Infrared Spec

• Every molecule has frequencies of IR light that it absorbs.

  Except molecules with only one element

  And it causes the vibration of the molecule to change
• IR light is shone through the unknown with a detector on the other end. The transmittance is detected.

  The transmittance will be low at the frequencies that are absorbed by the sample
• Results are plotted on an IR spectrum with transmittance on the y-axis and wavenumber on the x-axis
• Wavenmber represents the number of waves within 1cm. 1/wavelength (cm^-1)
• Points with lower transmittance are called absorptions, these reveal the presence of certain bonds
• alcohols= whale heads

  COOH= mountain range
• Every molecule has a unique pattern in the finger print region (below 1500cm^-1)
• The finger print region can be analysed by computors
• When molecules absorb more IR alight, they vibrate more leading to a rise in Kinetic Energy and temperature.

  Over time, these molecules release this energy as IR light.

  This happens in the atmosphere leading to glabal warming.