Classifying Matter

1. Classifying Matter 2.2

2. Pure Substances • A pure substance is matter that always has exactly the same composition. • Pure substances are classified into two categories: elements and compounds

3. Elements • Element- a substance that cannot be broken down by ordinary means. • Atom- smallest part of an element still having the properties of that element. • Examples: aluminum, gold, iodine

4. Compounds • Compound- 2 or more simpler substances combined chemically. • Elements present are in specific ratios. • Atoms are evenly distributed • Cannot be separated by ordinary means • Properties of compound differ from properties of simpler substances that make it up • Examples: • H2O water • NaCl salt

5. Mixtures • A mixture is when two or more substances are physically combined. • Not set in specific ratios, not chemically bonded • Not evenly distributed • Can be separated by ordinary means • Properties can vary because composition varies • Examples: pizza, salsa

6. Two Categories of Mixtures • Homogenous Mixture • Mixture looks the same throughout. • Can’t see different parts. • Kool-aid, salt-water • Heterogeneous Mixture • Mixture DOES NOT look the same throughout. • Can see different parts. • Mixed nuts, salad

7. 3 types of mixtures • More specifically, there are 3 types of mixtures based on particle size. • Solution • very small particles • won’t separate into layers • cannot be filtered • Ex: salt water

8. Suspension • large particles • separates into layers over time • can be filtered • Ex: Italian dressing.

9. Colloid • intermediate particles • cannot be filtered • Ex: milk • :