DP Chemistry (last assessment 2024)
Question 18M.3.sl.TZ2.a
| Date | May 2018 | Marks available | [Maximum mark: 2] | Reference code | 18M.3.sl.TZ2.a |
| Level | sl | Paper | 3 | Time zone | TZ2 |
| Command term | Show, Sketch | Question number | a | Adapted from | N/A |
a.
[Maximum mark: 2]
18M.3.sl.TZ2.a
Propene can polymerize to form polypropene.
Propene monomer: 
Sketch four repeating units of the polymer to show atactic and isotactic polypropene.
[2]
Markscheme
Do not accept syndiotactic (alternating orientation of the CH3 groups), eg,
for M1 or M2.
Accept any correct atactic ordering of CH3 groups.
Penalize missing hydrogens or incorrect bond connectivities once only.
Accept skeletal structures.
Ignore continuation bonds, brackets and “n” indices in structures.
[2 marks]