The weight of the BRICS

The weight of standard gold bricks is116.64g.

golden

GOLD (English gold), commonly known as gold, the symbol of chemical elements is Au, and the code name of gold is a kind of metal with yellow luster. Gold has good physical properties, stable chemical properties, high ductility and rare quantity. It is not only a special currency for reserve and investment, but also an important material for jewelry industry, electronics industry, modern communication, aerospace industry and other departments. Gold is gold with the chemical symbol Au. Gold is one of the rarest and most precious metals in the world. Gold is an early metal discovered and utilized by human beings. Because it is rare, special and precious, it has been regarded as the first hardware since ancient times and has the title of "King of Metals".

Calculate proportion

K gold (or gold) is an alloy formed by the fusion of gold and other metals. K gold is divided into 24K gold, 22K gold, 18K gold and 9K gold according to the gold content.

24karat= 100% gold, too soft, only suitable for making gold ornaments alone.

22k at = 9 1.7% gold, which is very soft and not suitable for jewelry.

18 carat =75.0% gold, exquisite jewelry, widely used in China.

14karat=58.3% gold, which can also be considered as jewelry, is widely used in Europe and America.

12 carat =50.0% gold, which is not recognized by the jewelry industry.

10karat=4 1.7% gold, which is defined as real gold by China law.

physical features

1. color: the beauty of golden yellow can be comparable to that of the sun. The steam released when gold melts is green; Its gold powder is usually brown when it is melted; If it is cast into thin slices, it can transmit green light.

2. Extensibility: unusually strong. 1 oz gold can be stretched to 50 miles long, and its ductility makes it easy to cast, making it a good choice for making jewelry. Of all metals, gold has the greatest pulling force.

3. Extensibility: second to none. It will cause extremely thin gold sheets to roll up easily. Gold weighing 1 ounce can be hammered into 1 foot thickness and 100 square foot thickness. The ancients hammered it into thin slices and threw it into temples and palaces for decoration. It is said that 1 ounce of gold can be used to build the roof of a house. If you have a chance to visit these ancient temples, you should pay attention, otherwise free gold coins will fall on your head!

The color of gold is golden yellow, with metallic texture and no cleavage. Hardness 2-3, pure gold 19.3, melting point1064.4℃; Good ductility, can be pressed into thin foil, and has high heat and thermal conductivity. Pure gold is the best electronic conductor material.

As a precious metal, gold has good physical properties. "Real gold is not afraid of fire" means that gold is not easy to melt under the general flame. High density and heavy touch. Good toughness and ductility, good electrical conductivity. Pure gold is bright yellow, but the color changes greatly after mixing with other metals, such as gold-copper alloy is dark red, and silver-containing alloy is light yellow or grayish white. Gold is easily ground into powder, which is also the reason why gold is dispersed in nature. Pure gold jewelry is also easy to wear and lose weight.

In Mendeleev's periodic table, the atomic number of gold is 79, that is, the nucleus of gold contains 79 protons, which are positively charged. At the same time, gold has good chemical stability because it conforms to the half-full law. In the metal market, gold and ruthenium, rhodium, palladium, osmium, iridium, platinum and other metals are collectively called precious metals.

Gold is a very soft metal, but it is not as good as lead and tin. It can trace on pure gold with nails, which makes gold very easy to process. But this is not ideal for the manufacturers of decorations, because it is easy to scratch the decorations, make them lose their luster and even affect their appearance. Therefore, when gold is used to make jewelry, copper and silver are usually added to improve its hardness.

Gold is easy to forge and extend, and can be ground into transparent and green gold foil with a thickness of 0.001mm. 0.5g of gold can be drawn into160m long gold wire.

physical quality

Gold is easy to wear and become very fine powder, so gold is often widely distributed in nature in a dispersed state.

Gold is a good conductor of heat and electricity, but it is not as good as copper, platinum, mercury, lead and silver.

The melting point of gold is 1063℃, and molten gold has high volatility, which increases with the increase of temperature.

The compressive strength of pure gold is 10kg/mm2, and the tensile strength is related to the pretreatment method, generally between 10-30kg/mm2. When the gold wire is cold-drawn, the force is the greatest.

Pure gold has excellent grass yellow metallic luster. It can be said that gold is the yellowest of all metals. There is no pure gold in nature, and metallic impurities (first of all, copper and silver) give gold various colors and tones, from light yellow to bright yellow and red. The color of gold also depends on the thickness of the metal block and its aggregation state. For example, thin gold foil is green under the light, so is molten gold, while unmelted gold is yellow-green, and finely dispersed gold is generally deep red or deep purple.

Natural gold is sometimes covered with a thin film of iron oxide. In this case, the color of gold may be brown, dark brown or even black.

Gold can alloy with many metals, because the atomic radius of these metals is very close to that of gold. The atomic radius of gold is equal to 1.46 angstrom; Bismuth 1.46 angstrom; Silver 1.44 angstrom; Platinum 1.39 angstrom. Therefore, gold can form gold-silver alloy, gold-copper alloy, gold-platinum alloy, gold-palladium alloy and so on. These alloys are not compounds, but solid melts. All metals in the alloy have lower melting points than pure metals. If gold is heated to near the melting point, it can be melted like iron, and fine gold particles can be melted into gold nuggets. (1 angstrom = 0.000000000 l cm)

Gold powder must be pressurized to fuse together at low temperature.

Melting gold with other metals can not only reduce its melting point, but also change the mechanical properties of gold itself. Containing silver and copper can obviously improve the hardness of gold; Containing arsenic, lead, platinum, silver, bismuth and tellurium can make gold brittle, and lead is more prominent in this respect. If the alloy containing only 1% lead is stamped, it will become fragments. If pure gold contains 0.0 1% lead, its good ductility will be completely lost.

Gold has the ability to absorb x-rays.

Gold is included in the list of compounds, just like the precious metal family, but it can react with some elements after all. Especially with halogen (chlorine, bromine, iodine) compounds to generate AuCl or AuC 13. Gold can also combine with cyanide, mercury and tellurium. In fact, there are only compounds of gold and tellurium in nature, and there are few compounds of gold and mercury. All other compounds are manufactured by hand, and "regin" (Au (NH) 3 (CH) 3) can also be manufactured by hand. "Regin" is easy to explode when it is impacted or heated.

Although gold is difficult to dissolve, it can still be dissolved in some solutions. A small amount of gold can also be dissolved in water containing chlorine, sulfuric acid or corrosive acid. In aqua regia and dilute cyanide solution, it is dissolved in a large amount in ionic state.

The crystal of gold belongs to the equiaxed system. Crystals are usually cubic or octahedral in shape. The crystal melts and then condenses, which is an irregular polygon. The slower the cooling, the bigger the crystal.