Chromatography

• What analytical technique is used to separate substances in a mixture?

  Chromatography
• What is the purpose of paper chromatography?

  To separate different dyes in ink
• What do we call the line drawn on the filter paper?

  Baseline
• What should you do after drawing the baseline on the filter paper?

  Add your sample of ink to the line
• What is the role of the solvent in paper chromatography?

  To dissolve the different dyes
• What should you avoid doing when placing the filter paper in the solvent?

  Submerging the pencil line
• What happens to the different dyes as the solvent moves up the paper?

  They separate at different rates
• What is the term for the pattern of spots left after chromatography?

  Chromatogram
• What are the two phases involved in chromatography?

  Mobile phase and stationary phase
• What is the mobile phase in paper chromatography?

  The solvent used in the process
• What is the stationary phase in paper chromatography?

  The filter paper used in the process
• How do different chemicals behave during chromatography?

  They switch between mobile and stationary phases
• What determines how fast a chemical moves up the paper?

  Its solubility in the solvent
• What happens to chemicals that are not soluble in the solvent?

  They stay on the baseline
• What is the rf value in chromatography?

  A ratio of distances traveled
• How is the rf value calculated?

  Distance traveled by substance / distance traveled by solvent
• If a pink substance traveled 6 cm and the solvent traveled 10 cm, what is the rf value?

  $0.6$
• What happens when chromatography is performed with a pure substance?

  It produces a single spot on the chromatogram
• How can changing the solvent or paper affect chromatography results?

  It can change the chromatogram appearance
• What must a chemist consider when looking up an rf value?

  The solvent and type of paper used
• What are the steps involved in performing paper chromatography?

  1. Draw a baseline on filter paper.
  2. Add ink sample to the baseline.
  3. Prepare a shallow solvent in a beaker.
  4. Place filter paper in solvent without submerging the ink.
  5. Cover the beaker to prevent evaporation.
  6. Wait for solvent to rise and separate dyes.
  7. Remove paper and let it dry to observe chromatogram.
• What factors affect the movement of substances in chromatography?

  • Solubility in the solvent
  • Attraction to the stationary phase
  • Time left in the experiment