paper chromotography

• What is chromatography used for?

  To separate mixtures and identify substances
• What are the two phases involved in chromatography?

  A stationary phase and a mobile phase
• What does separation in chromatography depend on?

  The distribution of substances between phases
• What is the formula for Rf value?

  Rf value = distance moved by substance ÷ distance moved by solvent
• How do different compounds behave in chromatography?

  They have different Rf values in different solvents
• What happens to a pure compound in chromatography?

  It produces a single spot in all solvents
• What is paper chromatography?

  A technique separating compounds by their speeds in solvent
• How does solubility affect movement in paper chromatography?

  The more soluble, the further it travels up the paper
• What does chromatography separate in colored substances?

  Different pigments
• What is a pigment?

  A solid, colored substance
• what is the stationary phase

  typically the chromatography paper as it stays still and thee solvent and dyes move through it
• whats the mobile phase

  typically the solvent as it carries the dye through the paper
• what would the most soluable ink be


  it would be less attracted to the stationary phase so it travels the farthest
• what would the least soluable ink be

  it would be most attracted to the stationary phase and travels the least
• what is the Rf value

  its the ratio of the distance travelled by the sample (spots) to the distance travelled by the solvent
• whats the Rf value formula

  distance moved by sample ÷distance moved by solvent
• Why should we use pencil for the baseline rather than pen?

  Pen ink would dissolve in the solvent and move up the paper 
• Should the baseline be submerged in the solvent?

  no