You can obtain a rough estimate of the size of a molecule by the followint simple experiment:?

Question

Let a droplet of oil spread out on a smooth surface of water. The resulting oil slick will be approximately one molecule thick. Given an oil droplet of mass 9.00x10^-7kg and density 918kg/m^3 that spreads out into a circle of radius 41.8 cm on the water surface, what is the order of magnitude of the diameter of an oil molecule?

Answer 1

I guess we're assuming oil molecules are perfect spheres, then (which isn't likely, but anyway...).

You use the equation V = Ad where A is the area of the oil slick and d is the diameter of an oil molecule (can you see this?).

You can find the volume by using the given mass and density. Remember that D = m / V where D is density, m is mass, and V is volume.