Question 1

In which of the following substances do you expect to find the strongest intermolecular hydrogen bonding forces?

Accepted Answer

A)   NH3
B)   H2S
C)   H2O
D)   CF4
E)   NaHF) A) and C)
G) A) and B)

Question 2

Which compound would you expect to have the highest vapor pressure at 25°C?

Accepted Answer

A)   C7H16 (BP = 98.4°
C)  
B)   C8H18 (BP = 125.7°
C)  
C)   C9H20 (BP = 150.8°
C)  
D)   C10H22 (BP = 174.3°
C)  
E)   It is impossible to tell which compound would have the highest vapor pressure because there is no relationship between vapor pressure and the boiling point of a compound.F) C) and E)
G) A) and E)

Question 3

refer to the table below:
‪ 
-What intermolecular force is most responsible for the difference in boiling point between octane and pentane?

Accepted Answer

A)   dispersion
B)   dipole-dipole interaction
C)   dipole-induced dipole interaction
D)   hydrogen bonding
E)   all of theseF) C) and D)
G) D) and E)

Question 4

In most cases, reading from left to right across a phase diagram, what is the order in which you would find the three states of matter?

Accepted Answer

A)   gas 
B)   gas 
C)   liquid 
D)   liquid 
E)   solid < liquid < gasF) A) and B)
G) C) and D)

Question 5

The following three compounds have similar molecular weights. Place them in order of increasing boiling point.
Formaldehyde: H2C=O &emsp; methanol: CH3OH &emsp; ethane: CH3CH3

Accepted Answer

A)   formaldehyde 
B)   ethane 
C)   ethane 
D)   methanol 
E)   none of theseF) A) and B)
G) C) and E)

Question 6

Which of the following compounds has the lowest vapor pressure?

Accepted Answer

A)   CCl4
B)   CBr4
C)   CF4
D)   CH4
E)   CI4F) A) and D)
G) C) and D)

Question 7

Which force must be overcome to melt solid pentane, C5H12?

Accepted Answer

A)   metallic bonding
B)   covalent bonding
C)   ionic bonding
D)   dispersion forces
E)   all of these must be overcome to melt pentaneF) A) and E)
G) None of the above

Question 8

For which of the following is the boiling point incorrectly given?

Accepted Answer

A)   CH3(CH2) 2CH3,  - 0.5 ℃
B)   CH3(CH2) 2CHO, 75 ℃
C)   CH3(CH2) 3OH, 100 ℃
D)   CH3(CH2) 2COOH, 95 ℃
E)   CH3(CH2) 3CHO, 103 ℃F) A) and B)
G) B) and E)

Question 9

Which of the following statements is correct for the solubilities of alcohols with the formula CH3(CH2) nOH?

Accepted Answer

A)   The solubility in water is minimal because the compound is organic.
B)   The solubility in water increases as n increases.
C)   The solubility in water decreases as n increases.
D)   The solubility in water is independent of n.
E)   The solubility in water depends only on the extent of hydrogen bonding.F) All of the above
G) B) and D)

Question 10

Pure benzene melts at 5.5°C. A solution of 1.25 g of CCl4 in 1.00 x 102 g of benzene would have what freezing point? (Benzene: kb = 5.1°C/m)

Accepted Answer

Question 11

Carboxylic acids with the general formula CH3(CH2) nCO2H have a nonpolar CH3-CH2- tail and a polar -CO2H head. What effect would increasing the value of "n" have on the solubility of carboxylic acids?

Accepted Answer

A)   The solubility would increase in both water and in nonpolar solvents such as CCl4.
B)   The solubility would decrease in both water and in nonpolar solvents such as CCl4.
C)   The solubility would increase in water but decrease in CCl4.
D)   The solubility would decrease in water but increase in CCl4.
E)   The solubility of carboxylic acids in both water and CCl4 would remain the same.F) D) and E)
G) A) and E)

Question 12

What is the molality of a bromine solution made by dissolving 39.95 g of Br2 in 5.00 x 102 g of CCl4?

Accepted Answer

A)   0.0800
B)   0.250
C)   0.500
D)   1.00
E)   2.00F) A) and C)
G) B) and C)

Question 13

What is the mole fraction of CCl4 (MW = 154 g/mol)  in a solution prepared by dissolving 32 grams of CCl4 in 75 grams of C6H6 (MW = 78.1 g/mol)  ?

Accepted Answer

A)   0.18
B)   0.22
C)   0.30
D)   0.48
E)   0.82F) B) and C)
G) C) and D)

Question 14

Rare gases, such as xenon, can be frozen to form solids. The intermolecular forces responsible for maintaining the solid are best described as:

Accepted Answer

A)   hydrogen bonds
B)   covalent bonds
C)   dipole-dipole forces
D)   dipole-induced dipole forces
E)   induced dipole-induced dipole forcesF) A) and B)
G) B) and C)

Question 15

refer to the phase diagram shown below.
 
-The regions labeled A,B, and C are

Accepted Answer

A)   the gas, liquid and solid phases, respectively.
B)   the solid and liquid phases and the triple point, respectively.
C)   the gas and liquid phases and the critical point, respectively.
D)   the solid, liquid and gas phases, respectively.
E)   pressure, temperature and moles, respectively.F) A) and C)
G) A) and B)

Question 16

Which of the following characteristics is associated with a low boiling point for a molecular substance?

