A monolayer containing 3.23 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

This is not unlike a question you asked earlier dealing with density. Again, density = mass/volume. You are given the density (0.895 g/ml) and are asked for the thickness (height) of the monolayer. From the information provided, you can calculate the volume of the monolayer, hence the thickness, since vol = area x height.

density = mass/volume

0.895 g/ml = 3.23x10^-6 g/x ml

x ml = 3.23x10^-6 g/0.895 g/ml = 2.89x10^-6 ml = 2.89x10^-6 cm³ = volume of the monolayer

volume = area x thickness

thickness = volume/area = 2.89x10^-6 cm³/20.0 cm² = 1.45x10^-7 cm

If you want the answer in terms of other units, then you have...

1.45x10^-4 mm

0.145 um

145 nm