chapter 15 15.1

Chapter 1515.1

Water and Its Properties

Anticipation GuideOThink-Make a PredictionOPair- Discuss your predictions with a partner

OShare- Your predictions with the class

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 VaporO IceO Snow

Water is a Simple Molecule

O 2-HydrogenO 1- OxygenO Oxygen has greater electronegativityO Oxygen has a stronger attraction to

HydrogenO PolarO Universal Solvent

Surface TensionO High Surface TensionO Does anybody know why?O Hydrogen bonds are formed within the

waterO Water molecules at the surface have an

unbalanced attraction and are pulled inward creating a High Surface Tension.

O Creates a skin or elastic wrapO Drop of water can be seen in a spherical

shape.

SurfactantO Decrease surface tensionO Interferes with the hydrogen bondingO Ex: Soaps or DetergentsO Ex: Dishwashing liquid

Vapor PressureO Water has a Low Vapor PressureO 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?

The Density of WaterO Ex: Ice TeaO 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.

Practice TonightO Pg. 512 #84O Become familiar with:

O Table 15.1 on Pg. 492

Surface Tension ActivityObjectives

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.

InstructionsO 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=

InstructionsO 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.