Question 1

Which of the following best describes what happens to the temperature of a substance during a phase change, such as melting or boiling, even as heat continues to be added?

Accepted Answer

The temperature remains constant.

Question 2

During the boiling of water, which type of bonds are broken?

Accepted Answer

Hydrogen bonds between water molecules

Question 3

Which of the following substances is most likely to sublime at standard temperature and pressure (STP)?

Accepted Answer

Carbon dioxide (CO$$_2)$$

Question 4

What is the main reason that water boils at a lower temperature on top of Mount Everest compared to sea level?

Accepted Answer

The atmospheric pressure is lower at high altitude.

Question 5

Which process describes the direct transition from a solid to a gas?

Accepted Answer

Sublimation

Question 6

A puddle of water slowly disappears on a warm day. Which process is primarily responsible for this observation?

Accepted Answer

Evaporation

Question 7

Which of the following statements about evaporation and boiling is correct?

Accepted Answer

Evaporation occurs at the surface and below the boiling point.

Question 8

What is the definition of the normal boiling point of a liquid?

Accepted Answer

The temperature at which a liquid boils at 1 atm (101.3 kPa) pressure.

Question 9

Which of the following best explains why naphthalene (C$$_{10}H$_8) $$sublimes at room temperature?

Accepted Answer

It has weak London dispersion forces.

Question 10

What is dynamic equilibrium in a closed container of liquid and its vapor?

Accepted Answer

The rates of evaporation and condensation are equal.

Question 11

Which of the following best describes what happens at the triple point of a substance?

Accepted Answer

Solid, liquid, and gas phases all exist together in equilibrium.

Question 12

Which of the following would increase the rate of evaporation of a liquid?

Accepted Answer

Increasing the surface area and temperature

Question 13

Which of the following best explains why dry ice (solid CO$$_2) is $$used to keep items cold during shipping?

Accepted Answer

It sublimes directly into a gas, absorbing heat from the surroundings.

Question 14

Which of the following is true about the boiling point of a liquid at high altitude?

Accepted Answer

It is lower than at sea level.

Question 15

Which of the following best describes what happens to the kinetic energy of particles as a solid is heated from below its melting point to above its melting point?

Accepted Answer

Kinetic energy increases before and after melting, but remains constant during the phase change.

Question 16

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

Accepted Answer

A substance with hydrogen bonding

Question 17

Which process is the reverse of sublimation?

Accepted Answer

Deposition

Question 18

A phase diagram shows the regions of solid, liquid, and gas for a substance. What does the line separating the solid and liquid regions represent?

Accepted Answer

The melting/freezing point

Question 19

Which of the following best explains why frost forms on a window during a cold night?

Accepted Answer

Water vapor in the air loses energy and deposits directly as ice.

Question 20

Which of the following best describes what happens to the temperature of water as it boils at constant atmospheric pressure?

Accepted Answer

The temperature remains constant until all the water has vaporized.

Phase Changes, Energy, and Intermolecular Forces: Study Notes for Introductory Chemistry

Study Guide - Practice Questions

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