Chapter 3 Section 3: Phase Changes

What is a phase change?

A phase change is the reversible physical change that takes place when a substance changes from one state of matter to another.

The phase change in which a substance changes from a gas into a liquid is called _____________

Condensation

What is deposition?

Deposition is the phase change in which a substance changes directly from a gas to a solid without changing to a liquid first.

the process that changes a substance from a liquid to a gas at temperatures below the substance's boiling point.

Evaporation

Dry ice can change directly from a solid to a gas without forming a liquid first. This process is an example of ______________________

Sublimation

What happens to the temperature of a substance during a phase change?

The temperature of a substance remains constant during a phase change.

the pressure caused by the collisions of particles in a vapor with the walls of a container.

Vapor Pressure

When liquid water freezes, the average kinetic energy of its molecules_____________ , and the arrangement of the molecules becomes more orderly.

decreases

What describes the behavior of a substance during a phase change.

either absorbs or releases energy.

A substance absorbs energy from its surroundings during a(n) ______________change.

endothermic

As water freezes, it releases heat to its surroundings. Freezing is an example of a(n) ___________ change.

exothermic

Is the following sentence TRUE or FALSE? A gas absorbs energy as it changes into a liquid.

false

Is the following sentence TRUE or FALSE? The temperature at which a substance freezes is lower than the temperature at which it melts.

false

The energy absorbed by one gram of ice as it melts is known as the______________ for water.

heat of fusion (334 J for one gram of ice to become water)

The energy absorbed by one gram of water as it changes from its liquid phase into water vapor is known as the ______________________for water

heat of vaporization (2260 J for one gram of water)

Vaporization is the phase change in which a substance changes from a(n)_____ into_______a(n) .

liquid; gas

Is the following sentence TRUE or FALSE? Water molecules have a more orderly arrangement in ice than in liquid water.

true

Is the following sentence TRUE or FALSE? When water vapor collects above the liquid in a closed container, the pressure caused by the collisions of this vapor and the walls of the container is called vapor pressure.

true