1. Chapter: 3 Water

2. Molecule That Supports All of Life

3. 3/4 of the Earth’s surface
Abundance is the main reason the Earth is habitable
Figure 3.1

4. Polarity of water molecules  Hydrogen bonds between molecules
 Properties
Hydrogen bonds + H
 –
Figure 3.2

5. Bonding to neighboring molecules Due to hydrogen bonding
Cohesion
Bonding to neighboring molecules
Due to hydrogen bonding
Hydrogen bonds + H
 –
Figure 3.2

6. Water conducting cells
Transpiration pull water up through the microscopic vessels of plants
Water conducting cells
100 µm
Figure 3.3

7. Surface tension
Figure 3.4

8. Water moderates air temperature
Absorbs heat from air that is warmer and releasing the stored heat to air that is cooler

9. Water High Specific Heat
Amount of heat absorbed or lost to change its temperature
 hydrogen bonds

10. Evaporative Cooling
Allows water to cool a surface

11. Hydrogen bonds in ice More “ordered” than in liquid water  less dense
Hydrogen bonds constantly break and re-form
Ice
Hydrogen bonds are stable
Hydrogen bond
Figure 3.5

12. Since ice floats in water
Life can exist under the frozen surfaces of lakes and polar seas

13. Polar regions of water molecule interact with ionic compounds
Solvent of Life
Polar regions of water molecule interact with ionic compounds
Negative oxygen regions of polar water molecules are attracted to sodium cations (Na+). +
Cl – –
Na+
Positive hydrogen regions of water molecules cling to chloride anions (Cl–).
Cl–
Figure 3.6

14. pH scale pH Scale 1 2 Increasingly Acidic [H+] > [OH–] 3 4 5 6
Increasingly Basic
[H+] < [OH–]
Neutral
[H+] = [OH–]
Oven cleaner 1 2 3 4 5 6 7 8 9 10 11 12 13 14
pH Scale
Battery acid
Digestive (stomach)
juice, lemon juice
Vinegar, beer, wine,
cola
Tomato juice
Black coffee Rainwater
Urine
Pure water
Human blood
Seawater
Milk of magnesia
Household ammonia
Household bleach
Figure 3.8

15. Buffers
Minimize changes in pH

16. Acid precipitation Can damage ecosystems More acidic Acid rain1 2 3 4 5 6 7 8 9 10 11 12 13 14
More acidic
Acid rain
Normal rain
More basic
Figure 3.9