Question 1

Diethyl ether, used as a solvent for extraction of organic compounds from aqueous solutions, has a high vapor pressure which makes it a potential fire hazard in laboratories in which it is used. How much energy is released when 100.0 g is cooled from 53.0°C to 10.0°C?

Accepted Answer

A)  10.1 kJ
B)  13.1 kJ
C)  16.1 kJ
D)  45.2 kJ
E)  48.6 kJF) A) and B)
G) C) and E)

Question 2

The phase diagram for xenon has a solid-liquid curve with a positive slope. Which of the following is true?

Accepted Answer

A)  Solid xenon has a higher density than liquid xenon.
B)  Solid xenon has the same density as liquid xenon.
C)  The phase diagram cannot be used to predict which phase of xenon is denser.
D)  Freezing xenon is an endothermic process.
E)  None of these choices are correct.F) All of the above
G) None of the above

Question 3

Liquid crystal displays are most commonly constructed of smectic type liquid crystals.

Accepted Answer

A) True 
 B)False

Question 4

What types of forces exist between molecules of CO2?

Accepted Answer

A)  Hydrogen bonding only.
B)  Hydrogen bonding and dispersion forces.
C)  Dipole-dipole forces only.
D)  Dipole-dipole and dispersion forces.
E)  Dispersion forces only.F) A) and D)
G) A) and C)

Question 5

Examine the following phase diagram and identify the feature represented by point B.

Accepted Answer

A)  Melting point
B)  Triple point
C)  Critical point
D)  Sublimation point
E)  Boiling pointF) A) and B)
G) A) and C)

Question 6

When the electron cloud of a molecule is easily distorted, the molecule has a high

Accepted Answer

A)  polarity.
B)  polarizability.
C)  dipole moment.
D)  van der Waals radius.
E)  compressibility.F) None of the above
G) C) and D)

Question 7

A metal with a body-centered cubic lattice will have __________ atom(s)  per unit cell.

Accepted Answer

A)  1
B)  2
C)  3
D)  4
E)  9F) A) and D)
G) B) and E)

Question 8

Examine the following phase diagram and identify the feature represented by point A.

Accepted Answer

A)  Melting point
B)  Critical point
C)  Triple point
D)  Sublimation point
E)  Boiling pointF) A) and B)
G) B) and D)

Question 9

Which of the following statements about ceramics is incorrect?

Accepted Answer

A)  Silicon carbide has a diamond-like structure.
B)  Boron nitride can exist in both diamond-like and graphite-like forms.
C)  Silicon carbide can be prepared by direct reaction of silicon and carbon.
D)  Superconducting ceramics present manufacturing difficulties owing to their brittleness.
E)  Superconducting ceramic compounds usually incorporate cobalt in a key role.F) C) and D)
G) A) and C)

Question 10

Examine the phase diagram for the substance Bogusium (Bo)  and select the correct statement.

Accepted Answer

A)  Bo( s) has a lower density than Bo( l) .
B)  The triple point for Bo is at a higher temperature than the melting point for Bo.
C)  Bo changes from a solid to a liquid as one follows the line from C to D.
D)  Bo changes from a liquid to a gas as one follows the line from C to D.
E)  Point B represents the critical temperature and pressure for Bo.F) A) and D)
G) B) and D)

Question 11

Which of the following should have the highest surface tension at a given temperature?

Accepted Answer

A)   
B)   
C)   
D)   
E)   F) None of the above
G) A) and B)

Question 12

Hexagonal close packing of identical atoms occurs when close-packed layers are stacked in an abcabc... arrangement.

Accepted Answer

A) True 
 B)False

Question 13

In which of the following compounds will the molecules not form hydrogen bonds with each other?

Accepted Answer

A)   
B)   
C)   
D)   
E)   F) All of the above
G) None of the above

Question 14

Lead crystallizes in the face-centered cubic lattice. What is the coordination number for Pb?

Accepted Answer

A)  4
B)  6
C)  8
D)  10
E)  12F) C) and E)
G) A) and E)

Question 15

The phase diagram of a substance shows the energy changes associated with changes of state.

