Crystalization is a type of chemical reactions
Chemical Reaction: a process that leads to the chemical transformation of one set of chemical substances to another.
Why scientist need Crystalization?
Sometimes when multiple products are formed, the chemist may want to separate one compound from the others.
One way is using a process called recrystallization, where a solution of compounds can be dissolved in hot water and then cooled.
As it cools, one substance crystalizes (becomes crystals), and can be removed from the rest of the liquid, which holds the other compound.
Why do crystals appear as the mixture cools?
Every solid that can be dissolved in water has a solubility,
Solubility: is the largest quantity of the solid that can be dissolved in the water to make a clear solution.
Saturated: When the water starts getting cloudy and you can see solid particles floating around, that means no more solid can dissolve into the water and the solution (water and solid mixture).
The solubility of most solids increases as the mixture is heated, so more of the solid can be dissolved in hot water than in cold water.
Example: imagine you are making a cup of tea, you can dissolve more sugar in hot tea than in iced tea. Sugar crystals at the bottom of the iced tea glass, even after you have stirred it.
When a hot saturated solution is cooled, however, there is suddenly more solid in the solution than can normally be contained by the cooler water.
The hot saturated solution is known as a supersaturated solution
Supersaturated: when more solid was dissolved in it than can be dissolved under normal (cooler) conditions.
Because it can no longer stay dissolved in the water, some of the bits of solid fall out of the solution. They bump into each other, stick together, and form larger and larger pieces, called crystals
All commercial Crystals are available in the market is Ammonium dihydrogen phosphate Crystal. Since Ammonium dihydrogen phosphate is relatively non toxic (not edible), and almost foolproof way to make crystal growing
Crystals grow in a supersaturated solution by the orderly addition of material onto the faces of a seed crystal.