Mixtures and Chromatography C1

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

  Chromatography
• What is the specific type of chromatography 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. Prepare 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 move up the paper.
  7. Remove the paper and let it dry to observe the chromatogram.
• 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 the properties of substances affect their movement in chromatography?

  More soluble substances move faster in the mobile phase
• What is the formula for calculating the rf value in chromatography?

  rf = 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?

  $rf =$$\frac{6 \text{ cm}}{10 \text{ cm}} =$$0.6$
• What happens when chromatography is performed with a pure substance?

  It will not separate and will show a single spot on the chromatogram
• How can the chromatogram change with different solvents or papers?

  The chromatogram may look different and the rf value will change
• Why must a chemist consider the solvent and paper type when looking up rf values?

  Because different solvents and papers can affect the separation and rf values
• What should you do to prevent the solvent from evaporating during chromatography?

  Place a lid on top of the beaker
• What is the role of the solvent in paper chromatography?

  The solvent acts as the mobile phase allowing substances to dissolve and move
• How does the solubility of a substance affect its movement in chromatography?

  More soluble substances spend more time in the mobile phase and move faster
• What happens to substances that are not soluble in the solvent during chromatography?

  They remain on the baseline and do not move up the paper
• What is the significance of the baseline in paper chromatography?

  It is where the sample is applied before chromatography begins
• Why is it important to use a pencil for the baseline in chromatography?

  Pencil does not dissolve in the solvent and will not interfere with results
• How does the chromatography process demonstrate the properties of different substances?

  It shows how different substances interact with the mobile and stationary phases