Zadanie 4e
(i) Explain why 1,2-dichloroethene, ClCH=CHCl, has two stereoisomers but 1,1-dichloroethene, CH2=CCl2, does not. (ii) State the hybridization of the carbon atoms in propene, CH3CH=CH2. (iii) Predict the number of signals and the relative…
Structure and stability of benzene
Discuss the evidence for the delocalized structure of benzene: equal C-C bond lengths, planar hexagonal shape, an enthalpy of hydrogenation lower than expected for three C=C bonds, and a preference for substitution over addition.
Tę umiejętność sprawdza 9 zadań wzorowanych na arkuszach IB z lat 2022–2026.
Zadania sprawdzające tę umiejętność: 9 Otwórz w wyszukiwarce z filtrami
Zadanie 13
In the 19th century benzene was proposed to be cyclohexa-1,3,5-triene, a ring with three localized carbon-carbon double bonds. Which observation contradicts this model? A. Benzene is a planar molecule with bond angles of 120° B. The enthalpy of hydrogenation…
Zadanie 2a
Describe the bonding represented by the circle in structure A.
- Materiał graficzny
Zadanie 2b
The ring in 4-methylstyrene is a benzene ring. State one chemical and one physical reason why structure A represents the benzene ring better than structure B.
- Materiał graficzny
Zadanie 7
In which set do all the species contain delocalized electrons? A. NH4+, C6H12, Si(s) B. CH3OH, SO2, C (diamond) C. C2H4, NO3−, SiO2 D. CO32−, C6H6, Cu(s)
Zadanie 10
Which pair of statements about the electrons in this molecule is correct? A. 3 non-bonding pairs of electrons and 8 electrons in π bonds B. 5 non-bonding pairs of electrons and 8 electrons in π bonds C. 5 non-bonding pairs of electrons and 10 electrons…
- Materiał graficzny
Zadanie 10
Resonance structures can be drawn for which of the following species? I. CO32− II. NH4+ III. C6H6 A. I and II only B. I and III only C. II and III only D. I, II and III
Zadanie 33
Benzene reacts with bromine in the presence of iron(III) bromide to form bromobenzene, not an addition product. Which statement best explains this? A. Benzene contains no carbon–carbon double bonds B. The carbon–carbon bonds in benzene are weaker than those in…
Zadanie 2d
Compare, giving a reason, the length of a carbon–nitrogen bond within the quinazoline ring system with the length of a carbon–nitrogen bond in the diethylamino group.
- Materiał graficzny