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Chemistry of Life

Chemistry of Life. I. Atoms A. 2 parts (sub-atomic) 1. nucleus 2. shell (s) = cloud (s) B. Periodic table of elements C. Definitions 1. elements 2. compounds 3. isotopes 4. ions II. Molecules A. Molecular bonds B. Hydrogen bonds III. Origins IV. Water.

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Chemistry of Life

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  1. Chemistry of Life I. Atoms A. 2 parts (sub-atomic) 1. nucleus 2. shell (s) = cloud (s) B. Periodic table of elements C. Definitions 1. elements 2. compounds 3. isotopes 4. ions II. Molecules A. Molecular bonds B. Hydrogen bonds III. Origins IV. Water

  2. Chemical Composition of Human Body

  3. I. Atoms A. 2 parts (sub-atomic) 1. nucleus 2. shell (s) = cloud (s) e- e- e- Inner shell fills first with a maximum of 2 e- p+ no e- e- Second shell fills next with a max of 8 e- e- e- p+ = protons e- no = neutrons Third shell next with a max of 8 (sort of) e- = electrons An atom’s raison d’etre is to fill its outer most shell.

  4. I. Atoms

  5. I. Atoms

  6. I. Atoms Neutral atom

  7. Oxygen has an atomic number of 8 and an atomic weight of 16.0. How many electrons does oxygen need to fill it’s outer shell? a. 1 c. 3 e. 6 b. 2 d. 4

  8. The reactivity of atoms is largely due to the • number of protons in the nucleus • ionic number • polarity of the bonds • electrons in the outer shell • number of neutrons in the nucleus

  9. Carbon Atom

  10. B. Periodic table of elements

  11. C. Definitions • Elements • Compounds • Ions • Negative ions • Positive ions H2O Emergent property NaCl Na+ + Cl- H+

  12. C. Definitions • Isotopes Radioactive Half-life Carbon 14 dating

  13. If an atom has 5 protons, 6 neutrons, and 7 electrons, its charge will be a. neutral b. positive 2 c. negative 2 d. positive 1 e. negative 1

  14. II. Molecules Linus Pauling A. Molecular bonds 1. covalent bonds a. number of bonds and molecular stability b. polar and nonpolar covalent bonds

  15. Representing molecules

  16. II. Molecules b. Polar and nonpolar covalent bonds Oxygen is electronegative

  17. II. Molecules 2. Ionic bonds NaCl Na+ + Cl- oxidized reduced (redox) Oxidation-reduction Rx

  18. II. Molecules B. Hydrogen bonds Dissolve

  19. Liquid, solid, gas

  20. II. Molecules B. Hydrogen bonds

  21. What is the fundamental difference between covalent and ionic bonding? A)Covalent bonding involves only the outer electron shell; ionic bonding also involves the next inner electron shell. B)Covalent bonds form between atoms of the same element; ionic bonds, between atoms of different elements. C)In a covalent bond, the partners have identical electronegativity; in an ionic bond, one of them is more electronegative. D)In a covalent bond, the partners share a pair of electrons; in an ionic bond, one partner captures an electron from the other. E)In covalent bonding, both partners end up with filled outer electron shells; in ionic bonding, one partner does and the other does not.

  22. Under what conditions do atoms interact with other atoms to create covalent bonds? a. when their electonegativies are significantly different b. when their charges are opposite c. when one has an inner shell unfilled and the other has an outer shell unfilled d. when both atoms have spaces in their outer shells that need to be filled

  23. III. Origins Big bang!

  24. IV. Water • Importance to life • Properties of water important to life • High capacity to absorb heat • Cohesion and adhesion • Universal solvent • Solute, solvent, solution • Hydrophilic, hydrophobic • Acid/ base chemistry • Acid • Base • pH (- log [H+] ) • Buffers

  25. The oxygen atom of a water molecule A)is more positively charged than the hydrogen atoms. B)is electrically neutral. C)is more electronegative than the hydrogen atoms. D)is attracted to the negatively charged atoms of other molecules. E)attracts electrons less strongly than the hydrogen atoms.

  26. 1. High capacity to absorb heat evaporation Water is a buffer to temperature change Temperature homeostasis

  27. 2. Cohesion and adhesion

  28. 3. Universal solvent a. Solute, solvent, solution b. Hydrophilic, hydrophobic

  29. B. Acid/ base chemistry 1. Acid 2. Base 3. pH (- log [H+] ) 4. Buffers [H+] > [OH-] Acid [OH-] > [H+] HOH H+ + OH- Base hydroxyl Neutral [H+] = [OH-] Most common physiological buffer: HCO3- bicarbonate Absorbs H+ up down low high high

  30. You are outside on a very cold day and take your temperature. It is 37C. This is because a. water molecules adhere together and prevent temperature change b. water has a high capacity to absorb heat without changing temperature c. heat is a solute that dissolves in water d. heat changes the pH of blood causing it to cool

  31. Solution A has a pH of 2.0 and solution B has a pH of 4.0. Which of the following is the difference between the two solutions? a. Solution A has twice as much hydrogen ion concentration as B b. Solution B has twice as much hydrogen ion concentration as A c. Solution A has 100 times as much hydrogen ion concentration as B d. Solution B has 100 times as much hydrogen ion concentration as A

  32. Challenge question: treeline Cascades: 7,000 feet Rocky mountains: 10,000 feet

  33. The end

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