Chapter summary

  • There are three states of matter: solid, liquid and gas.

  • Diffusion is the movement of particles from a high concentration to a low concentration. Brownian motion is the diffusion of many particles.

  • Melting point is the temperature at which a solid changes its phase to become a liquid. The process is called melting.

  • Freezing point is the temperature at which a liquid changes its phase to become a solid. The process is called freezing.

  • Evaporation is the process of going from a liquid to a gas. Evaporation from a liquid's surface can happen at a wide range of temperatures.

  • Boiling point is the temperature at which a liquid changes phase to become a gas. The process is called evaporation. The reverse process (change in phase from gas to liquid) is called condensing.

  • Sublimation is the process of going from a solid to a gas.

  • The kinetic theory of matter attempts to explain the behaviour of matter in different phases.

  • The kinetic theory of matter says that all matter is composed of particles which have a certain amount of energy which allows them to move at different speeds depending on the temperature (energy). There are spaces between the particles and also attractive forces between particles when they come close together.