IB DP Chemistry B.5 Vitamins HL Paper 3

Question

Outline why we need vitamins/micronutrients in our diets.

Answer/Explanation

Answer:

«mostly» not synthesized by body «and needed for proper growth/metabolism»

Question

Vitamins are micronutrients necessary for the correct functioning of the body.

(a) Outline why vitamins usually need to be obtained from food sources.

(b) State two factors, other than concentration, that must be controlled for correct metabolic functioning in the cytoplasm of a cell.

Answer/Explanation

Answer:

(a) cannot be synthesized «by the human body»

(b) temperature AND pH

Question 

Ascorbic acid and retinol are two important vitamins.
Explain why ascorbic acid is soluble in water and retinol is not. Use section 35 of the data booklet.

▶️Answer/Explanation

Markscheme
ascorbic acid: many hydroxyl/OH groups AND retinol: few/one hydroxyl/OH group
OR
ascorbic acid: many hydroxyl/OH groups AND retinol: long hydrocarbon chain [ $\boldsymbol{\sim}$ ]
ascorbic acid: «many» $\mathrm{H}-$ bond with water
OR
retinol: cannot «sufficiently» H-bond with water $[\boldsymbol{M}]$
Note: Do not accept “OH’/hydroxide”.

 
 
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