Changes of State

What are the three states matter can exist in

Solid, Liquid, and Gas

What causes a substance to change from one state to another?

Changes in temperature (and sometimes pressure) can cause a substance to change from one state to another

At what temperature does water melt (solid to liquid)?

0°C

At what temperature does water freeze (liquid to solid)?

0°C (same as melting point)

At what temperature does water boil or turn into vapor (liquid to gas)?

100°C

At what temperature does water condense (gas to liquid)?

100°C (same as boiling point)

Are changes of state— chemical or physical?

They are physical changes AS no new substance is formed

Why are melting point and boiling point considered physical properties?

Because they describe changes in state without altering the chemical composition of a substance.

Do water, ice, and steam have different chemical formulas?

No, they are all H₂O — just in different physical states.

What happens to the chemical identity of a substance during a change of state?

It stays the same— only the physical form changes.