DP Chemistry (last assessment 2024)
Question 19M.3.sl.TZ2.3
| Date | May 2019 | Marks available | [Maximum mark: 3] | Reference code | 19M.3.sl.TZ2.3 |
| Level | sl | Paper | 3 | Time zone | TZ2 |
| Command term | Describe | Question number | 3 | Adapted from | N/A |
3.
[Maximum mark: 3]
19M.3.sl.TZ2.3
Describe the characteristics of the nematic liquid crystal phase and the effect that an electric field has on it.
Shape of molecules:
Distribution:
Effect of electric field:
[3]
Markscheme
Shape of molecules:
linear
OR
rod «shaped» [✔]
Distribution:
no positional order AND «some» directional order [✔]
Note: Accept “partly ordered”.
Effect of electric field:
«directional» order increases
OR
molecules align in same direction [✔]
Examiners report
Most students were able to obtain at least one mark on this question. The distribution was the most challenging part.
