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

IUPAC Naming

Organic Chemistry

4. Alkanes and Cycloalkanes

IUPAC Naming

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2:50 minutes

Problem 34a

Textbook Question

Which of the following structures represent the same compound? Which ones represent different compounds?
(a)

Verified step by step guidance

Examine each structure carefully to identify the number of carbon atoms and their connectivity. This will help determine if they represent the same compound or different compounds.

Structure 1 and Structure 2 both have a straight chain of five carbon atoms, indicating they are likely the same compound, pentane.

Structure 3 has a branching at the second carbon, with two methyl groups attached, indicating it is 2,2-dimethylbutane, a different compound from Structures 1 and 2.

Structure 4 has a branching at the first carbon, with two methyl groups attached, indicating it is 2,2-dimethylpropane, a different compound from Structures 1, 2, and 3.

Structure 5 has a branching at the second carbon, with two methyl groups attached, similar to Structure 3, indicating it is also 2,2-dimethylbutane, the same compound as Structure 3.

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Key Concepts

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

Structural Isomers

Structural isomers are compounds that have the same molecular formula but differ in the connectivity of their atoms. This means that while they contain the same number of each type of atom, the arrangement of these atoms can lead to different chemical properties and reactivity. Understanding structural isomers is crucial for determining whether different representations of a compound are indeed the same or different.

Condensed Structural Formulas

Condensed structural formulas provide a simplified way to represent the structure of a molecule, showing how atoms are connected without depicting all the bonds explicitly. This notation helps in visualizing the arrangement of atoms and can highlight functional groups or branching in organic compounds. Recognizing condensed formulas is essential for comparing different structures to identify isomers.

Stereochemistry

Stereochemistry is the study of the spatial arrangement of atoms in molecules and how this affects their chemical behavior. It includes concepts such as chirality and geometric isomerism, which can lead to compounds with the same connectivity but different three-dimensional shapes. Understanding stereochemistry is important when analyzing whether different structures represent the same compound, especially in cases where spatial arrangement influences properties.