Carbon tetrachloride 〉Water 〉Benzene 〉Alcohol 〉Gasoline
Carbon tetrachloride
1, the physical and chemical constants of the substance
National Standard No. 61554
CAS No. 56-23-5
Chinese name tetrachloromethane
English name carbon tetrachloride; tetrachloromethane
Alias Carbon tetrachloride
Molecular formula CCl4 Appearance and properties Colorless transparent liquid with peculiar odor, very volatile
Molecular weight 153.84 Vapor pressure 13.33kPa(23℃)
Melting point -22.6℃ Boiling point: 76.5°C Solubility Slightly soluble in water, soluble in most organic solvents
Density Relative density (water=1) 1.60; Relative density (air=1) 5.3 Stability Stable
Hazardous Labeling 14 (with drugs) Main Uses Used in organic synthesis, cold-acting agents, insecticides. Also used as organic solvents
2, the impact on the environment
Carbon tetrachloride is a highly accumulative substances, can produce accumulation in the liver of mammals, salmon can cause liver cancer.
I. Health Hazards
Intrusion route: inhalation, ingestion.
Health hazards: strong irritation to eyes, skin, mucous membranes and respiratory tract. Inhalation may be fatal due to spasm, edema, inflammation of the larynx and bronchial tubes, chemical pneumonitis and pulmonary edema. Poisoning manifestations include burning sensation, cough, wheezing, laryngitis, shortness of breath, headache, cachexia heart and vomiting.
Two, toxicological information and environmental behavior
Acute toxicity : LD502350mg/kg (rat oral); 5070mg/kg (rat dermal); LC5050400mg/m3, 4 hours (rat inhalation); human oral 29.5ml, death; human inhalation of 320g/m3, 5 ~ 10 minutes after death; human inhalation 150～200g/m3, 1/2～1 hour life-threatening; human inhalation 15g/m35 minutes after vertigo, headache, insomnia, rapid pulse rate; human inhalation 1～2g/m3, 30 minutes after mild nausea, headache, pulse rate and respiratory acceleration; human inhalation 0.6～0.7g/m3, can be tolerated for 3 hours.
Subacute and chronic toxicity: animals inhalation 400ppm, 7 hours/day, 5 days/week, 173 days, some animals 127 days of logistical death, liver and kidney enlargement, hepatic steatosis, cirrhosis, renal tubular epithelial degeneration.
Mutagenicity: microbial mutagenicity: Salmonella typhimurium 20ul/L. DMA injury: mice 335umol/kg orally.
Reproductive toxicity: lowest toxic dose (TDL0) orally in rats: 2g/kg (7-8 days of gestation) caused increased post-implantation mortality. The lowest toxic oral dose (TDL0) in rats, 3619 mg/kg (male, 10 days), caused testicular, epididymal and vas deferens abnormalities.
Carcinogenicity: IARC Carcinogenicity Comments: positive in animals, suspect in humans. Increased incidence of hepatocellular carcinoma in mice at 1250 mg/kg/day x 78 weeks orally.
Teratogenicity: Inhalation of 300～1000ppm/day in rats (6～15 days of gestation) had teratogenic effects on embryos; inhalation of 50～400ppm in rats in three-generation reproduction test had no fetotoxicity or teratogenic effects.
Source of pollution: the production of carbon tetrachloride organic chemical plants, petrochemical plants and other enterprises may produce carbon tetrachloride pollution. Carbon tetrachloride is used as a solvent for oils, fats, real paints, fake paints, sulfur, rubber, waxes and resins, refrigerant, fumigant, dry cleaning agent for fabrics, metal cleaning agent, insecticide. It is also used in cleaning agent for electronic industry, leaching agent for oil and spice, extractant and other industries. Carbon tetrachloride is commonly used in the synthesis of fluorocarbons, the production of chlorinated organic compounds, semiconductor production, the manufacture of Freon and other industries.
