draw a linenear the bottom of a shet of filter paper
add a spot of the ink to the line + place the sheet in a beaker of solvent
the solvent used depends on what's being tested ( some compounds dissolve well in water)
make sure the ink isnt touching the solvent
place a lid on top of the container to stop the solvent evaporating
each different dye in the ink will move up the paper at a different rate
any insoluble dyes in ink = stay on baseline
when solvent has reached the top of the paper = take paper out + leave it to dry
mobile phase : where the molecule can move ( liquid or gas)
stationary phase : where the molecules cannot move (solid or thick liquid)
molecules with a higher solubility in the solvent + less attracted to the paper will spend more time in the mobile phase and will be carried up the paper
rf value : substance/ solvent
chromatography method
draw pencil line on chromatography paper
place spot of food colouring on start line
use a suitable solvent
place solvent in beaker
place paper in beaker
so paper is in solvent
solvent is below start line
use a lid to stop solvent evaporating
wait for solvent to travel up the chromatography paper untol top
mark solvent front
dry the chromatography paper
chromatogrpahy paper measurements:
measure distance between start line + centre of spot
measure distance between start line + solvent front
use of measurements to determine rf value
how different dyes are seperated by paper chromatogrpahy
solvent moves through paper
different dyes have different solubilities in solvent
differentattractions for the apper
carried different distances
mistakes
if start line is in ink = ink would move on the paper
if water level is above start line = colours dissolve into water