Question 1

What volume of concentrated (14.7 M)  phosphoric acid is needed to prepare 25.0 L of 3.0 M H3PO4?

Accepted Answer

A)   0.20 L
B)   0.57 L
C)   1.8 L
D)   3.6 L
E)   5.1 LF) A) and D)
G) A) and C)

Question 2

Two aqueous solutions are prepared: 2.0 m Cu(NO3) 2 and 2.0 m NaBr. Which of the following statements is true?

Accepted Answer

A)   The Cu(NO3) 2 solution has a higher vapor pressure and lower freezing point than the NaBr solution.
B)   The Cu(NO3) 2 solution has a higher vapor pressure and higher freezing point than the NaBr solution.
C)   The Cu(NO3) 2 solution has a lower vapor pressure and lower freezing point than the NaBr solution.
D)   The Cu(NO3) 2 solution has a lower vapor pressure and higher freezing point than the NaBr solution.
E)   None of these choices are correct.F) A) and B)
G) C) and D)

Question 3

Consider the expression below, showing the terms which contribute to the heat of solution, ΔHsoln: ΔHsoln = ΔHsolute + ΔHsolvent + ΔHmix
Which of the following sets correctly shows the signs (positive or negative)  of the three terms on the right hand side of the equation?

Accepted Answer

A)   ΔHsolute > 0; ΔHsolvent > 0; ΔHmix > 0
B)   ΔHsolute solvent mix 
C)   ΔHsolute > 0; ΔHsolvent > 0; ΔHmix 
D)   ΔHsolute solvent mix > 0
E)   ΔHsolute solvent > 0; ΔHmix < 0F) B) and E)
G) A) and B)

Question 4

A 0.100 m K2SO4 solution has a freezing point of -0.43°C. What is the van't Hoff factor for this solution? Kf = 1.86°C/m

Accepted Answer

A)   0.77
B)   1.0
C)   2.3
D)   3.0
E)   >3.0F) A) and E)
G) C) and D)

Question 5

Cinnamaldehyde ( b = 1.22°C/m, boiling point of pure ethanol = 78.5°C A)  62.4 g B)  67.8 g C)  76.2 g D)  78.5 g E)  79.6 g" class="answers-bank-image d-inline" rel="preload" > = 132.15 g/mol)  is used as a flavoring agent. What mass of cinnamaldehyde must be added to 175 g of ethanol to give a solution whose boiling point is 82.7°C? Kb = 1.22°C/m, boiling point of pure ethanol = 78.5°C

Accepted Answer

A)   62.4 g
B)   67.8 g
C)   76.2 g
D)   78.5 g
E)   79.6 gF) A) and B)
G) All of the above

Question 6

Copper(II)  bromide is used as a wood preservative. What mass of CuBr2 is needed to prepare 750.0 mL of a 1.25 M solution?

Accepted Answer

A)   134 g
B)   209 g
C)   372 g
D)   938 g
E)   > 1 kgF) C) and D)
G) A) and D)

Question 7

Safrole is used as a topical antiseptic. Calculate the vapor pressure of a solution prepared by dissolving 0.75 mol of safrole in 950 g of ethanol ( ethanol = 50.0 torr at 25°C. A)  1.8 torr B)  11 torr C)  15 torr D)  40 torr E)  48 torr" class="answers-bank-image d-inline" rel="preload" > = 46.07 g/mol) . P°ethanol = 50.0 torr at 25°C.

Accepted Answer

A)   1.8 torr
B)   11 torr
C)   15 torr
D)   40 torr
E)   48 torrF) B) and C)
G) A) and E)

Question 8

Which of the following aqueous solutions should demonstrate the most non-ideal behavior?

Accepted Answer

A)   0.1 M NaI
B)   0.2 M CuSO4
C)   0.5 M KBr
D)   2.0 M CuCl2
E)   2.0 M CsClF) C) and D)
G) A) and B)

Question 9

Calculate the molarity of a solution prepared by diluting 1.85 L of 6.5 M KOH to 11.0 L.

Accepted Answer

A)   0.28 M
B)   0.91 M
C)   1.1 M
D)   3.1 M
E)   3.9 MF) B) and D)
G) A) and D)

Question 10

In general, water is a good solvent for both polar and nonpolar compounds.

Accepted Answer

A) True 
 B)False

Question 11

The concentration of iodine in sea water is 60. parts per billion by mass. If one assumes that the iodine exists in the form of iodide anions, what is the molarity of iodide in sea water? (The density of sea water is 1.025 g/mL.)

