1. When you are using coloured pencils or paints which colours do you use to make Green or Purple?

2. Separating Dyes in Ink Learning Objectives:
To know that a mixture of two or more solutes which are soluble in a particular solvent can be separated by chromatography
To explain how chromatography separates solutes
To be able to conduct an experiment to separate dyes used in colour inks by chromatography
To use chromatography to identify materials

3. What is chromatography?
Chromatography is used to separate mixtures of coloured or non-coloured substances that are soluble in the same solvent.
spot of mixture
Method A
solvent
Method B
solvent
pipette
spot of mixture
A spot of the mixture is placed on some filter paper.
In method A, the solvent is soaked up the paper.
In method B, the solvent or is slowly dripped onto the paper.
The substances in the mixture get separated because more soluble substances spread along the paper faster.

4. Practical Activity Safety First: Wear safety goggles Stand up
Tuck your chair & bags under your desk
Tie back long hair

5. Chromatography experiment

6. Identifying dyes in a mixture
Chromatography can be used to find out if a dye is made up of a single coloured substance or a mixture.
mixture
mixture
The mixture consists of dyes
3 and 5.
Dots of known single dyes are placed alongside the dot for the unknown mixture.
After the solvent washes through the paper, the pattern of the dyes in the mixture is compared with the single dyes.
Which dyes does the mixture consist of?

7. Identifying dyes in a mixture
Which dyes are in the mixture?
mixture
mixture
The mixture consists of dyes 1 and 4.

8. Chromatography
Chromatography can be used to separate a mixture of different inks. Some example questions…
R G B X Z
1) Ink X contains two different colours. What are they?
2) Which ink is ink Z made out of?

9. Separating Dyes in Ink Learning Objectives:
To know that a mixture of two or more solutes which are soluble in a particular solvent can be separated by chromatography
To explain how chromatography separates solutes
To be able to conduct an experiment to separate dyes used in colour inks by chromatography
To use chromatography to identify materials