What is the approximate diameter of an oil molecule?

[xxcherry06xx]

You can obtain a rough estimate of the size of a molecule with 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 8.85 × 10^−7 kg and a density of 923 kg/m3 that spreads out to form a circle with a radius of 43.2 cm on the water surface, what is the approximate diameter of an oil molecule?
Answer in units of m.

 

[rl.bhat]

Hi xxcherry06xx, welcome to PF.

Volume = mass / density.

π*r^2*d = mass/density, where d is the diameter of the molecule.

Substitute the values and find d.

 

[xxcherry06xx]

I tried that but I still can't get the right answer. I keep getting 0.000000002 but it's saying it's not right on my homework.

 

[rl.bhat]

I tried that but I still can't get the right answer. I keep getting 0.000000002 but it's saying it's not right on my homework.

I am getting 1.635x10^-9m.

 

[xxcherry06xx]

Okay I will try it thank you! I have one more question for you... it is a picture because i don't know how to type it html style but the link is..

http://yfrog.com/jv42157278p

I assumed it was the sum of xi = 4.9 i + 6.06 where i =1 then take that answer and ^4.
I don't know what else that equation can mean? Can you please help.?

 

[rl.bhat]

Okay I will try it thank you! I have one more question for you... it is a picture because i don't know how to type it html style but the link is..

http://yfrog.com/jv42157278p

I assumed it was the sum of xi = 4.9 i + 6.06 where i =1 then take that answer and ^4.
I don't know what else that equation can mean? Can you please help.?

x₁ = 4.9*1 + 6.06

x₂ = 4.9*2 + 6.06

Continue till i = 4, simplify and add all.