# Graham's Law of Diffusion

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##### Graham's Law of Diffusion

*The relative rates at which two gases under identical conditions of
temperature and pressure will diffuse vary inversely as the square
roots of the molecular masses of the gases.*
Assume following temperature conditions for two
different gases:

** T**_{1} = T_{2}

and by this that these two gases has the same kinetic energy (**E**_{k}=1/2mv^{2})

**1/2m**_{1}v_{1}^{2} = 1/2m_{2}v_{2}^{2}

Moving **v**_{2} to the left and **m**_{1} to
the right side of the equation we get:

**v**_{1}^{2}/v_{2}^{2} = m_{2}/m_{1}

Taking the square root we get:

**v**_{1}/v_{2} = (m_{2}/m_{1})^{1/2}

If we know the mass/density and the velocity of a gas, also
knowing the mass/density or the velocity of a second gas, we
should be able to calculate the velocity or mass/density of the second
gas.

##### Graham's
Law of Diffusion

Equal amounts of Argon and Helium was placed in a porous
container and allowed to escape. Which gas will escape faster ?

Answer: Helium will escape 3.16 times faster tan Argon

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