Accepted Answer

A)   high molecular weight
B)   high vapor pressure
C)   strong intermolecular forces
D)   large dipole moment
E)   strong cohesion forcesF) B) and E)
G) B) and C)

Question 17

Which of the following will be most soluble in a nonpolar solvent such as carbon tetrachloride, CCl4?

Accepted Answer

A)   KI
B)   H2O
C)   NH3
D)   CBr4
E)   HFF) B) and D)
G) B) and C)

Question 18

Which of the following concentration units would change when the temperature of the solution changes? (Hint: remember that liquids expand and contract as the temperature changes.) 
(I)  molarity 
(II)  molality 
(III)  mole fraction of solute
(IV)  mole fraction of solvent

Accepted Answer

A)   I
B)   I and II
C)   I, II and III
D)   all of the above
E)   none of the aboveF) C) and D)
G) A) and C)

Question 19

Which of the following is true?

Accepted Answer

A)   Molarity (M)  is calculated by dividing the number of moles of solute by the number of liters of solvent.
B)   Molality (m)  is calculated by dividing the number of moles of solute by the number of liters of solvent.
C)   Mole fraction is calculated by dividing the number of moles of solvent by the number of moles of solute.
D)   Mole fraction is calculated by dividing the number of moles of solute by the number of moles of solvent.
E)   Statements (a)  through (d)  are all false.F) A) and B)
G) None of the above

Question 20

When a nonvolatile solute is dissolved in a volatile solvent, the vapor pressure, freezing point, and boiling point

Accepted Answer

A)   are all higher for the solution than for the pure solvent.
B)   are all lower for the solution than for the pure solvent.
C)   change differently, with vapor pressure increasing and boiling and freezing points decreasing.
D)   change differently, with boiling point increasing and vapor pressure and freezing point decreasing.
E)   do not change because the solute is nonvolatile.F) A) and D)
G) B) and C)

Exam 8: Liquids and Solutions

For which of the following is the boiling point incorrectly given?

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Carboxylic acids with the general formula CH3(CH2) nCO2H have a nonpolar CH3-CH2- tail and a polar -CO2H head. What effect would increasing the value of "n" have on the solubility of carboxylic acids?

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Which of the following will be most soluble in a nonpolar solvent such as carbon tetrachloride, CCl4?

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Rare gases, such as xenon, can be frozen to form solids. The intermolecular forces responsible for maintaining the solid are best described as:

Correct AnswerverifiedShow Answer

refer to the phase diagram shown below. -The regions labeled A,B, and C are

Correct AnswerverifiedShow Answer

In most cases, reading from left to right across a phase diagram, what is the order in which you would find the three states of matter?

Correct AnswerverifiedShow Answer

What is the molality of a bromine solution made by dissolving 39.95 g of Br2 in 5.00 x 102 g of CCl4?

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When a nonvolatile solute is dissolved in a volatile solvent, the vapor pressure, freezing point, and boiling point

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Which compound would you expect to have the highest vapor pressure at 25°C?

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Which of the following characteristics is associated with a low boiling point for a molecular substance?

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In which of the following substances do you expect to find the strongest intermolecular hydrogen bonding forces?

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What is the mole fraction of CCl4 (MW = 154 g/mol) in a solution prepared by dissolving 32 grams of CCl4 in 75 grams of C6H6 (MW = 78.1 g/mol) ?

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Pure benzene melts at 5.5°C. A solution of 1.25 g of CCl4 in 1.00 x 102 g of benzene would have what freezing point? (Benzene: kb = 5.1°C/m)

Correct AnswerverifiedShow Answer

Which of the following concentration units would change when the temperature of the solution changes? (Hint: remember that liquids expand and contract as the temperature changes.) (I) molarity (II) molality (III) mole fraction of solute (IV) mole fraction of solvent

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refer to the table below: ‪ -What intermolecular force is most responsible for the difference in boiling point between octane and pentane?

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Which of the following is true?

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Which force must be overcome to melt solid pentane, C5H12?

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Which of the following statements is correct for the solubilities of alcohols with the formula CH3(CH2) nOH?

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Which of the following compounds has the lowest vapor pressure?

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The following three compounds have similar molecular weights. Place them in order of increasing boiling point. Formaldehyde: H2C=O methanol: CH3OH ethane: CH3CH3

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Carboxylic acids with the general formula CH₃(CH₂) _nCO₂H have a nonpolar CH₃-CH₂- tail and a polar -CO₂H head. What effect would increasing the value of "n" have on the solubility of carboxylic acids?

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Which of the following will be most soluble in a nonpolar solvent such as carbon tetrachloride, CCl₄?

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What is the molality of a bromine solution made by dissolving 39.95 g of Br₂ in 5.00 x 10² g of CCl₄?

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What is the mole fraction of CCl₄ (MW = 154 g/mol) in a solution prepared by dissolving 32 grams of CCl₄ in 75 grams of C₆H₆ (MW = 78.1 g/mol) ?

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Pure benzene melts at 5.5°C. A solution of 1.25 g of CCl₄ in 1.00 x 10² g of benzene would have what freezing point? (Benzene: k_b = 5.1°C/m)

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Which force must be overcome to melt solid pentane, C₅H₁₂?

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Which of the following statements is correct for the solubilities of alcohols with the formula CH₃(CH₂) _nOH?

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The following three compounds have similar molecular weights. Place them in order of increasing boiling point. Formaldehyde: H₂C=O methanol: CH₃OH ethane: CH₃CH₃

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