3.6 Organic analysis (AS): analytical techniques
Our understanding of organic molecules, their structure and the way they react, has been enhanced by organic analysis. This section considers some of the analytical techniques used by chemists, including test-tube reactions and spectroscopic techniques.
- Identification of functional groups by test-tube reactions (organic analysis) - The reactions of functional groups listed in the specification. Students should be able to identify the functional groups using reactions in the specification. Assessment and practical opportunities Students could carry out test-tube reactions in the specification to distinguish alcohols, aldehydes, alkenes and carboxylic acids. Required practical Tests for alcohol, aldehyde, alkene and carboxylic acid.
- Mass spectrometry (AS and A2 analytical techniques) - This topic overlaps organic analysis for AS and A2. High resolution mass spectrometry can be used to determine the molecular formula of a compound from the accurate mass of the molecular ion. Understand that the fragmentation of a molecular ion: M+• → X+ + Y• gives rise to a characteristic relative abundance spectrum that may give information about the structure of
- Infrared spectroscopy (AS and A2 organic analysis) - [This topic is relevant to AS and A2 organic analysis topics] Bonds in a molecule absorb infrared radiation at characteristic wavenumbers. ‘Fingerprinting’ allows identification of a molecule by comparison of spectra. The link between absorption of infrared radiation by bonds in CO2, methane and water vapour and global warming. Assessment and practical opportunities Students should be able to use infrared spectra and the Chemistry Data
Students could carry out test-tube reactions in the specification to distinguish alcohols, aldehydes, alkenes and carboxylic acids.