Kinetic Molecular Theory
The model that explains gas behaviour in terms of large numbers of tiny particles in constant random motion.
Formula / equation
pV = ⅓ Nmc̄²
Unit
Dimensionless
In depth
Its postulates are that gas particles have negligible volume, exert no forces on one another, move randomly in straight lines, collide elastically, and have average kinetic energy proportional to absolute temperature. From these assumptions alone every ideal gas law can be derived mathematically.
Examples in the real world
It explains why heating a sealed can raises its pressure and why a gas expands to fill any container.