chromatography

Cards (7)

what is paper chromotography?
allows you to separate substances based on their different solubilities
why are different dyes in a substance separated in chromatography?
as the solvent moves through the paper,
different dyes which have different solubilities in the solvent
are carried different distances
due to different attractions to the paper
T/F? Less soluble substances are carried further distances.
False - more soluble substances travel further due to lower attraction to the paper
why must the starting line be drawn in pencil
pencil is insoluble in water - would not be carried up the paper and distrupt results
how to calculate Rf value
distance travelled by the substance / distance travelled by the solvent
Different substances may have the same Rf value. May need to repeat chromatography with other solvents to narrow down results
If a substance hasnt been analysed before, there won’t be an Rf value in the database
what is the mobile phase in chromatography?
the solvent which carries the substance through the stationary phase (the paper)