DP Chemistry (first assessment 2025)

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Question 21M.1A.HL.TZ1.37

Date	May 2021	Marks available	[Maximum mark: 1]	Reference code	21M.1A.HL.TZ1.37
Level	HL	Paper	1A	Time zone	TZ1
Command term	Determine	Question number	37	Adapted from	N/A

37.

[Maximum mark: 1]

21M.1A.HL.TZ1.37

How many chiral centres are there in the following molecule?

A. 2

B. 3

C. 4

D. 6

[1]

Markscheme

C

Syllabus sections

Structure 3. Classification of matter » Structure 3.2—Functional groups: Classification of organic compounds » Structure 3.2.7—Stereoisomers have the same constitution (atom identities, connectivities and bond multiplicities) but different spatial arrangements of atoms. Describe and explain the features that give rise to cis-trans isomerism; recognize it in non-cyclic alkenes and C3 and C4 cycloalkanes. Draw stereochemical formulas showing the tetrahedral arrangement around a chiral carbon. Describe and explain a chiral carbon atom giving rise to stereoisomers with different optical properties. Recognize a pair of enantiomers as non-superimposable mirror images from 3D modelling (real or virtual).