What is the density of gold

What is the density of gold and its alloys?

There is more than one mineral in nature that resembles aurum. Like all precious metals, gold has its own density. In order to determine the value of the yellow metal, you should know what the density of gold and alloys with it is.

What is the density of gold

Features of gold density measurement

Jewelry made of gold (earrings, rings, chains, etc.) do not weigh much, so specific gravity is not particularly important. And if you pick up a gold bar weighing about one kilogram, you can immediately feel its heaviness. The density of gold is measured in kg m3.

The density of the precious metal is 18-19 g per 1 cm3. Moreover, the density of the unrefined mineral will be slightly lower. The weight of a given volume of yellow metal weighs 20 times more than the same volume of water. The density of gold alloys is not so high and has a sample size of 583. They contain several types of metals.

What is the density of gold

If you wish, you can find out the density of a given metal yourself without outside help. First you should find out the weight of the product. Fill a special container with volume marks with water and place the decoration in it.

We see that the volume of water has increased. Now, using a formula that has been known since school (divide mass by volume), we find out the density of the product. You need to know that such precious jewelry does not contain pure gold. In this case, some correction is made for the density of the alloy.

 The difference between gold and fake

Today, in the age of great technological discoveries, all markets in the world are overflowing with goods made from counterfeit gold. There is a risk of buying jewelry that contains only 5% gold. But it happens that such a product is only an imitation of precious metal. Therefore, it is very important to know some rules when buying gold jewelry.

• The product you like needs to be inspected. Pay special attention to the sample, which must match the sample;
• The inside must be of high quality, just like the outside. You can also recognize real gold using density, but not in a store.

It is worth noting that there are many ways to determine the quality of precious metal jewelry, but they all require conditions. So, to use the strength test method, you need to scratch the product, which you won’t do in the store. Also, you will not apply chemical elements in front of the seller. For example, a drop of iodine on a piece of jewelry made of high-quality yellow metal will have a dark color.

Twins

The density of gold can be similar to some metals found in nature. These brothers are uranium and tungsten; the ρ of tungsten differs from gold by only three tenths of a unit. Despite this, tungsten is cheaper than the yellow metal. This feature of the element makes it more common among young fashionistas.

White gold is the result of combining pure yellow metal with certain metals, giving it a silvery color. The cost of jewelry made from this alloy is slightly higher. White gold generally resembles silver, which does not have a high price.

Gold alloys

Using pure gold in jewelry does not make sense, since the jewelry will have high prices. In addition, such products do not have good strength, as a result of which their wear resistance is significantly reduced. To improve characteristics, alloys of precious metals are created in certain proportions. In some cases, alloys also include base metals.

Thanks to this method (alloying), the resulting precious metals acquire properties such as strength, etc. Modern technologies make it possible to invent many new alloys.

Most alloys are found in the element gold. They may contain various metals. Moreover, each element brings certain properties.

So, silver adds more softness to this type of metal, changes in color, etc. A gold alloy with the addition of silver acquires a yellow-green color. Moreover, the higher the percentage of silver, the lighter the alloy. If the silver content in the alloy is more than 50%, then it becomes white.

Source: http://luxediamond.ru/plotnost-zolota-splavov

Density of gold: table from 333 to 99 samples, specific gravity and properties, influence of temperature | mk-soyuz.rf

Hello, dear gold lovers! Many people admire its pleasant shine, although not everyone knows that it is due to the structure of its energy levels and the highest number of electrons among metals.

Every woman wants to feel the pleasant weight of a massive precious necklace on her neck, not realizing that the reason for the large weight of gold jewelry is the high density of gold.

Read this article - and you can easily figure out what this value means and what practical significance it has.

This is a physical quantity determined by the ratio of body mass to the volume it occupies. It is usually measured in kg/m3. Accordingly, the more the same volume of metal weighs, the greater its density.

Thus, a metal cube made of lithium with half-meter edges will weigh only 66.25 kg, and the same cube smelted from gold will be unliftable - its weight will be almost two and a half tons.

Properties and composition of gold

It was the properties of gold that determined this metal to be noble. The main chemical property of a precious metal for us is its inertness - in our usual environment, it remains unchanged for thousands of years, without oxidizing or losing its appearance.

Basic physical properties of Au:

• softness,
• ductility,
• plastic,
• low resistance,
• high thermal conductivity,
• high density.

These qualities are what made the yellow metal so valuable.

The composition of 999.9 fine gold is pure Aurum, its density is 19.30 grams per cubic centimeter or 19,300 kg per m³.

It is known that, due to its softness and high specific gravity, products made from high-grade gold are impractical, so jewelers use the precious metal in their products only in an alloy with others - to give strength or a different shade. Thus, the traditional 585 standard contains, in addition to gold, copper and silver.

Density of gold depending on the sample

In terms of density, the yellow metal is surpassed only by platinum. All other metals in the alloy reduce the overall density of the product.

This table clearly shows the correlation between density and ligature.

Try	Color	Compound	Density g/m³
750	Yellow	Au, Ag, copper Au, AgAu, Ag, palladiumAu, Ag, nickel, zinc	15,45 15,9616,4415,38
Green
White
White
585	Red	Au, Ag, copper Au, Ag, copperAu, Ag, copperAu, Ag, palladiumAu, Ag, nickel, zinc, copper	13,24 13,6013,9214,7412,85
Yellow
Green
White
White
375	Red	Au, Ag, copper	11,54
375	Pink	Au, Ag, palladium, copper	11,56

How does temperature affect density?

