression constant (Kf)for water is 1.86°C/m.

Accepted Answer

A)  -0.45°C 
B)  +0.45°C 
C)  -0.23°C 
D)  +0.23°C 
E)  1.23°C 
A)  -0.45°C 
B)  +0.45°C 
C)  -0.23°C 
D)  +0.23°C 
E)  1.23°C

Question 5

The boiling point of an aqueous 1.83 m (NH4)2SO4 (molar mass = 132.15 g/mol)solution is 102.5°C.Determine the value of the van't Hoff factor for this solute if the Kb for water is 0.512°C/m.

Accepted Answer

A)  3.0 
B)  3.6 
C)  1.8 
D)  2.7 
E)  2.3 
A)  3.0 
B)  3.6 
C)  1.8 
D)  2.7 
E)  2.3

Question 6

Choose the aqueous solution with the lowest vapor pressure.These are all solutions of nonvolatile solutes and you should assume ideal van't Hoff factors where applicable.

Accepted Answer

A)  0.120 m C2H6O2 
B)  0.040 m (NH4)2SO4 
C)  0.060 m Li2CO3 
D)  0.030 m RbC2H3O2 
E)  They all have the same vapor pressure. 
A)  0.120 m C2H6O2 
B)  0.040 m (NH4)2SO4 
C)  0.060 m Li2CO3 
D)  0.030 m RbC2H3O2 
E)  They all have the same vapor pressure.

Question 7

The Henry's Law constant of methyl bromide,CH3Br,is k = 0.159 mol/(L ∙ atm)at 25°C.What is the solubility of methyl bromide in water at 25°C and at a partial pressure of 270.mm Hg?

Accepted Answer

A)  0.0565 mol/L 
B)  0.355 mol/L 
C)  0.448 mol/L 
D)  42.9 mol/L 
A)  0.0565 mol/L 
B)  0.355 mol/L 
C)  0.448 mol/L 
D)  42.9 mol/L

Question 8

Calculate the osmotic pressure,in torr,of a solution containing 3.00 mg of a sugar
(342 g/mole)in 15.0 mL of water at 25°C.

Accepted Answer

The answer of Calculate the osmotic pressure,in torr,of a solution...

Question 9

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

Question 10

What is the mole fraction of oxygen in a gas mixture that is 37% oxygen and 63% nitrogen by volume?

Accepted Answer

A)  0.20 
B)  0.37 
C)  0.32 
D)  0.52 
A)  0.20 
B)  0.37 
C)  0.32 
D)  0.52

Question 11

A solution is prepared by dissolving 16.2 g of benzene (C6H6)in 282 g of carbon tetrachloride (CCl4).The concentration of benzene in this solution is ________ molal.The molar masses of C6H6 and CCl4 are 78.1 g/mol and 154 g/mol,respectively.

Accepted Answer

A)  7.36 × 10-4 
B)  0.736 
C)  0.102 
D)  0.0543 
E)  5.43 
A)  7.36 × 10-4 
B)  0.736 
C)  0.102 
D)  0.0543 
E)  5.43

Question 12

A solution is 2.25% by weight KHCO3.How many grams of KHCO3 are in 150.0 g of solution?

Accepted Answer

A)  1.50 g 
B)  3.38 g 
C)  66.7 g 
D)  225 g 
A)  1.50 g 
B)  3.38 g 
C)  66.7 g 
D)  225 g

Question 13

What is the mole fraction of I2 in a solution made by dissolving 55.6 g of I2 in 245 g of hexane,C6H14?

Accepted Answer

A)  0.0715 
B)  0.0770 
C)  0.133 
D)  0.154 
A)  0.0715 
B)  0.0770 
C)  0.133 
D)  0.154

Question 14

A solution is prepared by dissolving 38.6 g sucrose (C12H22O11)in 495 g of water.Determine the mole fraction of sucrose if the final volume of the solution is 508 mL.

Accepted Answer

A)  4.09 × 10-3 
B)  7.80 × 10-2 
C)  1.28 × 10-3 
D)  7.23 × 10-2 
E)  2.45 × 10-3 
A)  4.09 × 10-3 
B)  7.80 × 10-2 
C)  1.28 × 10-3 
D)  7.23 × 10-2 
E)  2.45 × 10-3

Question 15

A solution is prepared by dissolving 7.00 g of glycerin (C3H8O3)in 201 g of ethanol (C2H5OH). The freezing point of the solution is ________°C.The freezing point of pure ethanol is -114.6°C at 1 atm.The molal-freezing-point-depression constant (Kf)for ethanol is 1.99°C/m.The molar masses of glycerin and of ethanol are 92.1 g/mol and 46.1 g/mol,respectively.

Accepted Answer

A)  -121.3 
B)  0.752 
C)  -107.9 
D)  -113.8 
E)  -115.4 
A)  -121.3 
B)  0.752 
C)  -107.9 
D)  -113.8 
E)  -115.4

Question 16

Explain why the van't Hoff factor for MgCl2 is less than its predicted value.

Accepted Answer

The hydrated Mg²⁺ and Cl⁻ ions

Question 17

Fluids used for an intravenous transfusion must be ________ with bodily fluids.

