People for a long time use copper in everyday life. A very important parameter for modern people is its density and proportion.
These data are used in the calculations of the composition of materials in the production of various communications, parts, products and components in the technical industry.
Main information about copper
Copper is the most common non-ferrous metal. Its name in Latin - Cuprum - she received in honor of the island of Cyprus. There, it was mined ancient Greeks thousands of years ago. Historians even invented the copper eyelidswhich lasted from the IV century v. e. At that time, people did from the popular metal:
- instrument;
- dishes;
- jewelry;
- coins.
Table D.I. Mendeleeva she takes the 29th place. This element has unique properties -physical, chemical and mechanical. In ancient times, in a natural environment, it was possible to find copper in the form of nuggets, sometimes very large sizes. People heated the breed on the outdoor fire, and then sharply cooled. As a result, it was cracking, which made it possible to carry out the restoration of the metal. Such a simple technology allowed to start mastering the popular element.
Properties
Copper is a non-ferrous color metal with a pinkendowed with high density. In nature, there are more than 170 species of minerals in their composition CUPRUM. Only 17 are manufactured by industrial production of this element. The bulk of this chemical element is contained in the composition of ore metals:
- halcosina - up to 80%;
- booking - up to 65%;
- kovelina - up to 64%.
Of these minerals, copper enrichment and its smelting is carried out. High thermal conductivity and electrical conductivity are distinctive properties of non-ferrous metal. It begins to melt at a temperature of 1063 o C, and boils at 2600 o C. Brand Cuprum will depend on the production method. Metal happens:
- cold-drawn;
- rolling;
- cast.
For each type there are special parametric calculations that characterize the degree of resistance to the shift, deformation under the influence of loads and compression, as well as an indicator of elasticity when tensile material.
The colored metal is actively oxidized during the heating process. At a temperature of 385 o C, copper oxide is formed. Its content reduces the thermal conductivity and electrical conductivity of other metals. When interacting with moisture, the metal forms buying, with an acidic medium - vitrios.
Due to its properties, this chemical element is actively used in the production of electrical and electronic systems and many other products of another destination. The most important property is its density of 1 kg per m 3Because with the help of this indicator the weight of the product produced is determined. The density shows the mass ratio to the total volume.
The most common system for measuring density units is 1 kilogram on m 3. This indicator for copper is 8.93 kg / m 3. In a liquid form, the density will be at the level of 8.0 g / cm 3. The overall density rate may vary depending on the brand of metal having various impurities. This uses the specific gravity of the substance. It is a very important characteristic when it comes to the production of materials, which contains copper. The proportion characterizes the ratio of the mass of copper in the total volume of the alloy.
The proportion of copper will be 8.94 g / cm 3. The parameters of specific density and weight in copper coincide, but such a coincidence is not typical for other metals. The specific mass is very important not only in the production of products with its content, but also when processing scrap. There are many techniques with which you can rationally choose materials for the formation of products. In international systems, the specific weight parameter is expressed in Newton for 1 unit volume.
It is very important to produce all calculations in the design stage of devices and mechanisms. Specific density and weight are different values, but they are necessarily used to determine the mass of blanks for various parts, which contains Cuprum.
If compare copper and aluminum densitywe will see a big difference. Aluminum, this indicator is 2698.72 kg / m 3 in the state at room temperature. However, with an increase in temperature, the parameters become different. When moving aluminum into a liquid state when heated, the density will be within 2.55-2.34 g / cm 3. The indicator always depends on the content of alloying elements in aluminum alloys.
Technical indicators of metal alloys
The most common copper-based alloys brass and bronze are considered. Their composition is also formed from other elements:
- zinc;
- nickel;
- tin;
- bismuth.
All alloys differ in the structure. The presence of tin in the composition allows the bronze alloys of excellent quality. In cheaper alloys included nickel or zinc. CUPRUM based materials 
possess the following characteristics:
- high plasticity and wear resistance;
- electrical conductivity;
- resistance to aggressive medium;
- low friction coefficient.
