Finding the approximate diameter of an oil molecule

[joshuas09]

How do you solve a question like this ? :you can obtain a rough estimate of the following simple experiment-let a droplet of oil spread out on a fairly large but smooth water surface .the resulting oil slick that forms On the surface of the water will be approximately one molecule thick. Given an oil droplet with a mass of 9.00 x 10^-7kg and a density of 918kg/m^3 that spreads out to form a circle with a radius of 41.8 cm on the water surface , what is the approximate diameter of an oil molecule?

 

[MarkFL]

I have moved your post into its own thread in a better suited forum. Tagging this question onto an exiting thread in a probability forum would likely have resulted in your question being largely ignored.

I would begin with the relationship between density and volume. We are given mass and density of the drop of oil, can you find the volume?