Zadanie 7b
Wzorowane na: Chemistry HL Paper 3, May 2023, TZ2, pytanie 7(b). Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Polecenie
A student separates the coloured dyes in a sample of black ink by paper chromatography, using water as the solvent. Explain how paper chromatography can separate and identify the dyes in a mixture.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
Any two of:
the sample is spotted on the paper/stationary phase AND the solvent/mobile phase moves up the paper ✔
the dyes have different attractions to/solubilities in the mobile phase and the stationary phase, so they travel different distances ✔
the dyes are identified by their Rf values/retardation factors, compared with those of known dyes run under the same conditions ✔
Schemat punktowania
Any two of the three points, [2] max. Rf is the distance travelled by the component divided by the distance travelled by the solvent front; do not require a locating agent.