A substance that is a solid, a liquid, or a gas, may be a solute or a solvent. A solution forms when the attractive forces between the solute and the solvent are similar. Some solutions form quickly and others form slowly. The rate depends upon several factors including size of solute, shaking or stirring, or heat. When a solution holds a maximum amount of solute at a certain temperature, it is said to be saturated.
Any excess solute appears as a solid in the container.
Generally, heating the solution can increase the amount of solute that dissolves. Most solids are more soluble in water at higher temperatures. Solubility must be expressed as quantity of solute per quantity of solvent at a specific temperature. In this experiment, you will study the solubility of potassium nitrate in water. By dissolving different quantities of this salt in a given amount of water at a temperature close to the water's boiling point, the start of crystallization will be noted and recorded.