What are the factors that affect the growth of copper sulfate crystals?

The factors influencing the growth of copper sulfate crystals are as follows.

Effect of solution concentration.

Copper sulphate solution.

The higher the concentration, the higher the copper sulfate content, and the more copper sulfate products crystallized at the same temperature.

Effect of the acidity of the solution.

The more acid in the solution, the finer the crystal particles and the lighter the color. When the amount of acid in the solution is too high, loose and fine scale-like crystals are formed, which are very light in blue and contain a large amount of mother liquor.

Effect of the amount of impurities in the solution.

The more impurities in the solution, the more the crystallization rate of copper sulfate slows down, and the product is impure, the crystal is fine, the color is not correct, and it is mostly green, which does not meet the product standard.

Factors influencing the crystallization state.

Crystals grown at high temperatures are mostly turbid and cracked, while crystals grown at lower temperatures are generally transparent and intact.

Effect of crystallization time on crystallization amount.

The time it takes to crystallize is basically the time it takes for the solution temperature to drop to room temperature. When the temperature of the solution drops to room temperature (or outdoor room temperature), the solid-liquid separation can be carried out by extending the appropriate time slightly. However, due to various factors in production, the time required for the temperature to drop to normal temperature is also different, so the crystallization time is also different.

However, it is best to go through the lowest room temperature (room temperature) during the crystallization process to increase the amount of crystallization. Due to the large amount of natural evaporation in summer, extending the crystallization time will also increase some crystallization.

Are you using copper sulfate saturated solution to recrystallize to make crystals?

The solution should be clean.

Crystallization on a fine line should be trimmed neatly.

The concentration of the solution should not be too low.

The questions regarding the preparation and growth of copper sulfate crystals are as follows:

The principle of preparing copper sulfate crystals

The solubility of copper sulfate gradually increases with the increase of temperature, and copper sulfate crystals can be prepared by cooling the hot saturated solution of copper sulfate. Cooling the hot saturated solution of copper sulfate will break the original dissolution equilibrium, and the excess solute will precipitate in the form of crystals.

For the precipitation and growth of crystals, there must be a core (i.e., crystal nucleus, crystal seed), so that the particles can be built up in a regular manner layer by layer. Repeated crystallization can make the crystals grow larger and larger, becoming large crystals.

During crystallization, if there are few seeds at the beginning, the excess solute can be concentrated on a small number of seeds, and the larger the crystals will be. The vibrations can hinder the orderly arrangement of the particles, making the crystal form incomplete. The crystal form is also related to the speed of cooling.

The conditions that need to be controlled for the preparation of larger crystals: less crystal species, complete crystal shape, shockproof and dustproof, and slow cooling.

Preparation of small crystals

First, the copper sulfate crystals are ground into powder. Then add 30 ml of distilled water to the beaker and add an appropriate amount of distilled water to another larger beaker so that the liquid level in the large beaker is slightly higher than that in the small beaker when placed in the large beaker.

Then the large beaker is placed on the asbestos net and heated until the heating is stopped when it is 70 °C higher than the room temperature, and the fine copper sulfate crystal powder is added to the small beaker, stirred, and prepared into a saturated solution. Filter while hot to obtain a clear solution of copper sulfate.

Cover the beaker with a clear copper sulfate solution with a clean white paper, put the beaker in a homemade styrofoam box, and let it stand overnight to make small crystals with complete crystal shape.

Small crystals "grow" into large crystals

Tie the small crystals with complete shapes with wires, put them into a clear saturated solution of copper sulfate that is slightly higher than the normal temperature before the temperature of Tongyou prepared in advance, keep warm, cool slowly, and the small crystals grow slowly. After repeated operation, the small crystals "grow" into large crystals.

3. All influencing factors:

1. The regularity and symmetry of the molecular chain structure, the simpler and more symmetrical the faster the crystallization speed;

2. Crystallization temperature, a slight change in temperature during the crystallization process will lead to a huge change in crystallization rate;

3. Nucleating agent: the addition of nucleating agent is conducive to improving the crystallization rate;

4. Molecular weight: the larger the molecular weight of the polymer, the worse the movement of the chain segment, and the slower the crystallization speed;

5. Solvents, stresses, etc. will induce polymer crystallization, thereby accelerating crystallization to a certain extent.

In chemistry, when a hot saturated solution cools, the solute precipitates in the form of crystals, a process called crystallization.

