3.3.6.3 infrared spectroscopy

• determines the functional groups present in organic compounds
• IR radiation is passed through a sample where the different types of bond absorb the radiation in different amounts
• these varying amounts of absorbance are measured and recorded allowing certain bonds and functional groups to be identified
• a spectrum is produced with curves for the different functional groups
• fingerprint region 


  from 0-1500, contains tiny differences from species to species which act as a molecules 'fingerprint', allowing it to be identified
• global warming 


  IR absorption occurs in the atmosphere with molecules such as ozone
• what does the ozone cause?

  the heat to be trapped within the Earth's atmosphere - important factor for the existence of life here
• CFCs 


  released into the atmosphere from human activity which enhances the heating effect and leads to global warming
• -OH alcohol group

  
• C=O group

  
• C=C group

  
• -OH acid group