1. Chemical Changes and Properties

2. Chemical Property Chemical Change
describes the ability of a substance to undergo changes in identity
Chemical Change
changes the identity of a substance
products have different properties

3. Signs of a Chemical Change
change in color or odor
formation of a gas
formation of a precipitate (solid)
change in light or heat

4. When substances are placed together and a chemical change occurs, there are often signs that it has happened.
Signs of a chemical change:
Photos by Patrick Haney
Change in Color

5. A precipitate forms Signs of a chemical change:
Photos by Patrick Haney
A precipitate forms
A precipitate is a solid that forms when two solutions are placed together.

6. Bubbles Signs of a chemical change:
If bubbling occurs when substances are placed together, then it is likely a chemical change has occurred.
Photo by Patrick Haney

7. Light and/or Heat are given off
Signs of a chemical change:
Light and/or Heat are given off
Photo by Patrick Haney
Photo by Patrick Haney

8. Some things you should simply recognize as chemical changes:
Photo by Nino Barbieri
Photo by Henry Muhlpfordt
Food
Spoilage
Acid Rain Damage
Burning/
Combustion
Rusting/
Corrosion
Photosynthesis

9. Substance
Unmixed (Describe crystal shape)
1. Mixed with water
(Add 20 drops)
2. Mixed with Vinegar (Add 20 drops)
3. Mixed with Iodine
(Add 5 drops)
Baking Powder
Flour
Baking Soda
Cornstarch
Sugar
Powdered Sugar

10. If you did not see a reaction, infer what kind of changes you saw?
Nothing
Which reactions were chemical changes and how did you know they were chemical changes?
If you did not see a reaction, infer what kind of changes you saw?
Baking Powder
Flour
Baking Soda
Cornstarch
Sugar
Powdered Sugar