Zadanie 4c
Wzorowane na: Chemistry HL Paper 2, November 2023, TZ1, pytanie 4(c). Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Informacja do zadań 4a-4c.
Carbonyl sulfide, COS, reacts with steam in a gas phase hydrolysis according to the overall equation
COS(g) + H2O(g) ⇌ CO2(g) + H2S(g)
Polecenie
Naturally occurring sulfur is a mixture of several isotopes. A sample was enriched in , giving the following composition:
| Isotope | Percent |
|---|---|
| 70 % | |
| 1 % | |
| 28 % | |
| 1 % |
(i) Calculate the relative atomic mass of the enriched sample to two decimal places.
(ii) The abundance of in natural sulfur is 0.750 %. Calculate how many atoms of this isotope are present in a 1.00 g sample of natural sulfur. Use sections 2 and 7 of the data booklet.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
(i) 0.700 × 32 + 0.010 × 33 + 0.280 × 34 + 0.010 × 36 ✔
Ar = 32.61 ✔
(ii) amount of «» = 2.34 × 10−4 «mol» ✔
number of atoms «= 2.34 × 10−4 mol × 6.02 × 1023 mol−1» = 1.41 × 1020 ✔
Schemat punktowania
(i) Award [2] for a correct final answer. M2 requires the answer to be given to two decimal places; 32.07, the data booklet value, is not accepted. (ii) Award [2] for a correct final answer; accept 1.40 × 1020–1.41 × 1020.