Question 23M.2.HL.TZ2.1
| Date | May 2023 | Marks available | [Maximum mark: 9] | Reference code | 23M.2.HL.TZ2.1 |
| Level | HL | Paper | 2 | Time zone | TZ2 |
| Command term | Deduce, Determine, Identify | Question number | 1 | Adapted from | N/A |
Analytical and spectroscopic techniques enable chemists to identify and determine structures of compounds.
An unknown organic compound, X, comprising of only carbon, hydrogen and oxygen was found to contain 48.6 % of carbon and 43.2 % of oxygen.
Determine the empirical formula.
[3]
«n(C) =» 4.05 «mol»
AND
«n(O) =» 2.70 «mol» ✓
«% H =» 8.2 %
OR
«n(H) =» 8.12 «mol» ✓
«empirical formula =» C3H6O2 ✓
Award [2] for the simplest ratio ″1.5 C: 3 H: 1 O″.
The infrared spectrum of X is shown.
[Source: SDBS, National Institute of Advanced Industrial Science and Technology.]
Identify the bonds making the major contribution to peaks A and B using section 26 of the data booklet.
A: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[2]
A:
O-H «in carboxylic acids» ✓
B:
C=O ✓
Deduce the structural formula of X.
[1]
Do not accept molecular formula/C2H6O2.
0.363 g of organic liquid Y was vaporized completely at 95.0 °C and 100.0 kPa. The gas volume was measured to be 81.0 cm3. Determine the molar mass of Y.
[3]
T=368 K AND P = 100.0 kPa AND V = 0.0810 dm3
OR
T=368 K AND P = 100 000 Pa AND V = 8.1 x 10−5 m3 ✓
✓
✓
Award [3] for correct final answer.