Zadanie 3
Wzorowane na: Chemistry SL Paper 1, May 2023, TZ1, pytanie 3. Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
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Polecenie
Magnesium ribbon of known mass was heated strongly in a crucible, and the heating was repeated until the mass no longer changed. The final mass of the solid was then recorded. Assume that magnesium oxide is the only product.
Which of the following can be deduced from these two masses?
I. Empirical formula of magnesium oxide
II. Molecular formula of magnesium oxide
III. Percentage composition by mass of magnesium oxide
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 ✔
«the mass of oxygen is the final mass minus the initial mass; the amounts of magnesium and oxygen give the ratio 1 : 1 (empirical formula) and the masses give the percentage composition; magnesium oxide is an ionic lattice, so it has no molecular formula, and masses alone cannot give a molar mass»
Schemat punktowania
One mark for the correct option.