It is interesting that the indicated values ​​are typical only for normal environmental conditions and a temperature of 20 ° C. The higher the temperature, the lower the density, and vice versa. This dependence is typical for most substances, except water, whose density is maximum at +4, and decreases with decreasing temperature.

Understanding the essence of density as a physical quantity will help us distinguish real gold from counterfeit gold. I'll tell you how to do this.

Au has virtually the highest density of any precious metal other than platinum, meaning that almost any gold item will weigh more than a gram.

The easiest way is to weigh the jewelry. The method is suitable for small openwork decorations.

Massive rings and chains, bracelets and earrings are checked based on the ratio of mass to volume.

We will need:

• precise scales with divisions down to a hundredth of a gram,
• beaker with volume graduation. The narrower it is, the higher the accuracy of the determined value. It can be purchased at chemical stores and sometimes in pharmacies.

For clarity, I will try to determine the authenticity (maybe the purity) of my rose gold bracelet:

1. I weigh the bracelet on the scales. It weighs 4.62 grams.
2. I pour water into a beaker and put the bracelet in it. The water should completely cover the decoration. The bracelet displaced 0.4 centimeters of cubic water. That is, I have a beaker with a CD of 0.1 cm3, the water level has risen by 4 divisions.
3. I make the calculation: 4.62/0.4=11.55.
4. I compare the obtained value with the table of metal densities and the table of Au density (depending on the sample).

Palladium is close to the obtained values ​​- 12.2, lead - 11.34, silver - 10.49. But my bracelet is a nice shade of pink, which means it most likely contains gold and copper. From the table we see that the density of my bracelet corresponds to 375 samples - the average value of gold, silver, palladium and copper.

The amount of pure element in the alloy is determined using the molar mass of gold using the formula M = m/n. The molar mass of Au is 196.9665 g/mol.

In my bracelet weighing 4.62 g and 375 samples, there is 4.63 * 0.375 = 1.74 g of gold, 1.74 g / 196.9665 g / mol = 0.001 mol of pure gold.

Gemini of gold

It happens that unscrupulous jewelers, knowing that the density of the yellow metal or its alloys is close in value to base metals, use this value for criminal purposes. Thus, lead with gold plating can easily pass for 375 standard, and tungsten, which has a molar mass close to platinum group metals, is often passed off by jewelers as precious metals.

Conclusion

Source: https://xn----ntbhhmr6g.xn--p1ai/dragmetallyi/plotnost-zolota-v-zavisimosti-ot-probyi-tablitsa-kak-proverit-podlinnost

Everything about the density of gold

All substances in nature differ in such physical components as density. Density is understood as a value that is found by dividing the mass of a given body by the volume it occupies. This value is denoted by the Latin letter p. SI units of measurement are kg/m*3, GHS are grams per cubic centimeter. Density as a quantity is also denoted by the letters D and d - from the Latin “denstas” - density.

Gold bars

The average density coefficient of a body represents the basic concept of density, because the average value is taken. It is important when the measurement object is heterogeneous. The density of gold is 19.3 g/mol.

If a substance consists of different substances, then a quantity is determined as the density of the body at a point. This is a more scrupulous measurement that requires detailing the object.

Gold density and molar mass are two quite important characteristics.

Chain selection

For different bodies, different criteria and methods for determining average density are used. M is the molar mass of the gas, Vm is the molar volume (approximately 22.4 l/mol).

The densities of gold and silver differ from each other.

Density of gold

Gold is a ductile, soft, yellow metal. It has increased thermal conductivity and low electrical resistance.

The metal, despite its softness, has a very high density. The density of pure gold is 19.32 g/cm*3. This property of gold is used in its mining. It is washed out of the rock with a stream of water.

Highest quality gold

The lighter components are washed out, and grains of gold remain at the bottom.

• Pure gold is practically never used in jewelry. Firstly, it is very heavy; the weight of the jewelry will be uncomfortable to wear.
• Secondly, the metal is very expensive, so the product will also be very expensive in cost.
• Pure metal is very soft and ductile, the product can be deformed.

Jewelry

To make jewelry, gold is alloyed with other metals. This gives the product hardness and a brighter shade. Metals are mixed in certain proportions. The term sample is used to denote the composition. Fineness is the gold content in the alloy; 900 fineness is especially valued.

For example, 585 standard means that if you take 1000 grams, then there is 585 grams of gold, the rest is other metals, 415 grams.

585 gold

The first place in purity and nobility is occupied by the red one. It contains up to 90% gold. This is 900 sample.

Gold Density and Molar Mass

In Russia, samples of 375, 500, 583, 585, 750 and 958 are used for gold jewelry.

In Europe, the USA and other countries of the world, the karat system for measuring pure gold has been adopted. 24 carats is the highest standard of gold, called British gold carat.

To standardize various quantities and their designations, a single system was adopted - SI, which is now mandatory throughout the world.

Under the metric system, the proportion of gold is defined as a percentage or quantity relative to the total mass. For 1000g of alloy there are 750 grams of gold and 250 grams of other metals. This amounts to 75%.

There is a specific table for converting to carats, shown in the photo.

375 standard is an alloy of silver and copper and 38% gold. Color from yellow to red. The product may fade when exposed to air.

