Particle theory

1. Particle theory • All matter is made up of very small particles. • All particles in a pure substance are the same. • There is space between the particles. • The particles are always moving. • The particles in a substance are attracted to each other. The strength of the attraction depends upon the type of particle.

3. Gases • Particles not in any organized pattern • Particles move freely and very quickly • Can be compressed • Takes up space and has weight • Try's to take up all of the space available in container

4. Liquids • Molecules not in a fixed order or location • Molecules move freely, but slowly • Cannot be compressed easily • Can Flow • Takes the shape of the container it is poured into

5. Liquids and Cohesion • Molecules in matter are attracted to each other. • Solid state has the highest level of cohesion. • In a liquid state molecules want to be attached to each other. This is why we see water droplets trying to remain together.

6. Solid • Particles in a fixed order and location • Particles can only move in their fixed location (they vibrate) • Cannot be compressed • Cannot flow

7. Phase Changes of Matter

8. Water Phase Change Graph E D 100 gas C Temperature º C. liquid B 0 A solid Time (minutes)

9. E D 100 gas C Temperature º C. liquid B 0 A solid Time (minutes)

10. E D condensing 100 evaporating C Temperature º C. B freezing 0 melting A Time (minutes)

11. 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 CO2 Deposition (Gas to Solid) *Water Vapor to Ice – On windows in the winter.

12. 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)

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

14. Heat and Particle Theory • Heat of fusion – The amount of energy required to turn a sample of solid matter into a liquid (ex. Ice to water) • Heat of Vaporization – The amount of energy required to turn a sample of liquid matter into a gas

15. Temperature and Theory of Kinetic Energy • Kinetic Energy – Energy produced by the constant motion and collision of particles of matter • - Temperature – The measure of the amount of kinetic energy in matter • How are Kinetic Energy and Temperature related?

16. Density of solids, liquids & Gases • Does water as a liquid, water a solid, or water as a gas have the highest density? Explain.

17. Density • Density can be described as the “crowdedness” of the particles that make up matter. • When you describe something as being “heavy” or “light” you are referring to that something’s density. • Each substance has its own, unique density. • The closer the particles are together in a substance, the higher its density is.