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 mass is 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
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.
Chemical properties of copper
Single-valve
The Cu+ ion is extremely unstable, especially in aqueous solutions. Examples of monovalent copper are:
- oxide (I) – Cu2O,
- sulfide (I) – C
Bivalent
This is the most characteristic oxidation state for copper. Also more stable and widespread, for example:
Trivalent
The rarest and most unstable oxidation state of this metal, which is an exception, for example:
- oxide (III) – Cu2O3,
- cuprate(III).
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://tvercult.ru/nauka/himicheskie-i-fizicheskie-svoystva-medi
Does copper interact with water - Metalworker's Handbook
The chemical properties of most elements are based on their ability to dissolve in aqueous media and acids. The study of the characteristics of copper is associated with a low-active effect under normal conditions.
A feature of its chemical processes is the formation of compounds with ammonia, mercury, nitric and sulfuric acids. The low solubility of copper in water is not capable of causing corrosion processes.
It has special chemical properties that allow the compound to be used in various industries.
Item Description
Copper is considered the oldest metal, which people learned to mine even before our era. This substance is obtained from natural sources in the form of ore. Copper is an element of the chemical table with the Latin name cuprum, the serial number of which is 29. In the periodic table it is located in the fourth period and belongs to the first group.
The naturally occurring substance is a pink-red heavy metal with a soft and malleable structure. Its boiling and melting point is more than 1000 °C. Considered a good guide.
Chemical structure and properties
If you study the electronic formula of a copper atom, you will find that it has 4 levels. There is only one electron in the 4s valence orbital. During chemical reactions, from 1 to 3 negatively charged particles can be split off from an atom, then copper compounds with an oxidation state of +3, +2, +1 are obtained. Its divalent derivatives are most stable.
In chemical reactions it acts as a low-reactive metal. Under normal conditions, copper has no solubility in water. Corrosion is not observed in dry air, but when heated, the metal surface becomes covered with a black coating of divalent oxide.
The chemical stability of copper is manifested under the action of anhydrous gases, carbon, a number of organic compounds, phenolic resins and alcohols. It is characterized by complex formation reactions with the release of colored compounds.
Copper has slight similarities with alkali group metals due to the formation of monovalent derivatives.
This is the process of formation of homogeneous systems in the form of solutions when one compound interacts with other substances. Their components are individual molecules, atoms, ions and other particles. The degree of solubility is determined by the concentration of the substance that was dissolved when obtaining a saturated solution.
The unit of measurement is most often percentages, volume fractions or weight fractions. The solubility of copper in water, like other solid compounds, is subject only to changes in temperature conditions. This dependence is expressed using curves. If the indicator is very small, then the substance is considered insoluble.
Solubility of copper in aqueous media
The metal exhibits corrosion resistance when exposed to sea water. This proves its inertness under normal conditions. The solubility of copper in water (fresh) is practically not observed. But in a humid environment and under the influence of carbon dioxide, a green film forms on the metal surface, which is the main carbonate:
Cu + Cu + O2 + H2O + CO2 → Cu(OH)2 · CuCO2.
If we consider its monovalent compounds in the form of salts, then their insignificant dissolution is observed. Such substances are subject to rapid oxidation. The result is divalent copper compounds. These salts have good solubility in aqueous media. Their complete dissociation into ions occurs.
Solubility in acids
The usual conditions for reactions of copper with weak or dilute acids do not favor their interaction. The chemical process of the metal with alkalis is not observed. Copper solubility in acids is possible if they are strong oxidizing agents. Only in this case does interaction take place.
Solubility of copper in nitric acid
This reaction is possible due to the fact that the process of oxidation of the metal with a strong reagent occurs. Nitric acid in diluted and concentrated form exhibits oxidizing properties with the dissolution of copper.
In the first option, the reaction produces copper nitrate and nitrogen divalent oxide in a ratio of 75% to 25%. The process with dilute nitric acid can be described by the following equation:
8HNO3 + 3Cu → 3Cu(NO3)2 + NO + NO + 4H2O.
In the second case, copper nitrate and nitrogen oxides are obtained, divalent and tetravalent, the ratio of which is 1 to 1. This process involves 1 mole of metal and 3 moles of concentrated nitric acid. When copper dissolves, the solution heats up strongly, resulting in thermal decomposition of the oxidizing agent and the release of an additional volume of nitrogen oxides:
4HNO3 + Cu → Cu(NO3)2 + NO2 + NO2 + 2H2O.
The reaction is used in small-scale production associated with recycling scrap or removing coatings from waste. However, this method of dissolving copper has a number of disadvantages associated with the release of large amounts of nitrogen oxides. To capture or neutralize them, special equipment is required. These processes are very expensive.
The dissolution of copper is considered complete when the production of volatile nitrogen oxides completely ceases. The reaction temperature ranges from 60 to 70 °C. The next step is to drain the solution from the chemical reactor. At its bottom there are small pieces of metal that have not reacted. Water is added to the resulting liquid and filtered.
