Measurement of the Size of Oleic Acid molecule

The estimation of enormous distances is simple. We realize very well how to magnify. We use kilometers for terrestrial applications, light years for a long time for heavenly applications, and 1 parsec (3.26 light-years) for galactic applications. On the opposite end of the scale, we have a little measure. We can get millimeters and our naked eyes can see up to 0.1 mm however after that it is extremely difficult to imagine. 

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An electron magnifying lens is a microscope that enlightens the sample with light emission electrons. This permits the electron microscope to concentrate pointedly on a little item, for example, an atom. This electron can be made to have a short frequency, right around multiple times shorter than the visible light, along these lines giving the electron microscope a better resolution than an optical magnifying instrument. A transmission electron magnifying instrument can accomplish superior to 50 Picometer (10-12) resolution and you ought to remember that atoms range from 30 – 300 Pico meters.

Prior to the innovative progressions, however, we just had a rough estimate of the size of the atom. Let's examine a few of the methods or techniques now. 

Oleic Acid: Thin Film Method

The particles/molecules of oleic acid and other such vegetable oils have a place with a classification called lipids. These are normally called 'fat particles/molecules '. Their structure is hydrophobic, which implies that they are inadequately dissolvable in water. Molecules that can be dissolved in water are called hydrophilic. The word originates from the Greek term signifying 'water-loving'. Fatty acid molecules, for example, oleic acid are fascinating because they have parts that are hydrophilic and hydrophobic parts.  

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In the image of oleic acid, note that the oleic acid particle/molecule is remaining on the – OH end of the molecule. This was done deliberately in light of the fact that when oleic acid particles/molecules experience water they stand upon it with this end down. Oleic acid buoys on water because of lower thickness. A noteworthy bit of the molecule is hydrophobic. Just the –OH end is hydrophilic. 

Since it is so larger than the hydrophilic end, the whole molecule isn't solvent in water. At the point when putting on water, oleic acid molecules will stand up and bolster each other on end in light of attractive forces between the hydrophobic parts of the molecules. If oleic acid is dropped onto water, we make the supposition that it spreads out to a thickness of just a single particle/molecule.

There is a need to dissolve 1 cm3 of oleic acid in 400 cm3 of liquor to get a centralization of 1 part by 400. After that take a big water container and to the surface, we include a uniform layer of lycopodium powder. To this, we include one drop of oleic acid. The drop rapidly extends into a thin, huge circular film of molecular thickness. This is the oleic acid molecules remaining on their hydrophilic ends. 

How To Calculate The Thickness Size of A Molecule?

We can quantify the distance across this circle utilizing which we can compute the area 'A'. 

Let us assume that the volume of one drop is 'v'

Then,

The volume of n drops is 'nv' for the solution.

So, 

The volume of oleic acid in ‘n’ drops of solution = (nv/400) cc 

If the area is A cm2 and thickness is ‘t’

Thickness can be calculated as: (with the assumption that the thickness is equivalent to one layer of molecules) 

\[A^\ast t=\frac{nv }{400}\]

This implies the thickness is:

Thickness=Volume/Area 

\[t=\frac{nv }{A^\ast 400}\]

In light of the assumption that the layer is one molecule thick, we acquire the estimation of the size of the oleic acid molecule. The value of the thickness comes out to be in the order for 10-9 m. Taking into account how basic this exhibition is, this technique has generally excellent precision.