Hazardous Characteristics: This product will not burn, but when exposed to open flame or high temperature is easy to produce highly toxic phosgene and hydrogen chloride fumes. It gradually decomposes into phosgene and hydrogen chloride in humid air.
Combustion (decomposition) products: phosgene, chloride.
3, on-site emergency monitoring methods
Water quality detection tube method; direct water sample gas chromatography
Quick detection tube method; portable gas chromatography "sudden environmental pollution emergency monitoring and treatment and disposal of technology," Wan Bentai edited
Gas quick test tube (Germany, Dr?ger products)
4, laboratory monitoring methods
4, laboratory monitoring methods <
Monitoring Methods Source Category
Top Air Chromatography GB/T17130-1997 Water Quality
Pyridine-Alkali Colorimetry Methods for the Determination of Hazardous Substances in the Air (Second Edition), edited by Hang Shiping Air
Gas Chromatography Handbook of Testing and Analyzing and Evaluating of Solid Wastes Translated by the China Environmental Monitoring General Bureau Solid Wastes
Gas Chromatography Gas Chromatography of Pesticide Residues, edited by the State Administration of Commodity Inspection Grain
Chromatography/Mass Spectrometry U.S.A. EPA524.2 Methods Water
5. Environmental Standards
China (TJ36-79) Maximum Permissible Concentration of Hazardous Substances in Workshop Air 25[pi]mg/m3
China (GB5749 -85) Drinking Water Quality Standard 3μg/L
China (GHZB1-1999) Environmental Quality Standard for Surface Water (Specific Value for Class I, II, and III Waters) 0.003mg/L
China (GB8978-1996) Sewage Comprehensive Emission Standard Grade 1: 0.03mg/L
Second Grade: 0.06mg/L
The maximum allowable concentration of harmful substances in workshop air 25[pi]mg/m3
China (GB5749-85)
Tertiary: 0.5mg/L
Japan (1993) Environmental Standards Surface Water: 0.002mg/L
Wastewater: 0.02mg/L
Soil Leachate: 0.002mg/L
Olfactory Threshold Concentration 200ppm
6. Emergency Treatment and Disposal Methods
I. Emergency treatment of leakage
Rapidly evacuate the people in the leakage contaminated area to the safe area, and isolate and strictly restrict the access.
1) Carbon tetrachloride is a colorless liquid, occurred on the ground with the emergency treatment of pollution with trichloromethane:
①Rapidly use soil, sand or other materials that can be taken to build a dam to stop the flow of liquid, especially to prevent it from flowing into the nearby body of water, cover it with soil and absorb it. It may also be possible to dig a pit downstream of its flow, collect it in the pit to prevent it from spreading around, and then collect the liquid in a suitable container.
②Do not use iron tools (e.g., iron spoons, iron containers, shovels, etc.) during treatment, but use other tools instead, because iron helps tetrachloromethane decompose to produce the more toxic phosgene. If possible, the operator should wear a gas mask, or other protective equipment during treatment.
③The contaminated soil will be removed and stripped and then concentrated for treatment, there are the following methods can be selected as appropriate:
a. Heating the soil and adding water, so that the tetrachloromethane generation of formic acid, carbon monoxide and hydrochloric acid;
b. Concentrated lye will be added to the soil so that it reacts with tetrachloromethane to generate carbon monoxide;
c. Dilute sodium hydroxide or potassium hydroxide added to the soil, so that it reacts with the tetrachloromethane to generate carbon monoxide;
c. potassium hydroxide to the soil to react with tetrachloromethane to form sodium or potassium formate;
The above operations should be avoided under light conditions.
d. The soil is treated by incineration to ensure complete combustion to prevent phosgene production.
(2) Since carbon tetrachloride is very stable in the environment, some of the disposal techniques of trichloromethane are not applicable to it, and only its volatile characteristics can be utilized for natural or artificial mandatory volatilization to the atmosphere. When a large number of gaseous carbon tetrachloride volatile dispersion, should be evacuated downwind of the source of contamination of the crowd, in order to prevent poisoning.
