Molecular Kinetic Theory

Brownian motion

• Smoke particles are bombarded by the air
• at any given instant, there are more collisions on one side of the particle than the other
• therefore the change in momentum on each side is unequal
• therefore a force F results.

Ideal gas equation

pV=nRT

p = k/V (at a constant temperature)

When volume V decreases:

• molecules travel less distance before they collide with the container
  • therefore there are more collisions every second with the container
  • therefore rate of change of momentum increases
  • therefore pressure increases.

p = kT (at a constant volume)

When temperature T increases:

• molecules have a greater velocity
  • therefore there are more collisions every second with the container
  • therefore rate of change of momentum increases
  • therefore pressure increases.

pV=(1/3)Nm<c²>

Where

• N = the number of molecules
• m = the mass of each molecule (kg)
• <c²> = the mean square speed

Zeroth law

When you place two bodies in contact and there is no net energy transfer between them:

• they are in thermal equilibrium
• therefore they have the same temperatures.