Chem 321 Exam 2

  1. Torsional strain
    eclipsing strain
  2. angle strain
    deviation from ideal of SP3 (109°)
  3. enantomers
    pair of non superimposable mirror images
  4. chiral
    a molecule that is non superimposable on its mirror image
  5. Meso Compound
    achiral molecules with 2 or more stereogenic centers that is superimposable on its mirror image
  6. achiral
    molecule that is super imposable on its mirror image; often has plane of symmetry
  7. catalyst
    a material that increases the rate of a reaction without being consumed by it
  8. absolute configuration
    arrangement in space of the atoms in an enantiomer
  9. optically active molecule
    a molecule that rotates plane polarized light
  10. dextrorotatory
    a molecule that rotates plane polarized light clockwise
  11. levorotatory
    a molecule that rotates plane polarized light counterclockwise
  12. racemic
    a 50:50 mixture of R/S enantiomers
  13. conformational isomers
    molecules that are interconvertible through rotations about bonds within the molecule
  14. stereoismers
    molecules that have the same connectivity of constituents but different arrangements of their parts in space
  15. angle strain
    the increase in energy caused by the deviation of an angle from the ideal demanded by hybridization
  16. torsional strain
    the destabilization induced in a molecule due to eclipsed bonds
  17. van der waals strain
    strain caused by having elements too close together
  18. chiral exceptions:
    • helicenes with ≥6 benzene rings
    • Substituted biphenyl
    • substitued allenes
  19. substituted alleges chiral if...
    contains even number of consecutive pi bonds
  20. substituted allenes achiral if...
    contains add number of consecutive pi bonds
  21. Distortion from planarity relieves ?
    torsional and some angular strain
  22. Calculate torsional strain in planar cyclic molecules
    2x #C = kcal/mol
  23. cyclic compound angle strain trend
    decreases to cyclohexane
  24. torsional strain trend
    constantly increases as #H increases
  25. Cyclopentane 3D shape
  26. cyclobutane 3D shape
  27. cyclopentane 3D shape
    envelope and twist
  28. cyclohexane 3D shape
    chair, half chair, twist, boat
  29. energy for cyclohexane half chair
    10.8 kcal/mol
  30. energy for cyclohexane twist
    5.5 kcal/mol
  31. energy for cyclohexane boat
    7 kcal/mol
Card Set
Chem 321 Exam 2