Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

4. Alkanes and Cycloalkanes

Cis vs Trans Conformations

Organic Chemistry

4. Alkanes and Cycloalkanes

Cis vs Trans Conformations

Previous problemNext problem

Problem 58

Textbook Question

Which of the following represents a cis isomer?

Verified step by step guidance

Step 1: Understand the concept of cis and trans isomers. Cis isomers have substituents on the same side of the molecule, while trans isomers have substituents on opposite sides.

Step 2: Analyze the chair conformations in the image. Look at the positions of the methyl groups (CH₃) on the cyclohexane ring in each structure.

Step 3: For each structure (A, B, C, D), determine whether the methyl groups are both on the same side (cis) or on opposite sides (trans). This can be identified by checking if both substituents are either axial or equatorial.

Step 4: In structure A, the methyl groups are on the same side of the ring (both equatorial or both axial), indicating a cis isomer. In structure B, the methyl groups are on opposite sides (one axial and one equatorial), indicating a trans isomer.

Step 5: Similarly, analyze structures C and D. Structure C has methyl groups on opposite sides (trans), while structure D has methyl groups on the same side (cis).

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Play a video:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Cis-Trans Isomerism

Cis-trans isomerism is a type of stereoisomerism where molecules with the same molecular formula have different spatial arrangements of atoms. In cis isomers, similar or identical groups are on the same side of a double bond or a ring structure, while in trans isomers, they are on opposite sides. This difference in arrangement can significantly affect the physical and chemical properties of the compounds.

Double Bonds and Restricted Rotation

Double bonds consist of one sigma bond and one pi bond, which restricts the rotation of the bonded atoms. This restriction is crucial for the existence of cis and trans isomers, as it allows for distinct spatial arrangements. In contrast, single bonds allow free rotation, leading to the same molecular structure regardless of the orientation of substituents.

Identifying Isomers

To identify cis and trans isomers, one must analyze the substituents attached to the double bond or ring structure. By examining the positions of these groups, one can determine whether they are on the same side (cis) or opposite sides (trans). Drawing the molecule or using molecular models can aid in visualizing these arrangements and confirming the isomer type.

Watch next

Master How to draw chairs. with a bite sized video explanation from Johnny

Start learning

Related Videos

Related Practice

Textbook Question

Name the following compounds. Remember that two up bonds are cis; two down bonds are cis; one up bond and one down bond are trans.

(e)

(f)

Textbook Question

Use your results from Problem 3-27 to complete the following table. Each entry shows the positions of two groups arranged as shown. For example, two groups that are trans on adjacent carbons (trans-1,2) must be both equatorial (e,e) or both axial (a,a).

Textbook Question

The cyclohexane chair shown in Figure 3-22 has the headrest to the right and the footrest to the left. Draw a cyclohexane chair with its axial and equatorial bonds, showing the headrest to the left and the footrest to the right.

Textbook Question

Draw two different chair conformations for each of the following molecules. Make sure that your drawings clearly show the cis–trans stereochemistry.

(c)

Textbook Question

Name the following cycloalkanes using the IUPAC system of nomenclature.

Textbook Question

Is each of the following a cis isomer or a trans isomer?

Multiple Choice

Which structure is cis-1,3-dimethylcyclopentane?

Textbook Question

Name the following compounds. Remember that two up bonds are cis; two down bonds are cis; one up bond and one down bond are trans.

(c)