Crystallization principle: The process of solute precipitation from solution can be divided into two stages: crystal nucleation (nucleation) and crystal growth, and the driving force of both stages is the supersaturation of the solution (the concentration of solute in the solution exceeds the value of its saturated solubility). There are three forms of crystal nucleation formation: primary homogeneous nucleation, primary heterogeneous nucleation, and secondary nucleation.

At high supersaturation, the process by which the solution spontaneously generates crystal nuclei is called primary homogeneous nucleation; The process by which a solution is induced by foreign substances (such as dust in the atmosphere) to form crystal nuclei is called primary heterogeneous nucleation. And the process of nucleation in a solution containing solute crystals is called secondary nucleation. Secondary nucleation is also a heterogeneous nucleation process, which occurs under the induction of tiny grains produced between crystals or when crystals collide with other solids (vessel walls, stirrers, etc.).

Crystallization method: The process by which crystals are formed in solution is called crystallization.

There are generally 2 methods of crystallization:

One is the evaporation solvent method, which is suitable for substances where temperature has little effect on solubility. "Salt drying" in coastal areas is a method that is used;

The other is the cooling hot saturated solution method. This method is suitable for substances with increased temperature and increased solubility.

The main factor affecting the size of the crystallization rate is the supersaturation of the solution, the high supersaturation, the crystallization rate will be faster, but the crystal nuclei will be more, and the crystals produced at this time will be smaller, and the crystallization speed will be slow, and the crystals will be larger.

The solubility is different depending on the temperature, followed by the air pressure, and the amount of the solution, i.e. the concentration, will also be affected.

【Principle】There are two methods for preparing crystals from saturated solutions, and for solid solutes whose solubility is not affected by temperature, the method of evaporating solvents is commonly used. For solid solutes whose solubility increases significantly with increasing temperature, such as copper sulfate, alum, potassium nitrate, etc., the method of cooling hot saturated solution is commonly used.

Supplies] beakers, surface dishes, iron frames, alcohol lamps, asbestos nets, funnels, graduated cylinders, glass rods, tweezers, filter paper, fine wires, copper sulfate crystals (CuSO4·5H2O).

Operation] 1. Prepare small crystals In a beaker containing 100ml of water, add 10g of finely ground copper sulfate powder, and add 1ml of dilute sulfuric acid (to prevent copper sulfate hydrolysis), heat, and completely dissolve the crystals. Continue to heat to 80-90, filter while hot, and the filtrate flows into a beaker that has been washed and warmed with hot water, and the lid is allowed to stand. After a few hours or overnight, you will notice the formation of several small crystals at the bottom of the cup.

2. The growth of small crystals Pick a crystal with a relatively complete crystal shape, tie it with a thin wire, hang it in a beaker containing saturated copper sulfate solution, and cover it to stand. Add a small amount of slightly hot saturated copper sulfate solution to the beaker every day, and the small crystal will gradually grow into a large crystal.

Success or failure is the key to success. 1) The reagent used must be pure, if it contains impurities, it is difficult to obtain a complete crystal form.

2) Control the concentration of the solution, if the solution is too concentrated, the crystallization rate is too fast, and it is not easy to form crystals with complete crystal shape; If the concentration of the saturated solution is not large, the crystallization rate is too slow, and the small crystals grow slowly. When preparing small crystals, use a saturated solution 20 -30 above room temperature; The saturated solution added later should be a solution higher than room temperature 15 -20, the amount of each addition is about 1 10 of the original solution, the crystals should be taken out when added, and the crystals should be immersed after the temperature of the solution is uniform.

3) Pay attention to the change of ambient temperature, the saturated solution should be cooled slowly, and the beaker can be wrapped with cloth or cotton. The crystals can be removed during the day when the temperature is high and put back into the solution at night.

4) The container used must be clean and covered to prevent dust from falling in.

3. Preparation of small crystals Once crystallized, if the precipitated crystals are too small, a few crystals with complete crystal shape can be picked up, and then cultivated with a saturated solution higher than room temperature, so that they can be tied with a thin wire. You can also hang a fine line in the filtrate, and when the solution cools, small crystals will be precipitated on the fine line, and one crystal shape will be kept intact (the rest will be peeled off) to make the crystal seed, and it will grow according to step 2.

4. Alum, potassium dichromate, nickel sulfate and other substances are easy to cultivate into large crystals with complete crystal shape, and students can be advised to use the method of evaporation solvent to make large crystals of alum at home.

