| Date | May 2011 | Marks available | 1 | Reference code | 11M.1.HL.TZ1.6 |
| Level | Higher level | Paper | Paper 1 | Time zone | Time zone 1 |
| Command term | Question number | 6 | Adapted from | N/A |
Question
Which statement about water is correct?
A. The atoms within a molecule of water are held together by hydrogen bonds.
B. Water has a low heat capacity allowing enzymatic reactions to happen at a wide range of temperatures.
C. Water molecules are polar, therefore fatty acids do not dissolve.
D. Ice has a higher density than liquid water, therefore some organisms can live under the ice.
Markscheme
C
Examiners report
This question discriminated well. However, many candidates went for the incorrect choice, A. This showed a lack of understanding of covalent bonds and hydrogen bonds. The requirement for candidates to know that fatty acids do not dissolve in water because it is polar was questioned in a G2. This would be covered in 3.1.5 under solvent properties of water, 3.2.7 under use of lipids in energy storage and again in 2.4.2 when explaining hydrophobic in relation to phospholipids.
