1. Chapter 3
Chemical Reactions

2. Physical Properties of Matter
Physical Property - any property of matter that can be observed or measured without changing the identity of the matter
Examples:
color
shape
taste
state/phase
density
D = m V

3. Physical Change ( Reaction)
Physical Change – a change that affects one or more physical properties of a substance
* a change in shape, size, color, or state
a change without a change in chemical composition
a change that is reversible
Examples:
tearing paper
cutting your hair
change in state ex. Solid to liquid leaves changing color

4. Chemical Properties of Matter
Chemical Property - any property of matter that describes a substance based on its ability to change into a new substance that has different properties
Examples
flammability
reactivity with vinegar
reactivity with oxygen
Iron + Oxygen  Iron oxide (rust)
2Fe + 3O2  Fe2O3

5. Chemical Change (Reaction)
Chemical Change -a change in which a substance becomes another substance having different properties
a change that is not reversible using ordinary physical means
Changes that usually cause heat, sound, light, odor, fizzing/foaming, color changes
You usually need more than one of the above characteristics to be considered a chemical change!
Examples: combining sulfuric acid and sugar
burning a piece of wood
soured milk

6. Signs of a Chemical Reaction
fire
Bubbles/fizzing
color changes
rust
precipitate
A solid that is produced as a result of a chemical reaction in a solution, the solid is called the precipitate.

7. Chemical or Physical Property?
Paper is white
Boiling point of H2O is 100oC
Zinc reacts with hydrochloric acid and creates hydrogen gas
Nitrogen does not burn
Sulfur smells like rotten eggs
Physical Property
Physical Property
Chemical Property
Chemical Property
Physical Property

8. Comparing Physical and Chemical Properties
Substance/Matter
Physical Property
Chemical Property
Helium
Less dense than air
Nonflammable
Wood
Grainy texture
Flammable
Baking soda
White powder
Reacts with vinegar to produce bubbles
Powdered sugar
Does not react with vinegar
Rubbing alcohol
Clear liquid
Red food coloring
Red color
Reacts with bleach and loses color
Iron
Malleable
Reacts with oxygen

9. Chemical or Physical Change?
Bending a Paper Clip
Baking a cake
The phase change of carbon dioxide
Crushing an aluminum can
Vinegar and baking soda combining to create salt and water
Physical Change
Chemical Change
Physical Change
Physical Change
Chemical Change

10. Is evaporation a physical change or a chemical reaction?7
Is evaporation a physical change or a chemical reaction?
[This object is a pull 

tab]
Answer A A
Physical Change B
Chemical Reaction C
May be either

11. Is dissolving in water a physical change or a chemical reaction?8
Is dissolving in water a physical change or a chemical reaction?
[This object is a pull 

tab]
Answer A A
Physical Change B
Chemical Reaction C
May be either

12. Is burning paper a physical change or a chemical reaction?9
Is burning paper a physical change or a chemical reaction?
[This object is a pull 

tab]
Answer B A
Physical Change B
Chemical Reaction C
May be either

13. Is baking a cake a physical change or a chemical reaction?10
Is baking a cake a physical change or a chemical reaction?
[This object is a pull 

tab]
Answer B A
Physical Change B
Chemical Reaction C
May be either

14. Are smoke and flame signs of a physical change or a chemical reaction?11
Are smoke and flame signs of a physical change or a chemical reaction?
[This object is a pull 

tab]
Answer B A
Physical Change B
Chemical Reaction C
May be either

15. Are bubbles a sign of a physical change or a chemical reaction?12
Are bubbles a sign of a physical change or a chemical reaction?
[This object is a pull 
tab]
Answer C
Bubbles can form when something evaporates, like boiling water.
Bubbles can form when chemicals react like vinegar and baking soda. A
Physical Change B
Chemical Reaction C
May be either