What is copper in chemistry

Copper as a metal and raw material in construction: its features and processing nuances

Most industrial sectors use a metal such as copper. Due to its high electrical conductivity, not a single area of ​​electrical engineering can do without this material.

It produces conductors with excellent performance characteristics. In addition to these features, copper has ductility and refractoriness, resistance to corrosion and aggressive environments.

And today we will look at the metal from all sides: we will indicate the price for 1 kg of scrap copper, we will tell you about its use and production.

Copper is a chemical element belonging to the first group of the Mendeleev periodic table. This ductile metal has a golden-pink color and is one of three metals with a distinct color. Since ancient times, it has been actively used by man in many areas of industry.

The main feature of the metal is its high electrical and thermal conductivity. When compared with other metals, the conductivity of electric current through copper is 1.7 times higher than that of aluminum, and almost 6 times higher than that of iron.

Copper has a number of distinctive features over other metals:

1. Plasticity . Copper is a soft and ductile metal. If you take copper wire into account, it bends easily, takes any position and does not deform. It is enough to press the metal itself a little to check this feature.
2. Corrosion resistance . This photosensitive material is highly resistant to corrosion. If copper is left in a humid environment for a long time, a green film will begin to appear on its surface, which protects the metal from the negative effects of moisture.
3. Reaction to rising temperature . You can distinguish copper from other metals by heating it. In the process, the copper will begin to lose its color and then become darker. As a result, when the metal is heated, it will turn black.

Thanks to these features, this material can be distinguished from brass, tin, bronze and other metals.

below will tell you about the beneficial properties of copper:

The advantages of this metal are:

• High thermal conductivity;
• Resistance to corrosion;
• Quite high strength;
• High plasticity, which is maintained up to a temperature of -269 degrees;
• Good electrical conductivity;
• Possibility of alloying with various additional components.

Read below about the characteristics, physical and chemical properties of the metal substance copper and its alloys.

Properties and characteristics

Copper, as a low-active metal, does not interact with water, salts, alkalis, or weak sulfuric acid, but is subject to dissolution in concentrated sulfuric and nitric acid.

Physical properties of metal:

• The melting point of copper is 1084°C;
• The boiling point of copper is 2560°C;
• Density 8890 kg/m³;
• Electrical conductivity 58 MOhm/m;
• Thermal conductivity 390 m*K.

Mechanical properties:

• The tensile strength in the deformed state is 350-450 MPa, in the annealed state - 220-250 MPa;
• Relative narrowing in the deformed state is 40-60%, in the annealed state – 70-80%;
• The relative elongation in the deformed state is 5-6 δ ψ%, in the annealed state – 45-50 δ ψ%;
• The hardness in the deformed state is 90-110 HB, in the annealed state - 35-55 HB.

At temperatures below 0°C this material has higher strength and ductility than at +20°C.

Structure and composition

Copper, which has a high electrical conductivity coefficient, has the lowest impurity content. Their share in the composition can be equal to 0.1%. In order to increase the strength of copper, various impurities are added to it: antimony, zinc, tin, nickel, etc. Depending on its composition and the degree of pure copper content, several grades are distinguished.

The structural type of copper may also include crystals of silver, nickel, calcium, aluminum, gold and other components. All of them are characterized by comparative softness and plasticity. The copper particle itself has a cubic shape, the atoms of which are located at the vertices of the F-cell. Each cell consists of 4 atoms.

To learn where to get copper, watch this video:

Under natural conditions, this metal is found in native copper and sulfide ores. Ores called “copper luster” and “copper pyrite”, which contain up to 2% of the required component, are widely used in the production of copper.

Most (up to 90%) of the primary metal copper is obtained through the pyrometallurgical method, which includes a lot of stages: the enrichment process, roasting, smelting, processing in a converter and refining. The remaining part is obtained by the hydrometallurgical method, which consists of leaching it with diluted sulfuric acid.

Copper is actively used in the following areas:

• Electrical industry , which consists primarily of the production of electrical wires. For these purposes, copper must be as pure as possible, without foreign impurities.
• Manufacturing of filigree products . Copper wire in the annealed state is characterized by high ductility and strength. That is why it is actively used in the production of various cords, ornaments and other designs.
• Melting cathode copper into wire . A wide variety of copper products are melted down into ingots, which are ideal for further rolling.

Copper is actively used in a wide variety of industries. It can be part of not only wire, but also weapons and even jewelry. Its properties and wide scope of application have favorably influenced its popularity.

Below will talk about how copper can change its properties:

Source: http://stroyres.net/metallicheskie/vidyi/tsvetnyie/med/kak-syire-v-stroitelstve.html

How to properly connect copper and aluminum wire

Aluminum electrical wiring can often be found in older buildings. Now everyone understands that this is not the best metal for current. Today, during a major renovation, all the wiring of an old building is usually changed. However, with partial repairs, it becomes necessary to connect aluminum and copper wires.

Is it possible to connect aluminum wires to copper

First of all, you need to return to the school curriculum in chemistry and physics. There is such a thing as a “galvanic cell” - a simple battery that generates electric current. It is formed by the interaction of metals in an electrolyte. Twisting copper and aluminum cable wiring will essentially be the same battery.

Wire connections

Galvanic current quickly destroys metal. Despite the fact that it does not form in dry air, and the twist in the socket will not fall apart in a day, problems are guaranteed when the wiring is used for a long time.

