Finding the area of an oil slick

[iamjohnny56]

Homework Statement

Assume that an oil slick consists of a single layer of molecules and that each molecule occupies a cube 0.792 nm on a side.
Determine the area of an oil slick formed by 1.56 m^3 of oil.
Answer in units of m^2.

Homework Equations

1 nanometer = 1.0E9 meters

The Attempt at a Solution

.792 nm = 7.92E-10 m

(1.56 m^3) / (7.92E-10 m) = 1.97E9 m^2

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I think I'm doing everything right, but it's coming up as wrong...could someone please look through my work and point out anything I'm doing wrong?

That would be much appreciated, thanks!

 

[lewando]

If you imagine the volume of oil as a cube consisting of a stack of many one-molecule-thick layers, then what you have calculated is the area of a single layer.

 

[iamjohnny56]

Thanks, lewando. I realized that I forgot the "+9" after the E when entering the problem in uTexas...although that's never been an issue before, I guess uTexas now requires that for exponents.

 

[lewando]

I'm glad it you figured that out. Please disregard my prior post altogether. I am flat-out dyslexic and it resulted in me giving you bad information.

 

[rwisz]

Your solution looks correct to me. However, it is important to note that an oil slick is not a perfect cube and the molecules may not be perfectly aligned, so the actual area may vary slightly. Additionally, the units should be m^2, not m, so the final answer should be 1.97E9 m^2. It is possible that the answer is being marked wrong due to rounding errors, so you may want to try using more significant figures in your calculations to get a more precise answer.