Zadanie 9a
Wzorowane na: Chemistry HL Paper 3, May 2024, TZ1, pytanie 9(a). Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Polecenie
A student used thin-layer chromatography to investigate the artificial colourings in a boiled sweet. A solution of the sweet was spotted on the start line and the plate was developed. The developed chromatogram is shown with a ruler in centimetres, whose zero is level with the start line. Measure to the centre of each spot.
The table gives the RF values of six colourings in the same solvent.
| Colouring | RF value |
|---|---|
| Tartrazine (E102) | 0.12 |
| Sunset yellow (E110) | 0.27 |
| Allura red (E129) | 0.44 |
| Azorubine (E122) | 0.57 |
| Ponceau 4R (E124) | 0.71 |
| Brilliant blue FCF (E133) | 0.83 |
Determine whether azorubine (E122) is present in the sweet by calculating the RF values of the spots and comparing them with the data in the table.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
yes AND the fourth spot from the bottom has «which matches 0.57» ✔
Schemat punktowania
Accept an RF value from 0.57 to 0.59 for the fourth spot. Accept answers in which "yes" is implied by the comparison. Do not award for "yes" without a calculated RF.