This can be achieved by changing variables that affect solubility such as temperature, or the presence of a second solvent. Thus it is important to use the minimum amount of solvent because a saturated solution must be maintained. If the molecules come together in a disorganized arrangement, they do not occupy the closest packed space. However, if the molecules come together in an ordered array, they pack together in a much smaller space. The proper packing uses less space and is also of lowest energy, which is the most stable condition.
Sublimation is the change of a substance from the solid state directly to a vapor.
Sublimation can be used to purify solids that readily vaporize. An impure substance is heated so that it vaporizes, leaving nonvolatile impurities behind. When the flask containing the solid is heated, the solid initially sublimes. The vapor then condenses on the cold finger. Condensation is the conversion of a vapor to a solid.