1. Welcome to Grade 12 Biology!  Bios = life  Ology = the study of  Biology is the study of life and living processes! Introduction to biology video:  http://www.youtube.com/watch?v=VgTPg9 9V_JM http://www.youtube.com/watch?v=VgTPg9 9V_JM

2. 02/09/09 Chemistry Review- what? I thought it was Bio....

3. Chemistry of Life

4. All life is hierarchically organized

5. What is matter?  All “stuff” is matter  matter has mass  Fundamental unit = atom  compounds – combinations of elements eg. NaCl

6. Elements essential to life  All life forms require 25 elements  The Big 4 a.CHON i.Carbon ii.Hydrogen iii.Oxygen iv.Nitrogen Makes up 96% of living matter

7. Elements essential to life  All life forms require 25 elements  The Little 4 b. PCaSK i.Phosphorous ii.Calcium iii.Sulphur iv.potassium Makes up 3% of living matter

8. Elements essential to life  All life forms require 25 elements  Trace elements Essential in small amounts Makes up < 1%

9. Elements essential to life

10. Trace elements are important

12. Calculating subatomic particles

14. Atomic Bonds

15. Electronegativity! Electronegativity: The ability of an atom to attract an electron in a chemical bond Each atom has an associated number- the higher the number the higher the attraction of the electron

17. Atomic Bonds

18. Number of bonds

19. Chemical Reactions

20. Water as a solvent

21. 02/09/09 3. Water is a universal solvent  Water can dissolve ionic compounds by "surrounding" the ions

22. Other properties of water

25. Cohesion and Adhesion  Water molecules tend to stick together  Water can rise up a plant’s xylem against gravity

26. Unique Properties of Water Chemistry of Water Video Summary: http://www.youtube.com/watch?v=DAilC0sjvy0 How do these unique properties make life possible?...

27. Hydrophilic vs. Hydrophobic Ionic / polar compounds “love” water! Nonpolar compounds “fear” water!

28. Properties of Acids Low pH Sour taste React with some metals to produce H 2 A good conductor of electricity in solution Release H + ions in solution (actually, hydronium H 3 O + ions) Indicators: – Blue litmus turns red

29. Example of an Acid: HCl (aq)  H + (aq) + Cl - (aq) Note: aq stands for aqueous or dissolved in water

30. Properties of Bases High pH Bitter taste Slippery and soapy to the touch A good conductor of electricity in solution Release OH - (hydroxide) ions in solution Indicators: – Red litmus turns blue

31. Example of a Base: NaOH (aq)  Na + (aq) + OH - (aq)

32. Is Distilled Water Acidic? H 2 O (l) H + (aq) + OH - (aq) Autoionization of water!

33. The pH Scale Used to identify how acidic or basic a solution is based on a scale of 1 to 14 A very acidic solution has a LOW pH A very basic solution has a HIGH pH A neutral solution has a pH of 7 (water)

34. The pH Scale

35. pH Is a measure of how acidic a substance is – Acid examples  Hydrochloric acid, Sulfuric Acid, Citric Acid It is measured on a scale (pH scale) from 1-14 7 (Neutral) = Water and Blood < 7 (Acidic) = e.g. Vinegar > 7 (Basic) = e.g. Ammonia (household cleaner)

36. Logarithims The pH scale is a logarithmic scale One spot on the scale is a 10 fold difference in the concentration of the solution Examples: pH 3 vs pH 4 - the 1st is 10 times more acidic pH 3 vs pH 5 - the 1st is 100 times more acidic

37. NOTE: As pH INCREASES the solution becomes more BASIC As pH DECREASES the solution becomes more ACIDIC

38. Neutralization Reactions When an acid reacts with a base pH moves towards 7 Double displacement reactions – E.g. HCl (aq) + NaOH (aq)  HOH (l) (H 2 0) (l) + NaCl (aq) Produces a salt and water Acid + Base  Water+ Salt

39. Neutralization Examples HCl + NaOH  H 2 O + NaCl H 2 SO 4 + 2KOH  2H 2 O + K 2 SO 4 Basically… H + + OH -  HOH = H 2 O The other portions of the acid and base join to make a salt.

40. What is a salt? Any combination of positive and negative ions formed by the reaction of an acid and a base (ionic compound). Not necessarily table salt (NaCl)!

41. What is a Buffer? A chemical that resists pH changes in a solution by accepting or donating H+ ions. e.g. carbonic acid in your blood helps to regulate the pH within a narrow range of 7.35-7.45 HCO 3 - + H + H 2 CO 3 If the blood is too acidic (too many H + ions), they bind to the bicarbonate ions and get locked up as H 2 CO 3 If blood is too basic (too few H + ions) the reaction goes the other way (right to left)

42. Acids and Bases Song! https://www.youtube.com/watch?v=u9nOIZD dvRw https://www.youtube.com/watch?v=u9nOIZD dvRw