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Particle movement and pressure

A gas in a closed container exerts a pressure on that container.

When a particle in a gas collides with one of the walls of its container it applies a force on the wall. Many particles collide with the walls every second, each applying a small force.

Since pressure is equal to force over area, this results in pressure being applied to the wall.

The pressure on one wall of the container is equal to the $$$\dfrac{\Tred{\text{sum of all the forces from collisions of particles with wall}}}{\Tblue{\text{area of wall}}}$$$

Because the gas particles move about at random, the pressure exerted by the gas is the same everywhere.

The pressure is higher if:

  • The particles collide with the walls of the container more frequently.

  • The particles in the gas have more mass or more energy.

Particles in a gas are in constant motion.
Particles in a gas are in constant motion.