Question

A latex balloon, wall thickness 3.091 x 10-4 m, contains helium at a concentration of 0.35 kg m-3. Under these conditions the total surface area of the balloon is 0.57 m2. The diffusion coefficient of He in latex at room temperature is 4.9 x 10-9 m2s-1. Calculate the rate of helium effusion (in g/hr) from the balloon.

Answer 1

maybe:
0.52*(4.9*10^-9)*(concentration in mole/0.52)
then multiply solution (molar flow rate) with molar mass of helium.
solution should be effusion rate.
its just a suggestion, all other interested are invited to post their opinion/formula...

Answer 2

Could someone insert the data into the formula?

Answer 3

This is a question from the second midterm of 3.091x by edx. Stop cheating, it's silly and pointless.

Answer 4

what is the formula?

Answer 5

Fick’s Law
M= -D•(Δρ/Δx)•A,
where
M = m/t = mass flux [kg/s],
D= 4.9•10 ⁻⁹ m ²/s is the diffusion coefficient (diffusivity) [m²/s],
Δρ/Δx is the gradient of density [kg/m⁴],
A is the area [m²].

M= - 4.9•10⁻⁹•(0 - 0.35)/3.091•10⁻⁴)•0.88 =
4.9•10⁻⁹•0.35•0.88/3.091•10⁻⁴=
=4.88•10⁻⁶ kg/s= 17.58 g/hr