585 standard - contains up to 59% pure gold and metals such as silver, copper, nickel and palladium. The alloy is hard and durable. Nickel imparts resistance to aggressive factors and hardness. Products do not fade in air.

750 standard - the composition is almost the same, but the gold content is 75%. Color ranges from bright yellow to red. It lends itself perfectly to forging, the composition is very durable.

It is worth noting that the jewelry industry uses exactly the above options.

Higher standards are not used for jewelry. Because the metallic substance is soft and dull in color. It is poured in an ingot-shaped form.

In our country, the production of gold products is regulated by a certain law. All products must be sealed and have a Russian stamp. There is a special assay supervision.

In addition to the imprint on the ring, there is also an imprint of the person named who made the jewelry.

All these measures are needed to control the circulation of gold, because this metal has been highly valued since ancient times. It has not lost its significance to this day. Each country has its own reserve of this metal for conversion. The high cost is due to the fact that the content of this metal in the earth’s crust is quite low. Gold deposits on an industrial scale are relatively rare. Most often it is mined from placers.

One of the main mining methods is washing and beneficiation of ore using chemical interaction with other substances, in particular with mercury or arsenic compounds. This poses a great risk to the health of miners and gold mining workers.

A frequently occurring native form with a greenish tint. Basically, all reserves of mined gold are distributed in a similar way.

The bulk of gold is in the vaults of the Central State Banks of the countries. The leaders in gold production are China, Australia and Russia.

Source: http://zolotoigid.ru/plotnost-zolota

What is the density of gold?

There is no such person who has not seen yellow metal in his entire life. There are several minerals found in nature that are similar in appearance to the yellow metal. But as they say: “all that glitters is not gold.” In order not to confuse the precious metal with other materials, you need to know the density of gold.

Density of noble metal

Molecular structure of gold.

One of the important characteristics of a precious metal is its density. The density of gold is measured in kg m3.

Specific gravity is a very significant characteristic for gold. This is usually not taken into account, since jewelry: rings, earrings, pendants have very little weight. But if you hold a kilogram ingot of real yellow metal in your hands, you can see that it is very heavy. The significant density of gold makes it easier to mine. Thus, washing at sluices ensures a high level of gold recovery from washed rocks.

The density of gold is 19.3 grams per cubic centimeter.

This means that if you take a certain volume of precious metal, it will weigh almost 20 times more than the same volume of plain water. A two-liter plastic bottle of golden sand weighs about 32 kg. From 500 grams of precious metal you can lay out a cube with a side of 18.85 mm.

Table of density of gold of various samples and colors.

The density of the original gold is several units lower than that of the already purified metal and can vary from 18 to 18.5 grams per cubic centimeter.

583 gold is less dense, as this alloy consists of different metals.

At home, you can determine the density of gold yourself. To do this, you need to weigh the precious metal product on ordinary scales, in which the division value must be at least 1 gram. After this, a container with a volume marking must be filled with liquid, in this case water, into which the decoration should be lowered. Care must be taken to ensure that the liquid does not overflow.

After this, we measure how much the volume of liquid has changed after lowering the gold item into the container. Using a special formula, known from school, we calculate density: mass divided by volume.

It must be remembered that a precious metal product is not made of pure gold, so it is necessary to make an adjustment for the density of the alloy sample.

How to distinguish real yellow metal from a fake

At the moment, there is a very large percentage of counterfeit gold on both the Russian and foreign markets. There is a huge risk of purchasing gold jewelry containing up to 5% of the precious metal or without it at all. Basic rules when buying gold will help you avoid feeling deceived.

First, you should take a good look at the product. There must be a sample on it. Moreover, it should not consist of crooked numbers or blurry marks. Otherwise, this is the first sign of a counterfeit.

A sample of a unified state hallmark for gold products.

The next sign of a fake is the reverse side of the precious metal jewelry. It must be as well executed as the front side, otherwise it is a low-quality product. It is also possible to determine the quality of a product using a characteristic such as gold density, but it is impossible to conduct such an experiment in a store.

There is also a way to determine it, called a strength test. True, it is not always possible to scratch a gold item in front of the seller, so this method cannot be implemented.

The following chemical methods can serve as good ways to determine the quality of a product. You can drop a little iodine on the yellow metal jewelry. If the speck is dark in color, then we can speak with confidence about the quality of the product being offered. Table vinegar can also help. If, after three minutes spent in it, the precious metal has darkened, then you can safely take the product to a landfill.

Gold chloride can be a great help in determining quality. From the chemistry course, it became known not only the density of gold, but also the fact that it cannot enter into any chemical reactions. Therefore, if after applying gold chloride to a precious metal it begins to deteriorate, then this is a real fake and should belong in the trash.

One of the best ways to protect yourself from purchasing counterfeit goods is to purchase precious metal products in well-known specialized stores.

In this case, there is a high probability of purchasing a truly high-quality product. Even though their price is a little higher than in various shops and markets, the quality is worth it. Otherwise, you can purchase a counterfeit product and very much regret the money saved.

Lead Density

The purer the gold, the less hard it is, so in the past the yellow metal was bitten to test. This method is unreliable. The jewelry can be made of lead, covered with a very thin layer of gold. Lead also has a soft structure. You can try to scratch the jewelry from the wrong side, and underneath a very thin layer of precious metal you may find base metal.

The density of the element of the periodic table - lead and its brother - gold is different. The density of lead is much less than gold and is 11.34 grams per cubic centimeter. Thus, if we take the yellow metal and lead of the same volume, then the mass of gold will be much greater than that of lead.

