DP Chemistry (last assessment 2024)
Question 21N.2.sl.TZ0.b(ii)
| Date | November 2021 | Marks available | [Maximum mark: 2] | Reference code | 21N.2.sl.TZ0.b(ii) |
| Level | sl | Paper | 2 | Time zone | TZ0 |
| Command term | Explain | Question number | b(ii) | Adapted from | N/A |
b(ii).
[Maximum mark: 2]
21N.2.sl.TZ0.b(ii)
1-chloropentane reacts with aqueous sodium hydroxide.
The reaction was repeated at a lower temperature.
Explain the effect of lowering the temperature on the rate of the reaction.
[2]
Markscheme
«rate is» lower AND «average» kinetic energy of molecules is lower
OR
«rate is» lower AND less frequent collisions
OR
«rate is» lower AND fewer collisions per unit time ✔
«rate is» lower AND fewer/smaller fraction of molecules/collisions have the E ≥ Ea ✔
Lower «rate» needs to be mentioned once only.
Do not accept “fewer collisions” without reference to time/frequency/probability for M1.
