What substances react with copper

Electronic configuration and structure of the calcium atom

In sciences with a physical and mathematical bias, in order to solve problems, it is sometimes necessary to know the atomic structure of matter. In chemistry lessons, each of the elements of the periodic table (table) of Dmitry Ivanovich Mendeleev and its atomic structure are studied. Calcium is no exception. However, first you should familiarize yourself with the basic concepts and provisions on the principles of the formation of the electronic shell for various materials, which determines their important properties.

General information

Every chemical element is made up of molecules whose components are atoms. The latter consist of the following structural units:

The latter rotate around the nucleus in orbits that are only displayed in the drawings (graphical diagram). Orbit is a symbol for the distance between the nucleus and electrons held by Coulomb attractive forces.

Based on an analysis of the crystal lattice structure, scientists have discovered some very important physical and chemical properties of substances. For example, thanks to the study of the structure of the potassium atom, it was placed in the series of alkali metals.

It reacts instantly with water to form an alkali.

Atomic nucleus

The nucleus is the main component of an atom in which the bulk of the mass is concentrated. It has a positive charge that attracts electrons and is made up of protons and neutrons. Protium (a light isotope of hydrogen) is the only chemical element that does not contain neutrons. If the nucleus is considered as a particle, then chemists and physicists call it a nuclide, and nucleons are a collection of positively charged atomic units.

The number of protons is denoted by the letter “Z”, and the number of neutrons by N. These 2 coefficients are usually equal. However, sometimes N is greater or less than Z. In this case, the chemical element is said to be an isotope or isotone, that is, non-standard. To distinguish them from each other, you should remember 2 rules:

1. The same Z and different N are isotopes.
2. The same N and different Z are isotones.

The number “Z” corresponds to the serial number in D.I. Mendeleev’s table. The algebraic sum of Z and N is equivalent to the atomic mass number A, which is also indicated in the periodic table. It also has another name - the molecular weight of a chemical element. In addition, the core has other characteristics. The main ones include the following:

The Z factor determines the level of electrical charge. It was first discovered by the scientist G. Moseley in 1913 experimentally, by measuring the electromagnetic wavelength of hydrogen.

For other elements, the same dependence on the ordinal number of the element was established. The charge of the protons that make up the nucleus acts on the electrons that rotate around it.

It should be noted that a positive particle cannot attract a negative one, since the field that creates the connection between them is not capable of doing this.

In some cases, the charge cannot hold an electron. In this case, the latter “comes off” from the orbital. As a result of this process, an ion is formed, that is, an atom that can interact with others.

The structure of the structure can be interpreted with the planets orbiting the Sun. The latter cannot attract them, since there is not enough attractive force, which depends on distance and mass.

The next characteristic of the nucleus is mass. It is measured in atomic mass units - a. a.m. One “a.u.m.” is equivalent to 1/12 the mass of a carbon atom, which is designated by the letter “C”.

Information about electrons

An electron is an elementary particle that has a negative charge. Its mass is much less than that of the nucleus. Each particle has its own orbital, which shows the valency of the chemical element. Electrons are not only part of the atom, but are also free, i.e., they affect the electrical conductivity of substances. Based on this statement, scientists concluded that materials can be classified into conductors, semiconductors and dielectrics.

The former have free electrons, while the latter appear only under the influence of any external forces capable of “tearing out” negatively charged elementary particles from the orbital. They are absent in dielectrics or insulators.

Physicochemical properties of calcium

Calcium is a chemical element that belongs to the alkaline earth metals. It is designated by the letter "Ca". In the periodic table it is located under the serial number “20”. In addition, it has an atomic mass of 40 a. u.m. (A = 40 a.u.m.). Its main source in nature is calcium carbonate or chalk, the chemical formula of which is CaCO3.

The melting point of Ca is 854 degrees Celsius. Under high pressure, it passes electric current in one direction. When interacting with oxygen, which is part of the atmospheric air, it is oxidized (Ca2O). An example of an oxidative reaction is chalk, which crumbles and, upon impact, breaks into pieces.

