Solid, liquid and gas

What are the three states of matter and how do their particles differ?

Solid: particles fixed and very close.

Liquid: particles close but move randomly.

Gas: particles far apart and move randomly.

How do solids, liquids, and gases differ in shape and volume?

Solid: definite shape + volume.

Liquid: definite volume but takes container's shape.

Gas: takes both the shape and volume of its container.

How do intermolecular forces compare between the three states?

Solid: very strong → liquid: strong → gas: essentially none.

What is evaporation/vaporization?

Liquid → gas.

Molecules with enough kinetic energy escape from the surface by overcoming intermolecular forces.

It is endothermic and requires heat.

Why does evaporation cool a substance or your skin?

Higher-energy molecules escape, and vaporization requires heat, removing energy from what remains.

What is condensation?

Gas → liquid.

Intermolecular forces form and energy is released.

What is a closed system?

A system where matter cannot enter or leave.

What is dynamic equilibrium between a liquid and its vapor?

Vaporization and condensation continue happening, but their rates are equal, so the amounts of liquid and vapor remain constant.

What are the six phase changes?

Melting: solid → liquid

Freezing: liquid → solid

Vaporization: liquid → gas

Condensation: gas → liquid

Sublimation: solid → gas

Deposition: gas → solid

Which phase changes are endothermic vs. exothermic?

Endothermic (energy absorbed): melting, vaporization, sublimation.

Exothermic (energy released): freezing, condensation, deposition.

What happens to the system's energy when going solid → liquid → gas?

Energy increases.

Going gas → liquid → solid: energy decreases.

ADD energy

S → L → G

Melting → Vaporization → Sublimation

REMOVE energy

G → L → S

Condensation → Freezing → Deposition