Question 1

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 bonds

Question 2

The surface tension of water is lowered when a detergent is present in solution.

Accepted Answer

A) True 
 B)False

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.

Question 4

Smectic liquid crystals are more highly ordered than either nematic or cholesteric liquid crystals.

Accepted Answer

A) True 
 B)False

Question 5

Which of the following atoms should have the greatest polarizability?

Accepted Answer

A)   F
B)   Br
C)   Po
D)   Pb
E)   He

Question 6

How do the electrical properties of semiconductors differ from those of metals?

Accepted Answer

Metals are good conductors who...

Question 7

Which one of the following quantities is generally not obtainable from a single heating or cooling curve of a substance, measured at atmospheric pressure?

Accepted Answer

A)   melting point
B)   boiling point
C)   triple point
D)   heat of fusion
E)   heat of vaporization

Question 8

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  * 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.

Question 9

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.

Question 10

Liquid sodium can be used as a heat transfer fluid. Its vapor pressure is 40.0 torr at 633 °\degree° C and 400.0 torr at 823 °\degree° 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 is correct.

Question 11

Which of the following should have the highest boiling point?

Accepted Answer

A)   CF4
B)   CCl4
C)   CBr4
D)   CI4
E)   CH4

Question 12

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

Accepted Answer

A)   
B)   
C)   
D)   
E)

Question 13

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

Accepted Answer

A)   Ek(g)  k(l) ; Ep(g)   ≈\approx≈  Ep(l) 
B)   Ek(g)  > Ek(l) ; Ep(g)   ≈\approx≈  Ep(l) 
C)   Ep(g)  p(l) ; Ek(g)   ≈\approx≈ Ek(l) 
D)   Ep(g)  > Ep(l) ; Ek(g)   ≈\approx≈ Ek(l) 
E)   Ep(g)   ≈\approx≈ Ep(l) ; Ek(g)   ≈\approx≈ Ek(l)

Question 14

When identical particles pack in a simple cubic lattice, there is/are ____ particle(s)  per unit cell.

Accepted Answer

A)   1
B)   2
C)   3
D)   4
E)   8

Question 15

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)   12

Question 16

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 point

Question 17

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)   6

Question 18

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)   dispersion

Question 19

Which of the following has a boiling point which does not fit the general trend?

Accepted Answer

A)   NH3
B)   PH3
C)   AsH3
D)   SbH3
E)   BiH3

Question 20

Germanium is a semiconductor. With the aid of diagrams showing bands of molecular orbital, explain why it is a poor conductor and how doping it with phosphorus increases its conductivity.

Accepted Answer

In pure Ge, very few electrons have suff...

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

Germanium is a semiconductor. With the aid of diagrams showing bands of molecular orbital, explain why it is a poor conductor and how doping it with phosphorus increases its conductivity.

Correct AnswerverifiedIn pure Ge, very few electrons have suff...View AnswerShow Answer

In hydrogen iodide __________________ are the most important intermolecular forces.

Correct AnswerverifiedShow Answer

The surface tension of water is lowered when a detergent is present in solution.

Correct AnswerverifiedShow Answer

Which one of the following quantities is generally not obtainable from a single heating or cooling curve of a substance, measured at atmospheric pressure?

Correct AnswerverifiedShow Answer

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

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

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

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

Correct AnswerverifiedShow Answer

Which of the following has a boiling point which does not fit the general trend?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

How do the electrical properties of semiconductors differ from those of metals?

Correct AnswerverifiedMetals are good conductors who...View AnswerShow Answer

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

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

Which of the following atoms should have the greatest polarizability?

Correct AnswerverifiedShow Answer

Smectic liquid crystals are more highly ordered than either nematic or cholesteric liquid crystals.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which of the following should have the highest boiling point?

Correct AnswerverifiedShow Answer

When identical particles pack in a simple cubic lattice, there is/are ____ particle(s) per unit cell.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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In pure Ge, very few electrons have suff...
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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 Answer
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The strongest intermolecular interactions between ethyl alcohol (CH₃CH₂OH) molecules arise from

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

Correct Answer
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Metals are good conductors who...
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Pentane, C₅H₁₂, boils at 35 $\degree$ C. Which of the following is true about kinetic energy, E_k, and potential energy, E_p, when liquid pentane at 35 $\degree$ C is compared with pentane vapor at 35 $\degree$ C?

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

Correct Answer
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