In laboratory conditions, it can be obtained by electrolysis of molten CaCl2. The last substance is called calcium chloride. Electrolysis is a physical and chemical process in which a direct current is passed through a substance. In this case, the ions (positively charged) are directed to the electrode (cathode), which has a negative potential (-), and cations to the positive potential (anode). In this case, the decomposition of calcium chloride can be written in this form: ion (Ca2+) and cation (Cl 2 2-).

The atomic structure and electronic configuration of calcium determine its other chemical properties. It reacts with most substances , both complex and simple. It is quite difficult to keep it pure. For example, to preserve “pure” Ca, you need to cover it with paraffin or kerosene in a container without additional access to oxygen.

Electronic shell

The electron shell of an atom is a form that allows one to scientifically prove the possibility of interaction of an element with other substances. The principles of its formation have the following formulations:

1. Minimum energy: determines the energy exchange between electrons filling the orbitals.
2. Pauli: an orbital can only contain 2 negatively charged particles with opposite spins (rotation vectors).
3. Hunda: filling orbitals with the maximum number of electrons, taking into account spins.

The nucleus of an atom has a positive charge of “+20”, which corresponds to the atomic number in the periodic table of elements. The number of Z = 20 and N = 20. Therefore, there are 20 electrons moving around the nucleus, since the number of positive nucleons is equal to the number of negatively charged particles.

Schematically, the designation of a structure consisting of four orbits is as follows: +20 Ca)2)8)8)2. In this case, we can write the electronic configuration of the element: 1 s2 2 s2 2 p6 3 s2 3 p6 4 s2. If we add up the exponents of the sublevels of the orbits, we get “20”, i.e. 2+2+6+2+6+2. The electronic formula is filled in according to the following algorithm:

1. The serial number is written out: 20.
2. The first sublevel should have no more than 2:1 s2. The first orbital is filled.
3. Second orbit (up to 6 on sublevel 2p and 2 on 2s): 2s22p6.
4. The third consists of two sublevels, each of which can contain 2 and 6 particles, respectively: 3s2 3 p6.
5. The fourth also includes 2 sublevels 4s and 4p, but there are only enough particles for 4s: 4 s2.
6. Checking the number of electrons: 2+2+6+2+6+2 = 20 (the result is true, i.e. equal to Z).

Based on the electronic configuration, one more parameter of Ca can be determined, which is called valence. It is equal to 2 because the last orbital has only 2 electrons.

Thus, calcium is a divalent element and has physical and chemical properties that are inherent in alkaline earth metals.

Source: https://1001student.ru/himiya/elektronnaya-konfiguratsiya-i-stroenie-atoma-kaltsiya.html

Does copper react with water?

People studied the properties of copper, which is found in nature in the form of fairly large nuggets, back in ancient times, when dishes, weapons, jewelry, and various household products were made from this metal and its alloys.

The active use of this metal for many years is due not only to its special properties, but also to the ease of processing.

Copper, which is present in the ore in the form of carbonates and oxides, is quite easily reduced, which is what our ancient ancestors learned to do.

Copper ingot

Interesting things about copper

Initially, the process of recovering this metal looked very primitive: copper ore was simply heated over fires and then subjected to sudden cooling, which led to cracking of pieces of ore, from which copper could already be extracted. Further development of this technology led to the fact that air began to be blown into the fires: this increased the heating temperature of the ore. Then the ore began to be heated in special structures, which became the first prototypes of shaft furnaces.

The fact that copper has been used by mankind since ancient times is evidenced by archaeological finds, as a result of which products made from this metal were found.

Historians have established that the first copper products appeared already in the 10th millennium BC, and it began to be most actively mined, processed and used 8–10 thousand years later.

Naturally, the prerequisites for such active use of this metal were not only the relative ease of its extraction from ore, but also its unique properties: specific gravity, density, magnetic properties, electrical and specific conductivity, etc.

