1. Water

2. I.Water and hydrogen bonding II.Properties of water III.Acids and bases A bit about water....

3. Polar covalent bond : bond in which electrons are shared unequally. Water and hydrogen bonding

4. Hydrogen bonds

5. Cohesion Temperature stabilizing capacity Insulation of bodies of water by ice Solvent properties Properties of water

6. Due to H-bonding, water is highly cohesive. Cohesiveness accounts for high surface tension Cohesiveness

7. Water-conducting cells 100 µm Cohesiveness

8. Water and Temperature

9. Specific heat - amount of energy a substance must absorb per gram to increase temp 1 degree C Temperature stabilizing capacity

10. Specific heat - amount of energy a substance must absorb per gram to increase temp 1 degree C Temperature stabilizing capacity specific heat of water is 1 cal/gram

11. Specific heat of water is higher than most other liquids because of extensive H-bonding

12. Water and temperature

13. Effect of a large body of water on temperature

14. High specific heat buffers against temperature increases

15. Important in context of cell biology because cells release large amounts of energy during metabolic reactions. Release of heat would pose overheating problem were it not for high specific heat of water High specific heat of water

16. Evaporative Cooling

17. Ice Floats

18. Solvent of Life

19. Solvent properties Water is an excellent solvent for biological purposes because of its ability to dissolve great variety of solutes.

20. Hydrophilic Hydrophobic

21. Hydrophilic: polar molecules that dissolve readily in water; sugars, organic acids, some amino acids. Hydrophobic: non-polar molecules that are not very soluble in water. lipids, some proteins Solvent properties

22. Water is a polar solvent

23. Water Disassociates H+OH -

24. pH scale expresses hydrogen ion (H + ) concentration in a solution. –logarithmic scale ranging from 0-14 neutral = 7 Acids and bases

25. pH Acids dissociate in water to increase the concentration of H +. –pH values lower than 7 Bases combine with H + ions when dissolved in water, thus decreasing H + concentration. –pH values above 7

26. more OH- pH scale more H+

27. 10 0 1 2 3 4 5 6 7 8 9 3 Amount of base added Buffering range 452 pH Buffers act as a reservoir for hydrogen ions, donating or removing them from solution as necessary.

28. Acid Precipitation Coal

29. Damage from Acid Rain