Question 23M.2.HL.TZ1.8
| Date | May 2023 | Marks available | [Maximum mark: 3] | Reference code | 23M.2.HL.TZ1.8 |
| Level | HL | Paper | 2 | Time zone | TZ1 |
| Command term | Determine | Question number | 8 | Adapted from | N/A |
A series of experiments were carried out at different temperatures and the rate of reaction, in mol dm−3 s−1, was determined for each. The rate constant for the reaction of propanone (CH3COCH3) with iodine (I2) was calculated and the processed data is represented in the following graph.
Determine the activation energy for this reaction, stating the units. Use sections 1 and 2 of the data booklet.
[3]
«two construction lines shown on the graph, and slope calculated:
«(−1.0 − (−3.0))/(0.0032 − 0.0035) =» −6700 ✓
«gradient x R = -Ea»
«6700 × 8.31 J K−1 mol−1 /1000=» 56
OR
«6700 × 8.31 J K−1 mol−1 =» 56000 ✓
kJ «mol−1» ✓
OR
J «mol−1» ✓
Accept range 6400–7000 for M1.
Accept range 53–59 or 53000–59000 for M2.
Accept the unit as kJ or J without reference to per mol.
Award [2] for final answer without units.
Accept use of ln k1/k2 = −EA/R (1/T2−1/T1).
