pyridine, 2-chloro-5-fluoro-3-iodo-

This "gas-5-liquid-3-label" is related to the chemical properties and is quite crucial. Gas is often light and diffuse. Under certain conditions, it may react with other things or maintain a stable state. If this gas is a common gas, such as hydrogen, oxygen, nitrogen, etc., its properties are different. Hydrogen is flammable, burns in an open flame, and burns violently. It can combine with oxidation to generate water, which is one of its significant chemical properties. Oxygen is highly combustible. Many substances need to be able to burn in an aerobic environment, and it can oxidize with many metals and non-metals to form corresponding oxides. Nitrogen has relatively stable chemical properties and is difficult to react with other substances at room temperature and pressure. However, under specific high temperature, high pressure and catalyst conditions, it can also participate in certain reactions, such as the reaction of synthetic ammonia.
As for liquids, they also have their own unique chemical properties. Either acidic, alkaline, or neutral. If the liquid is acidic, it can neutralize with bases to form salts and water. For example, hydrochloric acid can react with sodium hydroxide to form sodium chloride and water. If it is an alkaline liquid, such as sodium hydroxide solution, it can react with acids and can also react with certain metal ions to form a precipitation reaction, such as copper ions to form a copper hydroxide blue precipitation. If it is a neutral liquid, its chemical properties are relatively mild, and it generally does not actively react with acids and bases. However, under certain conditions, it may participate in some complex chemical reactions.
This "labeled" thing, although not explicitly specified, is inferred according to chemical common sense, or is a label to identify the characteristics, composition, reaction conditions and other key information of the gas and liquid. It is essential in chemical experiments, industrial production and other fields. Knowing the chemical properties of gas and liquid can properly handle and use it, avoid danger, and achieve the expected chemical changes and production purposes.

"Tiangong Kaiwu" says: Mercury, that is, mercury, is mainly used in a wide range of applications. In alchemy, mercury is often the key thing. Ancient alchemists pursued the medicine of immortality, and mercury was often used to refine medicinal pills because of its unique chemical properties, hoping to achieve extraordinary results with its magical effects.
In the field of metallurgy, mercury also has important uses. The method of amalgamation can be used to extract precious metals such as gold and silver. Mixing gold and silver-containing ores with mercury can form amalgamations with gold and silver, and then evaporate the mercury by means of heating, leaving pure gold and silver. This process played an important role in the development of ancient mining.
Furthermore, in the field of traditional medicine, although mercury is toxic, it is also used in specific formulations. Some topical medicines use small amounts of mercury and its compounds to treat skin diseases such as scabies and sores. The ancients reduced the toxicity of mercury through special processing methods, so that it can be used for treatment.
In addition, in the production of traditional handicrafts, mercury also contributes. When making gilded utensils, mercury and gold need to be made into gold amalgam, applied to the surface of the utensils, and heated to evaporate the mercury. Gold attaches to the utensils to form a gorgeous gilt effect, adding beauty and value to the utensils.
In short, mercury played an important role in many fields such as ancient alchemy, metallurgy, medicine and handicraft production, and had a profound impact on the development of ancient technology and culture.