Accepted Answer

A) True 
 B)False

Question 16

Which of the following statements concerning a face-centered cubic unit cell and the corresponding lattice, made up of identical atoms, is incorrect?

Accepted Answer

A)  The coordination number of the atoms in the lattice is 8.
B)  The packing in this lattice is more efficient than for a body-centered cubic system.
C)  If the atoms have radius r, then the length of the cube edge is √8 × r.
D)  There are four atoms per unit cell in this type of packing.
E)  The packing efficiency in this lattice and hexagonal close packing are the same.F) A) and B)
G) D) and E)

Question 17

Octane has a vapor pressure of 40. torr at 45.1°C and 400. torr at 104.0°C. What is its heat of vaporization?

Accepted Answer

A)  39.0 kJ/mol
B)  46.0 kJ/mol
C)  590 kJ/mol
D)  710 kJ/mol
E)  None of these choices are correct.F) C) and E)
G) A) and B)

Question 18

A liquid may be made to boil at room temperature, simply by lowering the pressure.

Accepted Answer

A) True 
 B)False

Question 19

Ceramic superconductors often contain copper in unusual oxidation states.

Accepted Answer

A) True 
 B)False

Question 20

Select the pair of substances in which the one with the higher vapor pressure at a given temperature is listed first.

Accepted Answer

A)  C 7H 16, C 5H 12
B)  CCl 4, CBr 4
C)  H 2O, H 2S
D)  CH 3CH 2OH, CH 3-O-CH 3
E)  Xe, KrF) A) and C)
G) C) and D)

Exam 12: Intermolecular Forces: Liquids, Solids, and Phase Changes

Which of the following should have the highest surface tension at a given temperature?

Correct AnswerverifiedShow Answer

The phase diagram of a substance shows the energy changes associated with changes of state.

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Examine the following phase diagram and identify the feature represented by point A.

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When the electron cloud of a molecule is easily distorted, the molecule has a high

Correct AnswerverifiedShow Answer

Examine the phase diagram for the substance Bogusium (Bo) and select the correct statement.

Correct AnswerverifiedShow Answer

Which of the following statements concerning a face-centered cubic unit cell and the corresponding lattice, made up of identical atoms, is incorrect?

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Lead crystallizes in the face-centered cubic lattice. What is the coordination number for Pb?

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Which of the following statements about ceramics is incorrect?

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Ceramic superconductors often contain copper in unusual oxidation states.

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The phase diagram for xenon has a solid-liquid curve with a positive slope. Which of the following is true?

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In which of the following compounds will the molecules not form hydrogen bonds with each other?

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A liquid may be made to boil at room temperature, simply by lowering the pressure.

Correct AnswerverifiedShow Answer

Hexagonal close packing of identical atoms occurs when close-packed layers are stacked in an abcabc... arrangement.

Correct AnswerverifiedShow Answer

Octane has a vapor pressure of 40. torr at 45.1°C and 400. torr at 104.0°C. What is its heat of vaporization?

Correct AnswerverifiedShow Answer

Examine the following phase diagram and identify the feature represented by point B.

Correct AnswerverifiedShow Answer

Liquid crystal displays are most commonly constructed of smectic type liquid crystals.

Correct AnswerverifiedShow Answer

Select the pair of substances in which the one with the higher vapor pressure at a given temperature is listed first.

Correct AnswerverifiedShow Answer

What types of forces exist between molecules of CO2?

Correct AnswerverifiedShow Answer

A metal with a body-centered cubic lattice will have __________ atom(s) per unit cell.

Correct AnswerverifiedShow Answer

Diethyl ether, used as a solvent for extraction of organic compounds from aqueous solutions, has a high vapor pressure which makes it a potential fire hazard in laboratories in which it is used. How much energy is released when 100.0 g is cooled from 53.0°C to 10.0°C?

Correct AnswerverifiedShow Answer

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What types of forces exist between molecules of CO₂?

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