White gold is an alloy of yellow precious metal with platinum or other metals that give it a white, or rather matte silver, color. There is an opinion in everyday life that “white gold” is one of the names for platinum, but this is not so.

This type of gold costs a little more than usual. In appearance, the white metal is similar to silver, which is much cheaper. The density of such elements of the periodic table as gold and silver is different.

How to distinguish white gold from silver? These precious metals have different densities.

Silver is the least dense material of all those discussed in the article.

The density of gold is greater than that of silver. Its density is 10.49 grams per cubic centimeter. Silver is much softer than white metal. Therefore, if you run a silver item across a white sheet, a mark will remain. If you do the same with white precious metal, there will be no trace.

Source: http://golden-inform.ru/prochee/plotnost-zolota/

Density of gold: determination of purity based on density

The density of gold is one of the unique physical characteristics of this metal. Because it is soft, for practical use other metals are added to it to improve its manufacturability.

In jewelry, as we know, alloys of precious metals are used in different proportions. pure noble metal in an alloy is measured in thousandths: the 585th standard is an alloy with a pure gold content of 585 parts out of 1000. The corresponding indicator is stamped on the product. Accordingly, with the addition of other metals, the density of gold, that is, its alloy, changes. Based on this indicator, in places where gold products are received, their authenticity and compliance with the declared sample are determined.

Characteristics of gold

Precious gold is a heavy metal. Its pure density is 19,621 kg/m³. To perceive a dry fact as clearly as possible, imagine a small ball of pure metal with a diameter of 46 mm. Its mass will be 1 kilogram.

The high density of gold is also used in its mining: it is thanks to it that nuggets and sand can be sifted out from rocks by washing.

The density of gold in its pure form (that which is considered to be 999.99 fineness) is 19.3 g/cm3. Native, it has a slightly lower density: 18-18.5 g/cm3. This indicator is different in alloys of different samples. We will talk about them further.

Density of gold alloys

As we know from school courses, the density of a material is a physical property defined as the mass of a given unit of volume. It is measured through the ratio of body weight and its size.

To obtain alloys suitable for use in jewelry production, gold is mixed with copper, silver, nickel, platinum, palladium and other metals, both noble and not. Let's move on to data on the density of gold alloys of different grades.

The most popular, affordable and perfect for working with it is 585 standard. The density of 585 gold is 12.5-14 g/cm3. The same framework is determined by the 583rd sample (Soviet sample).

For coin samples, 900th and 917th, the figures are, respectively, 17.10-17.24 g/cm3 and 17.34-17.83 g/cm3.

Also commonly found in jewelry, the 750th sample has a density of 14.5-17.5 g/cm3.

The density of low-grade gold, 375 standard, is 11.54-11.56 g/cm3.

And finally, let's remember another noble metal - silver. It is significantly lighter than gold, and the density of silver alloys is also lower.

Thus, the density of the most common 925 alloy in products is 10.36 g/cm3. The second most used, 875th sample, is 10.28 g/cm3.

The density of gold and silver is an important indicator that helps determine the content of pure noble metal in an alloy using various methods. We will talk about one of them, accessible, further.

Hydrostatic method: determining a sample of a precious alloy

Institutions specializing in receiving gold products use many different methods to determine and confirm the sample of brought gold. Based on the knowledge that gold is a heavy metal with high density, the hydrostatic method was introduced.

It is based on determining the difference in weight when measuring parameters in the open air, under normal conditions, and in a liquid with a certainly known density.

Let’s make a reservation right away: this method of testing gold is only suitable for complete products, without stones or other inserts made from other materials. It is also impossible to obtain adequate data on hollow products consisting of many moving parts.

To carry out hydrostatic weighing of a gold item, you will need a jewelry scale, a measuring cup (or any other transparent one), fishing line or thin thread. Distilled water is usually used as a liquid of known density.

First, the gold product is weighed using the usual method, and the data is recorded. Then a glass of water filled more than half is placed on the scales, the scale readings are reset to zero (the scales must have a function for resetting the tare weight).

Our gold product, suspended on a fishing line, is completely lowered into the water, without touching the bottom and walls of the glass. The scale data is also recorded.

For density analysis, it is better to use a hydrostatic calculator, since manual calculations will take much longer and are not as accurate.

conclusions

So, in our article we looked at the density of gold - a precious metal that each of us has encountered in life and will still encounter. The data presented can be summarized as follows: the density of the most popular gold standard, 585, is 12.5-14 g/cm3, for other alloys it is lower or higher, respectively.

https://www.youtube.com/watch?v=UIipYThCQ-k

Based on the density of the gold alloy, the sample can be determined, which is an indicator of the pure gold content in the alloy. These methods are used in institutions that accept gold.

We hope our article was informative and gave you a few exciting minutes. Let there be only real high-grade gold in your box!

Source: https://autogear.ru/article/184/552/plotnost-zolota-opredelenie-probyi-na-osnove-plotnosti/

Gold

 

Gold

Gold is a mineral that is a natural solid solution of silver (traces, up to 43%) in gold; impurities (traces, up to 0.9%) of copper, iron, lead, less often - bismuth, mercury, platinum, manganese, etc. are known. Varieties with a high copper content are known - up to 20% (cuprous gold, cuproaurite), bismuth - up to 4 % (bismuth gold, bismuthaurite), platinoids (platinum and iridite gold; porpecite - Au, Pd, rodite - Au, Rh), natural amalgams (Au, Hg).

