KINETIC MOLECULAR THEORY AND CHANGES OF STATE
Kinetic energy is the energy of motion. The kinetic molecular theory is basically the same as the particle model of matter exept that is further explains the motion of the states of matter. The states of matter are solid, liquid, and gas.
Here are the basic ideas of kinetic molecular theory:
- There are spaces between the particles.
- Matter is composed of small particles.
- The particles are always moving. Solids
- The motion of the particlesis caused by energy. The more energy a particle has, the further and faster is moves. This means that a liquid had more energy than a solid, and a gas has even more energy than a liquid.
More energy = increased motion
- Solids - The particles are close together and hold a definite shape. They have less energy, so they only vibrate, and their shape is held because of the attraction between particles.
- Liquids - The particles are also close together, but since they have more energy, they can slide past one another. They take the shape of the container they are in.
- Gasses - The particles are spaced apart. Because they have the highest energy, they can move quickly in all directions and spread out. They also take the shape of the container they are in.
Changes in temperature result in changes in the energy of particles. When the temperature rises, the particles gain energy, increase their motion, and bounce off each other with more force. With increasing temperature, the particles separate from each other and cause a change of state from solid to liquid and to gas if the temperature rises high enough. Every type of matter will change state at different temperature.
There are specific names for the changes of states. When the temperature is decreasing, the change from gas to liquid occurs and is called condensation, and the change from liquid to solid is called solidification. When the temperature is increasing, the change from solid to liquid occurs and is called melting, and the change from liquid to gas is called evaporation. Remember that the opposite changes occur at the exact same temperature. Sometimes, matter skips the liquid state and changes directly from a solid to a gas. This is called sublimation. When it changes back from a gas to a solid, it is called deposition.
- Melting is the opposite of solidification
- Evaporation is the opposite of condensation
- Sublimation is the opposite of deposition