Zadanie 5a
Wzorowane na: Chemistry HL Paper 2, May 2026, TZ1, pytanie 5(a). Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Informacja do zadań 5a-5c.
Chlorine dioxide reacts with hydroxide ions in aqueous solution.
2 ClO2(aq) + 2 OH−(aq) → ClO3−(aq) + ClO2−(aq) + H2O(l)
A student measured the initial rate of the reaction in four experiments at constant temperature. The results are shown below.
| Experiment | Initial [OH−] / mol dm−3 | Initial [ClO2] / mol dm−3 | Initial rate / mol dm−3 s−1 |
|---|---|---|---|
| 1 | 0.0200 | 0.0200 | 1.47 × 10−3 |
| 2 | 0.0400 | 0.0200 | 2.95 × 10−3 |
| 3 | 0.0200 | 0.0400 | 5.89 × 10−3 |
| 4 | 0.0200 | 0.0600 | 13.2 × 10−3 |
Polecenie
Determine the order of reaction with respect to ClO2 and with respect to OH−.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz CKE i punktacja
Odpowiedź z klucza
ClO2: second order ✔ «experiments 1 and 3: [ClO2] doubles and the rate increases four times»
OH−: first order ✔ «experiments 1 and 2: [OH−] doubles and the rate doubles; experiment 4 agrees, as tripling [ClO2] makes the rate nine times larger»
Schemat punktowania
[2] M1: second order with respect to ClO2; M2: first order with respect to OH-. Accept 2 and 1, or 'second' and 'first'. Do not award a mark for an order that is justified only by comparing experiments in which both concentrations change.