| Date | May 2011 | Marks available | 1 | Reference code | 11M.3.hl.TZ1.F2 |
| Level | HL | Paper | 3 | Time zone | TZ1 |
| Command term | Identify | Question number | F2 | Adapted from | N/A |
Question
Anthocyanins and carotenes are both coloured substances found in many foods.
Explain, in terms of their molecular structure, why these compounds are coloured.
[1]
a.
Identify one other coloured compound commonly found in uncooked foods.
[1]
c.
Markscheme
both have extended regions of delocalized bonding/conjugated double bonds;
a.
chlorophyll / hemoglobin / heme / myoglobin;
c.
Examiners report
In part (a), very few candidates linked colour to extended regions of delocalised electrons or conjugated double bonds. There was much general discussion of absorption of visible light. Some were confused with colour in transition metal compounds.
a.
Many correct answers appeared in (c).
c.
