DP Chemistry (last assessment 2024)
Question 19M.3.hl.TZ2.b(i)
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.3.hl.TZ2.b(i) |
| Level | hl | Paper | 3 | Time zone | TZ2 |
| Command term | Determine | Question number | b(i) | Adapted from | N/A |
b(i).
[Maximum mark: 2]
19M.3.hl.TZ2.b(i)
A student synthesized aspirin, acetylsalicylic acid, in a school laboratory.
0.300 g of crude aspirin was dissolved in ethanol and titrated with sodium hydroxide solution, NaOH (aq).
NaOH (aq) + C9H8O4 (in ethanol) → NaC9H7O4 (aq) + H2O (l)
Determine the mass of aspirin which reacted with 16.25 cm3 of 0.100 mol dm−3 NaOH solution.
[2]
Markscheme
n(aspirin) «= n(NaOH) = × 0.100 mol dm–3 »= 1.625 × 10–3 «mol» [✔]
m(aspirin) «= 1.625 × 10–3 mol × 180.17 g mol–1 »= 0.293 «g» [✔]
Note: Award [2] for correct final answer.
Examiners report
A significant number of candidates were able to calculate the mass of aspirin correctly.