After a few months or years, the wires will begin to deteriorate - this will lead to an increase in resistance. When a powerful current consumer is connected to the outlet, the twist will overheat. If such a connection is used regularly, there is a risk of fire.

Wiring fires

Regulations prohibit the direct twisting of aluminum and copper conductors. However, in emergency situations, the transition must be made, so you need to follow certain rules.

What happens when copper and aluminum come into contact?

Any metal, including copper and aluminum, oxidizes when exposed to oxygen. This leads to the formation of an oxide film on the surface of the material. In the case of copper, it does not prevent the passage of electric current, but the film on aluminum increases its resistance.

If wires are connected, dissimilar metals will begin to interact tightly. Aluminum is considered more active, therefore, when moisture accumulates at the joints (it is present in the air in any case), the process of electrolysis begins, that is, aluminum ions are gradually transferred to copper.

Metal twisting

As a result, one of the conductors loses its mass. Voids and breakdowns form in aluminum - they also oxidize, which speeds up the electrolysis process. The speed of the process also depends on the volume of moisture. Towards the end of the reaction, an almost destroyed aluminum conductor is obtained - its cross-section decreases, and the current density increases. As already described above, the metal heats up and there is a risk of fire.

Rules for connecting copper wires to aluminum

There are safe ways to connect copper and aluminum wires:

Bolted connection

This method is considered the most affordable, reliable and simple. For arrangement you will need:

• Bolt;
• Screw;
• Steel washers (several pieces);
• Wrench.

It is unlikely that it will be possible to use this method to connect wires in an apartment junction box - today they are made too small, and the finished connecting unit is quite large.

However, if a Soviet-era box is installed in the building or you have to work in a distribution panel, then the bolt method is the best solution.

It is considered to be the ideal solution if you have to connect completely incompatible cores - with different cross-sections, from different materials, multi-core/single-core.

Important! The bolt method allows you to connect more than 2 conductors (their number depends on the length of the bolt).

Connection device process:

• Each of the wires will have to be stripped of the insulation layer - 2-3 cm from the edge.
• A ring is assembled from the cleaned ends around the circumference of the bolt so that they can be put on it without any problems.
• Next, a bolt is taken, and a washer is put on it, after which a ring of copper wire, then a second washer, a ring of aluminum conductor, and finally a third washer, the entire resulting structure is tightened with a nut.
• Finally, you need to secure the connection using insulating tape. It is important not to forget that there is an intermediate washer between the aluminum and copper. If you plan to work with several different conductors, then a washer is not necessary between conductors of the same material.

Bolted connection

A special advantage of this method is the versatility of the connection. It can be untwisted and re-twisted at any time and, if you need to add wires, or change the connection diagram.

Terminals

Another cheap and easy connection method is terminal blocks. They are easy to find and buy, especially considering that they are often not sold in whole sections, but are cut in the quantity required for work. The pads come in different sizes, which directly depends on the cross-section of the conductors.

Terminals

Terminal blocks for connecting aluminum and copper wires are a plastic frame with several cells. Inside each is a brass tubular sleeve. The stripped ends of the wires are threaded into the terminal from different sides and clamped with screws. Connection arrangement:

• Loosen the clamp, releasing one part of the sleeve in order to thread the bare part of the wire into the sleeve.
• At the end of the conductor, strip the insulation by 5–6 mm. The wire is inserted into the block, the screw is clamped, fixing the metal to the sleeve. The fastening must be tightened firmly, but not too tightly, otherwise it will break the core.
• Similar steps for connecting a copper wire - only on the opposite side of the terminal.

Important! All stages of work must be carried out sequentially, despite the fact that it is physically possible to loosen both screws, thread the wires and tighten them at once. This is necessary so that the copper and aluminum do not touch ends inside the sleeve.

The main advantage of the terminals is the simplicity of their design and speed of installation. The method is called detachable - one of the conductors can be pulled out without any problems to connect the other.

Lever terminals

The pads are not suitable for working with stranded wires. In this case, you will first have to mount the sleeve tip, which is crimped with a bundle of cores.

Another feature of the terminals is that under screw pressure at room temperature, aluminum sometimes leaks. This leads to the need to regularly check the pads and tighten the contacts. If this is not done, the contact weakens, the connection heats up and sparks - there is a risk of fire.

Wago terminal blocks

A quick and easy connection method - the wires must first be stripped and inserted into the terminals until they stop. There they are automatically fixed using a pressure plate - it strongly presses the material against the tire. The transparent terminal housing allows you to control the passage of the conductor. The problem with this method is the disposability of such devices.

If you need a reusable clamp, then it is better to buy lever terminals. The lever is raised to clear the passage into the hole - the stripped wire is inserted there. The lever is then lowered to lock the wire inside the terminal. This is a detachable connection of copper and aluminum - if necessary, the lever rises to reach the conductor out.

Interesting! WAGO self-clamping devices are very popular and trusted in the market. The company produces a special series of terminals equipped with Alu-plus contact paste. This is a mixture that protects aluminum and copper contacts from corrosion. The model can be distinguished by the special “Al Cu” marking.

Self-clamping structures are very easy to use. The terminal itself indicates how long the core insulation needs to be stripped.

