Properties of Matter Properties of Matter

Extensive and Intensive Properties Extensive and Intensive Properties

Physical and Chemical PropertiesPhysical and Chemical Properties

Physical change: a change in the physical properties of a substance.

Chemical change: the transformation of one or more substances into others.

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Phases of MatterPhases of Matter

Solid (s) ------ Liquid (l) --------- Gas (g)

Phases: ‘physical state’

Solids

Definite volume and shape

Liquids

Definite volume, but form determined by container it is in

Gases

No definite volume or shape

Solids

Strong attraction between molecules- fixed position (vibrate)

Heat breaks fixed arrangement

Liquids

Molecules ‘flow’

Gases

Heat causes attractions between individual molecules to be broken

Move in random manner

Bump into the container – ‘pressure’

Submicroscopic Level Submicroscopic Level

DiffusionDiffusion

Gas molecules continue to move and bump into each other

Move from higher concentration areas to lower areas of concentration

Occurs in:

Gases, liquids

Diffusion Animation

Phase ChangesPhase Changes

Animation

Process of EvaporationProcess of Evaporation

Molecules are heated below the surface, gain kinetic energy and bump into molecules at the surface

Surface molecules are released (attraction to other molecules broken)

Why is this a cooling process?The slower moving molecules left behind (lower temperature) cools the air or body (perspiration)

CondensationCondensationThis is a warming process

Why?

Gas particles cool and reach the surface. Kinetic energy absorbed by surface molecules. Molecules form attractions

This increases temperature