Zadanie 18
Wzorowane na: Chemistry HL Paper 1, May 2023, TZ2, pytanie 18. Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Polecenie
Curve X (dashed) shows the volume of oxygen formed when 25 cm3 of 1.0 mol dm−3 hydrogen peroxide solution decomposes in the presence of a manganese(IV) oxide catalyst at 25 °C.
2 H2O2(aq) → O2(g) + 2 H2O(l)
Which change would produce curve Y?
A. Raising the temperature to 35 °C
B. Using a larger mass of the catalyst
C. Diluting the solution to 50 cm3 by adding 25 cm3 of water
D. Using 25 cm3 of 2.0 mol dm−3 hydrogen peroxide solution
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
C ✔
«curve Y has a lower initial rate but the same final volume of oxygen, so the amount of hydrogen peroxide is unchanged and its concentration is lower; adding water halves the concentration without changing the number of moles. A and B increase the rate, and D doubles both the rate and the final volume»
Schemat punktowania
One mark for the correct option.