A monolayer containing 3.21 x 10^-6 g of oleic acid has an area of 20.0cm^2. The density of oleic acid is 0.895 g/mL. What is the thickness of the monolayer ( the length of an oleic acid molecule) ?

Question

A monolayer containing 3.21 x 10^-6 g of oleic acid has an area of 20.0cm^2. The density of oleic acid is 0.895 g/mL. What is the thickness of the monolayer ( the length of an oleic acid molecule) ?

Answer 1

Density = mass/volume

We have the mass = 3.21x10^-6 g

Find the volume:

3.21x10^-6 g x 1 ml/0.895 g = 3.587x10^-6 ml = 3.587x10^-6 cm³

We can now find the thickness (depth, D) as follows:

Volume = L x W x D and L x W = area

Volume = 20.0 cm² x D

3.587x10^-6 cm³ = 20.0 cm² x D

D = thickness = 3.587x10^-6 cm3/20.0 cm²

Thickness = 1.79x10^-7 cm