Average Oxygen Molecule Travel Distance in a Tank

[Kawrae]

In a tank full of oxygen, how many molecular diameters d (on average) does an oxygen molecule travel (at 1.00 atm and 21.0°C) before colliding with another O2 molecule? (The diameter of the O2 molecule is approximately 3.60 10-10 m.)

>> I don't know why webassign is telling me this is wrong and I can't figure out what I'm doing wrong. I used this equation:

l=1/[(2^.5)(pi)(d^2)(nsubv)]

Since n subv is equal to N/V which is equal to P/kb*T, I got 2.49e25.

Then I just plugged everything in... and got 1.43e7 and divided by the diameter to see how many times it would cross that distance... and I got 3.98e16

What did I do wrong??

 

[dextercioby]

The result is absurd.Check your numbers.
$$\lambda=\frac{1}{\sqrt{2}\pi n d^{2}}=\frac{kT}{\sqrt{2}\pi p d^{2}}$$

Plug the constants and the numbers in SI units correctly which means carefully.


Daniel.

 

[wais]

It seems like you have used the correct equations and values to calculate the average distance an oxygen molecule travels before colliding with another molecule. However, the answer you have obtained may not be correct. It is possible that there is a mistake in your calculations or in the values you have used. I would recommend double-checking your work and using the correct units for each value (e.g. converting temperature to Kelvin). Additionally, it may be helpful to ask your instructor or a classmate for assistance in solving this problem. Keep in mind that the answer may also vary slightly due to experimental error.