Question 1

Which of the following statements best explains why water has a much higher boiling point than methane ($\mathrm{CH_4}$), even though both have similar molar masses?

Accepted Answer

Water molecules form strong hydrogen bonds, while methane molecules only experience dispersion forces.

Question 2

A sample of liquid is observed to have a high surface tension and does not flow easily. Which of the following best describes the intermolecular forces present in this liquid?

Accepted Answer

The liquid has strong intermolecular forces, such as hydrogen bonding or strong dipole-dipole interactions.

Question 3

Which of the following best describes the process of condensation?

Accepted Answer

A gas is converted to a liquid, and heat is released in the process.

Question 4

Which of the following substances would you expect to have the highest boiling point, and why?

A. $\mathrm{CH_4}$
B. $\mathrm{NH_3}$
C. $\mathrm{CO_2}$
D. $\mathrm{C_2H_6}$

Accepted Answer

$\mathrm{NH_3}$, because it can form hydrogen bonds.

Question 5

A 50.0 g sample of water at $100\ ^\circ\mathrm{C}$ is completely vaporized. Given that the heat of vaporization of water at $100\ ^\circ\mathrm{C}$ is $40.7\ \mathrm{kJ/mol}$, how much heat (in kJ) is required? ($\mathrm{Molar\ mass\ of\ H_2O = 18.02\ g/mol}$)

Accepted Answer

$113\ \mathrm{kJ}$

Question 6

Which of the following best explains why oil and water do not mix?

Accepted Answer

Oil is nonpolar and water is polar, so their intermolecular forces are not compatible.

Question 7

Which of the following statements about the vapor pressure of a liquid is correct?

Accepted Answer

Vapor pressure increases with increasing temperature and decreases with increasing strength of intermolecular forces.

Question 8

Which type of crystalline solid is table salt ($\mathrm{NaCl}$), and what is the primary force holding it together?

Accepted Answer

Ionic solid; held together by electrostatic attraction between cations and anions.

Question 9

Which of the following best describes the difference between a crystalline and an amorphous solid?

Accepted Answer

A crystalline solid has a well-ordered, repeating arrangement of atoms or molecules, while an amorphous solid lacks long-range order.

Question 10

Which of the following substances would you expect to have the lowest melting point?

A. $\mathrm{NaCl}$
B. $\mathrm{H_2O}$ (ice)
C. $\mathrm{CO_2}$ (dry ice)
D. Diamond (C)

Accepted Answer

$\mathrm{CO_2}$ (dry ice), because it is a molecular solid held together only by dispersion forces.

Question 11

Which of the following is NOT a manifestation of intermolecular forces in liquids?

Accepted Answer

Electrical conductivity

Question 12

A 15.5 g ice cube at $0\ ^\circ\mathrm{C}$ melts completely. Given the heat of fusion for water is $6.02\ \mathrm{kJ/mol}$, how much heat (in kJ) is absorbed? ($\mathrm{Molar\ mass\ of\ H_2O = 18.02\ g/mol}$)

Accepted Answer

$5.18\ \mathrm{kJ}$

Question 13

Which of the following best explains why sweating cools the human body?

Accepted Answer

Evaporation of sweat is endothermic, absorbing heat from the skin.

Question 14

Which of the following molecules can form hydrogen bonds with itself?

A. $\mathrm{CH_4}$
B. $\mathrm{H_2O}$
C. $\mathrm{CO_2}$
D. $\mathrm{C_2H_6}$

Accepted Answer

$\mathrm{H_2O}$

Question 15

Which of the following statements about dispersion forces is correct?

Accepted Answer

Dispersion forces increase with increasing molar mass and size of the electron cloud.

Question 16

Which of the following best describes the process of sublimation?

Accepted Answer

A solid changes directly to a gas without passing through the liquid state.

Question 17

Which of the following is a correct statement about the boiling point of a liquid?

Accepted Answer

At the boiling point, the vapor pressure of the liquid equals the external pressure.

Question 18

Which of the following best explains why diamond has such a high melting point?

Accepted Answer

Diamond is a covalent atomic solid, with each carbon atom bonded to four others in a three-dimensional network.

Liquids, Solids, and Intermolecular Forces: Chapter 12 Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards