1. Water Makes up 70-90% of all living things
Covers 3/4 of earth’s surface

2. Chemical Formula of Water
H2O
2H2 + O2  2H2O
Chemical Structure

3. Characteristics of Water
Water is Polar
Hydrogen Bonds
High Surface Tension
Adhesion
Cohesion
Universal Solvent
Density
Temperature Moderation

4. 1. Water is Polar Water molecules are polar:
Polar molecules have an uneven distribution of electrons
The molecule has (+) and (-) end.

5. 1. Water is Polar 1. Water molecules are polar:
Polar molecules have an uneven distribution of electrons
The molecule has (+) and (-) end.

6. Hydrogen Bonds
The polarity of water results in Hydrogen bonding: weak bonds that are constantly broken/formed.
Water molecules are held together by hydrogen bonds
The positive hydrogen of one water molecule is attracted to the negative oxygen of another water molecule. The two atoms then ‘adhere’

7. 2. High Surface Tension Water has high surface tension Application:
Hydrogen bonds make it difficult to “break” through the surface of water.
Application:
Some organisms can “walk” on water

9. 3. Adhesion Water molecules are adhesive. H2O Application:
Water molecules stick to other surfaces
Application:
Water can travel up plant stems (capillary action).
H2O

10. 4. Cohesion Water molecules are cohesive Application:
Water molecules stick together
Application:
Water molecules move as waves (affects temperature, dissolved gases, nutrient/microorganism distribution)

11. 5. Universal Solvent Water is a universal solvent (dissolver).
Universal Solvent: Creates a solution and can dissolve many different solutions
Great solvent because it has positive and negative areas that attract ions
Application:
Water can carry minerals and nutrients with it through soils and in blood.

12. 5. Universal Solvent And this is important because…?
A universal solvent is important because it makes up many living organism’s bodies and will not create new substances when chemicals are added to it!
Solvent: What is doing the dissolving
Solute: What is being dissolved

13. Water = solvent
Salt = solute

14. 6. Density Ice is less dense than liquid water Application:
Water expands when frozen
Application:
Ice floats on top of water, and insulates water below it, keeping it from freezing

15. 7. Temperature Moderation
Water heats up and cools down very slow
Application
Keeps our body temperatures constant
Keeps the worlds temperature constant