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What is the approximate diameter of an oil molecule?

by xxcherry06xx
Tags: approximate, diameter, molecule
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xxcherry06xx
#1
Jun4-10, 09:49 PM
P: 3
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.
1. The problem statement, all variables and given/known data



2. Relevant equations



3. The attempt at a solution
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rl.bhat
#2
Jun4-10, 09:58 PM
HW Helper
P: 4,433
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
#3
Jun4-10, 10:25 PM
P: 3
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
#4
Jun4-10, 10:47 PM
HW Helper
P: 4,433
What is the approximate diameter of an oil molecule?

Quote Quote by xxcherry06xx View Post
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
#5
Jun4-10, 10:51 PM
P: 3
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
#6
Jun4-10, 10:59 PM
HW Helper
P: 4,433
Quote Quote by xxcherry06xx View Post
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.


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