A-LEVEL OCR ChEMISTRY NOTES
Amino Acids, Amides and Chirality
Made with ❤️by snaprevise.co.uk
- α-amino acids contain both the amine functional group and the carboxylic acid functional group (carboxyl group) attached to the same carbon atom.
- The general formula of an amino acid is RCH(NH2)COOH
- Amino acids are amphoteric, meaning they have both acidic and basic properties and can exist as zwitterions, having no charge overall.
- The isoelectric point is the pH at which the overall charge of a molecule is zero
- Amino acids undergo reactions with their carboxylic acid group and amine group
- Carboxylic acid group reacts with: metal oxides, alkalis, carbonates, alcohols
- Amine group reacts with: inorganic acids e.g. HCl
- Amides are a group of nitrogen-containing organic compounds. They contain both an amine group and an acyl group
- Optical isomers are species which are non-superimposable mirror images of each other. One isomer rotates plane-polarise light clockwise, and the other rotates it anticlockwise
- Optical isomerism is a form of stereoisomerism and occurs as a result of chirality in molecules
- A chiral centre is a carbon atom with 4 different groups attached (it is asymmetric). It is denoted by an asterisk
- Amino acids have a chiral centre, provided the R group is not just -H, -COOH or -NH2
- A 50:50 mix of the enantiomers (a racemic mixture) will have no overall effect on plane-polarised light as the effects from the two enantiomers cancel out