(3) the water body is contaminated with the treatment and disposal technology with trichloromethane: when the tetrachloromethane liquid into the water body, should try to block the polluted waters and other waters of the channel, the method for the construction of dams so that it stops the flow; ditching so that the flow to another body of water (eg, sewage canals) and so on. Since tetrachloromethane is a volatile halogenated hydrocarbon, the easiest way to treat water contaminated by it is to use the aeration (including deep-in aeration) method, so that it can quickly escape from the water body into the atmosphere. In addition, several methods of treating soil can be used as appropriate.
Waste disposal methods: by incineration. Waste materials mixed with other fuels and then incinerated, combustion should be sufficient to prevent the generation of phosgene. Hydrogen halides in the incinerator exhaust are removed by an acid scrubber. In addition, distillation should be considered to purify and recover carbon tetrachloride.
Two, protective measures
Respiratory protection: when the concentration in the air exceeds the standard, you should wear a direct-type gas mask (half mask). Wear an air respirator when rescuing or evacuating from an emergency situation.
Eye protection: wear safety goggles.
Body protection: wear anti-poison penetration work clothes.
Hand protection: wear chemical resistant gloves.
Others: Smoking, eating and drinking are prohibited at the work site. After work, shower and change clothes. Separate storage of clothes contaminated by poisons, wash and prepare for use. Pre-employment and regular medical examinations are practiced.
Third, first aid measures
Skin contact: Remove contaminated clothing and rinse skin thoroughly with soapy water and water. Seek medical attention.
Eye contact: lift eyelids and flush with running water or saline.
Inhalation: Remove quickly from the scene to fresh air. Keep the airway open. If breathing is difficult, give oxygen. If breathing stops, immediately perform artificial respiration. Seek medical attention.
Eating: Drink sufficient amount of warm water, induce vomiting, and wash stomach. Seek medical attention.
Fire extinguishing methods: firefighters must wear oxygen respirators, full body protective clothing. Extinguishing agent: dry powder, carbon dioxide. Water is prohibited.
Water
Water (H2O) is an inorganic substance composed of two elements, hydrogen and oxygen, and is a colorless, odorless and transparent liquid at room temperature and pressure. Water is one of the most common substances, is an important resource for the survival of all life, including human beings, and is the most important component of living organisms. Water plays an important role in the evolution of life. Humans began to produce a very early understanding of water, the East and West of the ancient simple view of matter in the water as a basic constituent element, one of the five elements; the four elements of the ancient Western say there is also water.
The nature of water
Water is a colorless, odorless, transparent liquid at room temperature and pressure. In nature, pure water is very rare, water is usually mostly a solution of acids, alkalis, salts and other substances, and it is still customary to call this aqueous solution water. Pure water can be obtained by several distillations with platinum or quartz vessels, which, of course, is pure water in a relative sense, and cannot be absolutely free of impurities. Water is a substance that can be transformed between liquid, gaseous and solid states. Water in the solid state is called ice; in the gaseous state it is called water vapor. When the temperature of water vapor is higher than 374.2 degrees Celsius, gaseous water cannot be converted to liquid water by pressurization.
At 20 ℃, the thermal conductivity of water is 0.006 J/s?cm?K, the thermal conductivity of ice is 0.023 J/s?cm?K, in the density of snow is 0.1 × 103 kg/m3, the thermal conductivity of snow is 0.00029 J/s?cm?K. The density of water is the largest in the 3.98 ℃, 1 × 103 kg/m3, the temperature is higher than the 3.98 ℃ When the temperature is higher than 3.98 ℃, the density of water decreases with increasing temperature , in 0 ~ 3.98 ℃, water does not obey the law of thermal expansion and contraction, the density increases with increasing temperature. Water at 0 ℃, the density of 0.99987 × 103 kg / m3, ice at 0 ℃, the density of 0.9167 × 103 kg / m3. so ice can float on the water surface.
