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Rf value

  1. Nov 24, 2004 #1
    just a simple question, do Rf have a unit?
    i'm measuring in cm, so do i use cm as unit for Rf or do just leave it blank?
     
  2. jcsd
  3. Nov 24, 2004 #2

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    Rf is a ratio, so it won't have any units. If your compound travels half as far up the TLC plate as you solvent, you find the Rf by dividing the two distance (measured in cm), so the units cancel, and you get 0.5.

    For column chromatography, I find it useful to think of Rf as "fraction of column volume." So an Rf of 0.5 means that when you push through one column volume of eluent, your compound will travel one half the length of the column.
     
  4. Nov 24, 2004 #3
    thanks, i get it now :biggrin:
     
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