Nowadays, it is already difficult to find copper in nature in the form of nuggets; it is usually mined from ore, which is divided into the following types.

• Bornite - this ore can contain copper in amounts up to 65%.
• Chalcocite, also called copper luster. Such ore can contain up to 80% copper.
• Copper pyrite, also called chalcopyrite (content up to 30%).
• Covelline (content up to 64%).

Chalcopyrite

Copper can also be extracted from many other minerals (malachite, cuprite, etc.). They contain it in different quantities.

Physical properties

Copper in its pure form is a metal whose color can vary from pink to red.

The radius of copper ions having a positive charge can take the following values:

• if the coordination index corresponds to 6 - up to 0.091 nm;
• if this indicator corresponds to 2 - up to 0.06 nm.

The radius of the copper atom is 0.128 nm, and it is also characterized by an electron affinity of 1.8 eV. When an atom is ionized, this value can take a value from 7.726 to 82.7 eV.

Copper is a transition metal with an electronegativity value of 1.9 on the Pauling scale. In addition, its oxidation state can take on different values.

At temperatures ranging from 20 to 100 degrees, its thermal conductivity is 394 W/m*K.

The electrical conductivity of copper, which is surpassed only by silver, is in the range of 55.5–58 MS/m.

Since copper in the potential series is to the right of hydrogen, it cannot displace this element from water and various acids.

Its crystal lattice has a cubic face-centered type, its value is 0.36150 nm. Copper melts at a temperature of 1083 degrees, and its boiling point is 26570.

The physical properties of copper are also determined by its density, which is 8.92 g/cm3.

Native copper

Of its mechanical properties and physical indicators, the following are also worth noting:

• thermal linear expansion - 0.00000017 units;
• the tensile strength to which copper products correspond is 22 kgf/mm2;
• the hardness of copper on the Brinell scale corresponds to a value of 35 kgf/mm2;
• specific gravity 8.94 g/cm3;
• elastic modulus is 132000 Mn/m2;
• the elongation value is 60%.

The magnetic properties of this metal, which is completely diamagnetic, can be considered completely unique.

It is these properties, along with physical parameters: specific gravity, specific conductivity and others, that fully explain the wide demand for this metal in the production of electrical products. Aluminum has similar properties, which is also successfully used in the production of various electrical products: wires, cables, etc.

The main part of the characteristics that copper has is almost impossible to change, with the exception of its tensile strength.

This property can be improved almost twice (up to 420–450 MN/m2) if a technological operation such as hardening is carried out.

Chemical properties

The chemical properties of copper are determined by its position in the periodic table, where it has serial number 29 and is located in the fourth period.

What is noteworthy is that it is in the same group with noble metals.

This once again confirms the uniqueness of its chemical properties, which should be discussed in more detail.

Shades of copper alloys

In conditions of low humidity, copper exhibits virtually no chemical activity.

Under such conditions, active oxidation of copper begins: a greenish film consisting of CuCO3, Cu(OH)2 and various sulfur compounds is formed on its surface. This film, called patina, performs the important function of protecting the metal from further destruction.

Oxidation begins to actively occur when the product is heated.

If the metal is heated to a temperature of 375 degrees, then copper oxide is formed on its surface, if higher (375-1100 degrees) then two-layer scale.

Copper reacts quite easily with elements that are part of the halogen group. If a metal is placed in sulfur vapor, it will ignite.

It also shows a high degree of affinity for selenium. Copper does not react with nitrogen, carbon and hydrogen even at high temperatures.

The interaction of copper oxide with various substances deserves attention. Thus, when it reacts with sulfuric acid, sulfate and pure copper are formed, with hydrobromic and hydroiodic acid - copper bromide and iodide.

The reactions of copper oxide with alkalis, which result in the formation of cuprate, look different.

The production of copper, in which the metal is reduced to a free state, is carried out using carbon monoxide, ammonia, methane and other materials.