The thermal stability of water is very strong, water vapor heated to more than 2000K, there is only a very small amount of dissociation into hydrogen and oxygen, but water in the conditions of electricity will dissociate into hydrogen and oxygen water. Has a great cohesion and surface tension, in addition to mercury, the surface tension of water is the largest, and can produce more obvious capillary phenomenon and adsorption phenomenon. Pure water has a very weak conductive ability, but ordinary water contains a small amount of electrolytes and conductive ability.
Water itself is also a good solvent, most inorganic compounds can be dissolved in water.
At -213.16°C, water molecules exhibit anaerobic behavior.
Origin of water
Earth is the only one of the nine planets in our solar system that is covered by liquid water. The origins of water on Earth are y divided academically, with dozens of different theories of water formation currently in existence. There are views that in the early stage of the formation of the Earth, the original atmospheric hydrogen, oxidation synthesis of water, water vapor gradually condensed down and formed the oceans; there are also views that the formation of the Earth's nebulae in the original existence of water components. There is also the view that water was originally present in the nebulae that formed the Earth. There is also the view that silicate and other substances in the primitive earth's crust were affected by volcanoes, which caused them to reflect and precipitate water. It has also been suggested that comets and meteorites attracted to the Earth are the main source of water on the planet, and that even now the amount of water on the planet continues to grow.
Impact on Climate
Water has a regulating effect on climate. Water vapor in the atmosphere blocks up to 60% of the Earth's radiation, protecting the planet from cooling. Oceans and land bodies of water absorb and accumulate heat in the summer to keep temperatures from getting too high, and slowly release heat in the winter to keep temperatures from getting too low.
Water in the oceans and on the land surface evaporates into the sky to form clouds, where it falls through precipitation to become rain, and in winter to become snow. The water that falls on the surface seeps into the ground to form groundwater; the groundwater emerges from the earth's layers to form springs, which flow into the sea through streams and rivers. A water cycle is formed.
Precipitation activities such as rain and snow have an important impact on climate. In temperate monsoon climates, the monsoons bring an abundance of moisture, creating distinct wet and dry seasons.
In addition, in nature, water appears and influences the climate and human activities in the form of hail, fog, dew and frost due to different climatic conditions.
Impact on Geography
Seventy-one percent of the Earth's surface is covered by water, making it a blue planet when viewed from the air. Water erodes rocky soil, washes away rivers, carries sediment, creates plains, and changes the shape of the surface.
The Earth's surface waters make up the hydrosphere, which includes oceans, rivers, lakes, swamps, glaciers, snow, groundwater and atmospheric water. Because the water injected into the oceans carries a certain amount of salt, and because of its accumulation and evaporation over the years, the water in the seas and oceans is salty and cannot be drunk directly. The water in certain lakes is also saline. The largest body of water in the world is the Pacific Ocean. The Great Lakes in North America are the largest freshwater system. The Caspian Sea in Eurasia is the largest saltwater lake.
The volume of water on Earth is about 1 360 000 000 cubic kilometers. Of this, the oceans account for 1,320,000,000 cubic kilometers (or 97.2%).
Glaciers and ice caps account for 25,000,000,000 cubic kilometers (or 1.8%).
Groundwater accounted for 13,000,000 cubic kilometers (or 0.9 percent).
Fresh water in lakes, inland seas, and rivers accounted for 250,000,000 cubic kilometers (or 0.02%).
Water vapor in the atmosphere accounted for 13,000 cubic kilometers (or 0.001%) at any known time.
Effects on life
Life on Earth first appeared in water. Water is an essential component of all living organisms. The human body is 70% water; and jellyfish are 98% water. A large number of aquatic organisms, such as aquatic vegetation, live in water.
Water facilitates chemical reactions in the body and also plays a role in the transportation of substances in living organisms. Water plays a great role in maintaining the stability of the temperature of the organism.
Types of water
Different disciplines have some different names for water:
Based on the quality of water, it can be categorized as:
Soft water: water with a hardness of less than 8 degrees is considered as soft water.