Solubility in sulfuric acid
Under normal conditions, this reaction does not occur. The factor determining the dissolution of copper in sulfuric acid is its strong concentration. A dilute medium cannot oxidize the metal. The dissolution of copper in concentrated sulfuric acid proceeds with the release of sulfate.
The process is expressed by the following equation:
Cu + H2SO4 + H2SO4 → CuSO4 + 2H2O + SO2.
Properties of copper sulfate
Dibasic salt is also called sulfuric acid and is designated as CuSO4. It is a substance without a characteristic odor and does not exhibit volatility. In its anhydrous form, salt is colorless, opaque, and highly hygroscopic. Copper (sulfate) has good solubility. Water molecules, when added to salt, can form crystalline hydrate compounds. An example is copper sulfate, which is a blue pentahydrate. Its formula: CuSO4·5H2O.
Crystalline hydrates have a transparent structure with a bluish tint and exhibit a bitter, metallic taste. Their molecules are capable of losing bound water over time. They are found in nature in the form of minerals, which include chalcanthite and butite.
Brazing torch for copper pipes
Susceptible to copper sulfate. Solubility is an exothermic reaction. The process of salt hydration generates a significant amount of heat.
Solubility of copper in iron
As a result of this process, pseudo-alloys of Fe and Cu are formed. For metallic iron and copper, limited mutual solubility is possible. Its maximum values are observed at a temperature of 1099.85 °C. The degree of solubility of copper in the solid form of iron is 8.5%. These are small numbers. The dissolution of metallic iron in the solid form of copper is about 4.2%.
Reducing the temperature to room values makes the mutual processes insignificant. When metallic copper is melted, it is able to well wet iron in solid form. When producing Fe and Cu pseudo-alloys, special blanks are used. They are created by pressing or baking iron powder in pure or alloyed form. Such workpieces are impregnated with liquid copper, forming pseudo-alloys.
Dissolution in ammonia
The process often occurs by passing NH3 in gaseous form over hot metal. The result is the dissolution of copper in ammonia, the release of Cu3N. This compound is called monovalent nitride.
Its salts are exposed to ammonia solution. The addition of such a reagent to copper chloride leads to the formation of a precipitate in the form of hydroxide:
CuCl2 + NH3 + NH3 + 2H2O → 2NH4Cl + Cu(OH)2↓.
Excess ammonia promotes the formation of a complex type compound that is dark blue in color:
Cu(OH)2↓+ 4NH3 → [Cu(NH3)4] (OH)2.
This process is used to determine cupric ions.
Solubility in cast iron
In the structure of malleable pearlitic cast iron, in addition to the main components, there is an additional element in the form of ordinary copper. It is this that increases the graphitization of carbon atoms and helps to increase the fluidity, strength and hardness of alloys.
The metal has a positive effect on the level of perlite in the final product. The solubility of copper in cast iron is used to alloy the original composition. The main purpose of this process is to obtain a malleable alloy.
It will have increased mechanical and corrosion properties, but reduced embrittlement.
If the copper content in cast iron is about 1%, then the tensile strength is equal to 40%, and the yield strength increases to 50%. This significantly changes the characteristics of the alloy.
Increasing the amount of metal alloying to 2% leads to a change in strength to 65%, and the fluidity rate becomes 70%. With a higher copper content in cast iron, spheroidal graphite is more difficult to form. The introduction of an alloying element into the structure does not change the technology for forming a viscous and soft alloy.
The time allotted for annealing coincides with the duration of such a reaction in the production of cast iron without copper admixture. It is about 10 hours.
The use of copper for the production of cast iron with a high silicon concentration is not able to completely eliminate the so-called ferruginization of the mixture during annealing. The result is a product with low elasticity.
Solubility in mercury
When mercury is mixed with metals of other elements, amalgams are obtained. This process can take place at room temperature, because under such conditions Pb is a liquid.
The solubility of copper in mercury disappears only during heating. The metal must first be crushed. When solid copper is wetted with liquid mercury, mutual penetration of one substance into another or a process of diffusion occurs.
The solubility value is expressed as a percentage and is 7.4*10-3.
The reaction produces a hard, simple amalgam similar to cement. If you heat it up a little, it softens. As a result, this mixture is used to repair porcelain products. There are also complex amalgams with an optimal content of metals. For example, dental alloy contains the elements silver, tin, copper and zinc. Their percentage ratio is 65: 27: 6:2. Amalgam with this composition is called silver.
Each component of the alloy performs a specific function, which allows you to obtain a high-quality filling.
To prepare amalgam, it is advisable to use an inert atmosphere or a protective liquid that forms a film. The metals that make up the alloy can be quickly oxidized by air. The process of heating cuprum amalgam in the presence of hydrogen causes the mercury to be distilled off, allowing the elemental copper to be separated. As you can see, this topic is not difficult to learn.
Now you know how copper interacts not only with water, but also with acids and other elements.
Source: https://ssk2121.com/vzaimodeystvuet-li-med-s-vodoy/