Copper-based alloys are widely used in industrial production. Of them produce dishes, jewelry, electric pipes and heating systems. Materials with Cuprum are often used to decorate the facade part of the houses, the manufacture of compositions. High stability and plasticity are basic qualities for the use of material.
There is no such person who would have seen a yellow metal in his entire lives. In nature, there are several minerals, which in appearance are similar to the yellow metal. But as they say: "Not all gold, which shines." To accurately not confuse the precious metal with other materials, it is necessary to know the density of gold.
The density of the noble metal
Molecular structure of gold.
One of the important characteristics of the precious metal is its density. Gold density is measured in kg m3.
Specific density Very significant characteristic for gold. It is usually not taken into account, as jewelry: rings, earrings, pendants have a very low weight. But if you hold the kilogram ingot of real yellow metal in the hands, you can make sure that it is very heavy. A significant density of gold contributes to the relief of its production. So, flushing on the gateways, provides a high level of extraction of gold from the washed rocks.
The density of gold is 19.3 grams per centimeter cubic.
This means that if you take a certain amount of precious metal, it will weigh almost 20 times more than the same volume of simple water. A two-liter plastic bottle of golden sand has a mass of about 32 kg. Of the 500 grams of the precious metallol, you can lay out a cube with a side of 18.85 mm.
Gold density table of various samples and colors.
The density of the initial gold is several units lower than that of the cleaned metal and can vary from 18 to 18.5 grams per centimeter cubic.
583 Gold sample is less dense, as this alloy consists of different metals.
At home, it is possible to determine the density of gold themselves. To do this, we need to weigh the product from the precious metal on ordinary scales, in which the division price should be at least 1 gram. After that, the capacity with the volume marking must be filled with liquid, in this case, water in which the decoration should be omitted. It is necessary to ensure that the fluid does not start to overflow through the edge.
After that, we measure how much the volume of fluid has changed after lowering the golden product in the container. According to a special formula, known from school bench, we calculate the density: the mass divided into volume.
It must be remembered that the product from the precious metallol consists not from pure gold, so it is necessary to make an adjustment on the sample density of the alloy.
How to distinguish a real yellow metal from fake
At the moment, both in Russian and foreign markets there is a very large percentage of fake gold. There is a huge risk to purchase a gold decoration, containing up to 5% of the precious metal or without anything. Do not feel deceived by basic rules when buying gold.
To begin with, it should be well inspecting the product. It must necessarily have a test. Moreover, it should not consist of digit curves or lubricated stamps. In the opposite case, this is the first sign of the confort.
Sample of single state brand for gold products.
The next sign of the fake is the iznanka decoration from the precious metallol. It should also be well done, like the front side, otherwise, is a poor-quality product. It is also possible to determine the quality of the product using this characteristic as the density of gold, but it is impossible to carry out such an experiment in the store.
There is also a method of determining as testing for strength. True, it is not always possible to scratch a gold product in front of the seller, so this method cannot be implemented.
Check iodine.
Not bad ways to determine the quality of the product can serve as the following chemical methods. You can drop on the decoration of yellow metal a little iodine. In case the speech is dark color, you can confidently talk about the quality of the goods offered. Can still help table vinegar. In case, after three minutes spent in it, the precious metal darkened, then you can safely attribute the product to the landfill.
In definition of quality, chlorine gold can help. Not only the density of gold became known from the course of chemistry, but also that it cannot enter into any chemical reactions. Therefore, if after applying to the gem metal of chlorine gold, it began to deteriorate, then this is the real fake and its place in the trash.
One of the best ways to fencing the acquisition of counterfeit is the purchase of products from the precious metallol in well-known specialized stores.
In this case, there is a high probability of purchase of a truly quality product. Let the price in them a little more than in various shops and in the markets, but the quality is worth it. Otherwise, you can buy a fake product and very much to regret the saved cash.
