RP2- Chromatography

Question 1

What is chromatography?

Answer 1

The separation technique used to extract coloured dyes from a mixture of dyes

Question 2

Chromatogram

Answer 2

A visible record showing the results of separating components of a mixture by chromatography

Question 3

Components in chromatography

Answer 3

The individual colours or pigments found in the ink

Question 4

Stationary phase in chromatography

Answer 4

The solid part that doesn’t move
Eg.paper

Question 5

Mobile phase in chromatography

Answer 5

The solvent that moves up the paper

Question 6

Why is necessary to use a lid in chromatography

Answer 6

To prevent evaporation

Question 7

Plan an investigation to determine Rf value for the dye in food colouring (6 marker)

Answer 7

• draw a start line on the chromatography paper in pencil
• place a spot of food colouring on the start line
  -use a suitable solvent
• place chromatography paper in a beaker so that the solvent is under the start line
  -use a lid
• measure the distance between the start line and the spot centre and the difference between the start line and the solvent front

Question 8

Solvent front

Answer 8

How far the solvent travel

Question 9

Why do you draw the start line in Pencil?

Answer 9

To stop the start line from separating

Question 10

Rf value equation

Answer 10

Distance moved by spot ÷distance moved by solvent

Question 11

Rf value equation

Answer 11

Distance moved by spot ÷distance moved by solvent