2. Unit 5 Section 2 Notes Matter and Energy

3. Kinetic Theory of Matter:  Useful for seeing differences in the 3 common states of matter on earth: solid, liquid, and gas.

4. Kinetic Theory of Matter 3 Main Points 1.All matter is made of atoms and molecules which act like tiny particles that are always in motion. 2.The higher the temperature, the faster the particles move. 3.At the same temperature, heavier particles move slower than lighter particles.

5. Kinetic Theory  Using the Kinetic Theory of matter, explain why a balloon filled with helium goes flat faster than one filled with regular air.  According to the Kinetic Theory, at the same temperature, heavier particles move slower than lighter particles. Since oxygen & carbon dioxide are more massive than helium, they don’t escape out of the tiny microscopic holes as fast as helium.

6. Solid SSSSolid: substances have a definite volume and definite shape. Substances have a fixed position; no freedom to change positions Particles are held closely together by strong chemical attractions Definite melting point

7.  Diagram:

8. Liquid  Liquid: substances have a definite volume but no definite shape  particles are closely packed, but can  particles are closely packed, but can still slide past each other Take the shape of their Take the shape of their container Particles are close but not as close as a solid Particles can move randomly and spread on their own

9. Liquid  Diagram:

10. Viscosity:  Viscosity:  Viscosity: resistance of a fluid to flow Determined by the attraction of particles: the stronger the attraction, the more viscous (thick) the liquid is. Fluids with a high viscosity flow slowly, and fluids with a low viscosity flow quickly. What is more viscous: apple juice or maple syrup?

11. Gas  Gas: particles do not have a definite volume or shape. Particles are in a constant state of motion and rarely stick together Expand to fill available spaces Free to spread in all directions from areas of high concentration to areas of low concentrations.  Example: scents of food or perfume Have a low density Have a low density

12. Gas  Diagram:

14. Gas  Gases exert pressure  Pressure: force exerted per unit area of a substance If there is too much pressure (too many helium particles) in a balloon, what happens? A gas under pressure will escape the container if possible. Think about an air filled balloon that you let go.

15. Fluids  Fluids: substances that can spread Both liquids and gases can spread, so they are considered fluids.

16. Plasma  Plasma: does not have a definite shape or volume; considered to have the properties of fluids. Most common state of matter in universe, but not Most common state of matter in universe, but not on Earth Makes up 99.9 % of the universe Plasma is superheated gas and is a collection of free moving electrons and ions Conducts electricity

17. Plasma  Examples of natural plasma on earth: lightning fire Aurora borealis Aurora borealis  Artificial plasma on earth includes fluorescent lights

18. Energy  Energy: the ability to change or move matter Examples of energy or sources of energy:  heat, light, spring coiling, batteries Energy must be added or removed to cause a change in state. Energy must be added or removed to cause a change in state.

19. Energy Energy must be ADDED to melt or evaporate substances  Aluminum must be melted before it can be recycled  As aluminum particles gain heat, particles move faster and break away from fixed positions and become liquids: called melting

20. Energy  Energy must be RELEASED to make a gas become a liquid or solid again. When H 2 O is a gas and molecules slow down the water vapor returns to a liquid (called condensation). When molecules slow down even more, the water goes to a solid (ice).

21. Energy  Energy relationship between solid, liquid, and gas diagram: liquidgas solid Energy ABSORBED Energy RELEASED

23. Important Note:  Changing the state of matter does NOT change the substance or mass.  Water, steam, and ice are all H 2 O: the only change is the nature of attraction between molecules

24. Phase Change Diagram: Melting Freezing Condensation Vaporization Sublimation Deposition Solid LiquidGas

25. Phase Changes  Evaporation: change of a substance from a liquid to a gas.  Condensation: change of a substance from a gas to a liquid.  Sublimation: change of a substance from a solid to a gas.  Deposition: change of a substance from a gas to a solid Example: Water vapor without becoming liquid- this is how snow forms in clouds.

26. Law of Conservation of Mass  Law of Conservation of Mass states that Mass cannot be created or destroyed. Example: Burning a match: consider what you start and end with.

27. Trivia Question  Trivia Question: If mass cannot be created or destroyed, then why do we have to replace our tires when the rubber “wears away”?

28. Law of Conservation of Energy  Law of Conservation of Energy states that Energy cannot be created or destroyed. Energy can be converted from one form to another.  Example: A wristwatch: from chemical energy to mechanical energy.