- #1
HelpaSista
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Homework Statement
A student working 3.0 m away from you in the chemistry lab creates a bad odour. The odour takes a while to get to you (assume that air currents are negligible). You then move 2.0 m further away, but the odour catches up with you in another 60 seconds. What is the diffusion coefficient of the molecules you smell?
hint: the root mean square distancee and the time must be measured from the source of the diffusing molecule.
Homework Equations
t= R^2 / 6D
The Attempt at a Solution
I first tried to find time from 0-3m by using the ratio between the two distances
2^2 / 6*s X 6T/^3 = 1 (1 since D is the same)
I found that t = 135s
I then added 135 to 60 seconds and used that as my total time and 5 as my total R and solved for D
D = R^2 / 6*T
= 25 / 6*195
=0.02136
However, my textbook says the answer is 0.044 and I don't see what I am doing wrong. :(
Any help will be much appreciated, thank you!