Tuesday, May 15, 2012

FINAL EXAM REVIEW YAYAYAY~~~~~~~~~

6) List the three main types of intermolecular forces and describe how each are formed. Which intermolecular forces are the strongest and why?
  1. London Dispersion Forces- between non-polar molecules (Weakest)
    • step 1: two molecules get close to each other
    • step 2: electrons in one molecule shift to form an instantaneous dipole (2 poles created by bonds + & -) 
    • step 3: momentary dipole in one molecule induces a dipole in the other and they form an interaction
      • only momentary dipole
      • low temperature and bigger atoms/molecule make LDF stronger
        • electrons move slower
      • contain more electrons that are held less firmly by nucleus- allows them to shift & form instant dipole
    • NOT A BOND ONLY A FORCE/ATTRACTION
  2. Dipole Interactions- between polar molecules (2nd Strongest)
    • positive pole is attracted to the negative pole
    • easily broken using boil/melt
      • permanent dipole
    • NOT A BOND ONLY A FORCE/ATTRACTION
  3. Hydrogen Bonds- (Strongest)
    • FORCE OCCURRING
    • Polar molecules that contain a bond between H and either O, N, or F
    • large electronegativity difference creates stronger dipoles
      • permanent dipole
  • Hydrogen and Dipole can ALSO have LDF

2 comments:

  1. What a wonderful post Ford!
    Although you have pointed out a lot of great facts on intermolecular forces, I managed to think of a few more nuggets of information... On the LDF, low temperature not only makes the bond stronger, but it makes the temporary dipoles more permanent, if you will. In addition, the melting and boiling points of hydrogen bonds are higher because it is very difficult to break up the strong bonding. Sorry, but I simply couldn't help adding some fun information about intermolecular forces. (Plus this is an assignment and I was required to add more info) Anyways, VERY NICE.

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  2. Great job Ford! I would like to add that in hydrogen bonds the boiling and melting points are higher because hydrogen bonds are the strongest bonds and therefore it is much more difficult to break apart the strong hydrogen bonds. Nice job!

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