Key Stuff - Module 4 + 6 Flashcards
Homologous Series
Series of organic compounds having the same functional group but with each successive member differing by CH2
Structural isomers
Compounds with the same molecular formula but different structural formulae
Radical
A species with an unpaired electron
Describe the trends in boiling points of alkanes
- ↑in chain length = ↑ points contact = ↑ induced d-d interaction - ↑ BP
- Branched molecules have ↓ points contact = ↓ induced d-d interaction - ↓ BP
Why do alkanes have relatively low reactivity?
- ↓ bond polarity of sigma bond
- ↑ bond enthalpy
Steroisomers
Compounds with same structural formula but with different arrangement in space
E/Z isomerism
- Causes by restricted rotation about the double bond
- requires X2 diff groups to be attached to each C atom of C=C
Cis/Trans Isomerism
- Special type of E/Z isomerism
- Where 2 of substituent groups attached to each C atom of C=C group are the same
Electrophile
Electron pair acceptor
Nucleophile
Electron pair donor
Outline mechanism for production of halogen radicals + breaking down of ozone layer
Evidance against Kekule’s benzene model
- C-C bonds all same length - C=C should be shorter
- It doesn’t undergo addition reactions easily
- ΔH hydrogenation about 152 kJ mol-1
less than expected
For electrophillic mechanism which way does the curly arrow go?
From double bond to the species
For nucleophillic mechanisms which way does the curly arrow go?
From the species to the compound
Why is benzene less reactive then its alkene?
- Benzene’s π electrons are delocalised whereas alkenes π electrons are localised bt/w 2 C’s - electron density lower in benzene
- The lower electron density means that electrophiles are less attracted
- Therefore less reactive
Why is phenol more reactive then benzene?
- As the lone pair of e- on the O
- Partially delocalised into the π ring
- Making phenol more susceptible to electrophilic attack
How do you name & draw an ester?
- ‘thyl’ - from alcohol
- ‘oate’ from acid/anhydride
- alchol on the right (attached to single bonded O)
Describe Zwitterion
- At specific pH - isoelectric pH + in crystalline solid - amino acid will exist as zwitterion
- Protons transferred internally from COOH to NH2
Optical isomerism
Non-superimposable mirror image about a chial centre
