# Kinetic Molecular Theory

## Terms and Formulae

#### Terms

Boltzmann constant  -  A constant, k, involved in the equation for average velocity. k = 1.38×10-23 J/K
Diffusion  -  Diffusion is the spread of one substance through another.
Effusion  -  Effusion is the rate at which a gas passes through a small hole into a vacuum.
Kinetic energy  - Ek = 1/2mv2
Kinetic molecular theory  -  A theory that models the interaction between individual gas molecules. See the summary for more details.
Maxwell-Boltzmann speed distribution  -  The distibution attained when molecule speed is set against the number of molecules sharing that speed.
Mean free path  -  The mean distance a molecule travels before it impacts another molecule; given the huge number of collisions in a gas, the mean free path is vastly smaller than any typical room or container. The equation for mean free path:

 λ =

mp -  The most probable velocity at which the most molecules in a gas travel. The formula for most probable velocity is:

 vp = =

Root mean square velocity  -  An equation to measure the typical velocity of molecules in a gas.

 vrms = = =

#### Formulae

Average velocity

 = =

 Kinetic energy Ek = 1/2mv2

Mean free path

 λ =

Formule for most probable velocity

 vp = =

Formula for root mean square velocity

 vrms = = =