Zadanie 23
Wzorowane na: Chemistry SL Paper 1, November 2023, TZ2, pytanie 23. Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Polecenie
A voltaic cell consists of a zinc electrode in aqueous zinc sulfate and a copper electrode in aqueous copper(II) sulfate, joined by an external circuit and by a salt bridge containing aqueous potassium nitrate.
What occurs during the operation of the cell?
I. The copper(II) sulfate solution becomes paler in colour.
II. Nitrate ions from the salt bridge flow into the half-cell containing the copper electrode.
III. The mass of the zinc electrode decreases.
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
B ✔
«Zinc is the more reactive metal, so zinc is the anode: Zn → Zn2+ + 2 e− and its mass decreases (III is true). At the copper cathode Cu2+ + 2 e− → Cu removes the blue ions from solution so the solution becomes paler (I is true). Anions of the salt bridge move towards the anode, which is the zinc electrode, so II is false»
Schemat punktowania
One mark for the correct option.