Question 17N.3.HL.TZ0.01
| Date | November 2017 | Marks available | [Maximum mark: 6] | Reference code | 17N.3.HL.TZ0.01 |
| Level | HL | Paper | 3 | Time zone | TZ0 |
| Command term | Explain, Outline, State | Question number | 01 | Adapted from | N/A |
Outline what happens when spinach extract is spotted on a TLC plate and placed into a container of solvent.
[2]
a. solvent will move up «the TLC plate/stationary phase»
b. pigments will move up «the TLC plate/stationary phase carried by solvent»
c. pigments will move at different rates/separate
[Max 2 Marks]
Explain what the Rf values represent in chromatography.
[3]
a.
OR
distance moved by pigment relative to distance moved by solvent
b. each pigment has/is represented by a specific Rf «value»
c. used to identify different pigments
d. Rf «value» depends on density/solubility/polarity of the pigment in solvent
Allow “compound” or “molecule” instead of pigment
[Max 3 Marks]
State two photosynthetic pigments that could be identified using chromatography.
[1]
chlorophyll
carotene
xanthophyll
Accept other valid pigments
Do not accept pigments named by colour
Award [1] for any two correct
Award [1] for chlorophyll a AND (chlorophyll) b
[Max 1 Mark]