Zadanie 8
Wzorowane na: Chemistry SL Paper 1A, May 2026, TZ2, pytanie 8. Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
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Polecenie
The three isomers of C4H8O in the table have the same molar mass. What is the reason for the increase in boiling points?
| Isomer | Structure | Boiling point / °C |
|---|---|---|
| Ethoxyethene | CH2=CH−O−CH2CH3 | 33 |
| Butanone | CH3COCH2CH3 | 80 |
| But-3-en-1-ol | CH2=CH−CH2CH2OH | 113 |
A. Increase in the number of covalent bonds per molecule
B. Increase in molar mass
C. Increase in the strength of intermolecular forces
D. Decrease in the strength of the covalent bonds within the molecules
Sprawdź rozwiązanieUkryj rozwiązanieKlucz CKE i punktacja
Odpowiedź z klucza
C ✔
«the molar masses are equal, so the London (dispersion) forces are similar; ethoxyethene has only weak dipole–dipole attractions, butanone has stronger dipole–dipole attractions because of the polar C=O bond and but-3-en-1-ol forms hydrogen bonds through its O–H group; the stronger the intermolecular forces, the higher the boiling point»
Schemat punktowania
One mark for the correct option; no partial credit.