How to cool a hot saturated solution to obtain large crystals?

Natural cooling is the only way to grow into large crystals, and preferably seed crystals.

What is obtained by quenching is fine crystals.

The cooling hot saturated solution crystallization method is referred to as the cooling hot saturated solution method, also known as the "cooling crystallization method". It is a method of crystallizing saturated solutions. The evaporative solvent crystallization method is referred to as the "evaporative solvent method", which is a method of crystallization of saturated solutions, and is suitable for substances whose solubility does not change much with temperature.

Cooling heat saturation is essentially the precipitation of solutes from the solution in the form of crystals by lowering the temperature (suitable for substances whose solubility increases significantly with increasing temperature). Generally, it refers to the process of lowering the temperature of a solution saturated at a relatively high temperature to precipitate the crystal.

Cooling the hot saturated solution and cooling crystallization are the same principle, the solution is saturated and the solute is precipitated by cooling, this method is generally used for solutes with large changes in solubility with temperature, the only difference is that the starting point of cooling is different.

Because the solvent is unchanging. However, most of the dissolution mold difficulty s increases with the increase of temperature t. Therefore, the saturated solution with a higher temperature is cooled, according to S 100g = m agent m.

S becomes smaller, M agent does not change, so the most dissolved M substance is reduced. So when it can no longer be dissolved, too many crystals will be precipitated.

The specific measure of recrystallization is to cool the hot-saturated solution, but cooling the hot-saturated solution is not necessarily for the purpose of recrystallization.

Recrystallization is the cooling of a hot-saturated solution multiple times.

The method of recrystallization is to cool the hot saturated solution.

a The temperature has changed, and the solubility has also changed.

b The crystal does not contain water, of course, the solvent quality does not change, b pair.

c After precipitation of crystals, the solute decreases and c is wrong.

d After the precipitation of the crystal, the solute decreases, while the solvent does not change, and the mass fraction decreases

b Correct.

a Solubility varies with temperature.

c Solute precipitation, of course, the mass in the solution changes.

d As the mass of the solute changes, so does the mass fraction.

The solution should be completely evaporated for evaporation crystallization, and the cooling hot saturated solution is not required; Evaporation crystallization generally requires an evaporation dish, but cooling hot saturated solutions does not need to.

Evaporation crystallization: the solubility remains unchanged, the solvent is reduced, and the solute is precipitated.

Cooling heat saturation: with the decrease of temperature, the solubility decreases, and the solute precipitates.

This depends on whether you want to precipitate higher solubility from low solubility or vice versa

The crystals precipitated by cooling of saturated solution must be --- saturated solution, otherwise there will be no crystal precipitation.

--- the saturated solution cools down, crystals will be precipitated from the solution, at this time, the mass of the solute in the solution decreases, the mass of the solution decreases, the mass of the solvent remains unchanged, and the mass fraction of the solute in the solution also decreases, but it is still a saturated solution. (This is for substances whose solubility increases with the increase in temperature, and the solubility increases).

What happens when an unsaturated solution heats up? The unsaturated solution will be more unsaturated when the temperature rises, and there will be no crystal precipitation, so the mass of the solution, the quality of the solute, the quality of the solvent, and the mass fraction of dissolved bright matter will not change, but the solubility increases, so the solution is still an unsaturated solution.