Copper, when interacting with a solution of iron salts, goes into solution, and the iron is reduced. This reaction is used to remove the deposited copper layer from various products.

Mono- and divalent copper is capable of creating complex compounds that are highly stable.

Such compounds are double copper salts and ammonia mixtures.

Both have found wide application in various industries.

Copper wire coils

Applications of copper

The use of copper, as well as aluminum, which is most similar in properties to it, is well known - in the production of cable products.

Copper wires and cables are characterized by low electrical resistance and special magnetic properties.

For the production of cable products, types of copper characterized by high purity are used.

If even a small amount of foreign metal impurities is added to its composition, for example, only 0.02% aluminum, then the electrical conductivity of the original metal will decrease by 8–10%.

The low weight of copper and its high strength, as well as the ability to be amenable to various types of mechanical processing, are the properties that make it possible to produce pipes from it that are successfully used for transporting gas, hot and cold water, and steam. It is no coincidence that these pipes are used as part of the engineering communications of residential and administrative buildings in most European countries.

Copper, in addition to exceptionally high electrical conductivity, is distinguished by its ability to conduct heat well. Thanks to this property, it is successfully used as part of the following systems:

• heat pipes;
• coolers used to cool elements of personal computers;
• heating and air cooling systems;
• systems that provide heat redistribution in various devices (heat exchangers).

Metal structures in which copper elements are used are distinguished not only by their low weight, but also by their exceptional decorative effect. This is precisely the reason for their active use in architecture, as well as for the creation of various interior elements.

  How to weld copper wires at home

Electrical copper busbar

Source: https://steelfactoryrus.com/reagiruet-li-med-s-vodoy/

Copper (II) oxide, properties, preparation, chemical reactions

Copper (II) oxide is an inorganic substance with the chemical formula CuO.

Brief characteristics of copper (II) oxide

Physical properties of copper (II) oxide

Preparation of copper(II) oxide

Chemical properties of copper (II) oxide

Chemical reactions of copper(II) oxide

Applications and Uses of Copper(II) Oxide

Brief characteristics of copper (II) oxide:

Copper (II) oxide is a black inorganic substance.

Since the valence of copper varies and is equal to one, two or three, copper oxide contains, respectively, two copper atoms and one oxygen atom, one copper atom and one oxygen atom, two copper atoms and three oxygen atoms.

Cuprous oxide contains one copper atom and one oxygen atom, respectively.

The chemical formula of copper (II) oxide is CuO.

Powder. Does not dissolve in water.

Physical properties of copper (II) oxide:

Parameter name:	Meaning:
Chemical formula	CuO
Synonyms and names in a foreign language	copper oxide (old Russian) copper (II) oxide (English) tenorite (Russian)
Type of substance	inorganic
Appearance	black powder
Color	black
Taste	—*
Smell	—
Physical state (at 20 °C and atmospheric pressure 1 atm.)	solid
Density (state of matter – solid, at 20 °C), kg/m3	6310
Density (state of matter – solid, at 20 °C), g/cm3	6,31
Boiling point, °C	2000
Melting point, °C	1447
Decomposition temperature, °C	800
Molar mass, g/mol	79,545

*Note:

- no data.

Copper (II) oxide is obtained as a result of the following chemical reactions:

1. copper oxidation:

2Cu + O2 → CaO.

2. thermal decomposition of copper ( II ) hydroxide, copper ( II ) nitrate, copper carbonate ( II ):

Cu(OH)2 → CuO + H2O (to);

2Cu(NO3)2 → 2CuО + 4NO2 + O2 (to);

CuCO3 → CuO + CO2 (to).

3. heating malachite:

Cu2CO3(OH)2 → 2CuO + CO2 + H2O (to).

Copper (II) oxide is a basic oxide.

The chemical properties of copper(II) oxide are similar to those of basic oxides of other metals. Therefore, it is characterized by the following chemical reactions:

1. reaction of copper (II) with hydrogen:

CuO + H2 → Cu + H2O (t = 300 oC).

