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Due to the polar nature of the water molecule itself, other polar molecules are generally able to dissolve in water. Most nonpolar molecules are water-insoluble (hydrophobic) at room temperature. Many nonpolar organic solvents, such as turpentine, are able to dissolve nonpolar substances.
The hydrophobic effect is the desire for non-polar molecules to aggregate in aqueous solutions in order to separate from water. [22] This phenomenon leads to minimum exposed surface area of non-polar molecules to the polar water molecules (typically spherical droplets), and is commonly used in biochemistry to study protein folding and other ...
An example of these amphiphilic molecules is the lipids that comprise the cell membrane. Another example is soap, which has a hydrophilic head and a hydrophobic tail, allowing it to dissolve in both water and oil. Hydrophilic and hydrophobic molecules are also known as polar molecules and nonpolar molecules, respectively. Some hydrophilic ...
The hydrophobic interaction is mostly an entropic effect originating from the disruption of the highly dynamic hydrogen bonds between molecules of liquid water by the nonpolar solute, causing the water to compensate by forming a clathrate-like cage structure around the non-polar molecules. This structure is more highly ordered than free water ...
The hydrophobic effect was found to be entropy-driven at room temperature because of the reduced mobility of water molecules in the solvation shell of the non-polar solute; however, the enthalpic component of transfer energy was found to be favorable, meaning it strengthened water-water hydrogen bonds in the solvation shell due to the reduced ...
Regarding the organization of covalent bonds, recall that classic molecular solids, as stated above, consist of small, non-polar covalent molecules. The example given, paraffin wax , is a member of a family of hydrocarbon molecules of differing chain lengths, with high-density polyethylene at the long-chain end of the series.
The cost of efficient molecular packing is compensated by hydroge-bonding. Ribbons of hydrogen-bonded urea molecules form tunnel-like host into which many organic guests bind. Urea-clathrates have been well investigated for separations. [26] Beyond urea, several other organic molecules form clathrates: thiourea, hydroquinone, and Dianin's compound.
The carbon–fluorine bond is one of the strongest in organic chemistry (an average bond energy around 480 kJ/mol [1]). This is significantly stronger than the bonds of carbon with other halogens (an average bond energy of e.g. C-Cl bond is around 320 kJ/mol [ 1 ] ) and is one of the reasons why fluoroorganic compounds have high thermal and ...