Separating techniques

• chromatography is used to separate inks or dyes into the separate dyes they are made of
• the base line in chromatography is drawn in pencil because it is insoluble in water so will not obstruct the results by bleeding
• Rf stands for retention factor
• to calculate Rf:

  distance travelled by substance / distance travelled by solvent
• if rf = 0, then no separation has occurred
• Rf should be a number between 0 and 1
• fractional distillation is used to seperate two liquids with different boiling points
• the fractionating column contains glass beads which provide a large surface area for the condensation of the liquid mixture