Paper Chromatography

• What is chromatography?


  A chemical analysis technique used to separate substances in a mixture.
• What is paper chromatography used for?

  Separating a mixture of a substance based on their solubility in a solvent.
• What is the name given for the pencil line in paper chromatography?

  The baseline
• When doing paper chromatography, why should we use pencil for the baseline rather than pen?

  Pencil doesn't dissolve in the solvent used for chromatography whereas pen ink does and move up the paper.
• What are the 2 phases of chromatography?

  1. Mobile phase - molecules can move usually liquid or gas. 2. Stationary phase - which molecules can't move usually solid or really thick liquid.
• When doing paper chromatography, what determines the amount of time molecules spend in the mobile and stationary phase?

  1. How soluble they are in the solvent (mobile phase)
  2. How attracted they are to the paper (stationary phase)
• When doing paper chromatography what happens to chemicals that have greater solubility in the mobile phase?

  A substance which is more soluble in the mobile phase will spend more time in the mobile phase. (travel faster)
• What is the formula to calculate an Rf value from a chromatogram?

  Distance travelled by substance / Distance travelled by solvent