RP7 - Chromotography Flashcards
1
Q
Why should you not use pen to mark the line?
A
Ink and pigments would mix
2
Q
Why should you draw solvent front line before filter paper dried?
A
Can’t see solvent
3
Q
Why’s it better to use Rf values than distance moved?
A
- Rf values can be compared
- Rf value is distance moved by spot divided by distance to origin front
4
Q
Why should you not move bottle once TLC paper is in it?
A
Pigments would not run straight
5
Q
Why should you measure from the centre of pigment spot?
A
- Standardise readings
- Comparisons can be made
6
Q
Describe how you would use chromotography to show chlorophyll is lost?
A
- Carry out chromotography at different times
- Find Rf value for chlorophyll
- Look for substance at predicted position
7
Q
Suggest and explain the advantage of having different coloured pigments in leaves
A
Absorb different wavelengths for photosynthesis
