Question 1

Dimethylglyoxime, DMG, is an organic compound used to test for aqueous nickel(II)  ions. A solution prepared by dissolving 65.0 g of DMG in 375 g of ethanol boils at 80.3°C. What is the molar mass of DMG? Kb = 1.22°C/m, boiling point of pure ethanol = 78.5°C

Accepted Answer

A)   44.1 g/mol
B)   65.8 g/mol
C)   117 g/mol
D)   131.6 g/mol
E)   553 g/molF) C) and D)
G) All of the above

Question 2

Calcium nitrite is used as a corrosion inhibitor in lubricants. What is the molality of a solution prepared by dissolving 18.5 g of calcium nitrite in 83.5 g of distilled water?

Accepted Answer

A)   0.0342 m
B)   0.0855 m
C)   0.222 m
D)   0.444 m
E)   1.68 mF) B) and C)
G) A) and B)

Question 3

Sodium hydroxide is a common ingredient in drain cleaners such as Drano. The mole fraction of sodium hydroxide in a saturated aqueous solution is 0.310. What is the molality of the solution?

Accepted Answer

A)   0.310 m
B)   0.690 m
C)   1.24 m
D)   12.4 m
E)   25.0 mF) All of the above
G) A) and B)

Question 4

Heats of solution may be either positive or negative.

Accepted Answer

A) True 
 B)False

Question 5

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) None of the above
G) B) and C)

Question 6

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) A) and B)
G) C) and E)

Question 7

Based only on the relative lattice energies of the compounds below, which one would be expected to have the lowest solubility in water?

Accepted Answer

A)   NaBr
B)   CaS
C)   NaOH
D)   KI
E)   CsClF) A) and B)
G) A) and C)

Question 8

Which of the following statements describes the correct method of preparation of 1.00 L of a 2.0 M urea solution? urea = 60.06 g/mol A)  Dissolve 120 g of urea in 1.00 kg of distilled water. B)  Dissolve 120 g of urea in 880 g of distilled water. C)  Dissolve 120 g of urea in enough distilled water to produce 1.00 L of solution. D)  Dissolve 120 g of urea in 1.00 liter of distilled water. E)  The density of urea is needed in order to do this calculation." class="answers-bank-image d-inline" rel="preload" > urea = 60.06 g/mol

Accepted Answer

A)   Dissolve 120 g of urea in 1.00 kg of distilled water.
B)   Dissolve 120 g of urea in 880 g of distilled water.
C)   Dissolve 120 g of urea in enough distilled water to produce 1.00 L of solution.
D)   Dissolve 120 g of urea in 1.00 liter of distilled water.
E)   The density of urea is needed in order to do this calculation.F) A) and E)
G) All of the above

Question 9

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) None of the above
G) C) and D)

Question 10

Select the weakest electrolyte from the following set.

Accepted Answer

A)   Na2SO4
B)   KCl
C)   CH3CH2COOH, propionic acid
D)   CaCl2
E)   LiOHF) C) and E)
G) A) and B)

Question 11

Helical segments of protein molecules arise through hydrogen bonding between C=O and N-H groups.

Accepted Answer

A) True 
 B)False

Question 12

Colloidal particles may be either solids, liquids, or gases.

Accepted Answer

A) True 
 B)False

Question 13

The density of pure water at 25°C is 0.997 g/mL. Considering water as being both solvent and solute, calculate its molarity.

Accepted Answer

The answer of The density of pure water at 25°C...

Question 14

Which, if any, of the following features is common to soaps, detergents, phospholipids, and channel-forming antibiotics?

Accepted Answer

A)   They all contain fatty acids.
B)   They all contain phosphate groups.
C)   They all contain polypeptide chains.
D)   Their function depends on the dual polarity of their molecules.
E)   They have none of the above features in common.F) B) and D)
G) A) and E)

Question 15

Cadmium bromide is used in photography and lithography. Calculate the molality of a solution prepared by dissolving 45.38 g of CdBr2 in 375.0 g of water.

Accepted Answer

A)   0.03035 m
B)   0.01600 m
C)   0.1210 m
D)   0.4446 m
E)   none of the aboveF) B) and E)
G) A) and E)

Question 16

Which of the following aqueous liquids will have the lowest freezing point?

