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

Alkyl Groups

Organic Chemistry

4. Alkanes and Cycloalkanes

Alkyl Groups

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6:43 minutes

Problem 43a,b

Textbook Question

There are eight different five-carbon alkyl groups.
a. Draw them.
b. Give them systematic names.

Verified step by step guidance

Step 1: Understand that five-carbon alkyl groups are derived from alkanes with five carbon atoms, known as pentane. These groups are formed by removing one hydrogen atom from pentane, resulting in different structural isomers.

Step 2: Begin by drawing the straight-chain alkyl group, which is the n-pentyl group. This is derived from n-pentane, where the hydrogen is removed from the terminal carbon. The structure is CH₃(CH₂)₄−.

Step 3: Next, draw the branched isomers. Start with the isopentyl group, which is derived from isopentane. Remove a hydrogen from one of the terminal carbons, resulting in the structure (CH₃)₂CHCH₂CH₂−.

Step 4: Continue with the neopentyl group, derived from neopentane. Remove a hydrogen from one of the terminal carbons, resulting in the structure (CH₃)₄C−.

Step 5: Draw the remaining isomers by considering different branching patterns. For example, the sec-pentyl group is derived from removing a hydrogen from the secondary carbon in n-pentane, resulting in CH₃CH₂CH(CH₃)CH₂−. Repeat this process to identify all eight isomers, ensuring each has five carbon atoms and one open valency for bonding.

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Key Concepts

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

Alkyl Groups

Alkyl groups are hydrocarbon chains that are derived from alkanes by removing one hydrogen atom, resulting in a structure that can attach to other molecules. In the context of the question, understanding the structure and naming of five-carbon alkyl groups is essential, as they form the basis for drawing and naming the compounds.

IUPAC Nomenclature

IUPAC nomenclature is the standardized system for naming chemical compounds, ensuring consistency and clarity in communication. For alkyl groups, this involves identifying the longest carbon chain, numbering the carbons to give substituents the lowest possible numbers, and naming the substituents accordingly. This concept is crucial for systematically naming the five-carbon alkyl groups.

Isomerism

Isomerism refers to the phenomenon where compounds have the same molecular formula but different structural arrangements. In the case of five-carbon alkyl groups, understanding isomerism is key to identifying all possible structural variations, including straight-chain and branched isomers, which must be drawn and named as part of the question.