Hard water: water with a hardness higher than 8 degrees is hard water. Hard water will affect the effectiveness of detergent, hard water heating will have more scale.
Drinking water can be categorized according to the content of sodium chloride:
Fresh water.
Saline water
In addition there are:
Biological water: water that exists in various states in various living systems.
Natural water:
Soil water: water stored within the soil
Groundwater: water stored underground
Ultra-pure water: water of very high purity, mostly used in the IC industry
Crystallized water: also known as hydrated water. In the crystalline material, with chemical bonding forces and ions or molecules combined, a certain number of water molecules.
Heavy water chemical molecular formula for D2O, each heavy water molecule consists of two deuterium atoms and an oxygen atom. Heavy water accounts for less than two-tenths of one percent of natural water, and heavy water obtained through electrolysis is more expensive than gold. Heavy water can be used as a decelerator and heat-carrying agent in atomic reactors.
Super heavy water has the chemical formula T2O, and each heavy water molecule consists of two tritium atoms and one oxygen atom. Superheavy water is extremely rare in natural water, accounting for less than one part per billion. The cost of producing superheavy water is tens of thousands of times higher than that of heavy water.
Deuterated water chemical formula for HDO, each molecule contains a hydrogen atom, a deuterium atom and an oxygen atom. It is not very useful.
Chemical reactions associated with water
Ionization of water and solution pH
Water is an extremely weak electrolyte that weakly ionizes: H2O + H2O?H3O++OH- Usually H3O+ is abbreviated as H+
Ionic product of water Kw=[H+][OH-]
Wat is Kw=1×10- at 25 degrees Celsius. 14
PH=-log10([H+])
PH<7, the solution is acidic, pH=7, the solution is neutral, pH>7, the solution is basic.
Acidic or basic oxides that are soluble in water can react with water to form the corresponding oxygenated acid or base. The acid and base undergo a neutralization reaction to form salt and water. Water can decompose into hydrogen and oxygen under the action of electric current. Alkali metals burn when they come in contact with water.
In the presence of a catalyst, inorganic and organic substances can undergo hydrolysis with water:
Hydrolysis of organic substances: some atom or group of atoms in the organic molecule is replaced by a hydrogen atom or hydroxyl group (-OH) of a water molecule, e.g., hydrolysis of methyl acetate:
Hydrolysis of inorganic substances: this is usually the hydrolysis of a salt, e.g., the weak acid salt sodium acetate combines with H+ in water to form a weak acid, giving a solution that is weak. into a weak acid, making the solution basic:
In addition, water itself can act as a catalyst.
Freshwater Shortage and Countermeasures
The total water reserves of the earth are about 1.36x1018m3, but only 2.5% of it is freshwater, excluding saltwater resources such as oceans. Freshwater and mainly in the situation of glaciers and deep groundwater, freshwater in rivers and lakes only accounted for 0.3% of the world's total freshwater.
The World Meteorological Organization pointed out in early 1996 that water scarcity is the primary problem facing cities around the world, and it is estimated that by 2050, 46% of the world's urban population will suffer from water scarcity. For regions with scarce water resources, water has gone beyond being a resource for living and has become a strategic resource, with the possibility of water wars breaking out becoming higher and higher due to the scarcity of water resources.
In order to make the whole world concerned about the shortage of freshwater resources, the 47th session of the United Nations General Assembly determined that every year on March 22 as the World Water Day.
Water Use
Water is an important resource for human life, especially for agriculture, which requires large amounts of water for irrigation, and most of the origins of human civilization are in large river basins. Early cities were generally established near water to solve the problems of irrigation, drinking and sewage. In human daily life, water plays an indispensable role in drinking, cleaning and washing.
With the development of science and technology, people built water conservancy to fight against natural disasters such as waterlogging and flooding. Therefore, the formation of a number of specialized water-related research areas, such as hydraulics, hydrological sciences, water treatment, and so on, and even produced a water-based industry water industry.