STRUCTURE

Crystal structure of gold

Crystallizes in the cubic system, in the form of octahedra, rhombic dodecahedrons, cubes and more complex crystals; Often they are distorted, strongly elongated, forming “wires”, “hairs”, or flattened parallel to the edge of the octahedron.

Native gold, especially low-grade gold, is characterized by a variety of growth forms; it is usually in the form of skeletal crystals, dendrites, thread-like and twisted-filamentary crystals.

Streak-like and irregular lump-like, “hooked” discharges are widespread; Their surfaces often contain imprints of crystals of other minerals, the aggregates of which included accumulations of native gold. Etching reveals the crystalline granular structure of the gold particles.

PROPERTIES

Gold bars and nuggets

Gold is a very heavy metal: the density of pure gold is 19.32 g/cm³ (a ball of pure gold with a diameter of 46.237 mm has a mass of 1 kg). Diamagnetic, that is, the magnetic field in gold weakens. Among metals, it ranks seventh in density after osmium, iridium, rhenium, platinum, neptunium and plutonium.

Tungsten has a density comparable to gold (19.25). The high density of gold makes it easier to extract, which is why even simple technological processes - for example, washing at sluices - can provide a high degree of gold recovery from the washed rock.

Gold is a very soft metal: hardness on the Mohs scale is ~2.5, on the Brinell scale 220-250 MPa (comparable to the hardness of a fingernail).

Gold is also highly ductile: it can be forged into sheets up to ~0.1 µm (100 nm) thick (gold leaf); With such a thickness, gold is translucent and in reflected light has a yellow color, in transmitted light it is colored bluish-greenish, complementary to yellow. Gold can be drawn into wire with a linear density of up to 2 mg/m.

The melting point of gold is 1064.18 °C (1337.33 K), boils at 2856 °C (3129 K). The density of liquid gold is less than solid gold and is 17 g/cm3 at the melting point. Liquid gold is quite volatile and actively evaporates long before its boiling point.

Source: http://mineralpro.ru/minerals/gold/

Gold Density (Au), Meaning and Examples

Gold is an excellent conductor of heat and electric current, second only to silver and copper in this regard.

Rice. 1. Gold. Appearance.

Pure gold is characterized by high softness, malleability, ductility, high thermal and electrical conductivity, but the presence of impurities negatively affects these properties.

Molten gold can dissolve significant amounts of oxygen, which is released when metals solidify, often causing them to spatter.

The main constants of gold are given in the table below.

Table 1. Physical properties and density of gold.

Density, g/cm3	19,32
Melting point, oС	1064
Boiling point, oС	2808

Gold forms colloidal solutions that are very stable and can last for decades. The color of colloidal gold solutions, depending on the size of the particles, can be green, yellow, red, blue, purple and even black. Colloidal gold particles impart a red color to glass (ruby glasses).

Finding gold in nature

Gold occurs in nature almost exclusively in the native state, mainly in the form of small grains embedded in quartz or contained in quartz sand. Gold is found in small quantities in sulfide ores of iron, lead and copper. Traces of it have been discovered in sea water. The total gold content in the earth's crust is only 5×10-7% (mass.).

Brief description of the chemical properties and density of gold

Gold is located in the stress series to the right of hydrogen and does not displace hydrogen from water and non-oxidizing acids.

Gold can be called the most “noble” metal. It is resistant to the action of nitric and sulfuric acids, but interacts with aqua regia, selenic acid, a mixture of hydrochloric acid and sodium hypochlorite:

Au + HNO3 + 4HCl = H[AuCl4] + NO + 2H2O.

Unlike copper, gold does not react with aqueous ammonia and hydrohalic acids. The reaction with cyanide occurs only in the presence of an oxidizing agent - hydrogen peroxide or oxygen:

4Au + 8NaCN + 2H2O + O2 = 4Na[Au(CN)2] + 4NaOH.

When heated, gold even reacts with polysulfides and thiosulfates of alkali metals to form thiosalts, with a solution of ferric chloride.

Preparatively, gold is transferred into solution either by interaction with aqua regia or by oxidation with chlorine in concentrated hydrochloric acid:

2Au + 2HCl + 3Cl2 = 2H[AuCl4].

Gold does not interact with alkalis. This metal does not react with oxygen even at high temperatures, but in the form of thin films it can be oxidized by oxygen plasma or ozone when irradiated with ultraviolet light.

Halogenation leads to the formation of gold(III) compounds: bromine reacts most energetically with it - the reaction occurs already at room temperature and is accompanied by heating of the mixture. Gold does not react directly with hydrogen, nitrogen and carbon even when heated. Hydrides, nitrides and carbides are obtained indirectly.

Examples of problem solving

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Properties, characteristics and samples of gold

For several millennia, gold has been considered a precious metal. But not only because it looks beautiful and is difficult to obtain, but also due to certain physical properties. In the laboratories where this metal was studied, it was determined that the density of gold, its thermal conductivity and ductility are properties that most elements do not possess.

Gold structure

Physical and chemical properties of gold

Of course, investors are mainly interested in gold prices. But there are also those who want to unravel the secret of the value of the metal. It was they who noticed the significant differences between gold and other metals. Gold is a yellow metal with a soft consistency. These characteristics apply only to the pure element, and not to samples in alloys where there are impurities of ore or other metals. 999 gold is easily deformed, scratches from fingernails, and can also be cut with a knife.

