1. Your notes will be made up of everything written in PURPLE throughout the powerpoint

2. Title your notes: Properties of Water
Primarily due to polarity

3. Video 1 “Properties of water” – 4 ½ min
You should be able to answer the following questions after the video (do not write them down)
Why is ice less dense than water?
How does ice floating on water impact the survival of the living organisms
Draw the water structure.
How does the term “polar” describe the water molecule?
What is the intermolecular force between water molecules called?
Explain surface tension in water

4. Intro to Water
Water molecules are electrically neutral (O atom holds a small neg. charge and the two H atoms hold small positive charges)
Water molecules are attracted to each other, creating hydrogen bonds (bonds determine almost every physical property of water and many of its chemical properties, too)
This electrical balance  polarity (gives water some of its remarkable properties)

5. Terms to know by the end of the lesson
Make sure that you write down all the terms and their definitions throughout the powerpoint!
Not now
Polarity
Hydrogen bond
Cohesion
Adhesion
Surface tension
Capillary action
Specific heat

6. Water has a high SPECIFIC HEAT CAPACITY
Water has the ability to absorb a lot of heat with a relatively small increase in temperature
This allows marine organisms to avoid drastic temperature fluctuations in the seawater.
This allows orchards grown on the coast to survive hot summers and severe winters.
Think about how long it takes water to boil…

7. Water “acts” like a magnet https://www.youtube.com/watch?v=0eNSnj4ZfZ8

8. Lewis e-dot structure of water molecule 2 lone pairs –bent shape DRAW THIS!

9. video clip “Why ice floats “ http://www. youtube. com/watch
Critical Thinking: If ice were more dense than liquid water, how would this impact the survival of the marine life?
(The floating layer of ice insulates the liquid water below, so that it wouldn’t freeze – this makes the ocean environment to easier to live in)

11. H2O is Polar As we know – water is neutral
(equal number of e- & p+ = zero Net Charge)
But because the O atom is more electronegative than the H atoms – electrons spend more of their time nearer the oxygen. (O atom attracts more than its “fair” share” of electrons).
This gives water a slight overall charge.
The oxygen end “acts” negative.
The hydrogen end “acts” positive.
POLARITY - OPPOSITE CHARGES

12. Oxygen “pulls” closer to it creating positive and negative sides of the polar molecule.

13. Water is a universal solvent
Water can dissolve more substances than any other solvent

15. “Like dissolves like” (due to its polarity)
Water (polar) + Styrofoam (non-polar)
Acetone (nonpolar) + Styrofoam (non-polar)
“Like dissolves like” (due to its polarity)

16. HYDROGEN BOND – intermolecular force between water molecules
Polarity really does allow bonding
They are hydrogen bonds and they are weak
They last for fractions of a second
Continuously break and reform
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Polar Bonding

17. Hydrogen Bonds (Formed between a highly Electronegative atom of a polar molecule and a hydrogen (O-H)
Opposites attract

18. Forces due to polarity
Cohesion
Adhesion

19. Cohesion (water is sticky)
COHESION: Attraction between particles of the same substance ( why water is attracted to itself)
Results in Surface tension (a measure of the strength of water’s surface)
Produces a surface film on water that allows insects to walk on the surface of water

20. SURFACE TENSION - A unified layer of molecules at the surface
Inside a drop of water polar water molecules attract to each other in a random fashion
At the surface of the drop, water does not attract to the air
There the water behaves like an flexible sheet allowing denser objects to “sit” on the surface.
Surface Tension

21. Surface tension (cohesion)
Can be seen as water
droplets form
Helps insects walk across
water
Surface tension (cohesion)

22. Adhesion Attraction between two different substances
Water will form hydrogen bonds with other surfaces such as glass, soil, plant tissues, and cotton
Adhesion Causes Capillary Action, which gives water the ability to “climb” structures.

23. Adhesion Form spheres & hold onto plant leaves
Can be seen as water droplets form on the spider web (another polar surface)
Form spheres & hold onto plant leaves
Adhesion

24. Because the positive and negative charges in the paper attract the polar water molecules (adhesion)
This property of adhesion is called capillary action.
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Capillary action

25. Cohesion is a tendency of molecules to stick together
Cohesion is a tendency of molecules to stick together. Surface tension is the measure of how difficult it is to stretch or break the surface of the liquid. Hydrogen bonds give water a very high surface tension which makes it behave as though it were coated with an invisible film.