DP Chemistry (last assessment 2024)
Question 19M.2.hl.TZ1.b(ii)
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.2.hl.TZ1.b(ii) |
| Level | hl | Paper | 2 | Time zone | TZ1 |
| Command term | Determine | Question number | b(ii) | Adapted from | N/A |
b(ii).
[Maximum mark: 2]
19M.2.hl.TZ1.b(ii)
This question is about the decomposition of hydrogen peroxide.
Hydrogen peroxide decomposes to water and oxygen when a catalyst such as potassium iodide, KI, is added.
2H2O2 (aq) O2 (g) + 2H2O (l)
Two more trials (2 and 3) were carried out. The results are given below.
Determine the rate equation for the reaction and its overall order, using your answer from (b)(i).
Rate equation:
Overall order:
[2]
Markscheme
Rate equation:
Rate = k[H2O2] × [KI] [✔]
Overall order:
2 [✔]
Note: Rate constant must be included.
Examiners report
Good performance but with answers that either typically included only [H2O2] with first or second order equation or even suggesting zero order rate equation.
