Paper Chromatography

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

  Chromatography
• What type of chromatography is specifically discussed in the video?

  Paper chromatography
• What is the purpose of paper chromatography?

  To separate different dyes in an ink
• What are the steps involved in performing paper chromatography?

  1. Draw a baseline on filter paper with pencil.
  2. Add the ink sample on the baseline.
  3. Fill a beaker with shallow solvent (water or ethanol).
  4. Place the filter paper in the solvent without submerging the ink.
  5. Cover the beaker to prevent evaporation.
  6. Wait for the solvent to rise and separate the dyes.
  7. Remove the paper and let it dry to observe the chromatogram.
• What is the baseline in paper chromatography?

  A pencil line drawn near the bottom of the filter paper
• Why is it important not to submerge the pencil line in the solvent?

  To ensure the ink sample can move up the paper
• What is a chromatogram?

  The pattern of spots left on the paper after chromatography
• What are the mobile and stationary phases in chromatography?

  The mobile phase is the solvent, and the stationary phase is the paper
• How do different chemicals move in paper chromatography?

  They dissolve in the solvent and bind to the paper repeatedly
• What determines how fast a chemical moves up the paper in chromatography?

  The solubility of the chemical in the solvent and its attraction to the paper
• What is the formula for calculating the rf value in chromatography?

  $rf =$$\frac{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 the chromatogram change with different solvents or papers?

  It may look different and produce different rf values
• Why must a chemist consider the solvent and paper type when looking up rf values?

  Because they affect the separation and rf values of the substances
• What should you do if you want to prevent solvent evaporation during chromatography?

  • Place a lid on top of the beaker
• What are the key terms associated with the phases in chromatography?

  • Mobile phase: substance that molecules can move in (liquid or gas)
  • Stationary phase: substance that molecules cannot move in (solid or thick liquid)