Metal has high thermal conductivity and low resistance. This means that gold is a good conductor of current and heat. But in practice, the precious metal is too expensive to be used on an industrial scale. Unless gold is found in old microcircuits and resistors and subjected to refining. This is painstaking work, since there is little precious metal in these parts, and it is not so easy to obtain it at home. Even SIM cards contain a metallic substance with a grain of gold added.

The malleability and malleability of the precious metal makes it possible for people to make gold leaf. These are special thin sheets, up to 100 nm thick, with which gold is applied to objects. Moreover, the sheets also have strength and all other properties inherent in gold.

It’s hard to believe, but from one gram of pure gold you can make the thinnest wire three kilometers long without breaking. The ability of metal to reflect light is also valued; jewelers most often use this to make jewelry that shimmers and sparkles in the light.

If we talk about the density of the metal, it is one of the highest among all elements of the periodic table. Only platinum was ahead of gold. The density of the precious metal is 19.3 g/cm² (for platinum it is 21.45 g/cm²). These facts mean the following:

• if you take the same volumes of gold and water, the precious metal will weigh 19.3 times more;
• the weight of a liter bottle of gold is about 16 kilograms;
• half a glass of gold will weigh 1 kilogram.

Density of gold

It is this factor that greatly simplifies gold mining. High density makes it easier to find and filter metal. Since gold can accumulate on river banks and float downstream, special sluices are used to trap metal particles and then lift them to the surface. This method is called gold panning. It is performed several times, which allows the metal to be concentrated and deposited to the bottom.

Mining, as the simplest mining method based on the density of gold, was popular during the gold rush and the search for gold in the Klondike. And even now, in places where this metal is mined, especially where equipment is not provided or searches are not carried out on an industrial scale, local residents search for metal in this way.

This procedure has become so popular for ordinary people that many people want to try this method of finding precious metals. Today, special tours of amateur gold mining are organized. There, everyone can try sanding and even exchange their finds for small money.

If we compare the density of silver and gold, then the first metal has an indicator of 10.5 g/cm². Tungsten is even closer to gold in density than silver. But tungsten is more often used in industry, and its extraction is not so difficult, so its value is lower than precious metals. The remaining elements of the periodic table lag far behind the platinum group and gold.

The density of gold nuggets is significantly lower than the highest 999 standard. This is because large gold bars are formed through the processes of leaching and mineralization. This means that the nuggets contain more impurities. The latter, as well as minerals, are eliminated using chemical processes with the addition of aqua regia and subsequent precipitation.

Density of different grades of gold

Relationship between density and fineness of gold

The density of the 999 sample is closest to the number 19.3 g/cm². Therefore, if you do not know the sample of your product, you can determine it by density. This method will differ from the chemical one and using a jeweler. But nevertheless, it can be done even at home.

So, since all other metals are less dense, their impurities in gold make the final alloy less dense. If you have 585 red gold, it means that copper has been added to it, and the density of the product has decreased. Impurities from nickel and zinc will also reduce this indicator. Only palladium and platinum will increase the density of the ring.

Therefore, to determine a sample using density at home, you need to take a test tube or beaker. Next, measure the water levels before and after lowering the gold jewelry into the test tube. Weighing in water is an old method that was used even before the revolution. It gives a measurement error of approximately 20–30%.

The chemical properties of gold are an important indicator that influences the cost and indicates that the precious metal was not in vain chosen as luxurious and expensive. Perhaps these properties will be used more often in the future. But at the moment they are used only in a few areas of life.

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Source: https://DedPodaril.com/zoloto/imform/plotnost-zolota.html

Density of gold: table from 333 to 99 samples, specific gravity and properties, influence of temperature

Hello, dear gold lovers! Many people admire its pleasant shine, although not everyone knows that it is due to the structure of its energy levels and the highest number of electrons among metals.

Every woman wants to feel the pleasant weight of a massive precious necklace on her neck, not realizing that the reason for the large weight of gold jewelry is the high density of gold.

Read this article - and you can easily figure out what this value means and what practical significance it has.

What is metal density

This is a physical quantity determined by the ratio of body mass to the volume it occupies. It is usually measured in kg/m3. Accordingly, the more the same volume of metal weighs, the greater its density.

Thus, a metal cube made of lithium with half-meter edges will weigh only 66.25 kg, and the same cube smelted from gold will be unliftable - its weight will be almost two and a half tons.

585 gold: compositions of alloys with various metals, their density, application features

This metal has been familiar to people since time immemorial. And for almost as many years it has been a symbol of power, wealth and power. Coins were minted from it and amulets were made, and skilled craftsmen created unique crowns, tiaras, rings, earrings and bracelets. However, ancient jewelry was massive due to the nature of the soft and fragile material. Modern jewelers most often use ductile 585 gold.

Characteristics of the precious metal

It is hardly worth stating categorically that modern jewelry is entirely made of the noble solar metal, which ranks eleventh in the periodic table. This means that earrings, watches and rings are made from gold-containing alloys that are more suitable for jewelry production.

The attractive design of the work and the pleasant shine of the products on display are not a complete list of arguments for purchasing the same ring or pendant. To understand what quality of jewelry the seller offers, it’s worth remembering what 585 hallmark gold looks like in accordance with the state standard of the Russian Federation :

• a letter designating the specific State Assay Supervision Inspectorate that issued the mark;
• a girl's head in a kokoshnik, looking to the right;
• three numbers indicating how many parts out of a thousand are Aurum in a particular alloy - in fact, the sample itself.

