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
-
E
k = 1/2mv
2
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 = 
|
m
p
-
The most probable velocity at which the most molecules in a gas travel. The formula for most probable
velocity is:
v
p =  = 
|
Root mean square velocity
-
An equation to measure the typical velocity of molecules in a gas.
| v rms | = |
|
|
| = |
|
||
| = |
|
Formulae
Average velocity
|
|
= 
= 
| Kinetic energy | E k = 1/2mv 2 |
| Mean free path |
|
| Formule for most probable velocity |
|
| Formula for root mean square velocity |
|
