CHROMATOGRAPHY worksheet by ACQtcK82

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									A2 CHEMISTRY        CHROMATOGRAPHY WORKSHEET

  1   Explain, giving diagrams, the difference between separation by partition and
      separation by adsorption.




  2   Amino acids may be separated by using two-dimensional paper chromatography.
      This involves putting a spot of the mixture on the corner of a piece of
      chromatography paper and allowing a solvent to soak up the paper. The paper is
      then dried, turned through 90°and placed in a second solvent. This method gives
      better separation than a one solvent method.
          (i)     Paper chromatography relies on partition between the solvent applied
                  and another phase. What is this second phase composed of?

         ……………………………………….
3   Write a sentence to explain the difference between paper chromatography and
    thin layer chromatography.

…………………………………………………………………………………………

…………………………………………………………………………………………

4   In gas/liquid chromatography the mobile phase is a …………..

    (e.g. …………………..) and the stationary phase is a non-volatile ……………….

    coated on to small inert particles.
The graph below shows a GLC chromatogram of a mixture of organic chemicals.




                                                    propanone




                                                                                                Pentan-2-one
       Recorder




                                                                                      heptane
       response




                                     ethoxyethane




                                                                Hex-1-ene
                           ethanal




                       0                                        5             10                15

                                                                                   Time/min
                     Time of injection

(i)        Which compound is present in the largest amount?                    ……………………….
(ii)       Which compound has a retention time of 2 mins?                      ………………………
(iii)      What further method must be used to help identify unknown compounds after

           they have passed through a GLC column?                           ……………………………..


5       Give 3 differences between gas/liquid chromatography and high performance
        liquid chromatography.

…………………………………………………………………………………………

…………………………………………………………………………………………

…………………………………………………………………………………………

…………………………………………………………………………………………..

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…………………………………………………………………………………………..

6     Give one example each of an analytical use of

(i)      high performance liquid chromatography

…………………………………………………………………………………………..
(ii) gas/liquid chromatography

………………………………………………………………………………………….

								
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