1. Chapter 15 15.1 Water and Its Properties

2. Anticipation Guide O Think-Make a Prediction O Pair- Discuss your predictions with a partner O Share- Your predictions with the class

3. Could we live without Water? O Water covers about 70% of Earth's surface O Water makes up 65-75% of our bodies. O Water can be in the form of… O Vapor O Ice O Snow

4. Water is a Simple Molecule O 2-Hydrogen O 1- Oxygen O Oxygen has greater electronegativity O Oxygen has a stronger attraction to Hydrogen O Polar O Universal Solvent

5. Surface Tension O High Surface Tension O Does anybody know why? O Hydrogen bonds are formed within the water O Water molecules at the surface have an unbalanced attraction and are pulled inward creating a High Surface Tension. O Creates a skin or elastic wrap O Drop of water can be seen in a spherical shape.

6. Surfactant O Decrease surface tension O Interferes with the hydrogen bonding O Ex: Soaps or Detergents O Ex: Dishwashing liquid

7. Vapor Pressure O Water has a Low Vapor Pressure O What is vapor pressure? O Hydrogen bonds hold the molecules in liquid water together. O What would happen if water had a high vapor pressure?

8. The Density of Water O Ex: Ice Tea O Solid water has a lower density than liquid water. O As it begins to freeze its density increases until….(Refer to chart 15.1 pg. 492) O Why is ice less dense than liquid water? O Open framework of molecules in a hexagonal arrangement.

9. Practice Tonight O Pg. 512 #84 O Become familiar with: O Table 15.1 on Pg. 492

10. Surface Tension Activity Objectives O Visualizing the surface tension of water. O Drop water onto a penny with an eyedropper. O Visualize the changes in surface tension when a surfactant is added to the water.

11. Instructions O One piece of paper per group. O List all group members names at the top of the paper. O Write the following on your paper: O # of Drops- Water Only Prediction= Actual # of drops= O # of Drops- Liquid Water and Surfactant Prediction= Actual # of drops=

12. Instructions O 1. Take a clean penny and place it on a paper towel. O 2. Load you eyedropper with water. O 3. Take a guess…How many drops can a penny hold? O 4. Write down your guess. O 5. Carefully add water to the penny, one drop at a time. Counting each drop and observing the shape. O 6. Continue dropping water onto the penny until the surface tension breaks and the bubble collapses. O 7. Dry off your penny and repeat with the soapy water and a different eyedropper.