1. Aim: How can we describe compounds? Do Now: Copy and complete the following chart.

2. compound: substance made up of two or more elements chemically combined. Example: water is a compound made up of the elements hydrogen and oxygen. Example: sugar is a compound made up of the elements carbon, hydrogen, and oxygen Compound

3. What makes compounds different? compounds are formed as the result of a chemical change the elements combine to form a new substance with new properties a chemical change is also required to break a compound down A compound has a definite chemical composition. Example: Water is always H 2 O. Example : Carbon Dioxide is always CO 2

4. How can we tell whether a chemical change has occurred? Signs to look for: 1.Energy is released or absorbed (heat, light, electric). 2.Gas is released. 3.A color change occurs. **Remember – a chemical change cannot be reversed**

5. What about a physical change? A physical change is something that can be reversed. Examples include: Change in phase Change in shape Change in volume Etc…

6. A Quick Demonstration… Which changes (physical or chemical) is your teacher modeling for you? How do you know?

7. Activity Copy and complete the chart on page 71 in the classroom textbook.

8. Homework # Complete the worksheet you were given. A copy of this sheet will be posted online.