Phase Change 3 701

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 molecules during a phase change from solid to liquid?

Back

The molecules gain energy, move faster, and overcome some of the attractions between them, allowing them to flow.

Front

What happens to molecules during a phase change from liquid to gas?

Back

The molecules gain enough energy to completely overcome the attractions between them and move freely apart.

Front

What happens to molecules during a phase change from gas to liquid?

Back

The molecules lose energy, move slower, and come closer together, forming a liquid.

Front

What happens to molecules during a phase change from liquid to solid?

Back

The molecules lose energy, move slower, and are held closely together in a fixed position.

Front

What is the effect of temperature on phase changes?

Back

Increasing temperature generally adds energy, causing substances to change from solid to liquid to gas, while decreasing temperature removes energy, causing the reverse.

Front

What is the role of energy in phase changes?

Back

Energy is required to change the state of a substance; adding energy can cause melting or vaporization, while removing energy can cause freezing or condensation.

Front

What is melting?

Back

Melting is the phase change from solid to liquid that occurs when a substance absorbs heat.

Front

What is freezing?

Back

Freezing is the phase change from liquid to solid that occurs when a substance loses heat.

Front

What is evaporation?

Back

Evaporation is the process where liquid turns into gas at temperatures below boiling point, usually occurring at the surface of the liquid.