1. Describing Matter Chapter 2 Section 1

2. Matter Is anything that has mass and takes up space.

3. Pure Substance A pure substance is a single kind of matter that is pure, meaning it always has a specific makeup. For example: table salt, sugar and baking soda

4. Every form of matter has 2 kinds of properties. Physical properties Chemical properties

5. A physical property is a characteristic of a pure substance that can be observed without changing it into another substance.

6. For example, a physical property of water is that it freezes at a temperature of 0 degrees Celsius.

7. Physical properties can be used to classify matter. For example: Melting Point is a physical property.

8. A chemical property is a characteristic of a pure substance that describes its ability to change into different substances.

9. Chemical properties are also used to classify substances. A chemical property of methane is that it can catch fire and burn in air. Iron will combine with oxygen in air and form a new substance, rust.

10. An element is a pure substance that can’t be broken down into any other substance by chemical or physical means. Elements are the simplest substances.

11. You are already familiar with some elements. *Aluminum which is used to make outdoor furniture and foil. *Pennies are made from zinc

12. An atom is the basic particle from which all elements are made.

13. Pencil “lead” is made of mostly graphite, a form of carbon. Two ways to model atoms used in this presentation are shown here for carbon. Modeling an Atom

14. Molecules are groups of 2 or more atoms held together by chemical bonds.

16. A compound is a pure substance made of 2 or more elements chemically combined. For example: water (H 2 O)

17. When elements are chemically combined they form compounds having properties that are different from those of the uncombined elements. For example sugar C 12 H 22 O 11 It is made of carbon, hydrogen, and oxygen.

18. A mixture is made up of 2 or more substances – elements or compounds, or both – that are held together in the same place but NOT chemically combined.

19. A solution is…… A very well mixed mixture.

20. Examples of Solutions Saltwater Sugar water Air ( nitrogen gas and oxygen gas as well as other gases)

21. The End