Chromatography

• What is the aim of the investigation in paper chromatography?


  To separate and analyze colored substances
• What is paper chromatography used for?

  • Separating colored substances
  • Analyzing the composition of mixtures
• What is applied to the chromatography paper in the experiment?

  A small sample of a mixture
• What happens when the lower end of the chromatography paper is immersed in the solvent?

  The solvent rises up the paper
• How do different substances in the sample behave during paper chromatography?

  They separate as the solvent moves
• What can be observed to analyze the composition of the mixture in paper chromatography?

  The distinct bands that form
• What is calculated to help analyze the results of paper chromatography?

  Rf values
• What is the process of paper chromatography?

  1. Apply a sample near the bottom of chromatography paper
  2. Immerse the lower end in solvent
  3. Observe the solvent rising and substances separating
  4. Analyze the distinct bands formed
  5. Calculate Rf values for analysis
• What does chromatography literally mean?

  Color writing
• What is chromatography used for?

  To separate materials in a mixture
• What are the two phases in chromatography?

  Mobile phase and stationary phase
• How do components in a mixture separate during chromatography?

  Based on their affinity for phases
• What is the stationary phase used in this chromatography experiment?

  Paper
• Why do we use pencil to draw the baseline in chromatography?

  To prevent ink from leaking into the mobile phase
• How far from the base should the baseline be drawn?

  About 2 centimeters
• Why should the dots not be placed too close to the edge?

  It affects the separation process
• What colors of food coloring are used in the experiment?

  Blue, yellow, red, and green
• What does it mean for a material to be pure in this context?

  It contains only one color dissolved
• What is the purpose of the capillary tube in the experiment?

  To transfer small amounts of liquid
• What is capillary action?

  Movement of liquid through narrow spaces
• How should the food coloring be applied to the paper?

  Touch lightly and allow to spread
• Why is it important to let the colors dry between applications?

  To achieve a strong color without merging
• What is the mobile phase used in this chromatography experiment?

  Water
• How does the mobile phase affect the separation of colors?

  It dissolves colors and moves them up
• What should be done to ensure the water does not wash off the dots?

  Keep the water level below the dots
• What happens to the colors as the water rises up the paper?

  They separate based on their affinities
• How long should the chromatography be left in the solvent?

  About 15 minutes
• What does the distance traveled by the solvent indicate?

  It shows how far the solvent moved
• How do you determine the RF value in chromatography?

  Distance color traveled divided by solvent distance
• If the solvent traveled 100 mm and the yellow color traveled 20 mm, what is the RF value?

  $0.2$
• What does RF stand for in chromatography?

  Retention factor
• What does a higher RF value indicate about a dye?

  It is more soluble in the mobile phase
• How can you tell if a food coloring is pure or not from chromatography results?

  By observing distinct color spots