• Solid phase: Molecular spacing is minimal and there is little mobility or movement between molecules. Therefore, the solids are harder and are characterized by the constant volume and defined shape.
• Liquid phase: although small, molecular spacing and motility between molecules are greater than in solid bodies. In the liquid phase, substances are characterized by constant volume and undefined form.
• Gaseous phase: the molecular spacing is large and the mobility of molecules has no limit. Substances in the gas phase take the form of the container containing them and expand until they fill up all space, be it small or large.
