Zadanie 1c, Paper 2, maj 2025, TZ1, Chemia IB SL
Wzorowane na: Chemistry SL Paper 2, May 2025, TZ1, pytanie 1(c). 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
Heating a mixture of powdered tin and iodine gives the compound tin(IV) iodide, SnI4.
Polecenie
A student proposed that, because tin(IV) iodide might be ionic, electrolysing the molten compound with inert electrodes should regenerate tin and iodine.
(i) Label the diagram of the electrolytic cell to show which electrode is the anode and which is the cathode, and mark the direction in which each type of ion moves through the melt.
Powiększ(ii) Write a half-equation for the electrode process taking place at each of the two electrodes.
Negative electrode:
Positive electrode:
(iii) Contrast one physical property of tin and tin(IV) iodide.
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
(i) left electrode: anode AND right electrode: cathode ✔
I− ions move to the left electrode «the anode» AND Sn4+ ions move to the right electrode «the cathode» ✔
(ii) Negative electrode «cathode»: Sn4+ + 4 e− → Sn ✔
Positive electrode «anode»: 2 I− → I2 + 2 e− ✔
(iii) Any one of:
tin conducts electricity / heat AND tin(IV) iodide does not ✔
OR
tin is malleable / ductile AND tin(IV) iodide is brittle ✔
OR
tin has a metallic lustre / is silvery AND tin(IV) iodide is an orange crystalline solid with no metallic lustre ✔
OR
tin has a higher melting point «232 °C» than tin(IV) iodide «144 °C» ✔
OR
tin is denser than tin(IV) iodide ✔
Schemat punktowania
(i) Do not apply ECF. Award [1] if any two of the four elements (two electrode names, two ion directions) are correct, and [2] when all four are correct. (ii) Award [1 max] for correct equations written at the wrong electrodes. Do not accept reverse equations. Penalize equilibrium arrows once only. (iii) [1] for any one correct contrast that states the property for both substances; do not accept chemical properties or molar mass.
Komentarz. The student's proposal only sets up the exercise: nothing here asks whether tin(IV) iodide is really ionic, only that the electrolysis of the molten salt be worked through as if it gave simple ions.