organic analysis

• 1°, 2° alcohols


  Identified using acidified potassium dichromate, turns from orange to green if present
• 3° alcohols


  Not oxidised by acidified potassium dichromate, remains orange
• Alcohols


  • 1° and 2° alcohols
  • 3° alcohols
• Tollen's reagent


  Used to identify aldehydes, forms a silver mirror if present
• Fehling's solution


  Used to test for aldehydes, forms a brick red precipitate if present
• Aldehydes


  • Tollen's reagent
  • Fehling's solution
• Bromine water


  Used to test for unsaturated hydrocarbons, changes from orange-brown to colourless if a carbon-carbon double bond is present
• Alkenes


  • Bromine water
• Carboxylic acids


  React with sodium carbonate, producing CO2 which can be tested with limewater (turns cloudy)
• Carboxylic acids


  • Sodium carbonate
  • Limewater
• High resolution mass spectrometry


  More sensitive form of mass spectrometry, allows molecular formula to be determined to several decimal places
• Mass spectrometry


  • Used to identify compounds and determine their molecular formula
• Infrared (IR) spectroscopy


  Analytical technique that uses infrared radiation to determine the functional groups present in organic compounds
• Infrared (IR) spectroscopy


  • Different bonds absorb the radiation in different amounts, these varying amounts of absorbance are measured and recorded allowing functional groups to be identified
• • OH alcohol group


  Characteristic peak in the range 3230 - 3550 cm-1
• • OH acid group


  Characteristic peak in the range 2500 - 3000 cm-1
• C=C unsaturated group


  Characteristic peak in the range 1620 - 1680 cm-1
• C=O carbonyl group


  Characteristic peak in the range 1680 - 1750 cm-1
• Fingerprint region


  Contains tiny differences from species to species which act as a molecule's 'fingerprint', allowing it to be identified
• Infrared absorption in the atmosphere

  Causes heat to be trapped within the Earth's atmosphere, leading to global warming
• Chemicals such as CFCs released into the atmosphere from human activity enhance the heating effect, leading to global warming