Rivets

Rivets are used to create a permanent connection, which has the same advantages as a threaded connection, but does not require disassembly and reassembly without destroying the rivet and requires a special tool - a connector.

Today, the method is more often used to connect thin-walled elements when forming partitions and the interior of different rooms. Electricians choose rivets because of their low cost, durability, and ease of installation.

Rivets

The principle of installing an electrical connection is simple: a metal rod threaded through a tubular rivet with a head is pulled in and cut. The rod has a thickening - it expands the rivet as it passes through the tube. Retainers come in different lengths and sizes.

Before connecting the wires, they must be prepared in the same way as in the case of a threaded bundle. The diameters of the rings should be slightly larger than the diameters of the rivets - the optimal is 4 mm. An aluminum core is first put on the rivet, then a spring washer, then a copper conductor and a second washer. A steel rod is threaded into the electrical installation and the tool is clamped until it clicks (this is how excess steel is cut off). All is ready.

Connections, both threaded and permanent, are characterized by reliability. This method is used to splice, for example, aluminum wiring damaged during repair work. It is imperative to insulate exposed areas.

Soldering iron

Soldering wires consisting of different metals is a completely feasible solution, if you take into account certain operating rules. Copper does not cause difficulties when soldering, which cannot be said about aluminum. An amalgam is formed on its surface, which is characterized by strong chemical resistance - it does not provide the solder with proper adhesion.

Soldered wires

To work with two dissimilar metal wires, you will have to prepare a solution of copper sulfate, a Krona battery and a piece of copper wire. The future soldering area is carefully cleaned on the aluminum core. Then a solution of copper sulfate is applied to this place.

Copper wiring is connected to the positive pole of the Krona battery and immersed in vitriol solution. An aluminum conductor is connected to the negative pole. After some time, a copper layer will be deposited on the aluminum - solder clings to it without problems.

Adapters for connecting from aluminum to copper

Sleeve adapters for crimping are considered the most reliable and high-quality connection. Special copper-aluminum models are made, into which 2 wires are inserted, after which they are processed with a press. However, it should be noted that the sleeves require sections starting from 16 mm2, while in residential buildings from 1.5 to 4 mm2 are used. Therefore, it is better to connect using a standard aluminum sleeve. Pressure testing occurs according to the following algorithm:

• We strip the ends of the copper conductor with lead-tin solder - this helps prevent metal-to-metal contact.
• Get rid of aluminum oxide film.
• Pass the wires through from different ends and crimp them.
• Wrap the connections with electrical tape or heat shrink followed by heating.

Important! If excessive crimping is done inside the structure, the soldered layer at the copper end may be damaged, so the size of the sleeve and matrix must match the core.

The good thing about the adapter from aluminum to copper is that it can be embedded under the plaster without fear of the wiring catching fire. However, implementation will require a press, which entails certain costs.

Sleeves

It is recommended that when carrying out work, all electrical wiring is intact, without breaks or connections - this reduces the risk of fire. However, if there is an urgent need to join a copper and aluminum core, then you need to take into account all the recommendations and choose one of the most optimal methods.

Source: https://rusenergetics.ru/provoda-i-kabeli/kak-soedinit-medniy-i-alyuminieviy

Analytics

The London Metal Exchange notes an increase in copper prices compared to the previous week by $145/t, to $6,301/t. The positive dynamics of quotations is associated with an increase in metal consumption in China against the backdrop of the conclusion of a first phase trade agreement between Beijing and Washington to regulate export tariffs.

Note that according to the China Customs Union, copper imports in December increased by 9.1%, to 527 thousand tons compared to the previous month and by 22.8% compared to the same period last year.

At the same time, according to the National Bureau of Statistics of China, the industrial production index in December did not change and remained at the level of November - 50.2%, but compared to December last year, the increase was 0.8%. In current conditions, copper inventories on the LME decreased by 7.5% compared to last week, to 128.05 thousand tons.

Copper futures prices on the London Metal Exchange rose by 2.3% to $6,330/t. Futures quotes for copper on the Shanghai Metal Exchange for February delivery increased by 1.8% compared to last week, to $7,121/t.

Copper processing

There is a positive trend in the processing sector. The Canadian company First Quantum reported an increase in copper production in 2019 by 15.8%, to 702 thousand tons compared to the previous year due to the achievement of industrial concentrate production at the Cobre Panama mine. The company also forecasts metal production growth in 2020 by 25%.

The Australian company New World Resources announced the restoration of production at the Antler mine, USA, whose productivity was 70 thousand tons of copper per year (according to 1975 data). The Gécamines company (DR Congo) together with the Chinese CNMC began copper mining at the Deziwa deposit, with a capacity of 70 thousand tons of copper per year.

It should be noted that the estimated metal reserves at the deposit are 4.6 million tons.

Copper spot market

The spot market shows positive dynamics. Premium quotes for the price of copper cathode in the US increased compared to last week by 11 $/t, to the range of 167-189 $/t as a result of rising prices for rail and road transportation, as well as the strengthening of the contango effect on the LME. Note that, as of January 15, the spread between futures and spot quotes on the LME is at $38/t.

In China, premium quotes rose as a result of a reduction in metal supply on the eve of the holiday weekend. Note that from January 24 to January 30 in China are considered holidays in honor of the New Year celebration. Premium prices for copper cathodes increased by 2 $/t compared to last week, to 35-50 $/t CIF. Note that copper reserves on the Shanghai Exchange increased by 6.4%, to 273-282 thousand tons compared to data on January 13.

