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

Organic Chemistry

4. Alkanes and Cycloalkanes

Cis vs Trans

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2:29 minutes

Problem 53b

Textbook Question

For each of the following compounds, draw the possible geometric isomers and name each isomer:
b. 1,5-heptadiene

Verified step by step guidance

Identify the structure of 1,5-heptadiene. It is a seven-carbon chain with two double bonds located at carbons 1 and 5. The molecular formula is C7H10.

Determine if the double bonds in the molecule can exhibit geometric (cis-trans) isomerism. Geometric isomerism occurs when there is restricted rotation around a double bond and different groups attached to the double-bonded carbons.

Focus on the first double bond (C1=C2). Check the substituents on C1 and C2. If the substituents are different, this double bond can exhibit cis-trans isomerism. Similarly, analyze the second double bond (C5=C6) for the same condition.

Draw the possible geometric isomers for each double bond. For the first double bond (C1=C2), draw one structure where the higher-priority groups (based on Cahn-Ingold-Prelog rules) are on the same side (cis) and another where they are on opposite sides (trans). Repeat this process for the second double bond (C5=C6).

Name each isomer using the E/Z nomenclature system. Assign priorities to the groups attached to each double-bonded carbon using the Cahn-Ingold-Prelog rules, and determine whether the higher-priority groups are on the same side (Z) or opposite sides (E) of the double bond. Combine the E/Z designations for both double bonds to fully name each isomer.

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Key Concepts

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

Geometric Isomerism

Geometric isomerism occurs in compounds with restricted rotation around a double bond or a ring structure, leading to different spatial arrangements of atoms. In alkenes, this is often classified into cis and trans isomers, where 'cis' indicates that substituents are on the same side of the double bond, while 'trans' indicates they are on opposite sides. Understanding this concept is crucial for identifying and drawing the isomers of compounds like 1,5-heptadiene.

Alkenes and Their Structure

Alkenes are hydrocarbons that contain at least one carbon-carbon double bond (C=C). The presence of this double bond not only affects the physical properties of the compound but also its reactivity and potential for isomerism. In the case of 1,5-heptadiene, the double bonds located at the first and fifth carbon atoms create opportunities for geometric isomers based on the arrangement of substituents around these bonds.

Drawing Isomers

Drawing isomers involves representing the different structural configurations of a compound. For geometric isomers, it is essential to accurately depict the spatial arrangement of atoms around the double bonds. This includes labeling the isomers correctly, such as cis-1,5-heptadiene and trans-1,5-heptadiene, to reflect their distinct structures and properties, which is vital for understanding their chemical behavior.

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