Accepted Answer

A)   0.5 m C12H22O11 (sucrose) 
B)   0.5 m Ca(NO3) 2
C)   0.5 m NiSO4
D)   0.5 m Li3PO4
E)   pure waterF) A) and C)
G) A) and B)

Question 17

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 the above statements is true.F) C) and D)
G) All of the above

Question 18

If a 100-mL sample of a volatile liquid such as diethyl ether is introduced into a 250-mL flask which is immediately sealed, the pressure inside will increase above atmospheric pressure. Explain.

Accepted Answer

The pressure inside the flask will initi...

Question 19

Raoult's Law relates the vapor pressure of a solvent above a solution to the mole fraction of the solvent and the vapor pressure of the pure solvent.

Accepted Answer

A) True 
 B)False

Question 20

The backbone of a protein chain consists of carbon, nitrogen, and oxygen atoms.

Accepted Answer

A) True 
 B)False

Exam 13: The Properties of Mixtures: Solutions and Colloids

Helical segments of protein molecules arise through hydrogen bonding between C=O and N-H groups.

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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.)

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The backbone of a protein chain consists of carbon, nitrogen, and oxygen atoms.

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Sodium hydroxide is a common ingredient in drain cleaners such as Drano. The mole fraction of sodium hydroxide in a saturated aqueous solution is 0.310. What is the molality of the solution?

Correct AnswerverifiedShow Answer

If a 100-mL sample of a volatile liquid such as diethyl ether is introduced into a 250-mL flask which is immediately sealed, the pressure inside will increase above atmospheric pressure. Explain.

Correct AnswerverifiedThe pressure inside the flask will initi...View AnswerShow Answer

Heats of solution may be either positive or negative.

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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 AnswerverifiedShow Answer

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.

Correct AnswerverifiedShow Answer

Colloidal particles may be either solids, liquids, or gases.

Correct AnswerverifiedShow Answer

Which, if any, of the following features is common to soaps, detergents, phospholipids, and channel-forming antibiotics?

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Which of the following statements describes the correct method of preparation of 1.00 L of a 2.0 M urea solution? urea = 60.06 g/mol

Correct AnswerverifiedShow Answer

Raoult's Law relates the vapor pressure of a solvent above a solution to the mole fraction of the solvent and the vapor pressure of the pure solvent.

Correct AnswerverifiedShow Answer

Dimethylglyoxime, DMG, is an organic compound used to test for aqueous nickel(II) ions. A solution prepared by dissolving 65.0 g of DMG in 375 g of ethanol boils at 80.3°C. What is the molar mass of DMG? Kb = 1.22°C/m, boiling point of pure ethanol = 78.5°C

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Select the weakest electrolyte from the following set.

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Calcium nitrite is used as a corrosion inhibitor in lubricants. What is the molality of a solution prepared by dissolving 18.5 g of calcium nitrite in 83.5 g of distilled water?

Correct AnswerverifiedShow Answer

Based only on the relative lattice energies of the compounds below, which one would be expected to have the lowest solubility in water?

Correct AnswerverifiedShow Answer

The density of pure water at 25°C is 0.997 g/mL. Considering water as being both solvent and solute, calculate its molarity.

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Cadmium bromide is used in photography and lithography. Calculate the molality of a solution prepared by dissolving 45.38 g of CdBr2 in 375.0 g of water.

Correct AnswerverifiedShow Answer

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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Which of the following aqueous liquids will have the lowest freezing point?

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The pressure inside the flask will initi...
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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 CH₄will dissolve in 3.00 L of benzene if the partial pressure of CH₄is 1.48 atm?

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.

Correct Answer
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Correct Answer
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Correct Answer
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Which of the following statements describes the correct method of preparation of 1.00 L of a 2.0 M urea solution? _urea = 60.06 g/mol

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Correct Answer
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Dimethylglyoxime, DMG, is an organic compound used to test for aqueous nickel(II) ions. A solution prepared by dissolving 65.0 g of DMG in 375 g of ethanol boils at 80.3°C. What is the molar mass of DMG? K_b = 1.22°C/m, boiling point of pure ethanol = 78.5°C

Correct Answer
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Correct Answer
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Correct Answer
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Cadmium bromide is used in photography and lithography. Calculate the molality of a solution prepared by dissolving 45.38 g of CdBr₂in 375.0 g of water.

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

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Correct Answer
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