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

Naming Alkenes

Organic Chemistry

4. Alkanes and Cycloalkanes

Naming Alkenes

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8:09 minutes

Problem 1

Textbook Question

Draw structural formulas of at least two alkynes of each molecular formula.
1. C₆H₁₀
2. C₈H₁₂
3. C₇H₈

Verified step by step guidance

Step 1: Understand the general formula for alkynes, which is CnH2n-2. This will help you determine if the given molecular formulas can represent alkynes.

Step 2: For C6H10, verify that it fits the alkyne formula CnH2n-2. Here, n=6, so 2n-2=10, which matches. Now, draw possible structures. Start with a straight chain alkyne, such as hex-1-yne, and then consider branching, like 3-methylpent-1-yne.

Step 3: For C8H12, check if it fits the alkyne formula. Here, n=8, so 2n-2=14, which does not match. This means C8H12 cannot be a simple alkyne. Consider cyclic structures or multiple bonds to satisfy the formula.

Step 4: For C7H8, check if it fits the alkyne formula. Here, n=7, so 2n-2=12, which does not match. C7H8 is more likely to be an aromatic compound like toluene, rather than an alkyne.

Step 5: For each valid molecular formula, draw at least two structural isomers. Ensure that each structure adheres to the rules of valency and the alkyne's triple bond characteristics. Use line-angle formulas for clarity.

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Key Concepts

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

Alkyne Structure

Alkynes are hydrocarbons that contain at least one carbon-carbon triple bond, denoted as C≡C. This triple bond is a defining feature, giving alkynes their unique properties. The simplest alkyne is ethyne (acetylene), and the presence of the triple bond affects the molecule's geometry, making it linear around the bond.

Molecular Formula and Degree of Unsaturation

The molecular formula provides the number of each type of atom in a molecule. For alkynes, the degree of unsaturation helps determine the number of rings and/or multiple bonds. Each triple bond contributes two degrees of unsaturation, which is crucial for deducing possible structures from a given formula.

Isomerism in Alkynes

Isomerism refers to compounds with the same molecular formula but different structures. In alkynes, structural isomers can arise from variations in the position of the triple bond or branching of the carbon chain. Understanding isomerism is essential for drawing different structural formulas for a given molecular formula.

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