Accepted Answer

A)   4.8 × 10-13 M
B)   4.8 × 10-10 M
C)   4.8 × 10-7 M
D)   4.7 × 10-4 M
E)   4.7 × 10-1 MF) A) and B)
G) C) and E)

Question 12

An emulsion is a dispersion consisting of a

Accepted Answer

A)   solid in a liquid.
B)   liquid in a liquid.
C)   gas in a liquid.
D)   liquid in a solid.
E)   gas in a solid.F) C) and D)
G) B) and E)

Question 13

When two pure substances are mixed to form a solution

Accepted Answer

A)   heat is released.
B)   heat is absorbed.
C)   there is an increase in entropy.
D)   there is a decrease in entropy.
E)   entropy is conserved.F) A) and E)
G) D) and E)

Question 14

The mole fraction of potassium nitrate in an aqueous solution is 0.0194. The solution's density is 1.0627 g/mL. Calculate the molarity of the solution.

Accepted Answer

A)   0.0194 M
B)   0.981 M
C)   1.05 M
D)   1.96 M
E)   19.4 MF) A) and B)
G) A) and C)

Question 15

Methane has a Henry's Law constant (k)  of 9.88 × 10-2 mol/(L·atm)  when dissolved in benzene at 25°C. How many grams of CH4 will dissolve in 3.00 L of benzene if the partial pressure of CH4 is 1.48 atm?

Accepted Answer

A)   0.0667 g
B)   0.146 g
C)   2.34 g
D)   4.83 g
E)   7.02 gF) D) and E)
G) C) and D)

Question 16

Aqueous ammonia is commercially available in a solution that is 28% (w/w)  ammonia. What is the mole fraction of ammonia in such a solution?

Accepted Answer

A)   0.017
B)   0.023
C)   0.012
D)   0.24
E)   0.29F) None of the above
G) A) and B)

Question 17

Saccharin, one of the first non-nutritive sweeteners used in soft-drinks, is 500 times sweeter than sugar in dilute aqueous solutions. The solubility of saccharin is 1.00 gram per 290 mL of solution. What is the molarity of a saturated saccharin solution? (  saccharin = 183.2 g/mol)

Accepted Answer

A)   0.0188 M
B)   0.632 M
C)   1.58 M
D)   3.45 M
E)   None of these choices are correct.F) B) and C)
G) A) and E)

Question 18

The chemist, Anna Lytic, must prepare 1.00 kg of 15.0% (w/w)  acetic acid using a stock solution which is 36.0% (w/w)  acetic acid (d = 1.045 g/mL) . Which of the following combinations will give her the solution she wants?

Accepted Answer

A)   417 mL of 36% acetic acid in 583 mL of distilled water
B)   417 g of 36% acetic acid in 583 g of distilled water
C)   360 mL of 36% acetic acid in 640 mL of distilled water
D)   360 g of 36% acetic acid in 640 g of distilled water
E)   150 g of 36% acetic acid in 850 g of distilled waterF) B) and D)
G) A) and D)

Question 19

The heat of solution is the total enthalpy change when a solution is formed from the separated solute and solvent.

Accepted Answer

A) True 
 B)False

Question 20

Raoult's Law relates the vapor pressure of the solvent above the solution to its mole fraction in the solution. Which of the following is an accurate statement?

Accepted Answer

A)   Raoult's Law applies exactly to all solutions.
B)   Raoult's Law works best when applied to concentrated solutions.
C)   Raoult's Law works best when applied to dilute solutions.
D)   Raoult's Law applies only to non-ideal solutions.
E)   None of these choices are correct.F) C) and E)
G) All of the above

Exam 13: The Properties of Mixtures Solutions and Colloids

The heat of solution is the total enthalpy change when a solution is formed from the separated solute and solvent.

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Consider the expression below, showing the terms which contribute to the heat of solution, ΔHsoln: ΔHsoln = ΔHsolute + ΔHsolvent + ΔHmix Which of the following sets correctly shows the signs (positive or negative) of the three terms on the right hand side of the equation?

Correct AnswerverifiedShow Answer

The concentration of iodine in sea water is 60. parts per billion by mass. If one assumes that the iodine exists in the form of iodide anions, what is the molarity of iodide in sea water? (The density of sea water is 1.025 g/mL.)

