Question

Will these changes increase, decrease, or have no effect on the mean free path of the molecules in a gas sample?

Answer 1

According to the kinetic theory, the mean free path is the average distance a single atom or molecule of an element or compound travels with respect with the other atoms during a collision. The greater the mean free path, the more ideal the behavior of a gas molecule is because intermolecular forces are minimum. To understand which factors affect the mean free path, the equation is written below.

l = μ/P * √(πkT/2m), where
l is the mean free path
μ is the viscosity of the fluid
P is the pressure
k is the Boltzmann's constant
T is the absolute temperature
m is the molar mass

So, here are the general effects of the factors on the mean free path:

Mean free path increases when:
1. The fluid is viscous (↑μ)
2. At low pressures (↓P)
3. At high temperatures (↑T)
4. Very light masses (↓m)

The opposite is also true for when the mean free path decreases. Factors that are not found here have little or no effect.