water structure and properties

1. Structure & Properties of
Water

2. STRUCTURE
OF WATER
POLAR
MOLECULE
CAPILLARY
ACTION
SURFACE
TENSION
UNIVERSAL
SOLVENT
COHESION
ADHESION
DENSITY
SPECIFIC
HEAT

3. O
H H
1 molecule of water is
made up of 2 hydrogen atoms
bonded with 1 oxygen atom
STRUCTURE OF WATER

4. CHEMICAL FORMULA
H2O = RIGHT
H2O = WRONG
H2O = WRONG
2HO = WRONG

5. O
STRUCTURE OF WATER
The bond that forms water
is a covalent bond

6. Covalent and Hydrogen Bonding in water
molecule

7. O
H H
1 molecule of water

8. A LOT OF MOLECULES
OF WATER

9. Millions of molecules of water
make up 1 raindrop

10. POLAR MOLECULE
• A molecule that has electrically charged
areas.
• Also called a polar substance or polar
compound.
_
+ DURACELL

11. NON-POLAR SUBSTANCES
• Non-polar substances do not have
charged ends
DURACELL

12. O
H H
-
+ +

13. POLAR MOLECULE
The positive hydrogen ends of 1
molecule are attracted to the negative
end of the oxygen of another molecule.
O
H
H

14. POLAR MOLECULE
THE PROPERTIES OF:
Cohesion, adhesion, specific heat, universal
solvent, capillary action, surface tension
ALL HAPPEN BECAUSE WATER IS A
POLAR SUBSTANCE!

15. CAPILLARY ACTION

16. CAPILLARY ACTION
• The combined force of attraction
among water molecules and with the
molecules of the surrounding
material.
• Cohesion + Adhesion

17. SURFACE TENSION

18. SURFACE TENSION

19. SURFACE TENSION

20. SURFACE TENSION
• The tightness across the surface of water
that is caused by the polar molecules
pulling on one another.
• Makes the surface act like a solid

21. UNIVERSAL SOLVENT

22. UNIVERSAL SOLVENT
• This is a nickname given to water.
• Water dissolves LOTS of things.
• Remember:
SOLVENT = the thing doing the dissolving
SOLUTE = the thing that dissolves away
• Other polar molecules can be dissolved by
water.

23. NON-POLAR SUBSTANCES
• Non-polar substances DO NOT dissolve in
water.
• Can you think of some examples of non-
polar substances?
DURACELL

24. Universal Solvent
Why is water so good at dissolving things?
Because water is a polar molecule and is
shaped like a wedge, it is able to break up
substances into smaller pieces (dissolve).

25. COHESION
• Because water is a polar molecule, it
is attracted to itself.
• Cohesion – is the attractive force
between water molecules.
O
H
H

26. Water molecules
like to stick to
each other.
COHESION
Rubbing alcohol
doesn’t like to
stick to itself as
much as water.

28. ADHESION
• Because water is a polar molecule, it
is attracted to other substances.
• Adhesion – occurs when molecules
of water are attracted to other
substances.

29. WATER
DROPLET
WINDSHIELD Adhesion is going
on between the
windshield and the
water droplet.

30. ADHESION

31. COHESION
Water molecules like to stick
to each other.
ADHESION
Water molecules like to stick
to other things.

34. Density of Water
• Most dense at 4oC
• Contracts until 4oC
• Expands from 4oC
to 0oC
The density of water:
1. Prevents water from freezing from the bottom up.
2. Ice forms on the surface first—the freezing of the
water releases heat to the water below creating
insulation.
3. Makes transition between season less abrupt.

35. – When water reaches 0oC, water becomes locked into a
crystalline lattice with each molecule bonded to to the
maximum of four partners.
– As ice starts to melt, some of the hydrogen bonds
break and some water molecules can slip closer
together than they can while in the ice state.
– Ice is about 10% less dense than water at 4oC.

36. SPECIFIC HEAT
BEACH = 200°F
WATER = 75°F

37. SPECIFIC HEAT
• Specific Heat = the amount of energy
needed to increase the temperature of
something 1 degree C.
• Water has a really HIGH specific heat
• That means it takes a lot of energy for
water to increase its temperature.
• This is because of the STRONG
ATTRACTION between water molecules.
It’s POLAR!