chromatography

• Chromatography


  used to separate stuff in a mixture - once it's separated out, you can often identify the components.
• mobile phase 


  where the molecules can move. In both paper and thin-layer chromatography the mobile phase is a liquid solvent, such as ethanol or water.
• stationary phase 


  where the molecules can't move. In paper chromatography the stationary phase is a piece of chromatography paper. In thin-layer chromatography the stationary phase is a thin layer of solid, e.g. silica gel, on a glass or plastic plate.
• • The mobile phase moves through or over the stationary phase.
  • The components in the mixture spend different amounts of time in the mobile phase and the stationary phase.
  • The components that spend longer in the mobile phase travel faster or further.
  • The time spent in the different phases is what separates out the components of the mixture.
• Rf Value = distance moved by the solute / distance moved by the solvent