Industrial production and chemical production of large quantities of this cheap raw material. But the arbitrary discharge of untreated wastewater can cause water pollution. In order to solve this problem, sewage treatment becomes necessary. (See Water Pollution and Sewage Treatment.)
Water in the Ancient Worldview
In the early days of civilization, people began to explore the composition or classification of various things in the world, and water played an important role in this. Water was included in the four elements proposed by the ancient West; it was also included in the Four Great Elements of Buddhism; and in the ancient Chinese doctrine of the Five Elements, water represented all liquids, as well as things with a flowing, wetting, and yin and soft nature.
Water Worship
In the childhood of human beings, water has both nurturing and destructive power, inscrutable nature, produced feelings of love and fear, resulting in water worship. By endowing water with the spirituality of a god, they prayed for it to bring peace, harvest and happiness to mankind.
The traditional Chinese dragon king is the deification of water. Wherever there is a water source, there is a dragon king, and dragon king temples and halls are found all over the country. Sacrificing to the Dragon King to pray for rain is a traditional Chinese faith practice.
And colloquialization
Describes a person who is not productive, or who does not do things well enough.
For example, you are so watery. (You're so bad at it.)
Gao Shan Liu Shui (高山流水)
古代琴曲。 In the Warring States period, there were already stories about the music of "High Mountains and Flowing Water", so it was also rumored that "High Mountains and Flowing Water" was made by Boya. The music score was first published in the Ming Dynasty in the Miraculous Secret Score (Zhu Quan wrote it in 1425), and the explanation of the score's "High Mountains" and "Flowing Water" is titled: "The two pieces of "High Mountains" and "Flowing Water" are only one piece of music in the first place. The first one is about high mountains, which means that the benevolent people are happy with the mountains. Later, it was about flowing water, which means that the wise man is happy with the water. To Tang is divided into two songs, not divided into segments. To come, it was divided into four segments for high mountains and eight segments for flowing water." For more than 2,000 years, the two famous guqin tunes, "High Mountains" and "Flowing Water", together with the story of Boya's encounter with his soulmate by drumming the qin, have been widely circulated among the people.
"High Mountains and Flowing Water" is based on the story of "Bo Ya's encounter with his soulmate", and has a variety of scores. There are two kinds of music: zither music and zheng music, both of which have the same name and different styles.
With the development of qin performance art since the Ming and Qing Dynasties, "Gao Shan" and "Liu Shui" have changed a lot. The Secret Record of the Legend is not segmented, while the later zither scores are mostly segmented. Since the Ming and Qing dynasties, a variety of music scores in the Qing Dynasty Tang Yiming edited "Tianwenge music score" (1876) in the collection of the Sichuan School of qin Zhang Kongshan adapted the "running water" is particularly distinctive, adding a "roll, whisking, nicked, note" technique for the sound of running water in the sixth paragraph, also known as "seventy-two roll whisking running water It is also known as "Seventy-two Rolls and Flowing Water", and has been popularized for its distinctive image and scenario. According to zither experts, before the release of the Tianwenge zither score, all the zither scores of "Flowing Water" did not have the sixth section played by Zhang Kongshan, and the whole piece had only eight sections, which was in line with what was said in the explanation of the "Magical Mystery Score," but Zhang Kongshan's biography was also in line with what was said in the "Magical Mystery Score". The whole piece has only eight stanzas, which is consistent with the explanation of the Miraculous Mystery Score. Oh Gui? The first part of the song is "The Miraculous Secret Score", and the second part is "The Miraculous Secret Score".
There is another zheng music "high mountains and flowing water", music and zither music is very different, also taken from "Bo Ya drum qin meets the soulmate". There are a variety of existing schools of music. The most widely circulated and influential is the Zhejiang Wulin School's score, which has an elegant melody and timeless flavor, with the appearance of "towering mountains and flowing water".
