Zadanie 30
Wzorowane na: Chemistry SL Paper 1, May 2022, TZ2, pytanie 30. Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Polecenie
A solution of barium hydroxide of concentration 0.10 mol dm−3 was added dropwise to 25 cm3 of copper(II) sulfate solution of concentration 0.10 mol dm−3 until 25 cm3 of the barium hydroxide solution had been added. Two insoluble precipitates form.
Ba2+(aq) + 2 OH−(aq) + Cu2+(aq) + SO42−(aq) → BaSO4(s) + Cu(OH)2(s)
Which graph represents a plot of conductivity against the volume of barium hydroxide solution added?
A. Graph A
B. Graph B
C. Graph C
D. Graph D
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
C ✔
«conductivity depends on the concentration of mobile ions; every ion added with the barium hydroxide, and every ion already in the copper(II) sulfate, is removed in the precipitates, and 5.0 mmol of OH− in 25 cm3 reacts exactly with 2.5 mmol of Cu2+, so the conductivity falls to almost zero after 25 cm3 (graph C). A V-shape would need excess barium hydroxide beyond the end of the addition»
Schemat punktowania
One mark for the correct option.