Question 1

Ceramic superconductors often contain copper in unusual oxidation states.

Accepted Answer

A) True 
 B)False

Question 2

Pentane, C5H12, boils at 35°C. Which of the following is true about kinetic energy, Ek, and potential energy, Ep, when liquid pentane at 35°C is compared with pentane vapor at 35°C?

Accepted Answer

A)   Ek(g)  k(l) ; Ep(g)   Ep(l) 
B)   Ek(g)  > Ek(l) ; Ep(g)   Ep(l) 
C)   Ep(g)  p(l) ; Ek(g)   Ek(l) 
D)   Ep(g)  > Ep(l) ; Ek(g)   Ek(l) 
E)   Ep(g)   Ep(l) ; Ek(g)   Ek(l) F) B) and D)
G) A) and B)

Question 3

The strongest intermolecular interactions between pentane (C5H12)  molecules arise from

Accepted Answer

A)   dipole-dipole forces.
B)   London dispersion forces.
C)   hydrogen bonding.
D)   ion-dipole interactions.
E)   carbon-carbon bonds.F) All of the above
G) C) and D)

Question 4

Which one of the following substances will have hydrogen bonds between molecules?

Accepted Answer

A)   (CH3) 3N
B)   CH3-O-CH3
C)   CH3CH2-OH
D)   CH3CH2-F
E)   HIF) A) and D)
G) B) and C)

Question 5

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

Accepted Answer

A) True 
 B)False

Question 6

Comparing the energies of the following intermolecular forces on a kJ/mol basis, which would normally have the highest energy (i.e., be the strongest force) ?

Accepted Answer

A)   ion-induced dipole
B)   dipole-induced dipole
C)   ion-dipole
D)   dipole-dipole
E)   dispersionF) C) and D)
G) C) and E)

Question 7

A single water molecule can participate in at most two hydrogen bonds at any instant.

Accepted Answer

A) True 
 B)False

Question 8

The coordination number of sodium and chloride ions in the NaCl lattice, are, respectively:

Accepted Answer

A)   10 and 10
B)   8 and 8
C)   6 and 6
D)   4 and 4
E)   none of the aboveF) B) and E)
G) B) and C)

Question 9

In metals, the conduction bands and valence bands of the molecular orbitals are separated by a large energy gap.

Accepted Answer

A) True 
 B)False

Question 10

Which of the following statements about the packing of monatomic solids with different unit cells is incorrect?

Accepted Answer

A)   The coordination number of atoms in hcp and fcc structures is 12.
B)   The coordination number of atoms in simple cubic structures is 6.
C)   The coordination number of atoms in bcc structures is 8.
D)   A bcc structure has a higher packing efficiency than a simple cubic structure.
E)   A bcc structure has a higher packing efficiency than a fcc structure.F) A) and D)
G) A) and E)

Question 11

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

Question 12

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

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) B) and C)
G) D) and E)

Question 14

List the three common classes of liquid crystals in order of decreasing degree of order.

Accepted Answer

smectic > ...

Question 15

Which of the following pairs of substances is arranged so that the one with higher viscosity is listed first?

Accepted Answer

A)   A
B)   B
C)   C
D)   D
E)   EF) A) and E)
G) D) and E)

Question 16

A cubic unit cell has an edge length of 400. pm. The length of its body diagonal (internal diagonal)  in pm is therefore

Accepted Answer

A)   512.
B)   566.
C)   631.
D)   693.
E)   724.F) B) and E)
G) A) and E)

Question 17

The normal boiling point of ether is 307.8 K. Calculate the temperature at which its vapor pressure is exactly half of that at its normal boiling point. The heat of vaporization for ether is 26.69 kJ/mol.

Accepted Answer

A)   305 K
B)   302 K
C)   295 K
D)   289 K
E)   281 KF) A) and D)
G) A) and B)

Question 18

Which of the following should have the lowest boiling point?

Accepted Answer

A)   C5H12
B)   C6H14
C)   C8H18
D)   C10H22
E)   C12H26F) All of the above
G) C) and E)

Question 19

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 the above statements is true.F) A) and E)
G) B) and C)

Question 20

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

Accepted Answer

A)   
B)   
C)   
D)   
E)   F) A) and C)
G) A) and B)

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

The normal boiling point of ether is 307.8 K. Calculate the temperature at which its vapor pressure is exactly half of that at its normal boiling point. The heat of vaporization for ether is 26.69 kJ/mol.

Correct AnswerverifiedShow Answer

A single water molecule can participate in at most two hydrogen bonds at any instant.

Correct AnswerverifiedShow Answer

In metals, the conduction bands and valence bands of the molecular orbitals are separated by a large energy gap.

Correct AnswerverifiedShow Answer

Which one of the following substances will have hydrogen bonds between molecules?

Correct AnswerverifiedShow Answer

Ceramic superconductors often contain copper in unusual oxidation states.

Correct AnswerverifiedShow Answer

The coordination number of sodium and chloride ions in the NaCl lattice, are, respectively:

Correct AnswerverifiedShow Answer

Which of the following should have the lowest boiling point?

Correct AnswerverifiedShow Answer

A cubic unit cell has an edge length of 400. pm. The length of its body diagonal (internal diagonal) in pm is therefore

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

What types of forces exist between molecules of CO2?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which of the following statements about ceramics is incorrect?

Correct AnswerverifiedShow Answer

Comparing the energies of the following intermolecular forces on a kJ/mol basis, which would normally have the highest energy (i.e., be the strongest force) ?

Correct AnswerverifiedShow Answer

Pentane, C5H12, boils at 35°C. Which of the following is true about kinetic energy, Ek, and potential energy, Ep, when liquid pentane at 35°C is compared with pentane vapor at 35°C?

Correct AnswerverifiedShow Answer

The strongest intermolecular interactions between pentane (C5H12) molecules arise from

Correct AnswerverifiedShow Answer

Which of the following statements about the packing of monatomic solids with different unit cells is incorrect?

Correct AnswerverifiedShow Answer

Which of the following pairs of substances is arranged so that the one with higher viscosity is listed first?

Correct AnswerverifiedShow Answer

List the three common classes of liquid crystals in order of decreasing degree of order.

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What types of forces exist between molecules of CO₂?

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Pentane, C₅H₁₂, boils at 35°C. Which of the following is true about kinetic energy, E_k, and potential energy, E_p, when liquid pentane at 35°C is compared with pentane vapor at 35°C?

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The strongest intermolecular interactions between pentane (C₅H₁₂) molecules arise from

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