The European market is experiencing stabilization of quotations due to low seasonal demand. At the same time, the market is supported by a positive spread on the LME between spot and futures prices (as of January 15, contango was $38/t). Premium quotes for copper in the port of Livorno remained at the level of 45-55 $/t CIF Livorno.

Quotes at the port of Rotterdam did not change compared to last week and remained in the range of 40-50 $/t CIF, Rotterdam.

Popular:

Source: http://www.translom.ru/analytic/obzor-mirovogo-rynka-medi-nedelya-320_193.html

Copper and its characteristics

The total content of copper in the earth's crust is relatively small [0.01% (wt.)], however, it is more often than other metals found in a native state, and copper nuggets reach a significant size.

The most important minerals that make up copper ores are: chalcocite, or copper luster Cu2S; chalcopyrite, or copper pyrite CuFeS2; malachite (CuOH)2CO3.

Pure copper is a viscous, viscous metal of light pink color (Fig. 1), easily rolled into thin sheets. It conducts heat and electricity very well, second only to silver in this regard.

In dry air, copper remains almost unchanged, since the thin film of oxides that forms on its surface (giving copper a darker color) serves as good protection against further oxidation.

But in the presence of moisture and carbon dioxide, the copper surface becomes covered with a greenish coating of hydroxycopper carbonate (CuOH)2CO3.

Rice. 1. Copper. Appearance.

Atomic and molecular mass of copper

Since in the free state chromium exists in the form of monatomic Cu molecules, the values ​​of its atomic and molecular masses coincide. They are equal to 63.546.

Isotopes of copper

It is known that in nature copper can be found in the form of two stable isotopes 63Cu (69.1%) and 65Cu (30.9%). Their mass numbers are 63 and 65, respectively. The nucleus of an atom of the copper isotope 63Cu contains twenty-nine protons and thirty-four neutrons, and the isotope 65Cu contains the same number of protons and thirty-six neutrons.

There are artificial unstable isotopes of copper with mass numbers from 52 to 80, as well as seven isomeric states of nuclei, among which the longest-lived isotope 67Cu with a half-life of 62 hours.

Copper ions

The electronic formula demonstrating the orbital distribution of copper electrons is as follows:

1s22s22p63s23p63d104s1.

As a result of chemical interaction, copper gives up its valence electrons, i.e. is their donor, and turns into a positively charged ion:

Cu0 -1e → Cu+;

Cu0 -2e → Cu2+.

Copper molecule and atom

In the free state, copper exists in the form of monoatomic Cu molecules. Here are some properties characterizing the copper atom and molecule:

Atom ionization energy, eV	7,72
Relative electronegativity	1,90
Atomic radius, nm	0,128

Copper alloys

The most important alloys of copper with other metals are brasses (alloys of copper and zinc), copper-nickel alloys and bronze.

Brasses contain up to 45% zinc. There are simple and special brass. The latter contains other elements, such as iron, aluminum, tin, and silicon.

Copper-nickel alloys are divided into structural and electrical. Structural stones include cupronickel and nickel silver. Cupronickel contains 20-30% nickel and small amounts of iron and manganese, while nickel silver contains 5-35% nickel and 13-45% zinc. Electrical copper-nickel alloys include constantan (40% nickel, 1.5% manganese), manganin (3% nickel and 12% manganese) and copel (43% nickel and 0.5% manganese).

Bronzes are divided according to the main component in their composition (except copper) into tin, aluminum, silicon, etc.

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Source: http://ru.solverbook.com/spravochnik/ximiya/ximicheskie-elementy/med-i-eyo-xarakteristiki/

Properties of copper

The properties of copper, a metal that is also found in the form of fairly large nuggets, have been studied by people since ancient times. Then, copper and its alloys were used to create utensils, weapons, jewelry, and various household items.

Such a high popularity of this metal over the centuries was due not only to its special qualities, but also to its ease of processing. Copper, present in the ore in the form of carbonates and oxides, is quite easy to restore, which is what our ancestors learned to do in ancient times.

In this article we will talk about the properties of copper and methods for its determination.

Physical properties of copper

Pure copper is a metal whose color ranges from pink to red. The radius of positively charged copper ions can take the following values:

• with a coordination index of 6 - up to 0.091 nm
• with a coordination index of 2 - up to 0.06 nm.

The radius of the copper atom is 0.128 nm. The electron affinity reaches 1.8 eV. The process of ionization of a given atom increases the electron affinity from 7.726 to 82.7 eV. Copper is a transition metal. The value of its electronegativity reaches 1.9 units on the Pauling scale.

It is worth noting that the oxidation state can take on different values. At temperatures ranging from 20 to 100 degrees, the thermal conductivity is 394 W/m*K. The electrical conductivity index of copper, in terms of which it is second only to silver, ranges from 55.5–58 MS/m.

Since copper in the potential row is located to the right of hydrogen, it is not able to displace this element from water and various types of acids. Copper has a face-centered cubic crystal lattice, and its value reaches 0.36150 nm.

Melting of copper begins at a temperature of 1083 degrees, and it boils at 26570 degrees. The density of copper is determined by its physical properties and is 8.92 g/cm3.

