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Why Study Chemistry in Biology?

Why Study Chemistry in Biology?. Banana Cell with Starch Granules. The Size of an Atom. http:// www.youtube.com / watch?v = aQnbF-zpDiM. The Atom. Elements. Mass Number. Atomic Mass 12.0107 amu. Isotopes. Mass Number. Radioactive Isotopes. Carbon Dating.

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Why Study Chemistry in Biology?

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  1. Why Study Chemistry in Biology?

  2. Banana Cell with Starch Granules

  3. The Size of an Atom http://www.youtube.com/watch?v=aQnbF-zpDiM

  4. The Atom

  5. Elements Mass Number Atomic Mass 12.0107 amu

  6. Isotopes Mass Number

  7. Radioactive Isotopes

  8. Carbon Dating

  9. Bohr Atomic Model

  10. Lewis Dot: Only Valence Electrons

  11. Molecule

  12. Counting Atoms C6H12O6 Element subscript is the NUMBER of ATOMS So in this molecule, there are 6 carbon atoms, 12 hydrogen, and 6 oxygen

  13. Atoms Space

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

  15. 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.”

  16. 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!”

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

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

  19. 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

  20. pH- buffer

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

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

  23. LIFE DEPENDS ON THE UNIQUE PROPERITIES OF WATER

  24. 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?

  25. Human Composition • Cells are 70 to 95% water

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

  27. Formula and Bonds Formula: H2O Bonds: Covalent- electrons are shared between Oxygen and Hydrogen

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

  29. Hydrogen Bonds • Hydrogen Bonds- weak bondsslightly positive H is attracted to the slightly negative O of another water molecule

  30. 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

  31. 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

  32. 1-inchpaperclip over-filled water 3oz Dixie cup Cohesion • Water “sticks” to each other • Surface tension

  33. Jesus Christ Lizard

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

  35. 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-)

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

  37. Temperature and Water Boiling Point: 100 oC 212 oF • When you heat molecules move faster • When you cool molecules move slower • Water takes more energy to heat because energy must break hydrogen bonds

  38. 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

  39. Freezing Point 0 oC or 32 oF • 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?

  40. 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

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