explain the relationship between the rate of diffusion of gases and molecular weight.?

Answer 1

If the gas is heavy, the rate of diffusion will be low.
Actually, rate of diffusion is inversely proportional to the sqrt(Molecular wt)

Answer 2

The higher the molecular weight the slower the substance will diffuse.

Answer 3

According to Graham's law of Gaseous diffusion (1928) " The rate of diffusion of gas is inversly proportional to the square root of its density at same conditions of temperature and pressure ".

we also know that density is directly proportional to its molecular weight.

so we can conclude that rate of diffusion is inversly proportional to square root of mits molecular weight. which means that higher the molecular weight less will be the diffusion and vice versa.

for eg if we diffuse from two different sides of a glass tube NH3(ammonia ) and HCl( hydrochloric acid). the molecular weight ot ammonia will be 17 gm/mol while that of HCL will be 36.5 gm/mol so we can say that ammonia will diffuse faster compare to HCl.

Answer 4

Ok, since temperature is proportional to kinetic energy,
KEgas a = KEgas b

So you get : 1/2 (mass a) v^2 = 1/2 (mass b) v^2
Then you get: (velocity a)/(velocity b) = square root of (mass b/mass a)

Since velocity of a gas is proportional to rate of diffusion you get the final equation for the relation:

(rate diffusion of gas a)/(rate of diffusion of gas b) = square root of (mass of gas b/ mass of gas a)

Basically, the heavier gasses will diffuse slower and lighter gasses will diffuse faster.

Answer 5

From the kinetic energy formula it can be shown that

v^2 = 3kT / molecular mass, or v=sqrt(3kT/M)
with v (root mean square) in m/s, T in deg. Kelvin, and k is Boltzmann's Constant.

Conveniently, v(rms) is also the rate of diffusion