1. Why Study Chemistry in Biology?

5. Banana Cell with Starch Granules

7. The Size of an Atom

8. The Atom

11. Elements Atomic Mass 12.0107 amu Mass Number

12. Isotopes Mass Number

13. Radioactive Isotopes

15. Carbon Dating

16. Bohr Atomic Model

17. Lewis Dot: Only Valence Electrons

18. Molecule

19. Compound

20. Atoms Space

21. DO NOW Why if atoms have so much space can we be solid? Why if atoms have so much space can we be solid?

22. JOKE- Don’t Have to write this. A NEUTRON walks into a diner and sits down to order a meal. When the waitress brings the food over the neutron says “Can you bring the check? I am in a hurry!” The waitress replies, “Don’t worry about it, there is NO CHARGE for you.”

23. JOKE- Don’t have to write this. Two atoms walk down the street and collide. One atom says to the other, “Are you okay?” The second atom replies, “I think I lost an electron.” The first atom says, “Are you sure?” The second one says, “Yeah, I’m POSITIVE!”

24. ACIDS,BASES, and pH Acid- a solution high in H + ions (HCl) Base- a solution high in OH - ions

25. BUFFERS A substance that causes a solution to resist changes in pH Accept H + ions when levels rise Donate H + ions when levels fall

26. THE pH SCALE pH Scale- describes how acidic or basic a solution is Ranges from 0 (most acidic) to 14 ( most basic) Each number is 10 times the previous

28. COVALENT BOND Number of bonds depend on how many electrons are needed to fill the outermost shell

29. IONIC BONDS Ionic Bonds- transfer of electrons between atoms Ion- an electrically charged atom Gain electron; negative charge Lose electron; positive charge

30. LIFE DEPENDS ON THE UNIQUE PROPERITIES OF WATER

32. Questions to think about Why do put salt on the roads? Why do we salt a pot of pasta water? At a higher altitude why must we cook “boil” something longer?

33. Cells are 70 to 95% water Human Composition

34. Plant Composition As much as 95% plants can be made of water

35. Formula and Bonds Formula: H 2 O Bonds: Covalent- electrons are shared between Oxygen and Hydrogen

36. Because Oxygen has 8 Protons (+) it pulls the electrons more (Electron HOG) Oxygen acts Negative- Hydrogen acts Positive HH O How do we get Hydrogen Bonds?

37. Hydrogen Bonds Hydrogen Bonds- weak bonds slightly positive H is attracted to the slightly negative O of another water molecule

38. Polarity Polar molecule: molecule in which opposite ends have opposite electric charges Why? Water is a polar molecule: because Oxygen is an electron HOG POLAR COVALENT BOND

39. The polar nature of water and the effects of hydrogen bonding explain most of water's unique properties. Cohesion Adhesion Solubility Temperature moderation The lower density of ice

40. Cohesion Water “sticks” to each other Surface tension 1-inch paperclip over-filled water 3oz Dixie cup

41. Jesus Christ Lizard

42. Adhesion Water molecules are also attracted to certain other molecules. Ex. In trees/plants water goes against gravity Called capillary action

44. Water is the a Universal Solvent Water is able to dissolve other Polar & ionic compounds when mixed by causing the ions to break away and surround them. Water dissolves Salt (Na + Cl - )

45. Water (Polar) will not dissolve (Nonpolar) Like dissolve Like Water won’t dissolve oils

46. Temperature and Water When you heat molecules move faster When you cool molecules move slower Water takes more energy to heat because energy must break hydrogen bonds Boiling Point: 100 o C 212 o F

47. Does water boil faster if you add salt to it? Yes or No- pollseverywhere Water Boils when it has enough energy for the molecules to leave

48. Freezing Point What would happen if our oceans did not have salt in them? Why do we put salt on our roads? Why at effect does salt have on FREEZING POINT? 0 o C or 32 o F

49. LOW DENSITY OF ICE Density- amount of matter in a volume In most substances the solid state is more dense than the liquid state Water is the opposite ICE IS LESS DENSE THAN WATER and will FLOAT

50. LOW DENSITY OF ICE WHY????? Hydrogen bonds in ice (solid) keep molecules spaced out

51. LOW DENSITY OF ICE Floats Ice insulates the liquid water below allowing life to persist

52. Homework Questions 1. Explain how the structure of water molecules results in attractions among them. 2. Give an example of how cohesion among water molecules is important to living things. 4. Name three conditions on Earth that make the planet suitable for life. 5. Explain one way in which water can moderate temperature.

53. Why is this important for life? Water Boiling Point Ethanol Boiling Point

54. Why are higher altitude must we cook “boil” something longer?