1. Properties of Water

2. Water is a polar molecule
Its overall charge is unequally distributed
The oxygen region has a partial negative charge
Each hydrogen has a partial positive charge

3. The polarity of the water results in weak electrical attractions between neighboring molecules
Called hydrogen bonds

4. This polarity gives rise to water’s unique properties including:
1. Water’s cohesive nature
2. water’s ability to moderate temperature
3. floating ice
4. versatility of water as a solvent

5. Cohesive nature
Cohesion: the attraction of water molecules to each other
Due to hydrogen bonding

6. cohesion Creates surface tension
A measure of how difficult it is to stretch or break the surface of a liquid

7. cohesion
Vital for water transport in plants

8. adhesion
Adhesion: The attraction of water molecules to other polar substances
Due to hydrogen bonding

9. adhesion Ex. Glass has polar molecules Glass can hydrogen bond
Attracts the water molecules
Some of the pull is up
This makes the meniscus

11. 3. Moderation of Temperature by water
Water has a high specific heat
Specific heat: the amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1*c

13. so…

15. 4. Floating of ice on liquid
When temperature falls from 4*c to 0*c, water freezes because molecules move too slowly to break the hydrogen bonds
Form a crystalline lattice
Fewer molecules in ice than an equal volume of liquid water

17. In general, how is this important to life?

18. 5. water: the solvent of life