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Example of saponification reaction of a triglyceride molecule (left) with potassium hydroxide (KOH) yielding glycerol (purple) and salts of fatty acids ().. Saponification value or saponification number (SV or SN) represents the number of milligrams of potassium hydroxide (KOH) or sodium hydroxide (NaOH) required to saponify one gram of fat under the conditions specified.
Saponification is a process of cleaving esters into carboxylate salts and alcohols by the action of aqueous alkali. Typically aqueous sodium hydroxide solutions are used. [ 1 ] [ 2 ] It is an important type of alkaline hydrolysis .
Water molecules stay close to each other , due to the collective action of hydrogen bonds between water molecules. These hydrogen bonds are constantly breaking, with new bonds being formed with different water molecules; but at any given time in a sample of liquid water, a large portion of the molecules are held together by such bonds. [61]
For example, Paraffin has very large molecules and thus a high heat capacity per mole, but as a substance it does not have remarkable heat capacity in terms of volume, mass, or atom-mol (which is just 1.41 R per mole of atoms, or less than half of most solids, in terms of heat capacity per atom).
The driving mechanism for micellization is the transfer of hydrocarbon chains from water into the oil-like interior. This entropic effect is called the hydrophobic effect. Compared to the increase of entropy of the surrounding water molecules, this hydrophobic interaction is relatively small. The water molecules are highly ordered around the ...
The amount of energy consumed in breaking hydrogen bonds in the transition from ice to water is known as the heat of fusion. [12] [8] As with water, ice absorbs light at the red end of the spectrum preferentially as the result of an overtone of an oxygen–hydrogen (O–H) bond stretch.
An important basic value, which is not registered in the table, is the saturated vapor pressure at the triple point of water. The internationally accepted value according to measurements of Guildner, Johnson and Jones (1976) amounts to: P w (t tp = 0.01 °C) = 611.657 Pa ± 0.010 Pa at (1 − α) = 99%
Water molecules in ice I h are surrounded by four semi-randomly directed hydrogen bonds. Such arrangements should change to the more ordered arrangement of hydrogen bonds found in ice XI at low temperatures, so long as localized proton hopping is sufficiently enabled; a process that becomes easier with increasing pressure. [104]