Water Properties Lab

1
Water Properties Lab
2
Water is Polar Covalent
Uneven sharing of e-
Nonpolar Oxygen (even sharing of e-)
3
Hydrogen Bonds

• Weak bonds between like molecules

4
p. 3 Cohesion

• Attraction of water to water
• Makes a drop
• Polar ends and H-bonds attract

5
What forms a drop?

• Cohesion causes water to form drops
• surface tension causes them to be nearly
  spherical
• adhesion keeps the drops in place.

6
Surface Tension

• Water attracts itself and pulls in to form a
  film on its surface to form a drop.

7
Adhesion

• Attraction of water to an unlike substance
• (like glass)
• Note the drop is flatter than on wax paper

8
p. 4 Water Drop Shapes

• Rounder the drop, the stronger the H-bonds in the
  drop of water.
• Round drop on wax paper (not strong adhesion to
  water).
• As adhesion to glass is stronger pulls the
  water, it makes a flatter drop.

9
On wax paper On glass
10
p. 4 -6 top Water on wax paper

• Plain wax paper Soapy wax paper

You can break surface tension with soap.
11
Polar coheres to Polar not Nonpolar

• Water (Polar) has no adhesion to the wax
  (nonpolar) paper. It would roll right off.
• Water has more adhesion to a glass plate.

12
p. 6 Climbing Property of Water

• CHROMATOGRAPHYColors are separated by densities.
  Less dense colors go to the top.

• Black is composed of all the colors.
• Capillary action -cohesion (water to water)
  adhesion (water to paper)
• Polar water polar ink (dissolves)

Paper has pores, open spaces
13
Capillarity water climbs up small spaces

• The small spaces (pores of the paper) provide
  adhesion to the water.
• The water makes a column by cohesion to itself.
  (water to water because they are polar)

14
Adhesion to paperCohesion of water to water
15
p. 8 6 Oil is hydrophobic

• Oil and water do not mix.
• H-bonding is only in polar

Oil is on top Non-polar
polar
nonpolar
Water is on bottom Polar
polar
16
5 Likes dissolve likesPolar dissolves polar,
but not nonpolar

• Cell membrane is also amphipathic (polar
  nonpolar)

Inside the cell membrane
17
p. 9 6Food coloring dissolves in water.

• Water is polar H-bonds
• Food coloring is polar.
• Makes a solution (water surrounds the dye)
• Oil is nonpolar (no charge).
• And no H- bonds.
• Polar molecules dissolve
• polar molecules.

18
Dissolving

• A solute surrounds the molecules of a solvent to
  make a solution

19
Stirring oil and water

• The oil will go back to being separate from the
  water.

20
D. Oil sheen on water (oil on top of water in a
thin layer)
21
Interpret 6 Getting rid of oil on water
HowStuffWorks "How do you clean up an oil spill?
(pick a video)

• Detergent breaks up the oil into very small
  droplets.

Burn Off
Booms
Hi-pressure water
22
Slick Sack

• Absorbent
• pad

Hand washing
23
Oil Spills Problems

• a. dead sea life
• b. human life ills
• c. cost of clean-up

24
p. 9 Interpret 5 Amphipathic(bipolar)

• molecules have (hydrophobic) nonpolar end and to
  attract oil structure, but also have a region
  that is polar (hydrophilic) attracts water to
  wash it away.
• Like detergent.

25
Soap is a surfactant

• That reduces the surface tension
• Breaks the cohesion of water molecules