9729 organic chem notes

disclaimer: this set of notes is only comprehensive for the following sub-topics of organic chemistry for H2:- alkenes- arenes- halogen derivatives- alcohols & phenols- carbonyl compounds However, the mind maps included are comprehensive of all the organic chemistry reactions in the 9729 syllabus, minus free radical substitution of alkanes.

Physical properties Trend of boiling points down the homologous series (applicable to all):- As the number of carbon atoms increase, the size of the elctron cloud increases, and becomes more polarisable. - The strength of id-id increases, so more energy is required to overcome the id-id, leading to higher boiling points. cis vs trans isomer:- cis isomers have higher boiling points, as they have a net dipole moment- individual dipole moments cancel each other out in trans isomers- cis isomer is a polar molecule held together by pd-pd, while trans isomers are held together by id-id- more energy is required to overcome pd-pd than id-id- trans isomers have better symmetry than cis isomers, allowing them to pack together more efficiently in the solid state- closer packing allows for stronger id-id between molecules, which require more energy to overcome soluble in non-polar solvents- alkenes can form favourable id-id attractions with the solvent insoluble in water and other highly polar solvents- energy released from the id-id formed between alkenes and water molecules are insufficient to compensate for the energy required to overcome the id-id between alkene molecules and hydrogen bonding between water molecules. FAQ Why is XXX the major product?- the __ carbocation has more electron-donating alkyl groups attached to the positively-charged C atom- positive charge on the C atom becomes more dispersed, so the carbocation is more stable, hence (major product) is more likely to be formed Explain why the resulting mixture is optically inactive even though the product contains a chiral carbon.- the carbocation is trigonal planar wrt the positively-charged C atom- The _ nucleophile can attack the positively-charged C atom from either side of the plane with equal probability- equal amounts of both enantiomers are formed, forming a racemic mixture- the 2 enantiomers rotate plane-polarised light by the same extent but in Saytzeff’s Rule: When there is more than one alkene that can be formed from elimination, the major product is the alkene with the greatest number of alkyl groups bonded to C atoms in the C=C double bond. Markovnikov’s Rule: The electrophile is added to the C=C bond in a way such that the most stable carbocation intermediate is produced.

Mechanisms to know: Electrophilic Addition

Resonance : the p orbitals of carbon atoms in a benzene ring overlap sideways with one another, creating a continuous overlap of unhybridised p orbitals throughout the benzene ring. The π electrons delocalise across the benzene ring, creating a delocalised π electron cloud. identical C-C bond lengths- due to the delocalised elec