1. Do Now #7
A physical change occurs when a substance changes form, but stays the same.
A chemical change occurs when a substance changes into a new, different substance.
1. In which Station Activities did you observe physical changes?
2. In which Station Activities did you observe chemical changes?

2. Physical vs. Chemical Physical Property Chemical Property
characteristics observed without changing the identity of the substance
Characteristics such as color, density, odor
Chemical Property
describes the ability of a substance to undergo changes in identity

3. Physical vs. Chemical
Lets think about the penny. What is the penny made out of?
Please tell me you didn’t say just copper!
Lets take a look at what the penny has done over the years.
Composition?
Why would the penny change (think of physical properties, as well as chemical properties?
In the 1980s copper became too expensive to be the primary metal in pennies. Zinc was chosen to replace copper because of its availability and reasonable expense. Zinc is slightly less dense than copper. During WWII, copper was in short supply, so they produced zinc plated steel pennies

4. B. Physical vs. Chemical physical chemical melting point flammable
Examples:
melting point
flammable
density
magnetic
tarnishes in air

5. Classify Each of the following as Physical or Chemical Properties
The boiling point of ethyl alcohol is 78°C.
Physical property – describes inherent characteristic of alcohol – boiling point
Diamond is very hard.
Physical property – describes inherent characteristic of diamond – hardness
Sugar ferments to form ethyl alcohol.
Chemical property – describes behavior of sugar – forming a new substance (ethyl alcohol) 6

6. Changes in Matter
Physical Changes are changes to matter that do not result in a change of the fundamental components that make that substance (CHANGE IN CONDITION)
State Changes – boiling, melting, condensing
Chemical Changes involve a change in the fundamental components of the substance (CHANGE IN MATERIAL)
Produce a new substance
Chemical reaction
Reactants  Products 8

7. It’s a physical change if
It changes shape or size
It dissolves.

8. It changes phase (freezes, boils, evaporates, condenses)
It’s a physical change if...
It changes phase (freezes, boils, evaporates, condenses)

9. It’s a chemical change if….
It burns
Temperature changes without heating/cooling

10. It’s a chemical change if...
It bubbles (makes a gas)

11. It’s a chemical change if...
It changes color
It forms a precipitate

12. What kind of change is it if someone...
Tears up paper?
Physical change
Mixes salt and water?

13. What kind of change is it if someone...
Burns paper?
Chemical change
Evaporates salt water?
Physical change

14. Table salt is stirred into water (left), forming a homogeneous mixture called a solution (right)

15. No chemical change occurs when salt water is distilled

16. What kind of change is it if someone...
Mixes vinegar and baking soda?
Chemical change

17. Physical vs. Chemical chemical physical rusting iron
Examples:
rusting iron
dissolving in water
burning a log
melting ice
grinding spices

18. Classify Each of the following as Physical or Chemical Changes
Iron is melted.
Physical change – describes a state change, but the material is still iron
Iron combines with oxygen to form rust.
Chemical change – describes how iron and oxygen react to make a new substance, rust
Sugar ferments to form ethyl alcohol.
Chemical change – describes how sugar forms a new substance (ethyl alcohol) 10

19. Properties of Matter List of chemical changes possible.
Description by senses – shape, color, odor, etc.
Measurable properties – density, boiling point, etc.
PROPERTIES
Old substance destroyed.
New substance formed.
New form of old substance.
No new substances formed.
CHANGE
CHEMICAL
PHYSICAL