A drop of olive oil of radius 0.25mm spreads into a circular film of radius 10 cm on the water surface.Assuming the film to be of molecular thickness estimate the size of the molecule.

Let us suppose that olive oil spreads as a film which is one molecule thick on the water surface. then the thickness of the film would give an estimate of diameter of the molecule.

 

d= volume of the oil drop/ area of the film

 

= 4/3 *pi* (0.025cm)^3/(pi* (10 cm)^2

 

= 2.08X10^-7 cm