Two gas containers A and B have equal volumes and contain
different gases at same Temperature (T) and Pressure (P).
Show that there are equal nos. of molecules in the two
containers.
You could also use the formula
PV = NKT, where K is the boltzmann's constant, and N = num of
molecules
Thus, N = PV / KT
Since P, V, and T are equal for both gases, and K is a constant,
thus, N is equal for both gases (shown)
The molecules in container A have mass 4 times as great as the
molecules in container B. Sketch and label graphs on
http://i44.tinypic.com/2u4n8u1.jpg
to show how the molecular speeds are distributed in the two
containers, given that speed distribution curve for the molecules
in A peaks at 200 m/s.
Right where I am, tinypic is also blocked. So I shall attempt a
guess at this question first.
You should know the formula for kinetic energy of a molecule. If
I remember, it's 3/2 KT
So, 1/2 mv^2 = 3/2 KT
v = sqrt (3KT/m)
This means, the heavier the molecule, the lower the
velocity.
Hence, in general, molecules in B should travel about 2 times as
fast as molecules in A.
How does Kinetic theory account for the equal pressures at the
same temperature and volume?
It doesn't. PV = nRT. And n might not be the same for
both. Either that or the question isn't clear.