The reaction produces copper and water.

2. reaction of copper (II) oxide with carbon:

CuO + C → Cu + CO (t = 1200 oC).

The reaction produces copper and carbon monoxide.

3. reaction of copper (II) with sulfur:

CuO + 2S → Cu + S2O (t = 150-200 oC).

The reaction takes place in a vacuum. As a result of the reaction, copper and sulfur oxide are formed.

4. reaction of copper (II) with aluminum:

3CuO + 2Al → 3Cu + Al2O3 (t = 1000-1100 oC).

As a result of the reaction, copper and aluminum oxide are formed.

5. reaction of copper (II) with copper:

CuO + Cu → Cu2O (t = 1000-1200 oC).

As a result of the reaction, copper (I) oxide is formed.

6. reaction of copper (II) with lithium oxide:

CuO + Li2O → Li2CuO2 (t = 800-1000 oC, O2).

The reaction takes place in a flow of oxygen. As a result of the reaction, lithium cuprate is formed.

7. reaction of copper (II) with sodium oxide:

CuO + Na2O → Na2CuO2 (t = 800-1000 oC, O2).

The reaction takes place in a flow of oxygen. As a result of the reaction, sodium cuprate is formed.

8. reaction of copper (II) with carbon monoxide:

CuO + CO → Cu + CO2.

The reaction produces copper and carbon monoxide (carbon dioxide).

9. reaction of copper (II) with iron oxide:

CuO + Fe2O3 → CuFe2O4 (to).

As a result of the reaction, a salt is formed - copper ferrite. The reaction occurs when the reaction mixture is calcined.

10. reaction of copper (II) with hydrofluoric acid:

CuO + 2HF → CuF2 + H2O.

As a result of a chemical reaction, a salt is obtained - copper fluoride and water.

11. reaction of copper (II) with nitric acid:

CuO + 2HNO3 → 2Cu(NO3)2 + H2O.

As a result of a chemical reaction, salt is obtained - copper nitrate and water.

(II) with other acids proceed similarly

12. reaction of copper (II) with hydrogen bromide (hydrogen bromide):

CuO + 2HBr → CuBr2 + H2O.

As a result of a chemical reaction, salt is obtained - copper bromide and water.

13. reaction of copper (II) with hydrogen iodide:

CuO + 2HI → CuI2 + H2O.

As a result of a chemical reaction, salt is obtained - copper iodide and water.

14. reaction of copper (II) with sodium hydroxide:

CuO + 2NaOH → Na2CuO2 + H2O.

As a result of a chemical reaction, salt is obtained - sodium cuprate and water.

15. reaction of copper (II) with potassium hydroxide:

CuO + 2KOH → K2CuO2 + H2O.

As a result of a chemical reaction, salt is obtained - potassium cuprate and water.

16. reaction of copper (II) with sodium hydroxide and water:

CuO + 2NaOH + H2O → Na2[Cu2(OH)]2 (t = 100 oC).

Sodium hydroxide is dissolved in water. A solution of sodium hydroxide in water 20-30%. The reaction occurs at boiling point. As a result of a chemical reaction, sodium tetrahydroxycuprate is obtained.

17. reaction of copper (II) with potassium superoxide:

2CuO + 2KO2 → 2KCuO2 + O2 (t = 400-500 oC).

As a result of a chemical reaction, a salt is obtained - potassium cuprate (III) and oxygen.

18. reaction of copper (II) with potassium peroxide:

2CuO + 2K2O2 → 2KCuO2 (t = 700 oC).

As a result of a chemical reaction, a salt is obtained - potassium cuprate (III).

19. reaction of copper (II) with sodium peroxide:

2CuO + 2Na2O2 → 2NaCuO2 (t = 700 oC).

As a result of a chemical reaction, a salt is obtained - sodium cuprate (III).

20. reaction of copper (II) with ammonia:

3CuO + 2NH3 → N2 + 3Cu + 3H2O (t = 500-550 oC).

