Question about DIFFUSION OF GASES AND GRAHAM'S LAW?

Question

I have a test but cannot find answer for this. help thx!

1. A gas of unknown molecular weight is found to diffuse at a rate of 0.19cm/s compared to 0.59 cm/s for helium gas. Calculate the molecular weight of the unknown gas.

2. Which of all of the possible gases should have the highest rate of diffusion?

3. A balloon inflated with helium gas will rise to the ceiling of a room. However, after a certain period of time, the balloon will descend to the floor. Why does the balloon eventually descend?

4. If the cork containing the concentrated NH3(AMMONIA) solution were inserted into the glass tube several seconds after the insertion of the cork containing HCl, what effect would this have on the calculated value of the molecular weight of HCI???

Answer 1

http://en.wikipedia.org/wiki/Graham's_law

rate1/rate2 = sqrt(m2/m1)

or

(rate1/rate2)^2 = (m2/m1)

m1 = m2/(rate1/rate2)^2= 4/(0.19/0.59)^2 = 38.6 g/mol (this is probably fluorine gas, F2)

2. hydrogen H2 or perhaps atomic hydrogen H

3. even if the balloon doesn't leak, gases can diffuse through the membrane itself. since helium is at very low concentration in the atmosphere it will all diffuse out of the balloon, exchanging with air, so the balloon is no longer lighter than air.

4. i don't get this one. what's the context?

Answer 2

it grew to alter into into chanced on via graham that value of diffusion is inversely proportional to the muse of the density.and since the density is 2 circumstances the molar mass so that's likewise inversely proportional 2 molar mass and social amassing given via aj is real

Answer 3

The only gas I know about is methane because I eat a lot of vegetables!

Answer 4

why don't you find it in library?