how can we find the size of ocelic acid module
Answers
Answer:
The molecules of oleic acid and other such vegetable oils belong to a category called lipids. These are commonly called ‘fat molecules’. Their structure is hydrophobic, which means that they are poorly soluble in water. Molecules that dissolve in water are called hydrophilic. The word comes from Greek words meaning ‘water-loving’. Fatty acid molecules such as oleic acid are interesting because they have parts which are hydrophilic and parts which are hydrophobic.
In the picture of oleic acid, note that the oleic acid molecule is standing on the –OH end of the molecule. This was done on purpose because when oleic acid molecules encounter water they stand up on it with this end down. Oleic acid floats on water due to a lower density. A significant portion of the molecule is hydrophobic. Only the –OH end is hydrophilic. Because it is so much larger than the hydrophilic end, the entire molecule is not soluble in water. When placed on water oleic acid molecules will stand up and support one another on end because of attractive forces between the hydrophobic parts of the molecules.If oleic acid is dropped onto water we make the assumption that it spreads out to a thickness of only one molecule.
We dissolve 1 cm3 of oleic acid in 400 cm3 of alcohol to obtain a concentration of 1 part by 400. We take a big container of water and to the surface we add a uniform layer of lycopodium powder. To this we add one drop of oleic acid. The drop quickly spreads into a thin, large circular film of a molecular thickness. This is the oleic acid molecules standing on their hydrophilic ends. We can measure the diameter of this circle using which we can calculate the area ‘A’.
If ‘v’ is the volume of one drop, then the volume of n drops of solution is ‘nv’.
Volume of oleic acid in n drops of solution = (nv400) cc
If A cm2 is the area and‘t’ its thickness then assuming the thickness is equal to one layer of molecules we can calculate the thickness
A × t=nv400
This means that the thickness is
Thickness=VolumeArea
t = (nvA×400)