Zadanie 1a
Wzorowane na: Chemistry HL Paper 2, May 2026, TZ1, pytanie 1(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 1a-1f.
Nitric acid, HNO3, is manufactured industrially from ammonia in a three-step process known as the Ostwald process.
Polecenie
(i) The first step is the catalytic oxidation of ammonia gas to nitrogen monoxide.
4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g)
Determine the volume, in dm3, of nitrogen monoxide produced from 20.0 g of ammonia, at STP, using section 2 of the data booklet.
(ii) Calculate the new volume, in dm3, of nitrogen monoxide if the temperature changes to 40.0 °C, using the final volume from (a)(i). Use sections 1, 2 and 4 of the data booklet.
If you did not obtain an answer for (a)(i) use 20.0 dm3, although this is not the correct answer.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz CKE i punktacja
Odpowiedź z klucza
(i) n(NH3) = 20.0/17.04 = 1.17 «mol»; n(NO) = 1.17 «mol, 1 : 1 mole ratio» ✔
V(NO) = 1.17 × 22.7 = 26.6 «dm3» ✔
(ii) «T1 = 273.15 K, T2 = 313.15 K»
«dm3» ✔
«ECF: if 20.0 dm3 is used, as the question allows, V2 = 22.9 dm3»
Schemat punktowania
(i) [2] M1: amount of NO obtained from the amount of NH3 (n = m/M, then the 1 : 1 mole ratio); M2: volume using Vm = 22.7 dm3 mol-1. Award [2] for the correct final answer. (ii) [1] correct new volume from V1/T1 = V2/T2 with temperatures in kelvin; accept 273 K and 313 K or 273.15 K and 313.15 K; accept 22.9 dm3 if 20.0 dm3 was used; ECF from (i). Do not penalize units or significant figures.