What is fractional crystallization? And how is it used in real-world applications?
Fractional crystallization is a method of purifying chemicals based on their solubility differences. It occurs due to crystal growth (the formation of crystals) between the various substances in the solution.
If you allow a mixture of two or more substances in solution to crystallize, for example, by lowering or raising the temperature of the solution, a precipitate containing the majority of the least soluble substance will be formed.
But what exactly is fractional crystallization? Keep reading to learn more about this process now.
Difference Between Crystallization and Fractional Crystallization
All substances have a definite internal structure, whether in solid, liquid, or gaseous form. This is known as the molecules or atoms of a substance being “arranged in a definite pattern throughout the entire sample.”
The definitive internal structure of a substance is known as crystalline. In contrast, amorphous substances lack a definite internal structure.
A good way to think of the difference between crystalline and amorphous is to consider the difference between a pile of rocks and a bowl of soup. The rocks have a definite shape and structure, while the soup does not.
The process of a substance going from an amorphous state to a crystalline state is known as crystallization. The reverse process, in which a substance goes from a crystalline state to an amorphous state, is known as melting.
Fractional crystallization is simply a particular type of crystallization. It occurs when a mixture of two or more compounds in solution is allowed to crystallize, and the resulting precipitate contains a higher concentration of the least soluble compound.
This process is used to purify chemicals based on their solubility differences. The advantage of fractional crystallization over other methods, such as simple crystallization, is that it can be used to purify a wider assortment of compounds.
Loving this post? Make sure to check out our other article about fractional units before you go!
Fractional Crystallization Experiment Example
Let’s say you have a solution of two compounds, A and B. Compound A is more soluble than compound B.
If you allow the solution to crystallize, the resulting precipitate will be mostly compound B. However, if you remove the precipitate and allow the remaining solution to crystallize, the resulting precipitate will be mostly compound A.
This process can be repeated until you have a pure sample of each compound.
How Does Fractional Crystallization Work?
Fractional crystallization works because the solubility of a compound changes with temperature.
For example, let’s say you have a solution of salt and water. The salt is more soluble in hot water than it is in cold water.
If you allow the solution to cool, the salt will start to crystallize out of the solution. However, if you remove the salt crystals and heat the remaining solution, the salt will dissolve back into the solution.
This process can be repeated until you have a pure sample of salt.
The same principle applies to fractional crystallization. The solubility of a compound changes with temperature, so by removing the precipitate and heating the remaining solution, you can increase the concentration of the least soluble compound in the solution.
This process can be repeated until you have a pure sample of the least soluble compound.
FAQ About Fractional Crystallization
What is meant by fractional crystallization?
Fractional crystallization is the process of purifying chemicals based on their solubility differences. This process can be used to purify a broader range of compounds than other methods, such as simple crystallization.
What is fractional crystallization used for?
Fractional crystallization is commonly used in the chemical industry to purify various compounds. This process is used to filter chemicals based on their solubility differences. Through this process, it’s possible to purify a wider range of compounds than other methods, such as simple crystallization.
Closing on Fractional Crystallization
Fractional crystallization is an essential tool for chemists and other scientists. It can purify a wide range of compounds, from simple salts to complex organic molecules.
If you’re interested in learning more about fractional crystallization, or any other topic in chemistry, be sure to check out some other articles. With many sources of information online, you’re bound to find more information on this subject!