Shandong's "High Mountains and Flowing Water" is a combination of four small songs: "Zither Rhythm", "Wind Swinging Cuizhu", "Quiet Night Allan Bells", and "Book Rhythm", which is also known as "Four Sections of Songs" and "Four Sections of Brocade".
Henan School of "High Mountains and Flowing Water" is taken from the folk "old six board" board head song, the rhythm is fresh and bright, folk artists often play at the first meeting, to show respect for the friendship. These three and the guqin song "High Mountains and Flowing Water" have nothing **** the same place between them, are the same name and a different song.
The legend
Legend has it that the pre-Qin qin master Bo Ya once played the qin in the deserted mountains, and the woodcutter Zhong Ziqi was able to comprehend that this was a depiction of the "lofty ambition in the high mountains" and "oceanic ambition in the flowing water". Bo Ya was shocked and said, "Good, Zi Zhi's heart is the same as mine." After the death of Ziqi, Bo Ya lost his soulmate, broke his qin and never played it, hence the song of "High Mountains and Flowing Water".
During the Spring and Autumn Period, there was a man named Yu Bo Ya, who was proficient in music, and had a high level of skill in the qin, and was a famous qin master at that time. When Yu Bo Ya was young, he was smart and studious, and he studied under a master, and his zither skills reached a high level, but he always felt that he could not yet express his feelings about various things in an extraordinary way. Knowing his thoughts, Bo Ya's teacher took him to Penglai Island in the East China Sea by boat, so that he could enjoy the scenery of nature and listen to the sound of the waves of the sea. When Bo Ya lifted his eyes and looked out, he saw the waves surging and splashing; the sea birds flying and chirping in his ears; the mountains and trees, lush and green, as if he was in a fairyland. A wonderful feeling arose, as if the ear clucked up the harmony of nature's music. He couldn't help but take the zither and play, and the sound turned freely, melting the beauty of nature into the sound of the zither, and Boya experienced a realm he had never known before. The teacher told him, "You have learned."
One night Bo Ya took a boat trip. Facing the breeze and the moon, he was overwhelmed with thoughts, so he played the zither again, and the sound of the zither was melodious, getting better and better. Suddenly heard someone on the shore called. Bo Ya heard the sound out of the boat, only to see a woodcutter standing on the shore, he knew that this person is the soulmate immediately invited the woodcutter on board, excited to play for him. When Bo Ya played a tune in praise of the mountains, the woodcutter said, "That's great! Majestic and solemn, as if towering over Mount Tai!" When he played a tune expressing the surging waves, the woodcutter said, "How wonderful! Wide and voluminous, as if seeing the rolling water, the boundless sea in general!" Boya was excited and said excitedly, "You are my soulmate! You are really my soulmate." This woodcutter was Zhong Ziqi. From then on, they became very good friends.
One of the five elements. The five elements of the kidney is water, so often kidney, water and the same name. Also used to refer to the name of the disease or the pathogenesis of edema.
