1. Section 1: Matter and Elements
Unit 2: Matter and Atoms
Section 1: Matter and Elements

2. How many different kinds of substances can you identify?
What are things made of?
How many different kinds of substances can you identify?

3. What are things made of?
The “stuff” that we are made of is called matter.
Chemistry tells us how one kind of matter can be changed into a completely different kind of matter.

4. Corn oil is a pure substance
substance: a kind of matter that can’t be separated into other substances by physical means such as heating, cooling, filtering, drying, sorting, or dissolving.

5. Oil and vinegar dressing is a mixture of substances
Corn oil is a pure substance
mixture: matter that contains more than one substance.

6. Is “pure orange juice” a pure substance?
Water
Flavoring chemicals
Citric acid
Sugars
Fruit pulp …
The answer is “no.” Orange juice is composed of many kinds of substances mixed in together.
“Pure orange juice”

7. Look at your desk – What is it made of? wood, metal…
Can you think of a few physical properties?
is it heavy?
is it bendable?
does it feel cold?
can you scratch it? …
In the next slide, students will see that they have been listing physical properties: properties that they can see and measure.

8. Physical properties
Examples:
Mass
Density
Color
Physical properties can be measured or seen through direct observations.

9. Physical changes include changes in shape, phase or temperature.

11. Chemical properties are observed when a substance changes into a different substance.
Chemical change
Iron Rust

12. Signs
that a
chemical change
has occurred

13. Macroscopic and microscopic scales