Zadanie 18
Wzorowane na: Chemistry HL Paper 1, May 2022, TZ1, pytanie 18. Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Polecenie
Excess calcium carbonate reacts with 25 cm3 of hydrochloric acid of concentration 1.0 mol dm−3 in an open flask. The solid line shows how the decrease in mass of the flask and its contents changes with time.
The experiment is repeated at the same temperature with 50 cm3 of hydrochloric acid of the same concentration and the same excess of calcium carbonate of the same particle size. Which dashed line represents the results of the second experiment?
A. Curve A
B. Curve B
C. Curve C
D. Curve D
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
D ✔
«the amount of acid is doubled, so twice as much CO2 is lost (n(HCl) = 0.025 mol gives 0.55 g; 0.050 mol gives 1.10 g); the concentration is unchanged, so the initial rate and the initial gradient are the same as for the solid line, and the reaction simply continues for longer; this is curve D»
Schemat punktowania
One mark for the correct option.