Unit 2 Phase Changes Flashcard Review

Front

What is a phase change?

Back

A phase change is a transition of matter from one state (solid, liquid, gas) to another due to the addition or removal of energy.

Front

What happens to the molecules of a substance when it absorbs energy during a phase change?

Back

The molecules move faster and may transition to a higher energy state, such as from solid to liquid or liquid to gas.

Front

What happens to the molecules of a substance when it loses energy during a phase change?

Back

The molecules move slower and may transition to a lower energy state, such as from gas to liquid or liquid to solid.

Front

What is the difference between a solid, liquid, and gas in terms of molecular movement?

Back

In solids, molecules vibrate in place; in liquids, molecules move around each other; in gases, molecules move freely and are far apart.

Front

How does temperature affect the phase of a substance?

Back

Increasing temperature generally causes substances to absorb energy and change to a gas, while decreasing temperature causes them to lose energy and change to a solid.

Front

What is the role of energy in phase changes?

Back

Energy is required to overcome intermolecular forces during a phase change; adding energy can cause melting or vaporization, while removing energy can cause freezing or condensation.

Front

What is the significance of intermolecular forces in phase changes?

Back

Intermolecular forces determine the state of matter; stronger forces result in solids or liquids, while weaker forces allow for gases.

Front

What occurs during condensation?

Back

During condensation, a gas loses energy and transitions to a liquid state, causing the molecules to move closer together.

Front

What is evaporation?

Back

Evaporation is the process where molecules at the surface of a liquid gain enough energy to enter the gas phase.

Front

What is sublimation?

Back

Sublimation is the phase change in which a solid transitions directly to a gas without passing through the liquid phase.