Chromatography Flashcards
1
Q
Describe how you would use chromatography to separate out photosynthesis pigments from a leaf extract (3 marks)
A
- Draw an origin line at the bottom of the chromatogram
- Place concentrated spot of extract on the origin line
- Place chromatogram into the solvent with the origin line above the solvent
- Allow time to run then remove from solvent and mark the solvent font
2
Q
Why draw origin in pencil, not pen
A
Pigment molecules in ink will dissolve in solvent and mix with the pigments from the extract
3
Q
Why do pigment molecules separate
A
Different molecules have different solubilities in the solvent
4
Q
What is the equation for the Rf value
A
distance moved by molecule / distance moved by solvent
