Orgo Chemistry

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Orgo Chemistry
2012-06-11 15:20:04

o chem usm
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  1. The dissociation of a molecule into two neutral fragments.
    • Homolytic
    • Heterolytic
  2. An organic reaction in which the breaking of bonds leads to the formation of ion pairs.
    • Heterolytic
    • Homolytic
  3. What is a Nucleophile?
    "nucleus loving" which describes the tendency of an electron rich species to be attracted to the positive nuclear charge of an electron poor species, the electrophile .
  4. The more available the electrons the more nucleophilic system.
  5. Nucleophilicity follows the same rules as Electronegativity? True/False
    False, Within a group in the periodic table, increasing polarisation of the nucleophile as you go down a group enhances the ability to form the new C-X bond and increases the nucleophilicity, so I- > Br- > Cl- > F-. The electron density of larger atoms is more readily distorted i.e. polarised, since the electrons are further from the nucleus.
  6. Acidity increases down a group. True/False
  7. A Lewis _____ accepts an electron pair.
  8. A Lewis ____ donates an electron pair.
  9. A ______ base donates an electron pair.
  10. A _____ acid accepts an electron pair.
  11. A Bronsted _______ donates a proton.
  12. A Bronsted _____ accepts a proton.
  13. A ________ is a Lewis Base that donates an electron pair to an atom other than a Hydrogen.

  14. ............^...............^
    Lewis base....... Lewis acid
    Bronsted base... Bronsted Base
    Nucleophile....... Nucleophile

  15. ............^...............^
    Lewis base....... Lewis acid
    Bronsted base... Bronsted Base
    ucleophile....... Nucleophile
  16. Rate of reaction for SN1?
    • SN1 reaction is the same as SN2 except its a unimolecular, so it only depends on the concentration of nucleophile (weak nucleophile as protic solvent ex. MeOH)
    • Thus, in SN2 reaction, if you up the concentration of substrate or nucleophile, or both, the rate will go up. And in an SN1 reaction, if you up the concentration of the substrate, then ONLY the rate will go up; the concentration of the nucleophile doesn't matter. In this sense you can have a million molecules of nucleophile but 10 molecules of substrate, it will only go as fast as those ten molecules can react.
  17. What is the SN2 rate of reaction?
    SN2 means a bimolecular nucleophilic substitution reaction. The number 2 means that the rate law is dependant on two things. Since the reaction itself occurs in one step, the rate is:

    rate = k x [Substrate]*[Nucleophile]

    which means an arbitrary rate constant k times the concentration of substrate (alkyl halide, generally) times the concentration of nucleophile (which is strong, nucleophilic in a aprotic solvent)
  18. What is an a-elimination?
    A reaction in which both the groups or atoms are removed from the same carbon of the molecule is called α-elimination reaction.
  19. What is a b-elimination?
    A reaction in which functional group (i.e., leaving group) is removed from α-carbon and other group (Generally hydrogen atom) from the β-carbon is called β-elimination reaction. In this reaction there is loss of two σ bonds and gain of one π bond. Product of the reaction is generally less stable than the reactant.

  20. Stable to Least stable or Least stable to stable?

  21. Dieletics of < 15 are nonpolar.

  22. What is this molecule?
    Ethanol or Ethyl Alcohol
  23. What does protic mean?
    a solvent that has a hydrogen atom bound to an oxygen (as in a hydroxyl group) or a nitrogen (as in an amine group)
  24. An aprotic solvent favors which kind(s) of reactions?
    SN2 and E2
  25. What is a protic solvent?
    It has hydrogens that can easily be taken. Hydrogens bonded to an oxygen fore example. Not a carbon hydrogen bond.

  26. Although hydroxide ion promotes a bimolecular reaction, the tertiary alkyl halide won't undergo an SN2 mechanism because of the steric hindrance imposed by the three alkyl groups. Keep in mind Zaitsev's rule when determining the major elimination product.
  27. A beta carbon is a carbon to the left or right of the alpha carbon.

  28. What is Zaitsev's rule?

    • It will take the proton with the fewer hydrogens.
    • Hyperconjugation also says that the more stable double bond will be formed, so the carbon that is attached to more carbons will be more stable than the one with hydrogens.
  29. Heptane
  30. Hexane
  31. Pentane
  32. Methane