In addition to the above, it is worth highlighting the following physical and mechanical properties of copper:

• the thermal linear expansion index is 0.00000017 units
• the tensile strength indicator reaches 22 kgf/mm2
• copper hardness level on the Brinell scale is 35 kgf/mm2
• specific gravity is 8.94 g/cm3
• elasticity index is 132000 Mn/m2
• relative elongation is 60%.

The magnetic properties of this metal, which is completely diamagnetic, can be called absolutely unique. It is thanks to these indicators, together with physical properties, for example, specific gravity and conductivity, that one can explain such a wide popularity of this metal in the production of electrical products.

Aluminum has somewhat similar properties, which is also actively used in the manufacture of various electrical products, for example, wires, cables and other things.
The only characteristic of copper that can be changed is its tensile strength.

This indicator can be improved almost twice (up to 420–450 MN/m2) through a special technological operation called cold hardening.

Chemical properties of copper

The chemical characteristics of copper are determined by its location in Mendeleev’s periodic table of elements, where it is assigned the serial number 29. It is located in the fourth period and in the same group with noble metals. Thus, the uniqueness of its chemical qualities is once again confirmed, which we will discuss in more detail later.

If the moisture level is not high, then copper exhibits almost no chemical activity. However, everything changes dramatically when products are placed in conditions of high humidity and high carbon dioxide content. These are the conditions that are ideal for the start of active oxidation of copper.

During the oxidation process, a greenish film is created on the surface of a copper object, which consists of CuCO3, Cu(OH)2, as well as various sulfur compounds. This film is called patina and is very important because it protects the metal from further deterioration.

In addition to humidity, heating also triggers the oxidation process.

When heated to a temperature of 375 degrees, copper oxide is formed on the surface of the object; if the temperature is raised to 1100 degrees, then a two-layer scale is formed.

Copper reacts quite easily with elements in the halogen group. Under the influence of sulfur vapor, the metal ignites. Copper also shows a high level of relationship to selenium. The general properties of copper do not allow it to react with nitrogen, carbon and hydrogen even when heated.

Interaction with acids:

• the result of the reaction with sulfuric acid is sulfate and pure copper
• with hydrobromic and hydroiodic acid, copper bromide and copper iodide are formed, respectively.

But interaction with alkalis allows you to obtain cuprate.
Reactions for the production of copper, in which the metal is restored to a free state, are impossible without the presence of carbon monoxide, ammonia, methane and some other substances. The basic properties of copper allow it to interact with a solution of iron salts. The result of this reaction is the reduction of iron. This reaction is used to remove a previously deposited copper layer from various products.

Properties of copper salts

Mono- and divalent copper can form complex compounds that are distinguished by a high level of stability. Such compounds include double copper salts and ammonia mixtures. They are actively used in various industries. Copper (II) sulfate - CuSO4 in the anhydrous state is a white powder. When water is added it turns blue.

Therefore, it is used to detect residual water in organic liquids. An aqueous solution of copper sulfate has a blue-blue tint. Hydrated [Cu(H2O)4]2+ ions are responsible for this color; therefore, all other dilute solutions of copper (II) salts are of the same color. The exception is solutions containing colored anions.

From an aqueous solution, copper sulfate crystallizes with five molecules of water to form transparent blue crystals of copper sulfate. The resulting connection is used:

• in the process of electrolytic deposition of copper on metals
• for creating mineral paints
• as a starting material for the production of other copper compounds.

In the agricultural industry, a diluted solution of copper sulfate is very popular for spraying plants and soaking seeds before sowing because it destroys spores of harmful fungi. Copper (II) chloride - CuCl2. 2H2O. It is a dark green compound that is easily soluble in water. A high concentration of copper chloride makes it possible to obtain green solutions, and dilution leads to a blue-blue color. Copper (II) nitrate - Cu(NO3)2.3H2O.

It is obtained by dissolving copper in nitric acid. When heated, blue crystals of copper nitrate first release water, after which they easily decompose, releasing oxygen and brown nitrogen dioxide, becoming copper (II) oxide. Copper (II) hydroxycarbonate - (CuOH)2CO3. This substance can be found in nature in the form of the mineral malachite, which has a beautiful emerald green color.

In laboratory conditions, it can be created using the action of Na2CO3 on solutions of copper (II) salts. and green mineral paints.

Copper (II) acetate - Cu (CH3COO)2.H2O. This compound can be obtained by treating copper metal or copper(II) oxide with a solution of acetic acid.

Most often, it is a mixture of basic salts of different compositions and colors (from green to blue-green).

Remember that all copper salts, without exception, are poisonous. For this reason, to avoid the formation of copper salts, all copper utensils should be coated on the inside with a layer of tin.

Methods for determining copper

Determination of copper can be carried out by the following methods:

• chemical
• quantitative
• photometric.

Various chemical compositions can influence the splitting of molecules and atoms of a substance, therefore, its constituent parts can be distinguished. The chemical method for determining quantity is the electrolytic method of measuring the copper part in alloys of other metals. It is carried out using the following elements:

• acetylene
• wine acid
• aqueous ammonia
• ammonium nitrate
• disodium salt
• ethanol
• Cuprizone.

