Zadanie 3f, Paper 2, listopad 2025, TZ1, Chemia IB HL
Wzorowane na: Chemistry HL Paper 2, November 2025, TZ1, pytanie 3(f). Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Zadanie
Wspólne informacje do wiązki zadań
Many esters are still known by trivial names. Propyl ethanoate, CH3COOCH2CH2CH3, which has the odour of pears, is manufactured from propan-1-ol and ethanoic acid in the presence of an acid catalyst.
CH3CH2CH2OH(l) + CH3COOH(l) ⇌ CH3COOCH2CH2CH3(l) + H2O(l)
Both reactants can be synthesized from alkanes: propan-1-ol from propane via 1-bromopropane, and ethanoic acid from ethane via bromoethane and ethanol. The overall equation for the synthesis of the ester from the two alkanes is
Polecenie
(i) Sketch the Maxwell–Boltzmann energy distribution curve for the particles in this reaction mixture at 25 °C, marking on the diagram the activation energy both with and without the catalyst.
Powiększ(ii) On the same axes, sketch and label a second Maxwell–Boltzmann curve for this reaction mixture, now at 70 °C.
Korepetytor AI
Nie wiesz, jak ruszyć? Korepetytor zna to zadanie i poprowadzi Cię krok po kroku, bez gotowca.
3 rozmowy · bez karty · Zaloguj się
Sprawdź się
Odpowiedz i oceń, jak poszło. Klucz odsłoń dopiero, gdy masz swoją odpowiedź.
Zanim porównasz z kluczem
Jak poszło Ci z tym zadaniem?
Zaloguj się, żeby zapisać ocenę i wrócić do zadania później.
Pokaż rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
(i) curve starting at the origin, rising to a maximum and falling towards the x-axis at high energy without touching it ✔
Ea with catalyst marked at a lower kinetic energy than Ea without catalyst «both marked on the x-axis» ✔
(ii) second curve labelled 70 °C with a lower and broader peak shifted to higher kinetic energy, lying below the 25 °C curve at low energies and above it at high energies ✔
Schemat punktowania
(i) M1: correct shape from the origin, asymptotic to the x-axis at high energy; M2: Ea (catalysed) at a lower energy than Ea (uncatalysed) on the x-axis. (ii) [1] for a labelled curve with a lower peak displaced to the right that stays above the 25 °C curve at high energies; do not award the mark if the curve crosses the x-axis or rises above the 25 °C curve at low energies. Accept the label on either or both curves.
Komentarz. The area under both curves must be the same (same number of particles), and a catalyst moves the activation energy line, not the curve.