Question

a monolayer containing 3.21x10^-6 g of plein acid has an area of 20.0cm^2. The density of oleic acid is 0.895g/mL. What is the thickness of the monolayer (the length of the oleic acid)?

Answer 1

Let the length(thickness) of the acid be Xcm.

Therefore volume of the acid will be 20.0cm2 x Xcm = 20Xcm³

$Density=\dfrac{mass}{volume}$

Since 1cm3 =1mL, then

$0.895g/cm^3 = \dfrac{3.21x10^-6g}{20Xcm^3}$ cross multiplication give us;

$17.9Xg/cm^3 = 3.21x10^-6g$ dividing both sides by 17.9

$X = 1.79x10^-7cm$

The thickness of the acid mono layer is therefore, 1.79x10^-7cm