Summarize the substances with crystalline water in chemistry

Feso4·7H2O: green alum, alum, black alum (blue-green, green with streaks white.) The molecular weight is , the pH is 3, and the melting point is 64 degrees Celsius.

Strong thermal decomposition soluble in water, glycerol.

Insoluble in ethanol.

CuSO4·5H2O: Cholelum, blue alum, stone gallbladder (blue crystal, the amount of its molecular formula is. Moisture content 36%. It is copper sulfate.

Formed after water absorption. Cholelum is a chemical raw material for pigments, batteries, pesticides, wood preservation, etc.).

ZNSO4·7H2O: Haolu (colorless crystal, mainly used as astringent, preservative, pigment).

KAL (SO4)2·12H2O: alum, alum, potassium alum, potassium alum.

Potassium alum (colorless cubic crystals, sour, cold, toxic. Therefore, it has antibacterial effect, astringent effect, etc., and can be used as traditional Chinese medicine. Alum can also be used to prepare aluminum salts, baking powders, paints, tanning materials, clarifiers, mordants, papermaking, waterproofing agents, etc.).

Raw gypsum (refers to natural gypsum dihydrate, medicinal, to make tofu).

caso4·1 2H2O plaster (white solid, mainly used as powder, bandage, statue, etc.).

Miscanthus (monoclinic crystal system, the crystals are short columnar or needle-like; It usually forms a dense lumpy, fibrous aggregate. Colorless or white, vitreous luster, is an industrial raw material used as a laxative in medical treatment).

MgCl2·KCL·6H2O carnallite (pure, colorless to white, transparent to opaque, is the extraction of metal potassium.

Magnesium, a compound for the manufacture of potassium, a mineral raw material for potash fertilizers. )

H2C2O4·2H2O oxalic acid.

Common crystalline hydrates are: Na2CO3·10H2O (soda ash), CuSO4·5H2O (bile alum, blue alum), FeSO4·7H2O (green alum), ZNSO 4·7H2O (Haolu), MgCl2·KCl·6H2O (light stone), KAL(SO4)2·12H2O

Generally speaking, it is not necessary to write it. Unless crystals can be precipitated directly from solution.

When many substances are precipitated from aqueous solutions, the crystals often contain a certain number of water molecules, and such water molecules are called crystal water. Substances that contain crystal water are called crystal hydrates. Hydrates are solid compounds that contain a certain amount of water molecules.

The water in the hydrate is present in a definite amount, for example, the composition of the hydrate of the copper sulfate crystal is cuso·5h o, which is called copper sulfate pentahydrate.

Crystalline hydrate is pure, because the number of water molecules carried by each molecule is the same, the composition of the molecule is fixed, the molecule has a strong interaction with water, it is a hydrated molecule, such as bile alum cuso · 5h o, from the chemical formula, there is copper sulfate and water, it seems to be a mixture, but I don't know that copper sulfate and water are not simply mixed, but there is a strong interaction between the two, according to a certain mass ratio of the chemical cuso + 5h o = cuso · 5h o) into a new substance - bile alum, that is, copper sulfate pentahydrate, so cuso·5h o is pure.

I hope I can help you with your doubts.

Crystalline water is also known as bound water. Crystalline water is the water molecules that are bound in a chemical compound, and they are not liquid water. Many crystals contain crystalline water.

But not all crystals contain crystalline water. When the solute crystallizes and precipitates from the solution, a certain number of water molecules are bound to the crystal, and such water molecules are called crystal water. In a crystalline substance, a certain number of water molecules are bound to ions or molecules by chemical bonding force.

For example, under the condition of gradual heating, CuSO4·5H2O can lose crystal water step by step and transform into CuSO4·3H2O, CuSO4·H2O, and CuSO4 in turn. When heated, some hydrates may hydrolyze with the crystalline water they contain, turning them into oxides or basic salts. When a hydrate is exposed to drier air, it slowly loses its crystalline water, and the hydrate crystals become powdered anhydrous, a process called efflorescence.

Some anhydrous substances in the humid air will automatically absorb water and convert into hydrates, a process called deliquescent.

Hydrates refer to compounds that contain water, and their range is quite broad. The water can be linked to other parts by coordination bonds, such as hydrated metal ions, or it can be combined by covalent bonds, such as hydrated trichloroacetaldehyde. It is a white crystal formed by certain components of natural gas and moisture under certain temperature and pressure conditions, similar in appearance to dense ice and snow, with a density of g cm3.

Studies have shown that hydrate is a cage-shaped crystal envelope, in which water molecules are bonded by hydrogen to form cage-shaped crystals, and gas molecules are surrounded in a crystal lattice. When a compound crystallizes from an aqueous solution of its constituent ions, the resulting crystals are often gas hydrate structures. So hydrate is not simply mixed with water, hydrate is also pure.

The presence of liquid water is necessary for the formation of hydrates.

1.The substance precipitates crystals from the aqueous solution of sleepy clothes, and the crystals often contain a certain number of water molecules, and such water molecules are called crystal water.

2.Substances containing crystalline water are called crystalline hydrates.

3.Hydrates are solid compounds that contain a certain amount of water molecules.

4.The water difference slag in the hydrate exists in a definite amount, such as the composition of the hydrate of copper sulfate pentahydrate is cuso?·5h?o。

5.There are several different ways in which water in hydrates bind: one is as a ligand, coordinated on metal ions, and is quietly called coordination crystal water.

6.The other is bound to the anion and is called anionic crystal water.

7.Thus, 4 water molecules are coordinated on the copper ion as ligands, i.e., cu(h?o)4 2+, and the other 1 water molecule is bound to the sulfate, which is connected to the oxygen atom in the sulfate by hydrogen bonds.

<>1. Substances precipitate crystals from aqueous solutions, and the crystals often contain a certain number of water molecules, which are called crystal water. Substances containing crystalline water are called crystalline hydrates. Hydrates are solid compounds that contain a certain amount of water molecules.

2. The water in the hydrate is stored in the amount determined by the first shed, such as the composition of the hydrate of copper sulfate pentahydrate is cuso ·5h o. There are several different binding formulas for water in hydrates: one is as a ligand, coordinated on metal ions, and is called coordination crystal water.

The other is bound to the anion and is called anionic crystal water. Thus, 4 water molecules are coordinated on the copper ion as ligands, i.e., Cu(HO)4 2+, and the other 1 water molecule is bound to the sulfate and is linked to the oxygen atom in the sulfate through hydrogen bonding.

(1) Crystallization is the process of precipitation of solute that has been dissolved in the solution in the form of crystals due to the influence of factors such as the decrease in the temperature of the solution and the reduction of solvent evaporation; (2) Properties of substances with crystalline water: Some crystalline hydrates will melt on their own when heated, and this solute will dissolve in the solution formed by crystalline water (such as the melting of Na2S2O3·5H2O); Some crystalline hydrates will gradually lose their crystalline water in the air, a process called weathering, such as sodium chloride Na2CO3·10H2O

na2co3

10h2o；Many crystalline hydrates will gradually lose water molecules when heated and eventually turn into anhydrous, such as copper sulfate crystals of pentahydrate: CuSO4·5H2O

cuso4·3h2o

cuso4·h2o

CuSO4 (anhydrous copper sulphate, white); There are also many crystalline hydrates of strong acids and weak alkali salts that undergo hydrolysis reactions when heated, and eventually metal oxides are obtained instead of anhydrous salts, such as magnesium chloride hexahydrate: MaCl2·6H2O

mgo2hcl

5H2O, if MgCl2 is to be obtained, HCl gas needs to be continuously passed during heating to inhibit the hydrolysis of Mg(2+).