Ammonia is passed through heated copper(II) oxide. The chemical reaction produces nitrogen, copper and water.

6CuO + 4NH3 → 2Cu3N + N2 + 6H2O (t = 250-300 oC).

As a result of a chemical reaction, copper nitride, nitrogen and water are obtained.

21. reaction of copper (II) oxide and aluminum iodide:

6CuO + 4AlI3 → 6CuI + 2Al2O3 + 3I2 (t = 230 oC).

As a result of a chemical reaction, salt is obtained - copper iodide, aluminum oxide and iodine.

Applications and Uses of Copper(II) Oxide:

Copper oxide is used in the production of glass and enamels to give them the appropriate color (green, blue, copper-ruby).

Note: Photo //www.pexels.com, //pixabay.com

Site Map

copper oxide reacts acid 1 2 3 4 5 water
reaction equation compounds mass interaction of copper oxide
reactions with copper oxide

Source: https://xn--80aaafltebbc3auk2aepkhr3ewjpa.xn--p1ai/oksid-medi-ii-svoystva-poluchenie-himicheskie-reaktsii/

Organic chemistry - Chemistry at school No. 302 of the Frunzensky district of St. Petersburg

To do this, the gas is either set on fire - the combustion of alkanes is accompanied by a blue flame, or passed through a solution of potassium permanganate. Alkanes are not oxidized by potassium permanganate in the cold; as a result, the solution will not change color.

Qualitative reactions to alkenes 

a) Discoloration of potassium permanganate (Wagner reaction) .

In this case, ethylene is oxidized into the dihydric alcohol ethylene glycol .

CH2=CH2 + [O] CH2OH-CH2OH

b) Discoloration of bromine water:

C2H4 + Br2 —> C2H4Br2

a)  Discoloration of potassium permanganate (Wagner reaction) .

C2H2 + [O] -> HOOC-COOH (oxalic acid)

b)  Discoloration of bromine water:

C2H2 + 2Br2 —> C2H2Br4

c) Reaction with an ammonia solution of silver oxide (silver diamine hydroxide (I))  (Tollens reagent)

Only for alkynes with a triple bond at the outermost carbon atom (!)

C2H2 + 2[Ag(NH3)2]OH ——> Ag2C2↓+ 4NH3 + 2H2O

The resulting silver(I) acetylenide precipitates.

Alkynes with a triple bond in the middle (RC≡CR) do not enter into this reaction.

This ability of alkynes to replace a proton with a metal atom, like acids, is due to the fact that the carbon atom is in the sp-hybridization state and the electronegativity of the carbon atom in this state is the same as that of nitrogen. As a result, the carbon atom becomes more enriched in electron density and the proton becomes mobile.

 Qualitative reactions to aldehydes

a) Interaction with an ammonia solution of silver oxide (silver mirror reaction)

CH3-CHO + 2[Ag(NH3)2]OH -> CH3-COOH+ 2Ag↓ + 4NH3 + H2 O (reaction occurs when heated)

Note: the reaction of a silver mirror can also reveal methane (formic) acid HCOOH. What does acid have to do with it if we are talking about aldehydes? It's simple: formic acid is the only carboxylic acid that contains both aldehyde and carboxyl groups:

     During the reaction, methanoic acid is oxidized to carbonic acid, which decomposes into carbon dioxide and water: 

HCOOH + 2[Ag(NH3)2]OH -> CO2+ 2H2O + 4NH3 + 2Ag↓ (the reaction occurs when heated)

b) Interaction with copper (II) hydroxide (copper mirror reaction)

To do this, add aldehyde to freshly prepared copper (II) hydroxide and heat the mixture:

CuSO4 + 2NaOH —> Na2SO4 +Cu(OH)2↓

CH3-CHO+ 2Cu(OH)2 —> CH3-COOH + Cu2O↓ + 2H2O (reaction occurs when heated)

Copper oxide (I) Cu2O falls out - a red precipitate.

c) Interaction with a solution of fuchsinous acid.

