interesting knowledge of chemistry


Magnesium is also found in the human body and in plants and is the main component of chlorophyll.

Even during the Western Han Dynasty in China, there was a record that "Zeng Qing obtained iron and turned it into copper", that is, placing pieces of iron in a solution of copper sulfate can replace copper.

The reaction principle of welded rail is that aluminum and iron oxide react under high temperature conditions to form iron oxide and aluminum.

To remove soluble magnesium chloride impurities contained in coarse salt, coarse salt crystals are crushed, then washed with saturated salt water, and the purified salt is filtered.

interesting knowledge of chemistry

Characteristics of concentrated sulfuric acid 2: Corrosive activity (dehydration), concentrated sulfuric acid is very corrosive and can release hydrogen and oxygen in paper, wood, leather and other substances (all containing C, H, O and other elements) The elements are removed in according to the composition ratio of water to produce black carbon.

interesting knowledge of chemistry

71% of the earth is covered with water, which is the source of life and an important solvent.

interesting knowledge of chemistry

Normal saline is a solution with a mass fraction of a solute of 0.9%.

The juice of many plants can act as an acid-base indicator.

In my ancient country, it was recognized that copper in a copper salt solution can be replaced by iron. This method is the source of hydrometallurgy technology.

The smell of fish is due to the presence of methylamine in fish, which is easily soluble in ethanol. Therefore, adding wine when cooking fish may cause the methylamine to dissolve in ethanol and evaporate when heated. No more fishy smell.

interesting knowledge of chemistry

Iodized salt is the addition of potassium iodate to table salt.

Metal resources are widely distributed in the earth's crust and oceans. With the exception of a few very inactive metals such as gold, which exist as simple substances, the rest exist as compounds.

My country mastered the technology of iron production at the beginning of the Western Han Dynasty, more than 1000 years ahead of Western countries.

The main component of hematite is iron oxide, which is used in the production of iron.

interesting knowledge of chemistry

Light and "naughty" lithium

Lithium is a soft, silvery-white metal. Although it looks like other metals, it has a different character! Firstly, its density is very low, it is the smallest among all metals. Secondly, it is alive by nature and likes to be "friends" with other substances. For example, if you put a small piece of lithium in a glass vessel and put a frosted stopper on it, the lithium will quickly release air from the vessel and create a vacuum in the vessel. At this time, even if you do your best, don't even think about pulling out the plug. Obviously, such a "naughty" is very difficult to maintain, whether it is in water or kerosene, it will float on the surface of the liquid and burn. In the end, the chemists had to put him in paraffin oil or liquid paraffin to limit his "wildness" and keep him from "making trouble." Lithium was discovered over 170 years ago. For more than 100 years after his birth, he served the medical community mainly as a remedy for gout. It wasn't until the early 20th century that lithium began to make its way into industry and leave its mark. For example, an alloy composed of lithium and magnesium can float on water like a dragonfly touching water, and does not tarnish in air or sink in water. Lithium soon became the "darling" of the aviation and marine industries. In addition, lithium plays a role in advanced technologies. Lithium deuteride, for example, is an inexpensive and high-quality fuel for nuclear reactors, solid rocket fuel contains from 51% to 68% lithium. However, experts believe that the possibilities of lithium have not yet been fully used, and its potential is still great!

Mystery of the village of madmen

In the 1930s, a strange thing happened in a remote rural town in Japan. More than 10 people went mad one by one in the village, these people were mentally unbalanced, behaved abnormally, sometimes cried loudly, sometimes laughed, their limbs became stiff... Their illnesses brought misfortune to their families and caused great pain. The excitement of the people also alarmed the local government and the relevant medical institutions. The local police station and hospital sent an investigation team to conduct a large number of visits and examinations, examined the bodies and blood components of these patients, and found that the content of metallic manganese ions in their bodies is significantly higher than that of ordinary people. . It is these manganese ions that cause these people to become poisoned by too much manganese ions in the human body. In the beginning, this causes headaches, dizziness, heaviness in the limbs, inability to move, memory loss, and further development makes people stiff limbs, mental abnormalities, and sometimes bitter cries. , sometimes full of animal laughter, crazy, presenting a disgusting ugly appearance.

Where does the excess of manganese ions come from? It turns out that the inhabitants of this small town often throw their used waste dry batteries into the garbage pit.poison with a well. Over time, the manganese dioxide in the battery gradually turns into soluble manganese bicarbonate under the action of carbon dioxide and water. Soluble manganese bicarbonate entered the well, polluting the well water. People drank water containing a lot of manganese ions, which caused manganese poisoning, as a result more than 10 people went crazy in a short period of time.

