Zadanie 21
Wzorowane na: Chemistry HL Paper 1, May 2024, TZ2, pytanie 21. Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Polecenie
Excess zinc granules react with 40.0 cm3 of hydrochloric acid of concentration 1.00 mol dm−3 at 25 °C. The volume of hydrogen collected was measured over time and curve I was obtained.
The experiment is repeated at the same temperature with the same mass of zinc granules of the same size and 20.0 cm3 of hydrochloric acid of concentration 1.00 mol dm−3. Which curve corresponds to the repeated experiment?
A. Curve A
B. Curve B
C. Curve C
D. Curve D
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
C ✔
«the concentration of the acid and the zinc are unchanged, so the initial rate is the same; n(HCl) is halved to 0.0200 mol and zinc is in excess, so only 0.0100 mol of hydrogen forms and the final volume is half that of curve I»
Schemat punktowania
One mark for the correct option.