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…
Stereoisomers: cis-trans and optical isomerism
Explain why restricted rotation around C=C and in small rings gives cis-trans isomers, identify chiral carbons, draw enantiomers as non-superimposable mirror images with tetrahedral wedge formulas, and describe how enantiomers differ in optical activity.
Tę umiejętność sprawdza 36 zadań wzorowanych na arkuszach IB z lat 2022–2026.
Zadania sprawdzające tę umiejętność: 36 Otwórz w wyszukiwarce z filtrami
Zadanie 17
Which molecules exhibit cis-trans isomerism? I. Pent-2-ene II. 1,1-dichloroethene III. 1,2-dibromoethene A. I and II only B. I and III only C. II and III only D. I, II and III
Zadanie 17
Which of the compounds shown is chiral and so exists as a pair of enantiomers? A. Compound A B. Compound B C. Compound C D. Compound D
- Materiał graficzny
Zadanie 4a
The structure of galantamine is shown below. (i) State the name of the functional group that contains the nitrogen atom. (ii) Outline the effect of this functional group on the pH of water in which galantamine is dissolved, giving the direction of the change…
- Materiał graficzny
Zadanie 4b
Compound Y is chiral. Draw its two optical isomers, showing the three-dimensional arrangement of the groups around the chiral centre.
Zadanie 8e
Several stereoisomers exist among the dichloroalkenes of molecular formula C4H6Cl2. (i) Draw the structural formula of cis-2,3-dichlorobut-2-ene. (ii) Outline why the cis-isomer of 2,3-dichlorobut-2-ene is polar, whereas the trans-isomer is not. (iii)…
Zadanie 17
Which compound shows cis-trans isomerism? A. Compound A B. Compound B C. CH2=C(CH3)2 D. CH3CH=CH2
- Materiał graficzny
Zadanie 19
How many chiral centres does the molecule shown contain? A. 1 B. 2 C. 3 D. 4
- Materiał graficzny
Zadanie 20
Consider the molecule octa-1,3,5,7-tetraene. How many stereoisomers of octa-1,3,5,7-tetraene are possible? A. 3 B. 4 C. 8 D. 16
- Materiał graficzny
Zadanie 17
Which molecule contains a chiral centre? A. CH3CH(NH2)COOH B. (CH3)2CHCOOH C. CH3CH2CH(CH3)CH2CH3 D. ClCH2CH(OH)CH2Cl
Zadanie 17
Which of the following compounds show stereoisomerism? I. CH3CH=CHCH3 II. CH3CH(OH)CH2CH3 III. (CH3)2C=CH2 A. I and II only B. I and III only C. II and III only D. I, II and III
Zadanie 19
Which pair of compounds correctly illustrates the stated type of isomerism? A. Positional isomerism: CH3CH2CHO and CH3COCH3 B. Functional group isomerism: CH3CH2CH2CH2OH and CH3CH(OH)CH2CH3 C. Cis-trans isomerism: the two compounds…
- Materiał graficzny
Zadanie 6c
(i) Draw the structural formula of 2-chloropentane and that of the structural isomer in which the chlorine atom is attached to a tertiary carbon atom. (ii) Only one of the two isomers drawn in (c)(i) is chiral. Draw stereochemical formulas showing its two…
- Materiał graficzny
Zadanie 2e
Pentan-2-ol is optically active. (i) Sketch the two enantiomers of pentan-2-ol, showing how they are related. (ii) Deduce the organic product formed in each case when pentan-1-ol and pentan-2-ol are refluxed with acidified potassium dichromate(VI).…
Zadanie 5i
2-Chloropentane exists as two stereoisomers. (i) Using wedge-dash notation, draw the two stereoisomers of 2-chloropentane. (ii) Outline a way of telling the two enantiomers apart.
Zadanie 18a
3-Methylcyclohexanol is a cyclic alcohol. Draw circles around all chiral carbon atoms in the structure.
- Materiał graficzny
Zadanie 22a
Chloramphenicol is an antibiotic. A molecule of chloramphenicol contains two chiral carbon atoms. Identify the two chiral centres by marking each with an asterisk on the structure.
