Organic Chemistry Flashcards
What is (E) isomerism?
Opposite sides of the double bond.
What is (Z) isomerism?
Same side of the double bond.
What are the three types of structural isomerism?
- Chain
- Position
- Functional group
What are the two types of stereoisomerism?
- E/Z
- Optical
What name is given to a carbon atom attached to four different groups?
Chiral
What are a pair of optical isomers know as?
Enantiomers
What property of optical isomers means there is always a pair?
The two isomers are always non-superimposable
What is a racemic mixture?
An equimolar mixture of a pair of enantiomers which results in it being optically inactive
What property of the carbonyl groups means racemic mixtures are always formed if the resulting molecule is optically active?
The carbonyl group is planar so can be attacked from above or below with equal probability
How can optical isomers be distinguished?
They will rotate the plane of polarisation of plane polarised light in opposite directions
What property of carboxylic acids gives them higher boiling points?
They form dimers
What is the thermochemical evidence for the structure of benzene?
- The saturation enthalpy of C=C is -120kJ.mol-1
- This predicts the saturation of cyclohexatriene to be -360kJ.mol-1
- The saturation of benzene is actually -208kJ.mol-1
- The actual saturation is 152kJ.mol-1 less exothermic
- So benzene is more stable than cyclohexatriene
- Due to delocalisation of electrons
What is the structure of a zwitterion?
When amino acids form proteins what bond joins them?
Pepitide bond (amide link)
What are the two types of polymer?
- Addition
- Condensation
What is the repeating unit in terylene?
What is the repeating unit in nylon 6,6?
What is the repeating unit for kevlar?
