Tang 02a chemistry review-2012 update


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Tang 02a chemistry review-2012 update

  1. 1. What do you remember? Make sure you can answer the review questions on page 4 and 5!
  2. 2. Chemical Bonding Bonds are formed when electrons are shared or exchanged between atoms. 1. intermolecular bonds 2. intramolecular bonds bonds found between molecules bonds found between atoms WITHIN a molecule
  3. 3. Intermolecular Bonds The strength of these bond are relatively weak. 1. van der Waals interactions  attraction between nearby non-polar molecules  attraction of + and - ends of polar molecules 2. hydrogen bonding (H-bonding)  strongest type of polar molecule interactions
  4. 4. Intermolecular Bonds
  5. 5. Intramolecular Bonds 1. covalent bonds  sharing electrons between atoms; sharing may be equal or unequal 2. ionic bonds  electrostatic attraction between ions upon electron transfer
  6. 6. Why is it so important?
  7. 7. The Importance of Water Many of the properties of water are due to its polarity and H-bonding.
  8. 8. 1. Cohesion-Adhesion H-bonding allows water molecules to cling to each other and to other molecules.
  9. 9. 2. High Heat Capacity Water is capable of absorbing a lot of heat without increasing in temperature. Heat absorption of bodies of water during the summer keeps the air around it cooler. In the winter, the heat released warms the surrounding air.
  10. 10. 3. High Heat of Vaporization Water requires a lot of heat to evaporate from liquid to gas states.
  11. 11. 4. Low Density Solid Water is the only type of matter which becomes less dense when a solid.
  12. 12. 5. Very Good Solvent Many other molecules are able to dissolve in water. Organic matter may be hydrophilic or hydrophobic.
  13. 13. 6. Determines pH Organisms are very sensitive to pH. H2O <===> H+ + OH- pH = -log[H+]
  14. 14. Acid-Base Chemistry Is water an acid or a base? H2O + H2O H3O+ + OH- acid conjugate base base conjugate acid
  15. 15. Brønsted-Lowry Acids & Bases acid  compounds that will donate a proton in solution  results in a negative charge base  compounds that will receive a proton in solution  results in a positive charge
  16. 16. Do you remember your functional groups?
  17. 17. Carbon All organic molecules contain the carbon atom. Also mainly contain hydrogen, oxygen and nitrogen. This is important because it: 1. may participate in four covalent bonds. 2. can form long chains. 3. can form ring structures.
  18. 18. Carbon -Carbon can make 4 bonds -The 4 bonds can be a combination of single, double, and triple bonds methane, CH4 methanal, CH2O ethanenitrile, CH3CN
  19. 19. Drawing organic molecules 3 types of diagrams Structural diagram CH3CH2CH2CH2CH2CH3Condensed diagram Line diagram
  20. 20. Drawing organic molecules Line diagrams: Every end or point on a line diagram represents a carbon atom. Hydrogen atoms are not shown. 1 2 3 4 5 6
  21. 21. Functional Groups How an organic molecule will react is dependent on its functional groups.
  22. 22. Functional Groups Functional groups are like the gadgets on a Swiss Army knife. They determine the functions of the knife, similar to how functional groups determine the function of a molecule.