| Date | November 2013 | Marks available | 2 | Reference code | 13N.3.sl.TZ0.5 |
| Level | SL | Paper | 3 | Time zone | TZ0 |
| Command term | Explain | Question number | 5 | Adapted from | N/A |
Question
Vitamins are organic micronutrients essential for good health. The structures of vitamins A, C and D are given in Table 21 of the Data Booklet.
Only one of these three vitamins is soluble in water.
Vitamin D is the only vitamin that can be synthesized in the body, by the action of sunlight on the skin.
Identify by name two functional groups that are common to all three of these vitamins.
Identify this vitamin.
Explain why this vitamin is soluble in water.
State one effect of vitamin D deficiency.
Suggest why vitamin D deficiency diseases are becoming increasingly common in young people.
Markscheme
alcohol/hydroxyl group and alkene;
Accept carbon-carbon double bond.
Do not accept just double bond.
Do not accept hydroxide.
vitamin C / ascorbic acid;
several OH groups / polar molecule;
able to form hydrogen bonds with water;
softening/malfunctioning of bones / causes low/deficiency in calcium;
Accept rickets.
less time outdoors / skin not exposed due to clothing/sunscreen / OWTTE;
Accept answers that show link with outdoors/sunlight.
Examiners report
In (a) the alkenyl group was usually replaced by something else but it was pleasing to see the general absence of the answer “hydroxide”. Parts (b) and (c) were answered well and candidates seemed well aware of the dangers of modern technology keeping them indoors.
In (a) the alkenyl group was usually replaced by something else but it was pleasing to see the general absence of the answer “hydroxide”. Parts (b) and (c) were answered well and candidates seemed well aware of the dangers of modern technology keeping them indoors.
In (a) the alkenyl group was usually replaced by something else but it was pleasing to see the general absence of the answer “hydroxide”. Parts (b) and (c) were answered well and candidates seemed well aware of the dangers of modern technology keeping them indoors.
In (a) the alkenyl group was usually replaced by something else but it was pleasing to see the general absence of the answer “hydroxide”. Parts (b) and (c) were answered well and candidates seemed well aware of the dangers of modern technology keeping them indoors.
In (a) the alkenyl group was usually replaced by something else but it was pleasing to see the general absence of the answer “hydroxide”. Parts (b) and (c) were answered well and candidates seemed well aware of the dangers of modern technology keeping them indoors.