Another information can be obtained by carefully examining the product. As a rule, the manufacturer's name mark is found nearby. It is customary to mark products in many countries with symbols that allow one to understand the value of the purchased item.

Physical properties

In Russia, the percentage composition of 585 gold looks like this: the main component is 58.3% Au and the alloy is 8% Ag and 33.5% Cu. This allows the soft precious metal alloy to become harder and makes products made from it wear-resistant.

The share of the main noble component in alloys with the same digital combination on the stamp is also 585 parts by weight, even if the composition was manufactured in other countries. But the ligature may well be different. Therefore, we can definitely speak only about the content of the base substance in the 585 sample product.

The density of such gold ranges from 12.85 g/cm3 to 14.76 g/cm3 . The indicator how much heavier an ingot of this alloy is than the same volume of water directly depends on the characteristics of the added metals. The specific gravity of 585 gold is almost equal to the density indicator and is inextricably linked with it.

Adding new qualities

It is not known for certain when craftsmen first discovered that various metals could affect the properties of gold alloys. However, this discovery made it possible to create surprisingly thin and elegant products, while the thing was quite durable. Some additives allow the resulting alloys to be used in medicine and industry.

The alloy (the so-called addition to gold) can use one metal or a combination of two or three. Each of the components gives the alloy certain qualities :

• a content of 8 percent or more platinum will make the alloy elastic;
• the addition of palladium will provide plasticity;
• silver improves malleability;
• the copper alloy will add hardness while maintaining ductility, but at high concentrations (14% or more) the alloy can oxidize;
• the presence of zinc will increase fluidity;
• the alloy with nickel acquires greater hardness;
• aluminum gives the alloy anti-corrosion properties;
• cadmium, like zinc, lowers the melting point.

Color palette

The natural color of gold is bright, sunny yellow, but various alloys can make their own adjustments and give the alloys amazing shades. Jewelers use this property to create original products and do not refuse the opportunity to add less valuable metals with desirable qualities to noble metals.

Bright colors up to red are provided by the presence of copper. The silver additive, depending on the percentage, will give rise to a greenish tint at low doses or white-yellow if the argentum is about a third of the mass of the alloy. Chromium and cadmium alloy will color the alloy black. Such a product must be coated with a rhodium layer.

The use of noble platinum helps create the so-called white gold. The aristocratic and elegant trend has remained at the peak of popularity among jewelry lovers for several years now. But since the resulting alloy is very expensive, the jewelry industry often uses cheaper alloys :

1. The white tint of a gold alloy appears when it contains at least 10% palladium.
2. A greenish color may indicate the presence of zinc additives.
3. A pale yellow color can be achieved by adding nickel to the composition, but it is worth considering that this metal can cause magnetic and allergenic properties. Undesirable features of the influence of ligatures on humans are neutralized by a special coating of the product, which will have to be renewed.

Domestic traditions and modernity

In Russia, red gold has always been valued - the purest. Today, products made from a material with the same name can be either 18 carats (750 standard) or 22 carats.

Traditionally, copper is used . Thanks to its presence, red tones appear, the intensity of which depends on the percentage of this particular additive.

However, the 583 sample has become most widespread since Soviet times, and only in 1994 the transition to the international standard was made - 585 sample. This means that the alloy now contains 58.5% precious metal, 0.2% more.

Alloys and their features in different countries

Different countries formed their own jewelry traditions; different metals were included in the ligature, which is why the density and specific gravity of the alloys were different.

Even externally the products differed in color:

1. Arab craftsmen make jewelry from raw materials of at least 750 standard. Due to the low content of added metals and high gold content, the products have a characteristic yellow color.
2. In Italy, jewelers use gold alloys containing silver for their work. Thanks to this metal, a very specific cold shade of yellow is achieved, which connoisseurs and connoisseurs consider aristocratic and noble.
3. For Europeans and Americans, yellow gold is traditional. This is what wedding rings are usually made from. Moreover, in America, many products have only 9 carats, which corresponds to 375 fineness.

A little about investments

You can often hear the statement that when buying jewelry, a person is making a profitable investment, because gold practically does not depreciate. This is not entirely true. Indeed, antique unique items by famous masters can be very expensive, and auctions confirm this: collectors are willing to pay a lot of money for antiques.

However, they are not interested in ordinary “jewelry,” and in a pawnshop they will not offer the amount for which they were purchased for a beautiful ring or brooch that belonged to their mother. Moreover, they will only value gold, and even then as scrap. But considering that there are not so many antiques, what option remains?

Experienced experts advise: if you really want to invest money in precious metals, it is better to buy bank gold bars of 999 purity.

They are soft and require special storage conditions. Aurum in them is almost perfectly pure, its content is 99.9%. This is the highest grade in the metric system, but is rarely used for jewelry.

Source: https://zolotogid.ru/metally/zoloto-585-proby/

What is the density of gold and its properties

Gold is a precious metal that is one of the most attractive for investors from an economic point of view. For a long time, the most important questions remain: where can you buy it cheaper and then sell it at a higher price?

However, few investors are interested in issues that relate to the nature of gold, and it is the density of gold that is one of the most important factors determining its value; it is one of the highest.

