Paper chromatography

• What is the result of chromatography analysis called?

  Chromatogram
• What does the R_f value represent in chromatography?


  It is the ratio of the distance travelled by the solute to the distance travelled by the solvent
• How do you calculate the R_f value?


  $R_f =$$\frac{B}{A}$, where B is the distance travelled by the substance and A is the distance travelled by the solvent
• What does a larger R_f value indicate?


  It indicates that the substance has moved further through the stationary phase
• Why is chromatography performed with a reference sample?


  To determine if a certain substance is present in a mixture by comparing R_f values
• What does it mean if the R_f values of the reference and a spot in the mixture match?


  It suggests that the substance may be present in the mixture
• How does the solvent affect the R_f value?


  The R_f value changes if the solvent is changed
• What should you do if the R_f values match in some solvents but not others?


  It suggests that the reference compound is not present in the mixture
• What is the process of chromatography used for?


  • To separate components of a mixture
  • To identify substances based on R_f values
  • To analyze the presence of specific compounds
• What are the key components involved in calculating R_f values?


  • Distance travelled by the substance (B)
  • Distance travelled by the solvent (A)
  • Formula: $R_f =$$\frac{B}{A}$
• What is the result of chromatography analysis called?


  A chromatogram
• What does the R value represent in chromatography?


  It is the ratio between the distance travelled by the solute and the distance travelled by the solvent
• How do you calculate the R value in chromatography?


  $R =$$\frac{B}{A}$, where B is the distance travelled by the substance and A is the distance travelled by the solvent
• What does a larger R value indicate about a substance in chromatography?


  The substance has moved further through the stationary phase
• What is the purpose of running a pure sample alongside an unknown mixture in chromatography?

  • To determine if a certain substance is present in the mixture
  • If the R values match, the substance may be present
• What is the distance measured for calculating R values in chromatography?


  It is the distance from the baseline to the center of the spot
• What happens if the R values of the reference and a spot in the mixture match?


  The substance may be present in the mixture
• What is chromatography used for?


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


  The mobile phase and the stationary phase
• What is the mobile phase in chromatography?


  A phase where the molecules can move, always a liquid or gas
• What is the stationary phase in chromatography?


  A phase where the molecules can’t move, can be a solid or thick liquid
• What happens during a chromatography experiment?


  • Substances in the sample move between the mobile and stationary phases
  • This movement establishes an equilibrium
• How does the movement of substances in chromatography establish equilibrium?


  Substances constantly move between the mobile and stationary phases
• What is the definition of chromatography?


  It is an analytical method used to separate the substances in a mixture.