A compound of hydrogen and oxygen. Chemical molecular formula for H2O . In nature , pure water is rare, and water is usually a solution of many acids, bases, salts and other substances. Pure water is obtained by several distillations using platinum or quartz vessels. Water is a substance that can be transformed between liquid, gas, and solid states. The conditions for transformation are temperature and pressure. At standard atmospheric pressure, water has a freezing point of 0°C and a boiling point of 100°C. When the water vapor temperature is above 374.5°F, the water vapor temperature is above 0.5°F. When the water vapor temperature is higher than 374.2 ℃, the gaseous water can not be converted into liquid water. The specific heat capacity of liquid water is 4.18 Joule / (g - degrees Celsius), the specific heat capacity of ice is about 2.09 Joule / (g - degrees Celsius). In 1 standard atmosphere and 100 ℃, the heat of vaporization of water for 2253.02 J / g, at room temperature and pressure for 2441.12 J / g, water vapor condenses into liquid water when the same amount of heat released. At 0 ℃ and 1 standard atmospheric pressure, the heat of melting of ice is 333.146 J / g, when the water condenses into ice when the same amount of heat released. Water from a solid state directly into a gaseous state when the heat absorbed called the heat of sublimation, the heat of sublimation is equal to the heat of vaporization and the heat of fusion and the sum of the heat. At 20 ℃, the thermal conductivity of water is 0.006 Joule / (second - cm - degrees Celsius), the thermal conductivity of ice is 0.023 Joule / (second - cm - degrees Celsius), when the density of snow is 0.1 kg / liter, the thermal conductivity of snow is 0.00029 Joule / (second - cm - degrees Celsius). The density of water at 3.98 ℃ when the maximum , for 1 kg / liter, the temperature is higher than 3.98 ℃, the density of water with the temperature increases and decreases in 0 ~ 3.98 ℃, water a reverse thermal expansion and contraction of the law, the density with the increase in temperature and increase. Water at 0 ℃, the density of 0.99987 kg / liter, ice at 0 ℃, the density of 0.9167 kg / liter. The thermal stability of water is very strong, when the water vapor heated to more than 2000K, only a very small part of the dissociation of hydrogen and oxygen. Any acidic or basic oxides that are soluble in water can react with water to produce the corresponding oxygenated acids or bases. Pure water has a very weak ability to conduct electricity. The acidity and alkalinity of water is expressed in terms of pH, and the pH of natural water is 6.8 to 8.5. Water has a great cohesion and surface tension, in addition to mercury, the surface tension of water is the largest, and can produce the phenomenon of capillary and adsorption phenomenon.
Water can regulate the climate. Atmospheric water vapor can block 60% of the Earth's radiation, to protect the Earth from cooling. Oceans and land bodies of water in the summer can absorb and accumulate heat, so that the temperature is not too high, in winter can slowly release heat, so that the temperature is not too low. Water erodes rocky soil, silts rivers, carries sediment, creates plains, and changes surface patterns. Water makes life on earth, it is the main component of all organisms, global plants and animals and 4 billion people contain about 1,120 billion tons of water. Human society depends on water for survival and development. In ancient times, human beings take advantage of water to avoid harm, adapt to water and survival; in modern times, human beings on the water to benefit and eliminate harm, construction projects, the development of water conservancy, water damage control; modern times, with the development of society and production, the earth's available water is increasingly short of water, the water body is polluted, seriously affecting the environment for the survival of mankind, mankind gradually realized that the water is a kind of important resources and environmental factors, so that the water in a higher level began to carry out the The new Xingli avoid harm activities.
World Meteorological Organization in early 1996 pointed out that: water shortage is the world's cities face the primary problem, it is estimated that by 2050, the world's more than 2/3 of the population will be living in the city, and 46% of the world's urban population water shortages, it is necessary to balance the socio-economic development and management of the city's freshwater supply of water supply between the two, water resources, water resources storage, transportation and management of large-scale engineering construction.
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Water is a general term for posts of little value on a forum, and every such post is called a "water post. ", the act of posting water is called "flooding", some followers and are all water post post is called "water floor", often occupy a position not to speak called "diving ". Some forums like high post counts and encourage flooding, however academic forums generally prohibit flooding
Benzene
Benzene
Pinyin:běn
Chinese Character: 艹,部外笔画:5,总笔画:8 ; Traditional Character: 艹,部外笔画:5,TotalStrokes:11
Wuwen86&98:ASGF 仓颉. TDM
Stroke Number:12212341 Quadrangle Number:44234 UniCode:CJK Unified Chinese Character U+82EF
Basic Character Meanings
● Benzene
běn Bㄅㄆ?
◎ An organic compound, a colorless liquid, with a peculiar odor, which can be extracted from coal tar and petroleum, and is the raw material and solvent of a variety of raw materials and solvents for the chemical industry.
Chinese-English Translation
◎ benzene
benzene
English
◎ benzene; luxuriant
Detailed Character Meanings
◎ benzene běn