C25 nomenclature + isomerism

• to name organic compounds use the IUPAC naming system
• the IUPAC naming system is based on the number of carbons in the chain with functional groups added as prefixes and suffixes
• the suffix for alkenes is -ene
• the prefix for halogenoalkanes is halo-
• the suffix for carboxylic acids is -oic acid
• the suffix for esters is -oate
• the suffix for nitriles is -nitrile
• the suffix for aldehydes is -al
• the suffix for ketones is -one
• the suffix for alcohols is -ol

  the prefix for alcohols is hydroxy-
• the suffix for alkanes is -ane
• the suffix for amines is -amine

  the prefix for amines is amino-
• when naming compounds, if you have multiple functional groups, number them and use the prefix di, tri, tetra, penta, hexa, hepta, octa, nona, deca, etc
• when naming compounds, if you have multiple carbons and a functional group, use the lowest number possible
• when naming compounds, methyl is CH3, ethyl is CH2CH3, propyl is CH2CH3CH3, butyl is CH2CH3CH3CH3, etc
• when naming compounds, commas separate numbers, and hyphens separate words and numbers
• optical isomerism is a type of stereoisomerism where molecules have the same molecular formula but a different arrangement of atoms in space
• optical isomerism occurs when there is a chiral centre in a molecule
• a chiral centre is a carbon atom with 4 different groups attached to it so the molecule has no line of symmetry
• chiral centres are often indicated using an asterisk
• the presence of a chiral centre leads to the presence of two possible isomers which are mirror images of each other, they are optical isomers
• the two optical isomers are called a pair of enantiomers
• enantiomers can be told apart as they have different effects on plane-polarised light, each causes the rotation of the light in the opposite direction to the other
• the mixture formed when optical isomers are produced from a reaction in a 1:1 ratio is called a racemate
• when plane-polarised light is shone through a racemate, there is no visible effect as the effects of the two enantiomers cancel each other out
• the type of reaction that forms a racemate is nucleophilic addition
• in nucleophilic addition, the nucleophile can attack the carbonyl group from above or below the double bond, creating two possible products, these are the enantiomers
• stereoisomers cannot be easily separated as they have very similar properties