First of all, the copper composition (sample) is weighed. After this, it is sent to the prepared reagent solution. The sample should be completely dissolved in this solution. Next, the entire solution must be heated, since the heating process removes nitrogen oxides. The purified solution must be diluted with water and heated again to 40 °C. Now the mass can be subjected to the electrolysis process. Electrodes immersed in the solution are made of platinum.

Next, a current of 2.2 V is turned on and, under conditions of constant stirring, copper is released. The control test is a repeated electrolysis process. It is necessary to immerse the electrodes in the solution below the level of the isolated copper and connect the current. If the first reaction is carried out correctly, you will not see any metal deposits during the control procedure. The copper cathode obtained in this way must be washed with water without turning off the electric current, and then treated with ethyl alcohol and dried.

After this, the cathode must be weighed and the mass compared with the original weight. So, you will get the specific gravity of copper in the compound. A large number of types of chemical solutions have been developed for cleaning copper products.

Quantitative determination of the mass of copper in the total volume of metal is advisable to use for alloys with nickel, bronze or zinc. When exposed to a substance, copper is deposited and in this form it can be measured.

Precipitation can be carried out by inorganic and organic elements. Inorganic substances can be distinguished:

• ammonium tetrarhodanodiamine chromate, called Reinecke's salt
• Potassium thiocarbonate is capable of precipitating copper at temperatures above 80 °C
• Copper oxalate can be precipitated with acetic acid.

Organic substances used:

• hydroxyquinoline-8, which is capable of precipitating copper in combination with ammonia and alkaline solutions. Heating the precipitate leads to the formation of copper oxide
• α-benzoinoxime with the participation of alcohol can precipitate the metal in the form of flakes. The reaction is impossible if the composition contains nickel
• Potassium iodide is used in neutral and acidic environments. There is no point in using it when the alloy contains iron, antimony and arsenic.

The advantages of the photometric method are the high accuracy of measuring the amount of copper, as well as ease of use. To implement this method you will need the following connections:

• cuprizone
• Lead diethyldithiocarbamate.

The meaning of the photometric method for determining copper is to record the color intensity of the material that has passed through a concentrated solution. The solution consists of:

• ammonia
• ammonium citrate solution
• lead diethyldithiocarbamate
• sodium sulfate.

The substance in which the amount of copper needs to be determined is passed through the above solutions.
Note that it is important to maintain proportions here. Next comes the photometry process. Determination of copper is also possible in waste, sewer, river, sea waters, and in soil. There are three ways:

• atomic absorption direct
• atomic absorption with the participation of chelation
• atomic absorption, which involves the use of a graphite furnace.

To determine the amount of copper in the soil, the most reliable method is the method using a graphite furnace.
To do this, a soil sample must be placed in a graphite tube, dehydrated by combustion and sprayed. The sputtering procedure involves the separation of a substance into atoms, followed by filtration and separation of the desired metal from them. To evaluate a soil sample, you can use any photometric method for determining copper.

Source: http://mining-prom.ru/cvetmet/med/svoystva-medi/

Chemical and physical properties of copper

1001student.ru > Chemistry > Chemical and physical properties of copper

The chemical properties of copper are determined by its position in the periodic table of D.I. Mendeleev. The designation of this metal is Cu (cuprum); it has the 29th serial number, is in the first group (side subgroup), in the 4th major period.

There is a separate type of it: blister copper, which is oxygen when converting the product. Atomic (molar) mass is 63.5 g/mol; molecular weight - 63.5 a. eat.

Depending on the compound in which the metal is found, it can have a valence of +1 and +2, but in rare cases the oxidation state can be +3 and +5, which is an exception. The structure of the Cu atom and the electronic formula are shown in the figure:

The copper crystal lattice is a cube-shaped frame formed by straight lines. The lattice is quite strong, molecular, since there are molecules at the nodes.

• Physical properties and characteristics
• What does it react with?
• Relation to oxygen
• Interaction with water
• Reactions with acids
• Relation to halogens and non-metals
• Reactions with non-metal oxides
• Chemical properties of copper
• Conclusion

Physical properties and characteristics

Copper in its pure form is a fairly malleable, malleable, viscous metal with a reddish-brown color.

Its hardness is achieved by adding various impurities to the composition. It has high electrical and thermal conductivity, but impurities, which are often added to the alloy, worsen these indicators.

The advantage of this metal is its resistance to corrosion. The melting point is 1085 degrees Celsius, and the boiling point is 2562 degrees. Density is 8900 kg/m3. The specific gravity is 8930 kg/m3.

Copper in its pure form is diamagnetic, that is, it does not have magnetic properties. Only its alloys can be magnetized, where the concentration of copper itself is no more than 50%.

What does it react with?

Copper does NOT react with hydrogen, carbon, nitrogen, or silicon.

Reacts with acids and salts, oxides, halogens, oxygen and non-metals, but cannot react with alkalis, since it is in the electrochemical series after hydrogen. It also cannot react with fluorine, bromine, or chlorine.

Relation to oxygen

The metal exhibits weak activity towards oxygen, but when exposed to air for a long time, it becomes covered with a very thin, almost imperceptible greenish film, which is copper oxide.

Depending on the temperature at which the reaction occurs, cuprum forms 2 oxides: CuO and Cu2O.

Interaction with water

Due to the fact that copper is in the electrochemical voltage series after hydrogen, it does not displace hydrogen from water. But if oxygen is present, hydrogen can displace metal molecules, causing an oxidation-reduction reaction.

