This document discusses the properties and behavior of gases. It defines several key concepts: - Gases can be compressed or expanded depending on pressure and will exert an even pressure on their container. - The kinetic molecular theory of gases states that gas particles are in constant, random motion and collide elastically with each other and container walls. - Gas laws like Boyle's, Charles', and the combined gas law mathematically relate the pressure, volume, temperature and amount of a gas. - The ideal gas law combines these relationships into one equation that can be used to calculate gas properties under any conditions. - Avogadro's law states that equal volumes of gases under the same conditions contain