1. Chemistry of Life Water

2. The facts All living things depend on water
70-95% of our cells are made up of water

3. Structure Comprised of two Hydrogen (H) atoms and one oxygen (O) atom
O pulls electrons more strongly than H

4. Polarity Molecules with opposite electric charges Opposites attract!
The H+ is attracted to the O- and create Hydrogen Bonds

5. Hydrogen Bonds do not exchange electrons so they are not as strong as ________ bonds.

6. Water’s Life Supporting Properties
Cohesion and Adhesion
Temperature Moderation
Low Density of Ice
Ability to Dissolve other Substances

7. Adhesion Water being attracted to other molecules Causes water to
stick to substances
Combination of cohesion and adhesion pulls water upward through plants and tree trunks

8. Cohesion
The ability to stick to itself, water molecules attracted to other water molecules
Water has higher cohesion than other liquids
Example: Insects skating over a body of water without breaking the surface, also known as surface tension

9. Temperature Moderation
Water requires a large amount of energy to raise its temperature
It has to lose lots of energy to cool down, releases that energy locally and moderates temperatures in the air
When you sweat the Hydrogen bonds are being broken using your energy as the water is released into the air and that cools your body

10. Low Density of Ice
Most substances greatest density is in their solid state
Water is weird… its solid (ice) has lower density than the liquid form (water)
Allows life to survive under frozen ponds and lakes where they can get food and nutrients

11. Hydrogen Bonds

12. Water can dissolve other substances
Able to dissolve other substances
Water is a good solvent
Substance that dissolves other substance (solute)
Breaks apart ions and attracts them to the respective positive and negative sides.

13. Lab #1 Surface Tension Follow the direction on the handout.
Goal of today: Complete the three data charts (3 trials for each type of liquid)
Clean up your mess, wash your pipet, wipe off your table, and put your pennies back in the container.
Save your paper to finish on Monday.