Zadanie 3b, Paper 1B, listopad 2025, TZ1, Chemia IB HL
Wzorowane na: Chemistry HL Paper 1B, November 2025, TZ1, pytanie 3(b). Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Zadanie
Wspólne informacje do wiązki zadań
A student used paper chromatography to find out which coloured dyes had been mixed to make the brown ink of a marker pen, and to compare the polarities of those dyes. A spot of the ink was placed on the start line of each of two identical paper strips. The start line was drawn in pencil 1.5 cm from the bottom edge of the strip, and each strip was placed in a covered beaker containing a different solvent system, both mixtures of ethanol and water. System 1 was 25 % ethanol and 75 % water by volume; system 2 was 75 % ethanol and 25 % water by volume. Each run gave four coloured spots. The positions of the start line, the solvent front and the spots were measured from the bottom edge of each strip.
| Position measured from the bottom edge / cm | System 1 (25 % ethanol) | System 2 (75 % ethanol) |
|---|---|---|
| Start line | 1.5 | 1.5 |
| Solvent front | 17.5 | 15.5 |
| Violet spot | 16.2 | 5.6 |
| Blue spot | 14.1 | 11.3 |
| Orange spot | 11.1 | 7.8 |
| Yellow spot | 3.3 | 3.0 |
PowiększPolecenie
Explain why the start line must be horizontal and must be above the level of the solvent when the strip is placed in the chamber.
Korepetytor AI
Nie wiesz, jak ruszyć? Korepetytor zna to zadanie i poprowadzi Cię krok po kroku, bez gotowca.
3 rozmowy · bez karty · Zaloguj się
Sprawdź się
Odpowiedz i oceń, jak poszło. Klucz odsłoń dopiero, gdy masz swoją odpowiedź.
Zanim porównasz z kluczem
Jak poszło Ci z tym zadaniem?
Zaloguj się, żeby zapisać ocenę i wrócić do zadania później.
Pokaż rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
Horizontal start line:
the solvent moves straight up the paper at the same rate across its width/the solvent front stays parallel to the start line, so the spots separate «and are measured» consistently ✔
Above the solvent level:
otherwise the ink dissolves into the solvent «in the beaker» and washes off/spreads irregularly, so no spots are obtained ✔
Schemat punktowania
M1 (horizontal): consistent separation, a straight solvent front, or accurate measurement of the distances travelled (accept 'more consistent RF values'). M2 (above the solvent): the sample would dissolve in the solvent reservoir; accept 'the spot would not move up the paper' or 'the chromatogram would be blank'.