WJEC A Level Chemistry
WJEC A Level Chemistry 4.1 Stereoisomerism Exam Questions
Free WJEC A Level Chemistry exam questions on 4.1 Stereoisomerism, with mark schemes. Covers optical isomerism, chiral centres, enantiomers and E-Z isomerism.
4.1 Stereoisomerism exam questions
1 question pack of real past exam questions with its mark scheme. Answer every question without notes, then mark your answers line by line against the mark scheme.
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WJEC A Level Chemistry Flashcards (Anki & Quizlet)
Every answer is written in mark scheme wording, so you learn exactly what examiners give marks for. Use them on Anki or Quizlet, then test yourself with the questions on this page.
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About WJEC A Level Chemistry 4.1 Stereoisomerism
This topic covers 3D isomerism in organic molecules.
What you need to know
- Chirality A carbon with four different groups is a chiral centre.
- Enantiomers Non-superimposable mirror images that rotate plane-polarised light in opposite directions.
- Racemic mixtures Equal amounts of enantiomers have no net optical activity.
- E-Z isomerism Restricted rotation about C=C with different groups on each carbon.
Common mistakes in 4.1 Stereoisomerism
- Marking carbons with two identical groups as chiral.
- Saying enantiomers have different chemical properties in all reactions.
- Confusing racemic with pure enantiomer.
Try three 4.1 Stereoisomerism exam-style questions
1. State what is meant by a chiral centre. (1 mark)
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A carbon atom bonded to four different groups.
2. Explain why a racemic mixture is optically inactive. (2 marks)
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It contains equal amounts of both enantiomers (1), so their rotations cancel (1).
3. Explain why many drugs are made as a single enantiomer. (1 mark)
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Only one enantiomer fits the target receptor; the other may be inactive or harmful.
4.1 Stereoisomerism FAQs
What does Stereoisomerism cover?
Optical and E-Z isomerism.
How are enantiomers distinguished?
By the direction they rotate plane-polarised light.
Do I need to draw 3D structures?
Yes, using wedge and dash bonds.
Revise this topic with flashcards: WJEC A Level Chemistry Flashcards, with mark scheme answers for Anki and Quizlet.
