Solubility is the [?] of substance that is dissolved in a unit of water. The temperature is also important. The higher the [?], the substance is dissolved. The temperature is the [?] variable in an experiment; the [?] is the dependent variable.

Some substances are much more soluble in water than others. Sodium chloride is very , while other substance are only sparingly soluble. When no more of a [?] can be dissolved, the solution is called . If we make a saturated solution at high temperatures, and let it cool, then crystals of the solute will form.

Water is a good solvent because it is a [?] molecule. The oxygen end is slightly , while the hydrogen end carries a slightly charge. So most ionic substances dissolve well. Most covalent substances don't dissolve in water. Those that do have a polar nature to them.

Gases dissolve much better in liquids. If the liquid gets hot, the gas escapes.