1. Classification of Matter

2. Two classifications of matter are a pure substance or a mixture
defn. Mixture: A blend of two or more kinds of matter, each of which retains its own identity and properties. Most everyday items would be considered mixtures.
Examples: air, sugar water, soup, and gasoline.

3. defn. Pure substance: Has a fixed composition and differs from a mixture in the following ways:
1. Every sample of a given pure substance has exactly the same characteristic properties. EXAMPLE: Every sample of pure water has the same boiling point.
2. Every sample of a given pure substance has exactly the same composition EXAMPLE: Pure water always has a 2 to 1 ration of hydrogen to oxygen. It also has 88.8% oxygen and 11.2% hydrogen by mass.

4. MIXTURES
Mixtures can be placed into two categories, Homogeneous or Heterogeneous
defn. Homogeneous: Mixture is uniform in composition, is also referred to as a Solution.
Example: Sugar water, chlorine water.
** Homogeneous Mixtures can sometimes be confused with a Pure Substance. **

6. defn. Heterogeneous: A heterogeneous mixture is not uniform in composition.
Example: Oil and Water, Soup, dirty water.
Some mixtures can be separated by filtration or vaporization

7. PURE SUBSTANCES
A pure substance will always be homogeneous and will either be a compound or an element.
defn. Compound: A compound can be decomposed or broken down into two or more simpler compounds or elements by a chemical change.
Example: Water….can be broken down into hydrogen and oxygen by electrolysis.
defn. Element: A pure substance that cannot be decomposed or broken down by a chemical change.
Example: Hydrogen, Oxygen, Carbon