Correct AnswerverifiedShow Answer

Methane has a Henry's Law constant (k) of 9.88 × 10-2 mol/(L·atm) when dissolved in benzene at 25°C. How many grams of CH4 will dissolve in 3.00 L of benzene if the partial pressure of CH4 is 1.48 atm?

Correct AnswerverifiedShow Answer

An emulsion is a dispersion consisting of a

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Safrole is used as a topical antiseptic. Calculate the vapor pressure of a solution prepared by dissolving 0.75 mol of safrole in 950 g of ethanol ( = 46.07 g/mol) . P°ethanol = 50.0 torr at 25°C.

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What volume of concentrated (14.7 M) phosphoric acid is needed to prepare 25.0 L of 3.0 M H3PO4?

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Aqueous ammonia is commercially available in a solution that is 28% (w/w) ammonia. What is the mole fraction of ammonia in such a solution?

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Calculate the molarity of a solution prepared by diluting 1.85 L of 6.5 M KOH to 11.0 L.

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Copper(II) bromide is used as a wood preservative. What mass of CuBr2 is needed to prepare 750.0 mL of a 1.25 M solution?

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Two aqueous solutions are prepared: 2.0 m Cu(NO3) 2 and 2.0 m NaBr. Which of the following statements is true?

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When two pure substances are mixed to form a solution

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Saccharin, one of the first non-nutritive sweeteners used in soft-drinks, is 500 times sweeter than sugar in dilute aqueous solutions. The solubility of saccharin is 1.00 gram per 290 mL of solution. What is the molarity of a saturated saccharin solution? ( saccharin = 183.2 g/mol)

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Cinnamaldehyde ( = 132.15 g/mol) is used as a flavoring agent. What mass of cinnamaldehyde must be added to 175 g of ethanol to give a solution whose boiling point is 82.7°C? Kb = 1.22°C/m, boiling point of pure ethanol = 78.5°C

Correct AnswerverifiedShow Answer

The chemist, Anna Lytic, must prepare 1.00 kg of 15.0% (w/w) acetic acid using a stock solution which is 36.0% (w/w) acetic acid (d = 1.045 g/mL) . Which of the following combinations will give her the solution she wants?

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Which of the following aqueous solutions should demonstrate the most non-ideal behavior?

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In general, water is a good solvent for both polar and nonpolar compounds.

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The mole fraction of potassium nitrate in an aqueous solution is 0.0194. The solution's density is 1.0627 g/mL. Calculate the molarity of the solution.

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A 0.100 m K2SO4 solution has a freezing point of -0.43°C. What is the van't Hoff factor for this solution? Kf = 1.86°C/m

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Raoult's Law relates the vapor pressure of the solvent above the solution to its mole fraction in the solution. Which of the following is an accurate statement?

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Correct Answer
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Consider the expression below, showing the terms which contribute to the heat of solution, ΔH_soln: ΔH_soln = ΔH_solute + ΔH_solvent + ΔH_mix Which of the following sets correctly shows the signs (positive or negative) of the three terms on the right hand side of the equation?

Correct Answer
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Correct Answer
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Methane has a Henry's Law constant (k) of 9.88 × 10^-2 mol/(L·atm) when dissolved in benzene at 25°C. How many grams of CH₄ will dissolve in 3.00 L of benzene if the partial pressure of CH₄ is 1.48 atm?

Correct Answer
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Correct Answer
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Safrole is used as a topical antiseptic. Calculate the vapor pressure of a solution prepared by dissolving 0.75 mol of safrole in 950 g of ethanol ( = 46.07 g/mol) . P°_ethanol = 50.0 torr at 25°C.

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What volume of concentrated (14.7 M) phosphoric acid is needed to prepare 25.0 L of 3.0 M H₃PO₄?

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Correct Answer
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Copper(II) bromide is used as a wood preservative. What mass of CuBr₂ is needed to prepare 750.0 mL of a 1.25 M solution?

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Two aqueous solutions are prepared: 2.0 m Cu(NO₃) ₂ and 2.0 m NaBr. Which of the following statements is true?

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Cinnamaldehyde ( = 132.15 g/mol) is used as a flavoring agent. What mass of cinnamaldehyde must be added to 175 g of ethanol to give a solution whose boiling point is 82.7°C? K_b = 1.22°C/m, boiling point of pure ethanol = 78.5°C

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Correct Answer
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A 0.100 m K₂SO₄ solution has a freezing point of -0.43°C. What is the van't Hoff factor for this solution? K_f = 1.86°C/m

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Correct Answer
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