1.11 Chromatography

Question 1

What is chromatography?

Answer 1

A technique used to separate a mixture of substances

Question 2

Stages of paper chromatography are:

Answer 2

1)a starting line is marked on a piece of chromatography paper using a pencil. Crosses or origins are marked along this line
2)a micropipette is use to make a small, concentrated spot on the first origin. Spot allowed to dry then another spot is applied on top. Repeated
3)paper is suspended in a tank of solvent and left until the solvent is nearly at the top of the paper. Final position of solvent is marked in pencil - solvent front
4)the chromatogram is removed from the tank and dried
Locating agent added to see unseen compounds

Question 3

How to identify the mixture?

Answer 3

Compare the spots from the mixture with the spots produced by the known substances - see if they match

Question 4

Equation for the Rf value is:

Answer 4

Distance travelled by the spot/distance travelled by the solvent