Zadanie 15
Wzorowane na: Chemistry SL Paper 1, May 2022, TZ2, pytanie 15. Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Polecenie
Identical pieces of zinc, each of mass 0.65 g, are added to two solutions of hydrochloric acid, X and Y, at the same initial temperature. Each reaction takes place in an identical insulated container and the mixture is stirred.
| Solution | Volume / cm3 | Concentration / mol dm−3 |
|---|---|---|
| X | 100 | 0.40 |
| Y | 100 | 0.80 |
Which statement is correct?
A. Solution X reaches the higher final temperature.
B. Solution Y reaches the higher final temperature.
C. Both solutions show the same rise in temperature.
D. The solution with the higher final temperature cannot be predicted, as it is unclear which reactant is limiting.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
C ✔
«n(Zn) = 0.65/65.38 = 0.0099 mol, which needs 0.020 mol of HCl; solution X contains 0.040 mol and solution Y 0.080 mol, so zinc is the limiting reactant in both; the same amount of reaction releases the same heat into the same mass of solution, so the temperature rise is the same»
Schemat punktowania
One mark for the correct option.