The weir of Fuhai, the river, and the river has been repaired in ancient times. To build a weir, you need to first measure the topography. Observe the height of its terrain, observe the urgency of the current, and then determine the base site.
If a sea weir is built, its land is often close to the sea, and the wind and tide are turbulent, so the base site must be solid. Boulders can be used as the foundation, and the accumulated stones can be used as the embankment. The stones are connected by iron tenons, or filled with mortar, so that the stone embankment is integrated to withstand the impact of the sea tide. Salt-tolerant plants, such as Suaeda, can be planted on it to fix the embankment soil and reduce the tide force.
As for the river weir, the river flow is large and the water flow is rapid during the flood season When building a weir, it is advisable to choose a narrower part of the river to reduce the amount of work. The pile should be driven at the bottom of the water first, and the pile should be made of tough wood, and the soil needs to be deep. The pile should be laid horizontally with huge trees, and then the rock should be filled on it. On both sides of the weir, there should also be soft stone slope protection to prevent the river from washing. And the weir body should be set up with a drainage mouth, which can discharge flood during flood season, and can adjust the water level at ordinary times.
The system repair of the weir, because the river water is relatively stable, should not be ignored. The base site should be selected in a place with solid soil, and the foundation should be cleared first to remove silt and debris. Build a dike with soil, rammed layer by layer, and the top of the dike can be paved with bricks Inside and outside the embankment, trees such as willows are planted, their roots can fix the embankment soil, and their branches and leaves can slow down the water potential.
Ancient skilled craftsmen, in the construction of the weir, adapt to local conditions, and apply their own methods. Although the years have passed, there are many things to learn from their methods. Those who repair the weir in later generations should carefully observe the geography and refer to the ancient methods to build a strong weir and benefit all the people.

The price of all kinds of things in the world is often determined by supply and demand, materials, craftsmanship, and other things. Now when it comes to this thing, I want to know the price of its market.
Since this thing is listed in the market, the price depends first on the material used. If the material is commonly available, the price may not be high; if the material is scarce and rare, and it is difficult to harvest, the price must be high.
Furthermore, look at the craftsmanship. If the craftsmanship is crude, the craftsmanship is simple but not refined, and the price should be average; if the craftsmanship is complicated, the craftsman carefully crafted, and it is time-consuming and laborious, the price will rise.
Rethink the supply and demand of the city. If this thing is in the world, everyone needs it, and there are many people who ask for it, but there are few people who supply it, and the price will increase; if the supply exceeds the demand, and there is no need for it, the price will drop.
In addition, the location of the city, the atmosphere and customs, and the ups and downs of the time are also related to the price. In a prosperous and prosperous place, everyone is rich, but there are many good things, and the price may be slightly higher; when the luck is poor, the people are poor, and it is difficult to sell good things at high prices.
However, I do not know the material and craftsmanship of this thing, nor do I know the supply and demand of the city, so it is difficult to determine its price. Roughly speaking, if the material is ordinary, the craftsmanship is ordinary, and the supply and demand in the market are balanced, the price may be [X]; if the material is thin and the art is fine, and there are many applicants, the price may be doubled, or even several times; if the material is mediocre and the art is simple, the supply exceeds the demand, and the price may be as low as [X]. Although it is not known for sure, the approximate number can be deduced on this basis.

During the storage and transportation of mercury, lead, and cadmium, many key matters need to be paid attention to.
Mercury is a liquid metal, which is volatile and highly toxic. When storing, a sealed container must be used to prevent mercury vapor from escaping into the air, causing environmental pollution and human harm. During transportation, it is also necessary to ensure that the container is well sealed, and to take shock-proof and collision-proof measures. Mercury leakage caused by container damage is extremely difficult to clean up, and mercury toxicity is difficult to remove.
Although lead is relatively stable, it should still be stored in a dry environment to avoid moisture and oxidation. Because its oxides are converted into soluble lead salts under specific conditions, their toxicity and migration are increased. When transporting, avoid contact with corrosive substances such as acids and alkalis to prevent damage to the packaging and lead exposure.
Cadmium is also a toxic heavy metal. When storing, it needs to be isolated from other chemical substances, especially oxidizing substances, to prevent chemical reactions from occurring, changing the chemical form of cadmium and affecting its toxicity and stability. During transportation, strict safety regulations must be followed, and the packaging must be sturdy and durable, with significant warning signs, so that transporters can clearly understand its danger and take corresponding protection.
All three are toxic heavy metals, which pose a great threat to the ecological environment and human health. When storing and transporting, every step of the way, from packaging selection, environmental control to transportation operations, must be carried out with strict care, in accordance with relevant regulations and standards, to minimize the risk of leakage and protect the environment and human safety.