- Materiał graficzny
Zadanie 2b
2-Methylbut-1-ene reacts with hydrogen bromide, HBr, to give two structural isomers of C5H11Br. (i) Deduce which of the two isomers is formed in the larger amount and explain your choice. (ii) Using curly arrows to show the movement of electron pairs,…
Zadanie 17b
Menthol, used in medicinal rubs, has several chiral carbon atoms in its ring, which is numbered below. Draw circles around two chiral carbon atoms in this structure.
- Materiał graficzny
Zadanie 17c
A pharmaceutical chemist has a reference sample of the desired enantiomer of a chiral drug. Explain how a polarimeter can help establish whether a newly prepared sample contains that enantiomer.
Zadanie 35
How many optical isomers exist for menthol, the compound shown? A. 3 B. 6 C. 8 D. 9
- Materiał graficzny
Zadanie 37
Which compound gives an optically active product when it is reduced? A. Pentanal B. Pentan-3-one C. 3-Methylbutanal D. Pentan-2-one
Zadanie 3a
Halogenoalkanes form a homologous series. (i) Outline the meaning of homologous series. (ii) State the preferred IUPAC name of each of the two compounds shown. (iii) State which of the two compounds contains a chiral carbon atom and identify that carbon atom…
- Materiał graficzny
Zadanie 7f
One of the two products of the reaction of pent-1-ene with HCl can exist as stereoisomers. Draw the three-dimensional structures of the two stereoisomers, using wedge-dash notation, and show clearly the relationship between them.
Zadanie 19a
Ephedrine is a decongestant found in some cold remedies. Its structure is shown. Deduce which two carbon atoms in a molecule of ephedrine are chiral. For each of them, state the four different atoms or groups bonded to it.
- Materiał graficzny
Zadanie 35
Which compound is optically active? A. propan-2-ol B. butan-1-ol C. 2-methylpropan-2-ol D. butan-2-ol
Zadanie 36
A solution contains 2.0 g of one enantiomer of a chiral compound and 2.0 g of its mirror image in 100 cm3. The pure first enantiomer, at this concentration, rotates the plane of polarized light by +34.0° under the same conditions. What…
Zadanie 6a
Butanone can be synthesized from but-1-ene in a two-stage process. In the first stage but-1-ene reacts with water and sulfuric acid to form an intermediate compound X. In the second stage X reacts with reagent B to form butanone. (i) Draw the structural…
- Materiał graficzny
Zadanie 6a
Butanone can be synthesised from but-1-ene in a two-stage process. In the first stage the alkene reacts with water in the presence of sulfuric acid to form the intermediate compound [X]; in the second stage [X] is converted into butanone by reagent B. (i) Draw…
- Materiał graficzny
Zadanie 36
The structure of an isomer of 1,2-dichloroethene is shown. Which statement about this isomer is correct? A. It is the cis isomer and is polar. B. It is the cis isomer and is non-polar. C. It is the trans isomer and is polar. D. It is the trans isomer and is…
- Materiał graficzny
Zadanie 39
Separate pure samples of the two enantiomers of 2-chlorobutane are available. Which measurement can be used to distinguish between them? A. Boiling point B. Direction in which each rotates plane-polarized light C. Infrared spectrum D. 1H NMR spectrum in an…
Zadanie 39
Which observation can be used to distinguish between the two enantiomers of a chiral compound in an achiral environment? A. The direction in which plane-polarized light is rotated B. Boiling point C. The mass-to-charge ratio of the molecular ion D. The number…
Zadanie 5a
(i) State the IUPAC name of Compound B. (ii) Both compounds are liquids at room temperature. Identify the strongest intermolecular force between molecules of Compound B. (iii) State how many σ (sigma) bonds and how many π (pi) bonds one molecule of Compound A…
- Materiał graficzny
Zadanie 6b
Starting from a single enantiomer of 2-bromopentane, only one enantiomer of the alcohol product, pentan-2-ol, is obtained. Suggest, with a reason, whether the reaction follows an SN1 or an SN2 mechanism.
Zadanie 6c
State the name of an instrument that could be used to determine whether the pentan-2-ol obtained is a single enantiomer or a racemic mixture.
Zadanie 33
Which compound contains a chiral carbon atom? A. 1-chlorobutane B. 2-chloropentane C. 3-chloropentane D. 2-chloropropane