SOLIDS

PropertiesSolid particles have fixed positions

Particles are very close together

Solids have fixed shapes and fixed volumes

Usually exist in crystalline form

Solid Crystals

Can be very brittle, like salt

Can be very soft, like lead

Changing StatesDeposition (Frost forming)

◦Molecules in the gaseous state become part of the surface of a crystal

Sublimation◦Process in which a solid changes directly

into a gas◦Exothermic process

◦Energy released in decomposition is equal to the energy required for sublimation

Freezing◦Change in state in which a liquid

becomes a solid as heat is removed◦Exothermic process releases energy

Melting◦The change in state in which a solid

becomes a liquid by adding or changing pressure

◦Melting point and Freezing point are the same for pure substances

LIQUIDSParticles can move easily past each

other

Are fluids

Have fixed volumes, but take the shape of the container placed in

Liquid ForcesCohesion

◦Attraction for each other Water molecules stick each other

Adhesion◦Attraction for particles of solid

surfaces Water molecules do not stick to car wax

Combine the two and get capillary action

Surface TensionForce that acts on the surface of

a liquid and that tends to minimize the area of the surface

Liquids tend to decrease their surface area to the smallest possible size

Why liquids for spherical shapes (Drops), smallest surface area for a volume

Changing StatesCondensation

◦Gas becomes a liquid

Evaporation◦Liquid becomes a gas◦Endothermic process◦Boiling Point- temperature and

pressure when a liquid and gas are at equilibrium