DP Chemistry (last assessment 2024)
Question 17N.2.sl.TZ0.d.ii
| Date | November 2017 | Marks available | [Maximum mark: 2] | Reference code | 17N.2.sl.TZ0.d.ii |
| Level | sl | Paper | 2 | Time zone | TZ0 |
| Command term | Calculate | Question number | d.ii | Adapted from | N/A |
d.ii.
[Maximum mark: 2]
17N.2.sl.TZ0.d.ii
A student titrated an ethanoic acid solution, CH3COOH (aq), against 50.0 cm3 of 0.995 mol dm–3 sodium hydroxide, NaOH (aq), to determine its concentration.
The temperature of the reaction mixture was measured after each acid addition and plotted against the volume of acid.
Calculate the enthalpy change, ΔH, in kJ mol–1, for the reaction between ethanoic acid and sodium hydroxide.
[2]
Markscheme
«n(NaOH) = 0.995 mol dm–3 x 0.0500 dm3 =» 0.04975 «mol»
OR
«n(CH3COOH) = 1.91 mol dm–3 x 0.0260 dm3 =» 0.04966 «mol»
«ΔH = » –48 / –49 «kJ mol–1»
Award [2] for correct final answer.
Negative sign is required for M2.
