1. Changing Matter 2-3

2. Objectives
> Explain physical change, and give examples of physical changes.
> Explain chemical change, and give examples of chemical changes.
> Compare and contrast physical and chemical changes.
> Describe how to detect whether a chemical change has occurred.

3. Phases of Matter There are 4 phases of Matter
Solid, Liquid, Gas, Plasma
Molecules are always moving. They can vibrate and they can expand.

7. Molecular movement Solids – molecules constantly vibrating
Liquids- molecules are spreading
Gases – Molecules are expanding

8. Phases of Matter
Matter can change from form to form depending on the amount of energy (heat) is available.
Solid to liquid to gas.
Ice in a pan melts then begins to boil and turn to steam.

9. Phase changes & Temperature
___________ /
_________________
Phase changes occur at 1 temperature.

10. Physical Changes
Physical changes occur without creating something new. They effect the physical properties of a substance. Such as melting, mixing, or dissolving. If you can change it back it is a physical change.

11. Chemical changes
Chemical changes occur when the composition is changed and something different is created.
You can tell because of odor, bubbles, color changes, sound, heat or light.
Chemical Change Clip

12. Chemical changes
Chemical changes can not be reversed to go back to original state.
Chemical changes can break down compound such as water to create hydrogen and oxygen.

14. Phases of matter Solids- definite shape and volume
Crystalline- orderly arrangement of atoms- diamond
Amorphous-opposite- gum

15. Phases Cont’d Liquid- definite volume no definite shape.
Surface tension-force acting on particles at the surface causing droplets to form.

16. Phases Cont’d Gas- no definite shape and no definite volume.
Particles expand and spread out.

17. Change in phase/state
Condensation- energy released when gas changes to a liquid
Temperature and state do not change together

18. Energy Released to Solidify
Energy is absorbed when water vaporizes; the same amount of energy is released when the water vapor condenses.
100 90 80 70 60 50 40 30 20 10
Energy must be added to separate the particles as ice melts; the same amount of energy is released when water freezes.
Energy
absorbed
To vaporize
Energy
Released to condense
Energy Released to Solidify
Energy absorbed
to melt
– Relative energy Temperature (˚C)

19. Change in phase/state
Evaporization- energy required to change liquid to gas
Sublimation- energy required to change solid to a gas
States of Matter Clip

20. Particles Movement -
Temperature +

21. Kinetic Theory All matter is made of atoms that act like particles
Particles are always in motion, hotter= faster

22. Kinetic Theory Cont’d
At same temperature heavier particles move slower than lighter particles.

23. Energy The ability to change matter and the capacity to do work
Kinetic energy – energy of motion
Potential energy- energy of position

24. Energy Cont’d Temperature- Average kinetic energy.
Amount of particles do not matter
High temperature means high kinetic energy

25. Energy Cont’d
Thermal energy is the total kinetic energy of particles that make up the object.
The bigger the object more T.E.

26. Conservation of mass and energy– we cannot create or destroy either