Reactions with acids

Due to its position in the electrochemical series, it does not displace hydrogen from acids, so some of them do not act on it. But with sufficient access to oxygen, they dissolve in them, forming salts corresponding to acids.

Relation to halogens and non-metals

Copper reacts quite well with halogens. Under normal conditions the changes are not particularly noticeable, but over time a very thin layer of halides forms on the surface. And at elevated temperatures the reaction occurs very quickly and violently.

Cu reacts with sulfur, depending on the temperature, the following sulfides are formed: Cu2S, CuS.

Can form iodides (with iodine).

Reactions with non-metal oxides

Copper may not react with all non-metal oxides, depending on the non-metal, temperature and other conditions of the chemical reaction.

Conclusion

Copper is a common substance that is indispensable in many industries, as it is very flexible and fusible. It has high performance, in many ways comparable to iron, which allows it to be used to make many irreplaceable parts in manufacturing and mechanics.

Source: https://1001student.ru/himiya/svojstva-medi.html

Is copper a body or a substance? Properties of copper

Approximately the 3rd millennium BC is considered to be the transition from stone as the main industrial substance to bronze. The period of perestroika is considered to be the Copper Age. After all, it was this connection that at that time was the most important in construction, in the manufacture of household items, dishes and other processes.

Today, copper has not lost its relevance and is still considered a very important metal, often used for various needs. Is copper a body or a substance? What properties does it have and what is it needed for? Let's try to figure it out further.

General characteristics of the element copper

As a chemical element, copper has its location in the periodic table. It's as follows.

1. Fourth major period, first row.
2. First group, secondary subgroup.
3. Serial number 29.
4. Atomic weight - 63.546.
5. The electronic configuration of the outer layer is expressed by the formula 3d104s1.

The element has two stable natural isotopes with mass numbers 63 and 65. The element's Latin name is cuprum, which explains its chemical symbol Cu. In the formulas it is read as “cuprum”, the Russian name is copper.

Is copper a body or a substance?

To answer this question, you should first define the concepts of “substance” and “body”. They are studied at school levels, as they are fundamental. From the point of view of the science of chemistry and physics, all materials from which certain objects are made are considered a substance. That is, all chemical compounds of both organic and inorganic nature can serve as examples of substances.

The body is the object itself, which consists of some kind of substance. They can be artificially constructed by man, or have a natural origin. Examples of solids: nails, windows, plates, table, cabinet, flower pot, etc.

To distinguish between these two concepts, here are some comparative examples.

1. Sugar is the substance, the lollipop is the body.
2. Iron is a substance, a nail is a body.
3. A window is a body, glass is a substance.

It is obvious from these considerations that the question: “Is copper a body or a substance?” - the answer is clear. This is the substance. Now, if we are talking about a copper plate or a copper ring, then, of course, we should talk about them as a body.

From a chemical point of view, copper is a substance classified as a metal. It has a number of very valuable properties that underlie the widespread use of this compound.

The simple substance copper is a non-ferrous metal

As we have already indicated, copper is a metal. However, not all representatives of this group of substances are identical in their characteristics. There are soft and hard, white and yellow, red metals and so on. Copper is a non-ferrous soft metal.

The electronic structure of its atom makes it possible to accurately determine whether copper is a metal or a non-metal. After all, at the external level it has only one electron, which means that it can easily give it away, exhibiting typical metallic reducing properties. Consequently, there can be no doubt that it should belong to the category of metals. The physical properties of its simple substance also speak about this.

Is copper a substance or a body? You can be completely convinced of the correctness of the answer only by examining its physical properties. If we talk about this element as a simple substance, then it is characterized by the following set of properties.

1. The metal is red.
2. Soft and very malleable.
3. Excellent thermal and electrical conductor.
4. Not refractory, melting point is 1084.5 0C.
5. The density is 8.9 g/cm3.
6. In nature it is found mainly in its native form.

Thus, it turns out that copper is a substance known since ancient times. Since ancient times, many architectural structures have been created on its basis, dishes and household items have been made.

Chemical properties

In terms of chemical reactivity, copper is a body or substance with low reactivity. There are two main oxidation states of this element, which it exhibits in compounds. This:

It is very rare to find substances in which these values ​​are replaced by +3.

So, copper can interact with:

• by air;
• carbon dioxide;
• hydrochloric acid and some other compounds only at very high temperatures.

All this is explained by the fact that a protective oxide film is formed on the surface of the metal. It is this that protects it from further oxidation and imparts stability and low activity.

Of the simple substances, copper can interact with:

• halogens;
• selenium;
• cyanides;
• gray.

Often forms complex compounds or double salts. Almost all complex compounds of this element, except oxides, are toxic substances. Those molecules that monovalent copper forms are easily oxidized to divalent representatives.

Areas of use

Copper is a mixture or pure substance, which in any of these states is widely used in industry and everyday life. Several main industries for the use of copper compounds and pure metal can be identified.

1. Leather industry, which uses some salts.
2. Production of fur and silk.
3. Production of fertilizers, plant protection products against pests (copper sulfate).
4. Copper alloys are widely used in the automotive industry.
5. Shipbuilding, aircraft structures.
6. Electrical engineering in which copper is used due to its good anti-corrosion resistance and high electrical and thermal conductivity.
7. Various instrumentation.
8. Manufacturing of dishes and household items of economic importance.

