Chapter 2, Section 1 pages 58-67.

1. Chapter 2, Section 1pages 58-67. Describing Matter

2. What’s Chemistry? Chemistry is the study of properties of matter and how matter changes.

3. What is Matter? • Anything that has mass and takes up space. • All the stuff around you is matter. • Air, plastic, wood, glass, paper and cloth are all examples of matter. • Every form of matter has two kinds of properties-Physical and Chemical.

4. Properties of Matter • Matter can have many different properties, or characteristics. • Materials can be hard or soft, rough or smooth, hot or cold, liquid, solid or gas.

5. What is a Substance? • A single kind of matter that is pure, meaning it always has a specific kind of make-up. • Elements are the simplest substances. • Table salt and Sugar are examples of pure substances. • Figure 1, page 59.

6. Physical Properties of Matter • A physical property is a characteristic of a pure substance that can be observed without changing it into another substance. • Two physical properties of metals are luster (how shiny they are) and the ability to conduct (carry) heat and electricity. • Figure 2, page 60.

7. Chemical Properties of Matter • A chemical property is a characteristic of a pure substance that describes it’s ability to change into different substances. • A chemical property of methane is it can catch fire and burn in air. • Figure 3, page 61

8. What is an Element? • An element is a pure substance that cannot be broken down into any other substance by chemical or physical means. • Elements are the simplest substances. • Each element can be identified by it’s specific physical and chemical properties. • Figure 4, page 62.

9. What is an Atom? • The basic particle from which all elements are made. • Figure 5, page 63.

10. Chemical Bond • Chemical Bonds are formed when atoms combine. • This is caused by a force of attraction between two atoms. • Chemical bonds form Molecules. • Molecules are two or more atoms held together by chemical bonds. • Figure 6, page 63.

11. Compounds!!! • A pure substance made of two or more elements chemically combined in a set ratio. • Salt is a compound! • Figure 7, page 64. • When elements chemically combine, they form compounds having properties that are different from those of the uncombined elements.

12. Compound (Continue) • A compound may be represented by a chemical formula. • A chemical formula shows the elements in a compound and the ratio of the atoms. • Example-> Calcium Carbonate is a compound. It is written as CaCO3.

13. Mixtures • A mixture is made up of two or more substances, but are not chemically combined. • Heterogeneous mixture: You can see the different parts. • Homogeneous mixture: So evenly mixed you can’t see the different parts.

14. Solution • A solution is an example of a homogeneous mixture. • Air is a solution of Nitrogen gas (N2) and Oxygen gas (O2). • Brass is a solution of Copper and Zinc. • Figures 8 and 9, page 65.

15. Separating Mixtures • A compound is difficult to separate into it’s elements. • A mixture is easy to separate into it’s components because each component keeps it’s own properties. • Figure 10, pages 66-67.

16. Any Questions?