Not all people whose activities are connected with this metal know about its composition and thermal conductivity, but exact numbers in this regard are very important.

Undoubtedly, most investors today are a priori concerned about the quotes of 585 gold and 999 gold, but it is interesting why this precious metal has been “eternal value” for many centuries; it is the measure of the wealth of not only individuals, but also entire countries. Its uniqueness lies in the fact that it has unique physical properties, its composition is truly unique, and this is what allowed it to become known throughout the world. Such products have been among the most sought after in the world for centuries.

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Natural qualities and composition

If we take into account pure gold, which has no impurities, then it is a metal of increased softness, with a characteristic yellow color.

 Softness can be determined on a ten-point Mohs scale; according to this scale, the hardest is diamond, the hardness of which is measured at 10 points (as you know, diamond can be used to cut glass). If we compare it with gold, then its density on the Mohs scale is 2.5 - 3 points.

Speaking about the density of 585 gold, suffice it to say that it can be scratched simply by running a fingernail over it, and if you apply some effort, it can be cut without much difficulty with a knife.

Comparative table of densities of metals mined in nature

Thermal conductivity is high, resistance is low. It should be noted its special malleability, as well as its ductility. It is the ductility that distinguishes gold leaf, the sheets of which are unusually thin; the composition of such a material is truly unique.

It is noteworthy that in order to stretch a wire 3 km long, only 1 g of gold is enough. Polishing is also very easy, it should also be noted that it is highly reflective.

It is this quality that is very important not only in jewelry, but also in many other industrial fields.

As for gold miners, the most important quality for them is density. It should be noted that only metals belonging to the platinum group have a higher density.

1. The density of this metal is 19,300 kg/cubic meter. To make it clear, it must be explained that one of the most expensive metals in the world weighs 19.3 times more than water.
2. If a liter bottle is filled with gold sand, its weight will be approximately 16 kg.
3. 1 kg can be represented by a cube with a side of 37.7 mm or it can be represented as a sphere whose diameter is 46.2 mm.

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About notable properties

If you take an ordinary glass and fill it halfway with gold, its weight will be 1 kg. But as for the native version, its density is lower than that of the chemically pure one, here the indicators range from 18 to 18.5 g/cc. The weight of 585 gold is even lighter, since its density is lower, this is explained by the fact that we are talking about an alloy here.

But as for 999 gold, the density here is higher, so when talking about density, the sample is of great importance. It is the composition of the 999 sample that does not have any impurities, which is why its cost is one of the highest. If we talk about the composition of 585 sample, then there is silver, copper, nickel and palladium. Thanks to its unique qualities, this option is the most popular in the jewelry industry.

As for the 375 standard, the composition includes copper and silver, this option has a significant disadvantage - it darkens quite quickly.

It should be noted that it is precisely such an indicator as the high density of gold that is the main factor that contributes to its relatively easy extraction. Even the simplest technological processes (for example, washing at sluices) can provide a very high degree of recovery from rocks.

It is noteworthy that if large volumes are not expected, then grinding can be carried out independently; no expensive equipment is required for this, an ordinary washing tray is sufficient. This method of extraction has been widely used since ancient times.

When there was the famous “gold rush” in California and the Klondike, grinding was also actively used there. People have long understood that it is thanks to high density that they can easily obtain what is highly valued.

And there are no prerequisites for its value to decrease.

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Helpful information

The fact is that if you wash the yellow metal with a stream of water, you can get rid of minerals that have a lower density (and almost all minerals found in the earth’s crust have a lower density).

After intensive washing, they are washed off, after which the metal itself is concentrated in the heavy fraction, which is sand consisting of minerals of high density, this is called concentrate.

After which the concentrate should be washed to look for any jewelry that has settled in it.

If we talk about modern times, the mining method, which is based on the high density of the metal, has found wide application for extreme tourism. Such tourism in most cases is organized by the owners of private mines, which have already been developed and are economically unprofitable.

For a fee, tourists can be taught simple mining techniques. Of course, you should not expect that you can get a troy ounce in this way, but delight is undoubtedly guaranteed.

Who doesn't want to feel like a real gold miner! For such reasons, tourism of this type is one of the most popular.

If we talk about comparing the densities of gold and silver, the latter metal has a density of 10,500 kg/cubic meter. m. But the density of tungsten is very high, it is almost comparable to the density of one of the most expensive metals and is no more than 1% inferior to it.

These are the reasons why the value of gold and silver is very high all over the world. Of course, silver is significantly inferior in this regard. The composition here also varies - the fact is that pure silver is used very rarely.

This is explained by the fact that in its pure form it has increased softness, which creates certain difficulties. If we are talking about 925 silver, this means that its composition should include no more than 7.5% of various types of impurities. 925 silver contains platinum, and may also contain zinc, germanium and often silicon.

In this way, you can make silver not only less soft, but also affect the change in its color. And the physical properties also change for the better, for example, it is less susceptible to oxidation.

This kind of silver is one of the most common in the jewelry industry because it has an attractive appearance and unique physical properties. It was used in England for minting coins, which is a very important indicator.

If we compare with 960 standard, then, undoubtedly, products made from such metal are very sophisticated, but they are not particularly durable. Therefore, it is not possible to use it for everyday wear. Such jewelry can only be worn on special occasions, and the beauty of products of this type can cause true delight among all connoisseurs of beauty.

Source: https://grammzolota.ru/vidy/sostav-585-999-plotnost-volfram-proba.html