Gemini Gold
In nature there are several metals that have the same density as gold. It is uranium, which is radioactive, and tungsten. It is cheaper than yellow metal, but the density of tungsten and gold is almost the same, the difference is three tenths. Differs tungsten from gold that he has a different color, and it is much harder than yellow metal. Pure gold is very soft, it can be easily scratched with a nail.
The fake gold ingot filled with tungsten from the inside.
The fact that the density of the elements such as tungsten and gold is the same, very attracts counterfeiters. They produce the replacement of gold ingots on similar in density and weight tungsten, and from above are covered with a thin layer of precious metal. At the same time, the high cost of yellow metal makes tungsten more popular among young people. Wolframe products are much cheaper and more resistant to scratches.
Lead density
The cleaner gold, the less it is solid, so before the yellow metal for testing was superior. This method is unreliable. The decoration can be made of lead covered with a very thin layer of gold. And the lead also has a soft structure. You can try to scratch the decoration not from the front side, and intact metal can be detected under a very thin layer of precious metal.
The density of the Mendeleev table element - lead and his fellow - gold is different. Lead density is much smaller than gold and is 11.34 grams per centimeter cubic. Thus, if you take yellow metal and lead the same volume, the weight of gold will be much more than lead.
White gold is an alloy of a yellow precious machine with platinum or other metals that give it white, more precisely matte - silver color. There is an opinion that "White Gold" is one of the names of platinum, but it is not. This type of gold is a bit more expensive than usual. In appearance, white metal is similar to silver, which is much cheaper. The density of such elements of the Mendeleev table, like gold and silver is different. How to distinguish white gold from silver? These precious metals have different density.
Silver - the least dense material from all those considered in the article.
The density of gold is greater than the density of silver. Its density is 10.49 grams per centimeter cubic. Silver is much softer white metal. Therefore, if you spend a silver product over a white sheet, then the next will remain. If you do the same with a white precious metal, then there will be no trace.
Definition
Density of substance - This is the ratio of its mass to the volume:
M / V, [g / cm 3, kg / m 3]
The density of the solid is a reference value. Copper density is 9.0 g / cm 3. In elementary state, copper is a metal of red (Fig. 1). Its essential constants are presented in the table below:
Table 1. Physical properties of copper.
Copper is characterized by a significant density, quite high melting point and low hardness. Its tight and hardness is exceptionally large: copper can be pulled out in a wire with a diameter of 0.001 mm (about 50 times thinner of the human hair).
Fig. 1. Copper. Appearance.
Finding copper in nature
According to prevalence in nature, copper stands far behind the corresponding alkali metal. Its content in the earth's crust is estimated by the value of about 0.003% (mass.). Copper is mainly in the form of sulfur compounds and more often with sulfur ores of other metals. From individual copper minerals, chalcopyrite (CUFES 2) and HALKOZIN (CU 2 S) are most important. Oxygen-containing minerals have a much smaller industrial value - buy (Cu 2 O) and Malachite ((Cuoh) 2 CO 3).
Brief description of chemical properties and copper density
Copper forms alloys with many metals. In particular, it is melted with gold, silver and mercury.
Chemical copper activity is small. In the air, it is constantly covered with a dense greenish-gray film of the main carbon dioxide salts. It is connected to oxygen under normal pressure and when heated:
4CU + O 2 \u003d 2CUO;
2CU + O 2 \u003d 2CUO.
Does not react with hydrogen, nitrogen and carbon even at high temperatures.
At normal temperature, copper slowly connects with chlorine halogens, bromine and iodine:
Cu + Cl 2 \u003d CUCL 2;
Cu + Br 2 \u003d CUBR 2.
Copper is a weak reducing agent; Does not react with water and diluted with hydrochloric acid. Translated into a solution with non-oxidant acids or ammonia hydrate in the presence of oxygen or potassium cyanide. Oxisions with concentrated sulfur and nitric acids, "tsarist vodka", chalcoge and non-metal oxides. Reacts when heated with halogen hydrogen.