1. Prepare a large beaker;

2. Prepare copper sulfate into a saturated solution, the more the better;

3. Pick out a small crystal from the gall alum and tie it with a thin wire;

4. Use a glass rod or chopsticks to stand on the large beaker, and the gallum crystal is tied to the glass rod or chopsticks, and the crystal is immersed in the saturated solution near the bottom;

5. Place it outside the dust with good constant temperature, good ventilation and dust, so that the crystals can grow naturally;

6. When the solution is close to full dry, large copper sulfate crystals can be obtained at this time.

The things of the graduate students have moved out, my teacher is a professional crystallizer, but now few people cultivate crystals, I heard that there is an old professor in Shanghai Normal who is very powerful.

Summary. The product of the crystallization of copper sulfate solution is usually blue copper sulfate crystal pentahydrate with the chemical formula CuSO4·5H2O. This crystal is relatively stable in a dry environment, and in a humid environment, it is easy to lose crystal water and turn into white anhydrous copper sulfate.

Copper sulfate crystal pentahydrate is an important industrial raw material and reagent, which is widely used in the preparation of other copper salts and dyes, catalysts, wood preservatives and other fields. In the laboratory, it is also commonly used as a reference compound, a standard sample, and a quality control sample.

The product of the crystallization of copper sulfate solution is usually a blue five-trace hydrated copper sulfate crystal with the chemical formula CuSO4·5H2O. This crystal is relatively stable in a dry environment, and in a humid environment, it is easy to lose crystal water and turn into white anhydrous copper sulfate. Copper sulfate crystal pentahydrate is an important industrial raw material and reagent, which is widely used in the preparation of its source copper salts and dyes, catalysts, wood preservatives and other fields.

In the laboratory, it is also commonly used as a reference slippery state complex, as a standard sample, and as a quality control sample.

Can you add, I don't quite understand it.

The product of the crystallization of copper sulfate solution is usually a blue five-trace hydrated copper sulfate crystal with the chemical formula CuSO4·5H2O. This crystal is relatively stable in a dry environment, and in a humid environment, it is easy to lose crystal water and turn into white anhydrous copper sulfate. Copper sulfate crystal pentahydrate is an important industrial raw material and reagent, which is widely used in the preparation of its source copper salts and dyes, catalysts, wood preservatives and other fields.

In the laboratory, it is also commonly used as a reference slippery state complex, as a standard sample, and as a quality control sample.

<> Prepare the copper sulfate solution: add an appropriate amount of copper sulfate solids to a certain amount of water and stir well until the copper sulfate is completely dissolved. The concentration of the solution can be adjusted as needed.

Evaporation crystallization method: aPour the copper sulfate solution into a beaker or container and heat it.

Heating can be done using equipment such as a heating plate or water bath. Depending on the need, you can choose the right temperature. b.

Once the heating is stopped, allow the solution to cool naturally. As the temperature of the solution drops, the copper sulphate gradually precipitates and forms crystals. The crystals can be separated using a filter or funnel.

d.Finally, the crystals are washed with cold water and then dried or hygroscopic using a desiccant.

Slow cooling crystallization: aPour the copper sulphate solution into a container, heat it to a certain temperature, usually the temperature at which the solution boils, and then continue stirring.

b.Slowly reduce the temperature coarseness of the solution, which can be controlled with methods such as a cooler or cold water bath. Note the slow rate of cooling.

c.As the temperature of the solution decreases, copper sulfate crystals will gradually form. A gradual increase in crystals can be observed in the container.

d.Finally, the crystals are washed with cold water and then dried or hygroscopic using a desiccant.

Cooling crystallization method: aPour the copper sulphate solution into a container, heat it to a certain temperature, usually the temperature at which the solution boils, and then continue stirring.

b.To cool the solution quickly, the container can be put in cold water or use equipment such as a cooler. This will result in the rapid formation of copper sulphate crystals in solution.

c.To separate the crystals from the solution, you can use methods such as filters or funnels to repent. d.

Finally, the crystals are washed with cold water and then dried or hygroscopic using a desiccant.

When performing copper sulfate crystallization experiments, it is important to pay attention to personal safety, wear appropriate protective equipment, and avoid contact** or inhalation of gases. At the same time, it is also necessary to pay attention to safe operation to avoid the solution from splashing around or other accidents. Performing these operations in a lab or in a suitable environment is the best option.

The so-called "crystalline copper sulfate" is actually "copper sulfate crystal", also called "copper sulfate pentahydrate". The molecular formula is Cuh O S, which can also be written as Cuso ·5HO.

Copper sulphate crystals.