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Chapter 15 15.1 . Water and Its Properties. Anticipation Guide. Think -Make a Prediction Pair - Discuss your predictions with a partner Share - Your predictions with the class. Could we live without Water?. Water covers about 70% of Earth's surface Water makes up 65-75% of our bodies .
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Chapter 1515.1 Water and Its Properties
Anticipation Guide • Think-Make a Prediction • Pair- Discuss your predictions with a partner • Share- Your predictions with the class
Could we live without Water? • Water covers about 70% of Earth's surface • Water makes up 65-75% of our bodies. • Water can be in the form of… • Vapor • Ice • Snow
Water is a Simple Molecule • 2-Hydrogen • 1- Oxygen • Oxygen has greater electronegativity • Oxygen has a stronger attraction to Hydrogen • Polar • Universal Solvent
Surface Tension • High Surface Tension • Does anybody know why? • Hydrogen bonds are formed within the water • Water molecules at the surface have an unbalanced attraction and are pulled inward creating a High Surface Tension. • Creates a skin or elastic wrap • Drop of water can be seen in a spherical shape.
Surfactant • Decrease surface tension • Interferes with the hydrogen bonding • Ex: Soaps or Detergents • Ex: Dishwashing liquid
Vapor Pressure • Water has a Low Vapor Pressure • What is vapor pressure? • Hydrogen bonds hold the molecules in liquid water together. • What would happen if water had a high vapor pressure?
The Density of Water • Ex: Ice Tea • Solid water has a lower density than liquid water. • As it begins to freeze its density increases until….(Refer to chart 15.1 pg. 492) • Why is ice less dense than liquid water? • Open framework of molecules in a hexagonal arrangement.
Practice Tonight • Pg. 512 #84 • Become familiar with: • Table 15.1 on Pg. 492
Surface Tension ActivityObjectives • Visualizing the surface tension of water. • Drop water onto a penny with an eyedropper. • Visualize the changes in surface tension when a surfactant is added to the water.
Instructions • One piece of paper per group. • List all group members names at the top of the paper. • Write the following on your paper: • # of Drops- Water Only Prediction= Actual # of drops= • # of Drops- Liquid Water and Surfactant Prediction= Actual # of drops=
Instructions • 1. Take a clean penny and place it on a paper towel. • 2. Load you eyedropper with water. • 3. Take a guess…How many drops can a penny hold? • 4. Write down your guess. • 5. Carefully add water to the penny, one drop at a time. Counting each drop and observing the shape. • 6. Continue dropping water onto the penny until the surface tension breaks and the bubble collapses. • 7. Dry off your penny and repeat with the soapy water and a different eyedropper.