Zadanie 1e
Wzorowane na: Chemistry HL Paper 2, May 2024, TZ1, pytanie 1(e). Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Informacja do zadań 1a-1e.
An effervescent powder for a soft drink has the following composition by mass:
| Component | Percentage by mass |
|---|---|
| Sucrose, C12H22O11 | 20.0 |
| Tartaric acid, C4H6O6 | 33.0 |
| Sodium hydrogencarbonate, NaHCO3 | 47.0 |
When water is added, the tartaric acid reacts with the sodium hydrogencarbonate and the powder fizzes:
2 NaHCO3(s) + C4H6O6(aq) → Na2C4H4O6(aq) + 2 CO2(g) + 2 H2O(l)
Polecenie
State, giving a reason, how the lattice enthalpy of lithium tartrate, Li2C4H4O6, would differ from that of sodium tartrate.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
lattice enthalpy greater / higher «more endothermic» ✔
Li+ is smaller / has a greater charge density «same charge», so it is attracted more strongly to the tartrate ions ✔
Schemat punktowania
M1: direction; M2: reason based on ion radius or charge density. Do not award M2 without the ion size or charge density argument. Ignore references to atomic radius.
Komentarz
The data booklet defines lattice enthalpy as an endothermic quantity, so the stronger lattice has the larger positive value.