1. Physical and Chemical Changes

2. Qualitative Observations- Observed using our 5 senses
Qualitative Observations- Observed using our 5 senses. Quantitative Observations- Observations using numbers (counting, measuring)

3. Physical changes Indicators of a
Chemical change

4. Physical Change In a physical change, you do not get anything new.
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Publishing as Benjamin Cummings

5. What is a Physical Change?
A physical change is a change in which no new substance is formed, but properties may be changed.

6. What is a Chemical Change?
A chemical change is a change in which a new ________ with new _________is formed.
substance
properties

7. Take your paper and crumple it.
Do you have something new?
No, it is still paper although it looks
somewhat different.

8. If shape changes, then you’re observing a _______ change…
physical

9. Physical changes Indicators of a
Chemical changes
Change of shape

10. Take your paper and rip it into 2 pieces.
Do you have anything new?
No, it is still paper although it looks
somewhat different.

11. If you observe a change in size, then you’re observing a _______ change…
physical
Wet sponge
Dry sponge

12. Physical changes Indicators of a
Chemical changes
Change of shape
Change in size

13. Looking at the ice…..it has melted.
Do I have anything new?
No! It is still water. It has just changed its state from a solid to a liquid.

14. If you observe a change in state, then you’re observing a ________ change…
physical

15. Physical changes Indicators of a
Chemical changes
Change of shape
Change in size
Change in state of
matter

16. Measure out a ½ teaspoon of baking soda and put it into a cup.
Add 3 pipettes of vinegar.
Was something new produced?
YES! Bubbles were produced. That indicates
a gas was made. The gas is a new substance.

17. If you observe bubbling (not due to boiling or shaking), then a _______change is occurring…
chemical

18. chemical
If you observe fizzing, then you will know that a _________ change is occurring (unless you shook the substance)…

19. Physical changes Indicators of a
Chemical changes
Bubbles/fizzing are
produced
Change of shape
Change is size
Change in state of
matter

20. Rinse out cup and refill 1/3 way with water.

21. I will pour the cup of water into the cup of colored
Was the colored changed? Did you get anything new?
No, you just made the colored water not as
dark. You diluted it.

22. Physical changes Indicators of a
Chemical changes
Bubbles/fizzing are
produced
Change of shape
Change is size
Change in state of
matter
Diluting

23. Add a piece of Alka-Seltzer to your cup of water
Add a piece of Alka-Seltzer to your cup of water. Quickly place hand on side of cup for 3 seconds.
Did you get anything new?
Did you feel any temperature change?

24. Physical changes Indicators of a
Chemical changes
Bubbles/fizzing are
produced
Change of shape
Change is size
Change in temperature
Change in state of
matter
Diluting

25. When we burn something…..
Is a new substance produced?
Yes, soot is produced or ashes.

26. If you smell burning, then you know that a change is _________ occurring…
chemical

27. If you SEE burning, then a _________ change is occurring…
chemical

28. Physical changes Indicators of a
Chemical changes
Bubbles/fizzing are
produced
Change of shape
Change is size
Change in temperature
Change in state of
matter
Burning or cooking
Diluting

29. Is melting a chemical or physical change?

30. If I add salt to water, can I separate them back into water and salt?
YES! It is a mixture.
So physical or chemical change?

31. Why? When a substance is not changed into a new substance, the change is only physical.

32. Physical changes Indicators of a
Chemical changes
Bubbles/fizzing are
produced
Change of shape
Change is size
Change in temperature
Change in state of
matter
Burning or cooking
Diluting
Dissolving

34. Rusting? In a chemical reaction,
old bonds are broken and new bonds are formed.
A NEW SUBSTANCE IS FORMED.
Fe and O2 form rust (Fe2O3).

35. Dirty silver?

36. Physical changes Indicators of a
Chemical changes
Bubbles/fizzing are
produced
Change of shape
Change is size
Change in temperature
Change in state of
matter
Burning or cooking
Rusting/ tarnishing
Diluting
Dissolving

37. If you observe that matter is__________, then a __________change is occurring…
decaying
chemical

38. Physical changes Indicators of a
Chemical changes
Bubbles/fizzing are
produced
Change of shape
Change is size
Change in temperature
Change in state of
matter
Burning or cooking
Rusting/ tarnishing
Diluting
Odor produced/ decay
Dissolving

39. Mixing chemicals…. Glow stick
What was observed?
Pour 15–20 mL of copper II sulfate solution into a test tube so it is about ½ full.
Add about 10–20 drops of ammonia.
Add about 10–20 drops of hydrogen peroxide.

40. Physical changes Indicators of a
Chemical changes
Bubbles/fizzing are
produced
Change of shape
Change is size
Change in temperature
Change in state of
matter
Burning or cooking
Rusting/ tarnishing
Diluting
Odor produced/ decay
Dissolving
Change of color/
light produced

41. Physical changes Indicators of a
Chemical changes
Bubbles/fizzing are
produced
Change of shape
Change is size
Change in temperature
Change in state of
matter
Burning or cooking
Rusting/ tarnishing
Diluting
Odor produced/ decay
Dissolving
Change of color
Precipitate formed

42. What was formed was a precipitate
What was formed was a precipitate. Precipitate - a solid formed by mixing two or more liquids.

43. If you observe explosions because of burning, then a ________ change is occurring…
chemical

44. If you observe cooking, then a _______change is occurring…
chemical

45. If you observe bending (of metal, for example), then a __________change is occurring…
physical
Pulling metal into wires
is called _________
ductile

46. If you observe reshaping (into a tube, for example), then a _______change is occurring…
physical

47. If you observe pounding metal into sheets, then a _________change is occurring…
physical
This is called
______________.
malleable

48. If you observe cutting, then a __________change is occurring…
physical

49. If you observe melting, then a _______change is occurring…
physical

50. If you observe rusting, then a ______change is occurring…
chemical
Note: Rusting occurs when some metals react with the element
Oxygen, which is in the air. For this reason, rusting is also called oxidation.

51. If you observe cooling because refrigeration was added, then a _______change is occurring…
physical

52. If you observe warming without the use of fire or a heater, then a ________change is occurring…
chemical

53. If you observe warming with the use of fire or a heater, then a _______change is occurring…
physical

54. If you observe new matter being made, then a _________change is occurring…
chemical

55. Indicators of chemical reactions:
Production of a gas
Change in color
New substance produced
Change in the chemical formulas
Heat is produced or absorbed
Odor is produced

56. Some Examples of Chemical and Physical Changes

57. Learning Check 2 1 2 1 2 Classify each of the following as a
1) physical change or 2) chemical change.
A. ____Burning a candle.
B. ____Ice melting on the street.
C. ____Toasting a marshmallow.
D. ____Cutting a pizza.
E. ____Polishing a silver bowl. 2 1 2 1 2

58. Properties of Matter observations/ changes observations/ changes
Physical
Chemical
State of matter
solid, gas, etc
Melting Point
Gas produced
Decaying
Density
Taste
Precipitate
formed
Flammability
Burning
Hardness
Diluting
Color change
Tarnishing
Breaking/
ripped
Odor
Temperature
change