States of Matter click here to see animations of a solid, liquid and gas

Solids There is a strong force of attraction between the particles The particles are packed tightly together The only motion is vibration. A solid has a definite shape and volume Solids are not compressible because the particles are so tightly packed.

Crystalline Solids Crystalline solids are solids with an orderly, three dimensional arrangement of particles with repeating rows. Examples are: ice, iron, salt and diamonds. These solids tend to be harder and more rigid, with no compressibility.

Amorphous Solids Amorphous solids are solids whose particles are arranged randomly and have no specific arrangement or organized pattern. Examples are rubber, glass, plastic and wax. These solids tend to be flexible

Liquids The force of attraction between the particles is somewhat strong, but not as strong as that of solids The particles are close together, almost as close as a solid But the particles are free to move and slide past each other A liquid has a definite volume, but no definite shape so a liquid takes the shape of its container Liquids are considered not compressible because the particles are so close together

Gases There is no force of attraction between the particles Gas particles are far apart The high energy particles move freely A gas has no definite shape and no definite volume. Gases are very compressible due to the great space between the particles

More Animations Solids, liquids and gases in containers Molecular level phases

Changes of State (Phase Changes) – When matter changes from one state of matter to another. Melting (Solid to Liquid) Condensation (Gas to Liquid) Freezing (Liquid to Solid) Vaporization (Liquid to Gas) Sublimation (Solid to Gas) *Dry Ice-Solid CO 2 Deposition (Gas to Solid) *Water Vapor to Ice – On windows in the winter.

Evaporation vs. Boiling Both are a form of vaporization (liquid  gas) Evaporation happens at the surface of the liquid below the boiling point. (How can you speed-up evaporation?) Boiling happens throughout the liquid at the boiling point.

Adding Energy Phase changes that require the addition of energy are called endothermic changes. (endo = inside, therm = heat) Which phase changes are endothermic? –Melting (solid  liquid) –Vaporization (liquid  gas) –Sublimation (solid  gas)

Removing Energy Phase changes that require the removal of energy are called exothermic changes. (exo = outside, therm = heat) Which phase changes are exothermic? –Freezing (liquid  solid) –Condensation (gas  liquid) –Deposition (reverse sublimation) (gas  solid)

Characteristic Properties m.p. – the temperature at which S  L f.p – the temperature at which L  S b.p. - the temperature at which L  G c.p. - the temperature at which G  L m.p=f.p.and b.p.=c.p. The temperatures at which substances change state are characteristic properties and can be used to identify substances.

Changing the State of Water: qU&feature=related

Heat (thermal energy) Temperature º C A B C D E solid liquid gas Water Phase Change Graph

Heat (thermal energy) Temperature º C A B C D E solid liquid gas

Heat (thermal energy) Temperature º C A B C D E melting freezing condensing boiling Adding Heat - Endothermic Removing Heat - Exothermic