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

2. Molecular Representations

Intermolecular Forces

Organic Chemistry

2. Molecular Representations

Intermolecular Forces

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Problem 5a

Textbook Question

In each pair, which would you expect to have the higher melting point?
(a)

Verified step by step guidance

Step 1: Analyze the molecular structures of the two compounds. The first compound has a bulky tert-butyl group attached to a cyclohexane ring, while the second compound has a linear alkyl chain attached to a cyclohexane ring.

Step 2: Consider the impact of molecular symmetry and packing efficiency on melting point. Molecules with higher symmetry and better packing tend to have higher melting points.

Step 3: Evaluate the steric hindrance caused by the bulky tert-butyl group in the first compound. This group disrupts the packing efficiency, making it harder for the molecules to form a solid lattice.

Step 4: Compare the linear alkyl chain in the second compound. Linear chains generally allow for better packing in the solid state, leading to a higher melting point.

Step 5: Conclude that the second compound, with the linear alkyl chain, is expected to have a higher melting point due to its better packing efficiency compared to the first compound with the bulky tert-butyl group.

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Key Concepts

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

Melting Point

The melting point of a substance is the temperature at which it transitions from a solid to a liquid. It is influenced by the strength of intermolecular forces present in the substance. Generally, compounds with stronger intermolecular forces, such as hydrogen bonds or ionic interactions, exhibit higher melting points compared to those with weaker forces like van der Waals interactions.

Structural Isomerism

Structural isomerism occurs when compounds have the same molecular formula but different structural arrangements of atoms. This can lead to variations in physical properties, including melting points. In the given question, the two compounds are structural isomers, and their differing structures can significantly affect their melting points due to variations in packing efficiency and intermolecular interactions.

Steric Hindrance

Steric hindrance refers to the repulsion between atoms that occurs when they are brought close together, often due to the size of the groups attached to them. In organic compounds, increased steric hindrance can lead to less efficient packing in the solid state, which typically results in lower melting points. Understanding the steric effects in the given compounds is crucial for predicting their melting point behavior.