Why do long chain fatty acids have higher melting points?
Long chain fatty acids posses more carbon atoms. The carbon atoms are bonded together thereby resulting more bonds. Melting is as a result of breaking these bonds. The longer the carbon chains the higher the molecular weight of t6he fatty acids hence more energy that comes from a higher temperature.
Unsaturated fatty acids have lower melting points than saturated fatty acids of the same length. For example, the melting point of stearic acid is 69.6°C, whereas that of oleic acid (which contains one cis double bond) is 13.4°C. The melting points of polyunsaturated fatty acids of the C18 series are even lower.
- An unsaturated fat is a fat or fatty acid in which there is at least one double bond within the fatty acid chain. A fatty acid chain is monounsaturated if it contains one double bond, and polyunsaturated if it contains more than one double bond.
- Triacylglycerols (triglycerides) are carboxylic acids. Saturated fats have lower melting points than do unsaturated fats. Triacylglycerols (triglycerides) are composed of fatty acid residues and glycerol. Unsaturated fats are more likely than saturated fats to be liquid at room temperature.
- Size and properties of molecules. The size of a molecule has an effect on the properties that molecule shows. For example, the boiling point of hydrocarbons increases as the number of carbon atoms in the molecule increases. This is because forces between molecules increase as the size of the molecule increases.
The freezing point of lauric acid is 44 °C, based on the plateau observed at this temperature on the graph. 6. Freezing point depression: 44 °C - 42 °C = 2 °C. exists as neither a liquid nor a solid.
- Note that the molal freezing point depression constant, Kf, has a specific value depending on the identity of the solvent. The following graph shows the normal freezing point for water (solvent) as a function of molality in several solutions containing sucrose (a non-volatile solute).
- Lauric acid is a medium-length long-chain fatty acid, or lipid, that makes up about half of the fatty acids within coconut oil. It's a powerful substance that is sometimes extracted from the coconut for use in developing monolaurin.
- Benzoic acid
PubChem CID: 243 Chemical Names: Benzoic acid; 65-85-0; Benzenecarboxylic acid; Dracylic acid; Benzeneformic acid; Carboxybenzene More Molecular Formula: C7H6O2 or C6H5COOH Molecular Weight: 122.123 g/mol InChI Key: WPYMKLBDIGXBTP-UHFFFAOYSA-N
|Density||0.9408 g/cm3 (20 °C) 0.847 g/cm3 (70 °C)|
|Melting point||69.3 °C (156.7 °F; 342.4 K)|
- Myatt: Magnesium stearate is a simple salt made of two common nutritional substances, the mineral magnesium and the saturated fat stearic acid. It is used as a “flow agent” in many nutritional supplements and pharmaceuticals. Both magnesium and stearic acid are not only safe, they are beneficial to human health.
- Stearic acid also has important cleansing properties that make it useful in soaps. The ingredient acts as a surfactant, a substance that lowers the surface tension of oils. As a result, stearic acid helps to remove dirt, sweat and excess sebum from the skin and hair.
- So to sum this all up, when matter is transitioning from solid to liquid (melting) or liquid to solid (freezing), its temperature is fixed at the melting/freezing point, which is the same temperature.
Updated: 29th September 2018