When an aldehyde is added to a solution of fuchsulfuric acid, the solution turns light purple.

Alcohols, depending on the number of hydroxyl groups, are one-, two-, or polyhydric. For monohydric alcohols, the reactions are different.

Qualitative reactions on monohydric alcohols

a) Oxidation of alcohol with copper oxide.

To do this, alcohol vapor is passed over hot copper oxide. Then the resulting aldehyde is captured with fuchsulfurous acid, the solution turns purple:

CH3-CH2-OH+ CuO —> CH3-CHO + Cu + H2O

b) Interaction with sodium.

2CH3-CH2-OH + 2Na —> 2CH3-CH2-ONa + H2

Qualitative reactions to polyhydric alcohols

a) Interaction with copper (II) hydroxide.

Unlike aldehydes, polyhydric alcohols react with copper (II) hydroxide without heating. 

For example, when glycerol is added, copper (II) glycerate is formed (a dark blue chelate complex):

b) Interaction with sodium.

a) Litmus.

Red staining

Qualitative reactions to formic acid

a) Reaction of the silver mirror.

b) Reaction with concentrated sulfuric acid.

When concentrated sulfuric acid H2SO4 is added to a solution of formic acid, carbon monoxide and water are formed:

HCOOH + H2SO4—> CO + H2O

Carbon monoxide can be ignited. Burns with a blue flame:

2CO + O2 —> 2CO2

c) Oxidation with potassium permanganate.

Qualitative reaction to oleic acid (acid contains a double bond)

a) Discoloration of bromine water

Qualitative reaction to oxalic acid     H2C2O4 or HOOC-COOH

a) Interaction with solutions of copper (II) salts

By adding a solution of copper (II) salt to a solution of oxalic acid, copper (II) oxalate will precipitate:

Cu2+ + C2O42- ——>CuC2O4↓

b) Decomposition with concentrated sulfuric acid.

H2C2O4 + H2SO4—>CO + CO2 + H2O

Qualitative reactions to amines

a) Litmus

Blue color

b) Interaction with hydrogen halides (HHal)

 They form salts with hydrogen halides—a solid precipitate after evaporation.

Qualitative reactions to aniline

a) Interaction with bromine water.

C6H5NH2 +3Br2 —> C6H2NH2(Br)3↓+ 3HBr

b) Interaction with hydrogen halides (HHal)

 They form salts with hydrogen halides - a solid precipitate after evaporation.

c) Interaction with bleach.

Lilac color.

Qualitative reactions to phenol

a) Interaction with iron (III) chloride

A violet complex is formed. 

b) Interaction with bromine.

 Yellowish precipitate 2,4,6—tribromophenol

C6H5OH + 3Br2 —>C6H2OH(Br)3↓ +3HBr

c) Interaction with aldehydes.

Phenols give phenol-aldehyde resins when reacted with saldehyde in an acidic environment. In this case, soft porous masses of phenol-aldehyde resins are formed (polycondensation reaction) .

d) Interaction of phenol with sodium.

2C6H5OH + 2Na—> 2C6H5ONa + H2

Substances containing chlorine can turn the flame green. To do this, you need to dip the copper wire in alkyl chloride and bring it to the flame (Belstein test) .

Most carbohydrates have aldehyde and hydroxyl groups, so they are characterized by all reactions of aldehydes and polyhydric alcohols.

Qualitative reaction to starch

a) Interaction with iodine.

Starch in the presence of iodine turns dark blue. When heated, the color disappears; when cooled, it appears again.

 Proteins are detected mainly by reactions based on stains.

a) Xanthoprotein reaction

— Interaction with concentrated nitric acid.

 (OH)C6H4CH(NH2)COOH + HNO3 —> (OH)C6H3(NO2)CH(NH2)COOH↓ + H2O 

A yellow precipitate forms.

— Interaction with alkaline solution.

