Kinetic theory for matter is a theory used to explain the properties of matter. Several points of this theory that you must remember:
Matter is made up of tiny discrete particles.
- Solid: The particles are closely packed in an orderly manner.
- Liquid: The particles are loosely packed in a disorderly manner.
- Gas: The particles are randomly distributed.
The particles are in constant motion.
- Solid: Particles can only vibrate about a fixed point. (Remember that they are closely packed)
- Liquid: Particles can move about freely by sliding and rolling past each other. But there are still confined within a certain area.
- Gas: Particles are able to move about freely, usually at high speeds.
The kinetic energy of a particle changes with temperature.
- The higher the temperature, the faster the particles move.
- At fixed temperature, lighter particles move faster than heavier particles.
The average kinetic energy of all particles is directly proportional to the absolute temperature.
- At a fixed temperature, all the particles do not have the same kinetic energy. They do not travel at the same speed $\rightarrow$ there is a spread in the kinetic energy of the particles, i.e. some particles are very fast while some particles are slow.
Take note: The third and fourth point do not contradict each other. In fact, with the fourth point in place, the third point is redundant.
|Particle arrangement||Closely packed in orderly manner||Loosely packed in disorderly manner||Randomly arranged(Usually very far apart)|
|Particle motion||Vibrate about fixed point||Roll and slide past each other||Move in all directions|
|Avg. kinetic energy||Low||Moderate||High|