1. PHYSICAL AND CHEMICAL CHANGES

2. Physical Changes
In a physical change, the original substance still exists. It has only changed form.
Energy changes usually do not accompany physical changes, except in phase changes and when substances dissolve.

3. Physical Changes
Includes all changes of state (physical changes of a substance from one state to another)

4. Solid definite volume definite shape atoms are packed
together in fixed
positions
strong attractive forces
between the atoms
only vibrate in place

5. Liquid definite volume indefinite shape atoms are close together
atoms can overcome attractive forces to flow

6. Gases indefinite volume indefinite shape atoms move very quickly
atoms are far apart
pretty weak attractive forces

7. Changes of State

8. HEATING CURVE

9. Plasma high temperature state in which atoms lose their electrons
Ex. the sun

10. Physical Changes: Separation Techniques
Filtration- solid part is trapped by filter paper and the liquid part runs through the paper
Vaporization- where the liquid portion is evaporated off to leave solid

11. Physical Changes: Separation Techniques
Decanting- when liquid is poured off after solid has settled to bottom
Centrifuge- machine that spins a sample very quickly so that components with different densities will separate

12. Physical Change: Separation Techniques
Paper Chromatography- used to separate mixtures because different parts move quicker on paper than other

13. Physical Change: Dissolving of Salt

14. Physical Change: Boiling of Water

15. Physical Change: Melting of Ice

16. Physical Change: Cutting Grass

17. Physical Change: Ductile - Drawn or Stretched into Wire

18. Physical Change: Crushing a Rock

19. Physical Change: Condensation

20. Chemical Changes In a chemical change, a new substance is produced.
Energy changes always accompany chemical changes.

21. Chemical Changes in Matter
same as chemical reaction
doesn’t change the amount of matter present (Conservation of Mass)
reactants- substances that react
products- substances that form

22. Energy Changes in Matter
when any chemical change occurs, energy is always involved
energy can be in different forms (light, heat, etc.)
energy is never destroyed or created (law of conservation of energy)

23. Energy Changes in Matter
Exothermic Reaction- reaction that gives off energy (feels warm on outside)
Endothermic Reaction- reaction that uses up energy (feels cold on outside)

24. Chemical Change:Fireworks

25. Chemical Change:A Glow Worm Emits Light

26. Chemical Change: Rusting Chain

27. Chemical Change: Burning Candle

28. Chemical Change: Oxidation of Apples

29. Chemical Change: Plant Growing

30. Chemical Change: Rotting of Wood

31. Chemical Change: Burning of Magnesium

32. Fermenting of Grapes

33. Chemical Change: Tarnishing of Silver

34. Which of these represent a: (A) chemical change? (B) physical change?
1. combustion of gasoline
2. dissolving sugar in water
3. melting wax
4. rusting of iron
5. oxidation of apples

35. Which of these represent a: (A) chemical change? (B) physical change?
6. photosynthesis
7. digestion of food
8. grinding a rock
9. boiling of salt water
10. respiration

36. Which of these represent a: (A) chemical change? (B) physical change?
11. Acid on limestone produces carbon dioxide gas.
12. Milk sours.
13. Water is heated and changes to steam.
14. A pellet of sodium is sliced in two.
15. Sodium hydroxide dissolves in water.