Accepted Answer

A)  isosmotic 
B)  hyperosmotic 
C)  hyposmotic 
D)  neosmotic 
E)  magnosmotic 
A)  isosmotic 
B)  hyperosmotic 
C)  hyposmotic 
D)  neosmotic 
E)  magnosmotic

Question 18

What happens to a supersaturated solution of potassium acetate once it is cooled and a small crystal of solid potassium acetate is added?

Accepted Answer

The portion of potassium aceta

Question 19

0.300 moles of sodium nitrite are needed for a reaction.The solution is 0.450 M.How many mL are needed?

Accepted Answer

A)  0.667 mL 
B)  1500 mL 
C)  1.5 mL 
D)  667 mL 
E)  135 mL 
A)  0.667 mL 
B)  1500 mL 
C)  1.5 mL 
D)  667 mL 
E)  135 mL

Question 20

Define colloid.

Accepted Answer

A)  a mixture in which a substance floats on the dispersing medium 
B)  a mixture in which a substance is dissolved in a solute 
C)  a mixture in which a substance is dissolved in a solvent 
D)  a mixture in which a substance settles to the bottom of a dispersing medium 
E)  a mixture in which a dispersed substance is finely divided in a dispersing medium 
A)  a mixture in which a substance floats on the dispersing medium 
B)  a mixture in which a substance is dissolved in a solute 
C)  a mixture in which a substance is dissolved in a solvent 
D)  a mixture in which a substance settles to the bottom of a dispersing medium 
E)  a mixture in which a dispersed substance is finely divided in a dispersing medium

Exam 13: Solutions

Explain why water does not dissolve in gasoline.

The Dirty Dozen refer to twelve chemicals that are harmful for the environment.Identify the compound that was not used as an insecticide.

Identify the classification of opal.

Calculate the freezing point of a solution containing 5.0 grams of KCl and 550.0 grams of water.The molal-freezing-point-depression constant (Kf)for water is 1.86°C/m.

The boiling point of an aqueous 1.83 m (NH4)2SO4 (molar mass = 132.15 g/mol)solution is 102.5°C.Determine the value of the van't Hoff factor for this solute if the Kb for water is 0.512°C/m.

Choose the aqueous solution with the lowest vapor pressure.These are all solutions of nonvolatile solutes and you should assume ideal van't Hoff factors where applicable.

The Henry's Law constant of methyl bromide,CH3Br,is k = 0.159 mol/(L ∙ atm)at 25°C.What is the solubility of methyl bromide in water at 25°C and at a partial pressure of 270.mm Hg?

Calculate the osmotic pressure,in torr,of a solution containing 3.00 mg of a sugar (342 g/mole)in 15.0 mL of water at 25°C.

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?

What is the mole fraction of oxygen in a gas mixture that is 37% oxygen and 63% nitrogen by volume?

A solution is prepared by dissolving 16.2 g of benzene (C6H6)in 282 g of carbon tetrachloride (CCl4).The concentration of benzene in this solution is ________ molal.The molar masses of C6H6 and CCl4 are 78.1 g/mol and 154 g/mol,respectively.

A solution is 2.25% by weight KHCO3.How many grams of KHCO3 are in 150.0 g of solution?

What is the mole fraction of I2 in a solution made by dissolving 55.6 g of I2 in 245 g of hexane,C6H14?

A solution is prepared by dissolving 38.6 g sucrose (C12H22O11)in 495 g of water.Determine the mole fraction of sucrose if the final volume of the solution is 508 mL.

Explain why the van't Hoff factor for MgCl2 is less than its predicted value.

Fluids used for an intravenous transfusion must be ________ with bodily fluids.

What happens to a supersaturated solution of potassium acetate once it is cooled and a small crystal of solid potassium acetate is added?

0.300 moles of sodium nitrite are needed for a reaction.The solution is 0.450 M.How many mL are needed?

Define colloid.

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Calculate the freezing point of a solution containing 5.0 grams of KCl and 550.0 grams of water.The molal-freezing-point-depression constant (K_f)for water is 1.86°C/m.

The boiling point of an aqueous 1.83 m (NH₄)₂SO₄ (molar mass = 132.15 g/mol)solution is 102.5°C.Determine the value of the van't Hoff factor for this solute if the K_b for water is 0.512°C/m.

The Henry's Law constant of methyl bromide,CH₃Br,is k = 0.159 mol/(L ∙ atm)at 25°C.What is the solubility of methyl bromide in water at 25°C and at a partial pressure of 270.mm Hg?

A solution is prepared by dissolving 16.2 g of benzene (C₆H₆)in 282 g of carbon tetrachloride (CCl₄).The concentration of benzene in this solution is ________ molal.The molar masses of C₆H₆ and CCl₄ are 78.1 g/mol and 154 g/mol,respectively.

A solution is 2.25% by weight KHCO₃.How many grams of KHCO₃ are in 150.0 g of solution?

What is the mole fraction of I₂ in a solution made by dissolving 55.6 g of I₂ in 245 g of hexane,C₆H₁₄?

A solution is prepared by dissolving 38.6 g sucrose (C₁₂H₂₂O₁₁)in 495 g of water.Determine the mole fraction of sucrose if the final volume of the solution is 508 mL.

Explain why the van't Hoff factor for MgCl₂ is less than its predicted value.