Postulates of kinetic theory
Matter = particles. Particles move. Movement changes with temperature.
Kinetic theory makes a few core claims:
- All matter is made of tiny particles (atoms, ions or molecules).
- Particles are in constant, random motion.
- Temperature is a measure of the AVERAGE kinetic energy of these particles. Higher T = faster average motion.
- Particles collide with each other and with container walls.
- In an IDEAL gas, particles have negligible volume and don't attract or repel each other except during collisions.
The way particles move depends on the state:
- Solid: vibrate around fixed positions.
- Liquid: slide past one another while staying close.
- Gas: move freely at high speed in all directions.
Particles in a real sample don't all have the same speed at any moment. Some are slower, some faster — heating shifts the WHOLE distribution to higher speeds.
- All matter is particles in constant random motion.
- Temperature ∝ average kinetic energy of particles.
- Particles vibrate (solid), flow (liquid), or fly freely (gas).