(OH)C6H3(NO2)CH(NH2)COOH+ 2NaOH —> (ONa)C6H3(NO2)CH(NH2)COONa+ H2O 

Orange coloration of the solution.

b) Biuret reaction to detect the peptide bond (CO-NH):

Protein + CuSO4 + NaOH -> red-violet color

Source: https://www.sites.google.com/site/school302chemistry/opyty/kacestvennye-reakcii-10-klass

Copper oxide (I, II, III): properties, preparation, application:

As you know, in chemistry there are four classes of inorganic compounds. There are a lot of substances representing each of them, but the leading position is undoubtedly occupied by oxides. One chemical element can have several different binary compounds with oxygen at once. Copper also has this property. It has three oxides. Let's look at them in more detail.

Copper(I) oxide

Its formula is Cu2O. In some sources, this compound may be called copper hemioxide, dicopper oxide or cuprous oxide.

Properties

It is a crystalline substance with a brown-red color. This oxide is insoluble in water and ethyl alcohol. It can melt without decomposing at a temperature slightly above 1240°C. This substance does not interact with water, but can be transferred into solution if the participants in the reaction with it are concentrated hydrochloric acid, alkali, nitric acid, ammonia hydrate, ammonium salts, and sulfuric acid.

Preparation of copper(I) oxide

It can be obtained by heating copper metal, or in an environment where oxygen has a low concentration, as well as in a flow of certain nitrogen oxides and together with copper (II) oxide. In addition, it can become a product of the thermal decomposition reaction of the latter.

Copper (I) oxide can also be obtained if copper (I) sulfide is heated in a stream of oxygen. There are other, more complex ways to obtain it (for example, reduction of one of the copper hydroxides, ion exchange of any monovalent copper salt with alkali, etc.

), but they are practiced only in laboratories.

Application

Needed as a pigment when painting ceramics and glass; a component of paints that protect the underwater part of a vessel from fouling. Also used as a fungicide. Copper oxide valves cannot do without it.

Copper(II) oxide

Its formula is CuO. In many sources it can be found under the name copper oxide.

Properties

It is a higher oxide of copper. The substance has the appearance of black crystals that are almost insoluble in water. It reacts with acid and during this reaction forms the corresponding cupric salt, as well as water. When it is fused with alkali, the reaction products are cuprates. The decomposition of copper (II) oxide occurs at a temperature of about 1100°C. Ammonia, carbon monoxide, hydrogen and coal are capable of extracting copper metal from this compound.

Receipt

It can be obtained by heating copper metal in an air environment under one condition - the heating temperature must be below 1100°C. Also, copper (II) oxide can be obtained by heating carbonate, nitrate, and divalent copper hydroxide.

Application

Using this oxide, enamel and glass are colored green or blue, and a copper-ruby variety of the latter is also produced. In the laboratory, this oxide is used to detect the reducing properties of substances.

Copper(III) oxide

Its formula is Cu2O3. It has a traditional name, which probably sounds a little unusual - copper oxide.

Properties

It looks like red crystals that do not dissolve in water. The decomposition of this substance occurs at a temperature of 400 ° C, the products of this reaction are copper (II) oxide and oxygen.

Receipt

It can be prepared by oxidizing copper hydroxide with potassium peroxydisulfate. A necessary condition for the reaction is an alkaline environment in which it must occur.

Application

This substance is not used by itself. In science and industry, its decomposition products—copper (II) oxide and oxygen—are more widely used.

Conclusion

That's all copper oxides. There are several of them due to the fact that copper has a variable valence. There are other elements that have several oxides, but we’ll talk about them another time.

Source: https://www.syl.ru/article/97628/oksid-medi-i-ii-iii-svoystva-poluchenie-primenenie

Chemical properties of copper oxide

Copper (I) oxide - Cu2O. In nature it can be found in the form of the mineral cuprite. Its names are also known as cuprous oxide, copper hemicoxide and dicopper oxide. Copper (I) oxide belongs to the group of amphoteric oxides.