Paper Chromatography

Question 1

How do you calculate the Rf values?

Answer 1

Rf=distance moved by compound ➗ distance moved by solvent

This allows people to identify compounds in mixtures

Question 2

How can some mixtures be separated by chromatography?

Answer 2

Chromatography can be used to separate mixtures of coloured compounds. Mixtures that are suitable for separation by chromatography inclue dyes, inks and colouring agents in food

Question 3

What can paper chromatography used for?

Answer 3

Distinguish between pure and impure substances
Identify substances by comparing the pattern on the chromatography with the patterns formed by known substances
Identify substances by working out their Rf values

Question 4

What are the steps of paper chromatography?

Answer 4

Pencil line
Ink
Solvent below line
Leave 
Rf value

Question 5

What can chromatography find out?

Answer 5

Which coloured compounds the mixture contains

Question 6

What happens when the solvent moves along the strip of paper?

Answer 6

It carries the different substances in the mixture at different speeds so they are separated. The solvent is called the mobile phase

Question 7

What phase does the paper contain?

Answer 7

The stationary phase, through which the solvent and dissolved substances move

Question 8

What is the chromatogram?

Answer 8

The paper with the separated components