Zadanie 6b
Wzorowane na: Chemistry HL Paper 2, May 2024, TZ2, pytanie 6(b). Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Informacja do zadań 6a-6b.
A student studied the kinetics of the reaction between a purple dye, D+, and aqueous sodium hydroxide, represented by the equation below.
D+(aq) + OH−(aq) → DOH(aq)
The ion D+ is intensely purple and DOH is colourless.
In a preliminary experiment the student timed how long the purple colour of the mixture described in the table took to vanish, and estimated the rate of reaction from the expression below.
estimated rate = [D+]/ time for colour to disappear
| Initial [D+] / mol dm−3 | Initial [OH−] / mol dm−3 | Time for colour to disappear / s | Estimated rate / mol dm−3 s−1 |
|---|---|---|---|
| 2.50 × 10−6 | 4.00 × 10−2 | 140 | 1.79 × 10−8 |
Polecenie
Explain, in terms of collision theory, why raising the temperature of the reaction mixture from 20 °C to 30 °C increases the rate of the reaction between D+ and OH−.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
a larger fraction of the particles has energy of at least the activation energy, Ea ✔
successful collisions happen more often «per second»
OR
collisions are more frequent ✔
Schemat punktowania
M1: more particles with E ≥ Ea; M2: more frequent or more successful collisions. Do not accept 'particles move faster' alone.