Wzorowane na: Chemistry HL Paper 2, specimen 2025, pytanie 1(e). Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Informacja do zadań 1a-1e.
A monoprotic organic acid, HA, was purified from a plant oil. Elemental analysis gave the following percentage composition by mass.
| Element | Percentage by mass / % |
|---|---|
| C |
| H | 7.04 |
| O | 37.16 |
The IR spectrum of HA is shown. Two absorption bands are labelled: Y is a very broad band centred near and Z is a band of medium intensity near .
(i) Using section 20 of the data booklet, identify the functional group that gives rise to each of the bands Y and Z.
(ii) Draw one structural formula for HA that fits all of the evidence above.
(i) Y: O–H «of a carboxylic acid, broadened by hydrogen bonding» AND Z: C=C «alkene» ✔
(ii) «but-2-enoic acid» ✔
OR
OR
(i) [1]: both Y (O–H, accept hydroxyl) and Z (C=C, alkene) required. (ii) [1]: any C4H6O2 structure with one COOH group and one C=C double bond, as a full or condensed structural formula; a ring structure (cyclopropanecarboxylic acid) is not consistent with band Z and does not score.
Band Z lies below 1700 cm⁻¹, so it belongs to C=C (1620–1680 cm⁻¹) and not to the C=O stretch, which is the strong band just above it near 1710 cm⁻¹.
Porównujesz swoje rozwiązanie z kluczem? Maturownik+ oceni je analizą AI, policzy punkty wg schematu i zapisze Twoje błędy w kompendium.
Policz na kartce jak na maturze, odsłoń klucz i porównaj. Potem odhacz, żeby wiedzieć, co masz już za sobą.
ZrobioneOdhaczanie zapisuje się na Twoim koncie, więc wymaga darmowego konta. Zajmuje chwilę i wracasz do tego samego zadania.