Question 1

A certain solid metallic element has a density 7.87 g/cm3 and a molar mass of 55.85 g/mol. It crystallizes with a cubic unit cell, with an edge length of 286.7 pm. Calculate the number of atoms per unit cell.

Accepted Answer

A)   1
B)   2
C)   3
D)   4
E)   6F) A) and B)
G) B) and E)

Question 2

What word best describes the type of liquid crystal represented below?

Accepted Answer

A)   nematic
B)   cholesteric
C)   smectic
D)   isotropic
E)   elasticF) A) and B)
G) C) and E) A

Question 3

Which of the following factors contributes to a low viscosity for a liquid?

Accepted Answer

A)   low temperature
B)   spherical molecular shape
C)   hydrogen bonding
D)   high molecular weight
E)   high boiling pointF) A) and C)
G) C) and D)

Question 4

A temperature increase causes __________________ in the conductivity of a semiconductor.

Accepted Answer

A)   a decrease
B)   an increase
C)   a modulation
D)   an increase or decrease (depending on the semiconductor) 
E)   no changeF) A) and C)
G) B) and C)

Question 5

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 E)
G) B) and C) C

Question 6

Liquid sodium can be used as a heat transfer fluid. Its vapor pressure is 40.0 torr at 633°C and 400.0 torr at 823°C. Calculate its heat of vaporization.

Accepted Answer

A)   43.4 kJ/mol
B)   52.5 kJ/mol
C)   70.6 kJ/mol
D)   1.00 × 102 kJ/mol
E)   None of these choices are correct.F) A) and E)
G) None of the above

Question 7

In hydrogen iodide __________________ are the most important intermolecular forces.

Accepted Answer

A)   dipole-dipole forces
B)   London dispersion forces
C)   hydrogen bonding
D)   covalent bonds
E)   polar covalent bondsF) A) and B)
G) B) and D)

Question 8

The Clausius-Clapeyron equation is used in calculations of

Accepted Answer

A)   melting and freezing points.
B)   vapor pressures of liquids.
C)   osmotic pressures of solutions.
D)   heats of vaporization at different temperatures.
E)   crystal structure.F) A) and E)
G) C) and D)

Question 9

When liquid bromine is cooled to form a solid, which of the following types of solid would it form?

Accepted Answer

A)   atomic
B)   metallic
C)   molecular
D)   ionic
E)   covalent networkF) A) and E)
G) A) and C) C

Question 10

Which one of the following statements about unit cells and packing in solids is incorrect?

Accepted Answer

A)   In any unit cell of a solid crystal, each face of the cell must have an opposite face which is equal and parallel to it.
B)   The faces of a unit cell must all be at angles of 90° to each other.
C)   The coordination number of atoms in a close packed metal is 12.
D)   The packing efficiency in fcc structures is higher than in bcc structures.
E)   The packing efficiency in fcc and hcp structures is the same.F) A) and B)
G) B) and C)

Question 11

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 D)
G) C) and E)

Question 12

The strongest intermolecular interactions between ethyl alcohol (CH3CH2OH)  molecules arise from

Accepted Answer

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

Question 13

Which of the following properties measures the energy needed to increase the surface area of a liquid?

Accepted Answer

A)   capillary action
B)   surface tension
C)   viscosity
D)   cohesion
E)   specific elasticityF) C) and D)
G) C) and E)

Question 14

Ceramic superconductors often contain copper in unusual oxidation states.

Accepted Answer

A) True 
 B)False

Question 15

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) D) and E)
G) A) and D)

Question 16

The meniscus of mercury in a glass capillary tube is convex because of

Accepted Answer

A)   the very high density of mercury as compared with water.
B)   the low surface tension of mercury.
C)   the greater attraction of mercury atoms to the glass than to each other.
D)   the weaker attraction of mercury atoms to the glass than to each other.
E)   electrostatic repulsion between the glass and the mercury.F) A) and C)
G) B) and E)

Question 17

Which of the following atoms should have the smallest polarizability?

Accepted Answer

A)   Si
B)   S
C)   Te
D)   Bi
E)   BrF) C) and D)
G) A) and E)

Question 18

Crystal structures may be conveniently measured using

Accepted Answer

A)   X-ray diffraction.
B)   infrared spectroscopy.
C)   ultraviolet-visible spectroscopy.
D)   microwave spectroscopy.
E)   magnetic resonance imaging.F) A) and E)
G) C) and D)

Question 19

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

Accepted Answer

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

Question 20

A temperature increase causes __________________ in the conductivity of a conductor.

Accepted Answer

A)   a decrease
B)   an increase
C)   an increase or decrease (depending on the conductor) 
D)   a modulation
E)   no changeF) C) and E)
G) A) and E)

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

A certain solid metallic element has a density 7.87 g/cm3 and a molar mass of 55.85 g/mol. It crystallizes with a cubic unit cell, with an edge length of 286.7 pm. Calculate the number of atoms per unit cell.

Correct AnswerverifiedShow Answer

What word best describes the type of liquid crystal represented below?

Correct AnswerverifiedA

Which of the following factors contributes to a low viscosity for a liquid?

Correct AnswerverifiedShow Answer

A temperature increase causes __________________ in the conductivity of a semiconductor.

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 AnswerverifiedC

Liquid sodium can be used as a heat transfer fluid. Its vapor pressure is 40.0 torr at 633°C and 400.0 torr at 823°C. Calculate its heat of vaporization.

Correct AnswerverifiedShow Answer

In hydrogen iodide __________________ are the most important intermolecular forces.

Correct AnswerverifiedShow Answer

The Clausius-Clapeyron equation is used in calculations of

Correct AnswerverifiedShow Answer

When liquid bromine is cooled to form a solid, which of the following types of solid would it form?

Correct AnswerverifiedC

Which one of the following statements about unit cells and packing in solids is incorrect?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

The strongest intermolecular interactions between ethyl alcohol (CH3CH2OH) molecules arise from

Correct AnswerverifiedShow Answer

Which of the following properties measures the energy needed to increase the surface area of a liquid?

Correct AnswerverifiedShow Answer

Ceramic superconductors often contain copper in unusual oxidation states.

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?

Correct AnswerverifiedShow Answer

The meniscus of mercury in a glass capillary tube is convex because of

Correct AnswerverifiedShow Answer

Which of the following atoms should have the smallest polarizability?

Correct AnswerverifiedShow Answer

Crystal structures may be conveniently measured using

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

A temperature increase causes __________________ in the conductivity of a conductor.

Correct AnswerverifiedShow Answer

A certain solid metallic element has a density 7.87 g/cm³ and a molar mass of 55.85 g/mol. It crystallizes with a cubic unit cell, with an edge length of 286.7 pm. Calculate the number of atoms per unit cell.

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A

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C

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C

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The strongest intermolecular interactions between ethyl alcohol (CH₃CH₂OH) molecules arise from

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