1. Acids, Bases and Buffers
CHEMISTRY of WATER
Acids, Bases and Buffers

2. Structure and geometry of water

3. Four hydrogen bonds

4. PROPERTIES OF WATER Cohesion and adhesion High heat specificity
High heat of vaporization
Expands as freezes (less dense as solid)
Universal solvent

5. Adhesion and Cohesion
Adhesion – H bonds on water molecules attract to surfaces of another substance
ex – the sides of a vessel (xylem/phloem), causes meniscus shape in grad. cyclinders

6. Transpiration in plants

7. Water has a high specific heat

8. Why important to life? This property allows for life b/c
1. External environments are controlled in part b/c of this property. Ex. Large bodies of water stabilize air temperature due to HIGH SPECIFIC HEAT of water.
2. Internal environments of living organisms are controlled by this property. High Specific heat of water keeps internal temp. flucuations to a minimum.

9. High Heat of Vaporization

10. Why important?
Globally – this acts as a cooling device and maintains global climates (think Gulf Stream)

11. Protects terrestrial organisms from overheating – as liquid vaporizes, the water left behind actually loses the kinetic energy of the escaped molecules causing the remaining liquid to cool down

12. Expands as freezes

13. Why important?
Floating ice actually insolates the liquid water below allowing for life.
Oceans and lakes don’t freeze solid due to this property

15. Universal Solvent

16. Solutes that dissolve in water
Hydrophilic – water loving substances
ions, salts, polar molecules
Hydrophobic – water fearing
oils, hydrocarbon chains,
Nonpolar molecules

17. Link

18. Dissociation of Water

21. pH Scale

22. Buffers

23. Bicarbonate Buffer System

25. AP EXAM ESSAY
1.  The unique properties (characteristics) of water make life possible on Earth. Select three properties of water and:
for each property, identify and define the property and explain it in terms of the physical/chemical nature of water.
for each property, describe one example of how the property affects the functioning of living organisms.