Iodine and fingerprints will help solve the crime

In films, we often see a story about security officers using fingerprints to solve crimes. In fact, while we press our finger on a sheet of white paper, then we combine the place where the finger presses the paper with the neck of a test tube containing a small amount of iodine, and heat the bottom of the test tube. with alcohol. After the sublimated purple vapor of iodine in the test tube comes into contact with the paper, normally invisible fingerprints will gradually appear and a very obvious brown fingerprint will be produced. If you keep this white paper and do the above experiment a few months later, the fingerprints hidden on the paper may still be visible. Why is this?

It turns out that everyone's fingers are always covered with grease, mineral oil and sweat. When you press your finger on the paper, grease, mineral oil and sweat from the print remain on the paper, but the human eye does not see them. Pure iodine is a purple-black crystal with a metallic sheen. Interestingly, when most substances are heated, they usually change into three states: solid, liquid, and gaseous, but iodine is "unique" and can directly change from solid to gaseous state, bypassing the liquid when heated. The direct evaporation of a solid, such as iodine, is called sublimation. At the same time, iodine is easily soluble in organic substances. Since fingerprints contain organic substances such as fat, when iodine vapor rises and collides with these organic substances, it will dissolve into them, so fingerprints will also be displayed.

Most chemical elements

Oxygen is the most abundant element in the human body, accounting for about 65% of the total weight of the human body. At present, the purest elemental substance is the semiconductor material silicon, and its purity has reached 12 "9", namely: 99.999 999 999 9%. The elemental substance with the highest melting point is carbon, a high temperature of 372°C is required to melt carbon. Helium has the lowest melting point, which can be melted at -271.7°C. Gold is the most malleable, if 380 g of gold is pulled into threads, then they can be stretched from Beijing to Shanghai by rail. Only 50,000 thin sheets of gold are stacked together and are only 1mm thick. Silver has the best conductivity, which is 59 times greater than that of mercury. The most expensive metal is copper, 1 gamm copper is worth 10 million dollars.

Pure blue ink and blue-black ink

Reviewing the homework assignments we wrote earlier, we found that some of the handwriting is blurry and others are clear. Why is there such a big difference in handwriting from the same period? It turned out that the illegible handwriting was written in pure blue ink, over time the ink oxidized, and the color faded a little, or even completely disappeared, while the clear handwriting was written in blue-black ink, which was replaced by blue-black ink. After oxidation, they can Gradually generate a chemical that never fades - black acid iron, so the writing becomes clearer.

Usually, soluble blue organic dyes, sulfuric acid, phenol, glycerin and spices are added to blue-black ink. Sulfuric acid is added to keep the ink acidic and prevent it from settling; phenol, commonly known as carbolic acid, is a well-known preservative that can sterilize ink and prevent it from rotting and smelling; The chemical name of glycerin is glycerin, which is a widely used antifreeze. After adding glycerin, the freezing point of water can be greatly reduced, so that the ink is not easy to freeze in winter, and the addition of spices makes the ink fragrant and pleasant.

Cold-blooded killer

During the ancient Roman era, since lead was soft and easy to process, lead products were at that time a symbol of nobility and wealth, and were also yao, which was very popular among people. The ancient Roman nobility commonly used lead-containing utensils, utensils, and cosmetics, and was especially fond of drinking lead-containing grape juice. At the time when they were making amber-like grape juice, they always put the grapes in a lead cauldron or a cauldron lined with lead to boil for a very long time, until the juice was only one third of the original. This type of grape juice is particularly sweet and not easily spoiled, but its lead content is severely exceeded. The widespread use of these lead-containing items has led to the death of many people from lead poisoning. At the same time, the lead-pipe water supply and drainage system used in the ancient Roman Empire did not allow the civilian population to escape the misfortune of lead poisoning. However, in ancient Rome, they knew nothing about all this, which is one of the important reasons why ancient Rome went from its heyday to decline.

Lead is a heavy metal that poses a serious health hazard. Lead poisoning causes symptoms such as constipation, abdominal cramps, lead wires, and anemia. It can affect various systems and organs, such as human nerves, hematopoiesis, digestion, immunity, and bones. What is more serious is that it affects the growth and intellectual development of the infant.c, brain functions such as neurobehavior, learning and memory, and can cause dementia in severe cases.

A fire that is difficult to put out

Magnesium powder dumped in a warehouse burns with a blinding white light. There is a chemical warehouse next door, if it is not put out in time, a big fire is sure to happen. The keeper used a carbon dioxide fire extinguisher to extinguish the fire, but the fire was not extinguished and the fire became more prosperous. Later watering, also to no avail. As a result, experienced firefighters extinguished the fire with conventional methods and avoided a major fire. It's strange, but how did the firefighters put out the fire? That is: use a lot of yellow sand to put out the fire. Carbon dioxide will chemically react with magnesium, and magnesium can also react with water at high temperature. Yellow sand can be used to isolate the burning magnesium powder from the air and achieve the purpose of extinguishing fire.

(Original image network, captured and removed.)