It is obvious that, despite hundreds of years, the metal in question has only strengthened its position and proved its worth and indispensability in use.

Copper alloys and their properties

There are many copper-based alloys. It itself is distinguished by high technical characteristics, as it can be easily forged and rolled, is lightweight and quite durable. However, when certain components are added, the properties improve significantly.

In this case, the question to ask is: “Is copper a substance or a physical body when it comes to its alloys?” The answer will be: this substance. All the same, it is exactly that until any physical body, that is, a certain product, is made from the alloy.

https://www.youtube.com/watch?v=DXupvDLiDGE

What types of copper alloys are there?

1. An almost equal combination of copper and zinc in one composition is usually called brass. This alloy is characterized by high strength and resistance to chemical influences.
2. Tin bronze is a combination of copper and tin.
3. Cupronickel is nickel and copper in a ratio of 20/80 out of 100. Used to make jewelry.
4. Constantan is a combination of nickel, copper and the addition of manganese.

Biological significance

It is not so important whether copper is a substance or a body. Something else is significant. What role does copper play in the life of living organisms? It turns out to be quite important. Thus, the ions of the metal in question perform the following functions.

1. Participate in the conversion of iron ions into hemoglobin.
2. They are active participants in the processes of growth and reproduction.
3. They allow the amino acid tyrosine to be absorbed, therefore affecting the appearance of hair and skin color.

If the body does not receive enough of this element in the required quantity, then unpleasant diseases may occur. For example, anemia, baldness, painful thinness, etc.

Source: https://FB.ru/article/190552/med---eto-telo-ili-veschestvo-svoystva-medi

Notes from a programmer

The J-antenna, also known as the J-pole, is a popular antenna among radio amateurs, typically used on VHF. I recently decided to make a J-antenna for 2 meters, simply because I've never made one before. At the same time, it was decided to try a new material for me, copper pipes.

Theory

The shape of the J-antenna really does not resemble the Latin letter J:

In fact, a J-antenna is a vertical dipole fed from below. The upper part is an antenna sheet with a length of λ/2, that is, a dipole. The lower part of the antenna is the matching section. It is a two-wire line with a length of λ/4.

The coaxial cable is connected to the antenna at some point in this section, as shown in the picture.

This ensures matching of a coaxial cable, which has a characteristic impedance of 50 Ohms, and a dipole, which, when powered from the edge, has a high resistance of several thousand Ohms.

Why does such a scheme agree on anything at all? To answer this question, consider two edge cases. Let's say we decide to feed the J-antenna at the very bottom of the matching section.

The question is, what is the input impedance of the antenna at this point? It is not difficult to guess that here we have a short circuit, that is, a resistance of 0 Ohm. Okay, now let's move up λ/4 and try to power the antenna here.

What input resistance will we see? It turns out that it is infinitely large, since the λ/4 section is nothing more than a quarter-wave transformer with 0 ohms at the end.

Intuition suggests that somewhere between these two extremes you can find any active resistance, at least 50 Ohms, at least 75 Ohms, at least any other. And indeed, in practice this is exactly what happens.

Practice

It was decided to make the antenna from copper pipes with a diameter of 10 mm. I've never soldered copper pipes before. As it turns out, it's not that difficult:

You will need the following tools: a vice, a gas cylinder, a gas torch, soldering paste for copper pipes, gardening gloves, a round file. Optionally - lead-free solder, pipe cutter. Pipes are easy to cut, so if you don't have a pipe cutter, a hacksaw, Dremel, or something like that will do. Plumbers only use lead-free solder because lead is toxic. But we are not going to pump water through pipes, so the good old POS-61 will do.

The following materials were used in the antenna: SO-239 connector, some thick copper wire, a copper pipe with a diameter of 10 mm (at least 2 meters, better with a margin), two 90° angles and two couplings for it, as well as some epoxy glue.

Soldering is carried out as follows. Solder paste is applied to the soldering site, and the corresponding fitting is put on - an angle or a coupling. Heat with a gas burner until the paste becomes a characteristic silver color.

This means that the optimal temperature has been reached. We move the burner to the side and poke a little solder into the soldering area. It should melt right away. Turn off the burner and wait for the copper to cool.

In words it is most likely not very clear, but you will find a lot of videos about how this is done.

Important! Be extremely careful with the gas burner. The gas combustion temperature in it is about 1000°C.

The antenna dimensions are not very critical. In our case, the wavelength λ is equal to:

>>> 300_000_000/145_000_000
2.0689655172413794

I took exactly 2 meters. The distance between the conductors in the matching section is about 1-3% of λ. I used a piece of pipe 4 cm long at the bottom of the antenna. After soldering the corners, the total distance was 6 cm:

The couplings are soldered to the SO-239 connector as in the photo and put on the pipes. In order for the couplings to slide along the pipes, they need to be slightly processed from the inside with a file. We carry the antenna to a future location for permanent installation. Personally, I placed it on the balcony, attaching it with nylon ties to a PVC pipe. Then we match the antenna by moving the couplings along the matching section.

In my case, the EU1KY analyzer showed perfect agreement:

We go to the local repeater and make sure that the correspondents receive us well. All that remains is to solder the couplings in this position, seal the remaining holes in the pipes with epoxy, add a shut-off choke, and the antenna is ready!