Question

step of obtaining crystal from crystallisation​

Answer 1

Crystallization occurs in two major steps. The first is nucleation, the appearance of a crystalline phase from either a supercooled liquid or a supersaturated solvent. The second step is known as crystal growth, which is the increase in the size of particles and leads to a crystal state

Answer 2

Crystallisation Process

Crystallisation process results in a physical change in objects. It leads to the formation of crystal structures. Clear distinguish between processes of crystallisation is not possible. But we can identify two categories of crystallisation processes namely Cooling Crystallisation and Evaporative Crystallisation.

Cooling Crystallisation

Many substances, when dissolved in solvent, form crystals on cooling in favorable conditions in this process. However, this method is not very common and has many limitations. Usually, the substance is heated and then allowed to cool down in this method.

Evaporative Crystallisation

It is more common than cooling crystallisation. Evaporating sea water leaves salt behind. Pure Crystals of Substance are deposited after evaporation of solutions. But this method requires a high concentration of the substance in the solution. Therefore, its solute/solvent mass ratio should be high.

Experiment 1

• First of all, take some water in a beaker. Add a few drops of dilute Sulphuric Acid (H2SO4).

• Heat the mixture on a burner. Add Copper Sulphate Powder when it starts boiling.

• Keep stirring the solution. Keep adding Copper Sulphate Powder to the solution until it is soluble.

• Now filter the solution and allow it to cool down.

• You will see crystals of copper sulphate suspended in the solution.

Experiment 2

• Put 160 grams of sodium acetate in a flask and add 30 mL of water.

• Heat the flask on a burner or a hot plate until it starts boiling.

• Stir the solution unless the sodium acetate crystals dissolve.

• Now remove the flask from the heat and let it cool down for a while.

• Finally, place one or two sodium acetate crystals on a surface and pour the solution on top of it.

• Try to keep the stream of solution steady.

• The solution will solidify and form a vertical structure.