1. Elements, Compounds & Mixtures
EQ: How can a substance be identified as an element, compound or mixture?

2. Types of Matter Solids Liquids Gases
Tightly packed and vibrate about a fixed position
Liquids
Loosely packed and slide past one another
Gases
Move freely until they collide with each other or an object

3. What are elements? Elements are pure substances.
Elements are substances that are composed of only one kind of atom.
Elements cannot be broken down by chemical change.

4. What are compounds? Compounds are also pure substances.
A compound is a pure substance made of different elements, chemically bonded together, ALWAYS in the same proportions.

5. What are mixtures?
Mixtures are not pure substances; their composition can vary.
In each example above, there’s more than one thing there!

6. Practice! Given the diagrams X, Y, and Z below: What is X? What is Y?
                                                                                                                                             
What is X?
What is Y?
What is Z?

7. Practice!
Identify each as an element, compound, or mixture

8. Back to the big picture…
A pure substance can be represented by a chemical formula.
Elements and compounds
Examples: Fe, H2, NaCl, CO2
A mixture can NOT be represented by a formula
Examples: salt water, raisin bran

9. Types of Mixtures Heterogeneous mixtures Homogeneous mixtures
Can see the different parts of the mixture
Liquids are unstable and will settle out
EX. Pizza, Oil & water, etc.
Homogeneous mixtures
Can NOT see the different parts of the mixture
Solutions
Liquids are stable and typically won’t settle
EX. Alloys (metal mixtures), Salt water, etc.

10. Practice Sweet tea Calcium Calcium and oxygen in the same container
Calcium and oxygen atoms bonded
Water
Orange juice w/pulp