Examples of solving problems
Example 1.
| The task | Under action on a mixture of copper and iron, a mass of 20 g of an excess of hydrochloric acid was distinguished by 5.6 liters of gas (N.U.). Determine the massive lobes of metals in the mixture. |
| Decision | Copper does not react with hydrochloric acid, because it stands in a row of metal activity after hydrogen, i.e. The release of hydrogen occurs only as a result of the interaction of acid with iron. We write the reaction equation: Fe + 2HCl \u003d FECL 2 + H 2. We will find the amount of hydrogen substance: n (H 2) \u003d V (H 2) / v_m \u003d 5.6 / 22.4 \u003d 0.25 mol. According to the reaction equation: n (H 2) \u003d N (Fe) \u003d 0.25 mol. We find a lot of iron: m (Fe) \u003d n (Fe) × M (Fe) \u003d 0.25 × 56 \u003d 14 g Calculate mass fractions of metals in the mixture: w (Fe) \u003d M (Fe) / m Mixture \u003d 14/20 \u003d 0.7 \u003d 70%. w (Cu) \u003d 100% - w (Fe) \u003d 100 - 70 \u003d 30%. |
| Answer | The mass fraction of iron in the alloy is 70%, copper - 30%. |
The table shows the thermophysical properties of copper depending on the temperature in the range from 50 to 1600 degrees Kelvin.
Copper density is 8933 kg / m 3 (or 8.93 g / cm 3) at room temperature. Copper is almost four times harder and. These metals will float on the surface of liquid copper. The copper density values \u200b\u200bin the table are specified in the dimension kg / m 3.
The dependence of the copper density on its temperature is presented in the table. It should be noted that the density of copper during its heating decreases both in solid metal and in liquid copper. Reducing the density value of this metal is due to its expansion when heated - copper volume increases. It should be noted that liquid copper has a density of about 8000 kg / m 3 At temperatures up to 1300 ° C.
Copper thermal conductivity is 401 W / (m · hail) at room temperature, which is a rather high value that is comparable to.
At 1357k (1084 ° C), copper goes into a liquid state, which is reflected in the table with a sharp drop in the value of the coefficient of thermal conductivity of copper. It's clear that the thermal conductivity of liquid copper is almost two times lower than that of solid metal.
The thermal conductivity of copper during its heating tends to decrease, but at temperatures above 1400 K, the thermal conductivity value starts to increase again.
The table discusses the following thermophysical properties of copper at different temperatures:
- copper density, kg / m 3;
- specific heat, J / (kg · hail);
- teterolution, m 2 / s;
- thermal conductivity of copper, W / (M · K);
- lorentz function;
- the ratio of heat-capacity.
Thermophysical properties of copper: CTR and specific copper heat capacity
Copper has a relatively high heat of melting and boiling: the specific heat of melting of copper 213 kJ / kg; The specific heat of the boiling of copper 4800 kJ / kg.
The table below shows some of the thermophysical properties of copper depending on the temperature in the range from 83 to 1473k. The values \u200b\u200bof copper properties are indicated at normal atmospheric pressure. It should be noted that the specific heat capacity of the copper is 381 J / (kg · hail) At room temperature, and the thermal conductivity of the copper is 395 W / (m · hail) at a temperature of 20 ° C.
From the values \u200b\u200bof the coefficient of temperature expansion and heat capacity of copper in the table, it can be seen that the heating of this metal leads to an increase in these values. For example, copper heat capacity at a temperature of 900 ° C becomes equal to 482 J / (kg · hail).
The table is given the following thermophysical properties of copper:
- copper density, kg / m 3;
- specific heat capacity of copper, kJ / (kg · k);
- coefficient of thermal conductivity of copper, W / (m · hail);
- specific electrical resistance, Ohm · m;
- linear thermal expansion coefficient (CTR), 1 / hail.
Sources:
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