1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 19m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 18m
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 Acids3h 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

32. Lipids

Physical Properties of Fatty Acids

Organic Chemistry

32. Lipids

Physical Properties of Fatty Acids

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Physical Properties of Fatty Acids Example 2

Jules Bruno

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Here in this example question, it says within each pair, determine the fatty acid with a greater melting point. Now remember, if we increase our number of carbons, then that's gonna cause an increase in my melting point. And if I increase my number of pi bonds, that's gonna cause a decrease in my melting point. If we take a look here at our 2 fatty acids, we have Stearic Acid with 18, Oleic Acid with 18, So, we can't rely on the number of carbons. What we rely on instead is the number of Pi Bonds. Stearic Acid has 0 Pi Bonds, Oleic Acid has 1. Remember, increase the number of pi bonds decreases my melting point. So, stearic acid would be higher in terms of melting point. Next, we have Linolenic acid, which has 18 carbons and 3 pi bonds. And we have here, Met acid, which is 23. So both of them have the same number of pi bonds, but they have different number of carbons. Since this has more carbons, it'll have a higher melting point. Next, we have 18 carbons and 1 pi bond, 16 carbons and 1 pi bond. Again, the number of Pi Bonds are the same, but this one here has more Carbon, so it's gonna have a higher melting point. And then finally, we have 18 Carbons in 4 Pi Bonds, 20 Carbons in 3 Pi Bonds. There's 2 forces at work here. First, our second fatty acid has more Carbons which should result in a higher melting point and in addition to this, it has fewer Pi bonds, it has one less Pi bond which would also cause an increase in my melting point. So for those two reasons, this fatty acid would have a higher melting point. So, these are the different fatty acids based on each pair that would have the greater melting point.

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