Characteristics of explosive and harmful gases, most often found in tanks and underground structures. Pollutants and their impact on human health Colorless, odorless gas slightly lighter than air

Ethylene (ethene) is a colorless gas with a very faint sweet smell, slightly lighter than air, and slightly soluble in water.

C 2 - C 4 (gases)

C 5 - C 17 (liquids)

From 18 - (hard)

Alkenes are insoluble in water, soluble in organic solvents (gasoline, benzene, etc.)

lighter than water

With increasing Mr, the melting and boiling points increase

The simplest alkene is ethylene - C 2 H 4

Structural and electronic formula ethylene look like:

In the ethylene molecule, one s- and two p-orbitals of C atoms ( sp 2 - hybridization).

Thus, each C atom has three hybrid orbitals and one non-hybrid orbital. p-orbitals. Two of the hybrid orbitals of C atoms mutually overlap and form between C atoms

σ - connection. The remaining four hybrid orbitals of C atoms overlap in the same plane with four s-orbitals of H atoms and also form four σ-bonds. Two non-hybrid p-orbitals of C atoms mutually overlap in a plane that is perpendicular to the plane σ - bond, i.e. one is formed P- connection.

By it's nature P- connection sharply differs from σ - connection; P- the bond is less strong due to the overlap of electron clouds outside the plane of the molecule. Under the influence of reagents P- the connection is easily broken.

The ethylene molecule is symmetrical; the nuclei of all atoms are located in the same plane and the bond angles are close to 120°; the distance between the centers of C atoms is 0.134 nm.

SP 2 - hybridization:

1) Flat trigonal structure

2) Angle - HCH - 120°

3) Length (-C=C-) bond - 0.134 nm

4) Bonds - σ, P

5) Impossible to rotate relative to (-C=C-) connection

If the atoms are connected by a double bond, then their rotation is impossible without electron clouds P- the connection is not opened.

Carbon monoxide (carbon monoxide).

carbon monoxide- colorless gas, odorless, slightly lighter than air, poorly soluble in water, has a boiling point: - 191.5°C. In air, it ignites at a temperature of 700 ° C and burns with a blue flame to CO 2 .

Sources of release into the environment.

Carbon monoxide is part of the atmosphere (10%). Carbon monoxide enters the atmosphere as part of volcanic and swamp gases, as a result of forest and steppe fires, release by microorganisms, plants, animals and humans. From the surface layers of the oceans, 220x10 6 tons of carbon monoxide are released annually as a result of photodecomposition of red, blue-green and other algae, the waste products of plankton. The natural level of carbon monoxide in atmospheric air- 0.01-0.9 mg / m 3.

Carbon monoxide enters the atmosphere from industrial enterprises, primarily metallurgy. In metallurgical processes, smelting 1 million tons of steel produces 320-400 tons of carbon monoxide. A large number of CO is formed in the oil industry and at chemical enterprises (cracking of oil, production of formalin, hydrocarbons, ammonia, etc.). Another important source of carbon monoxide is tobacco smoke. The concentration of carbon monoxide is high in coal mines, on coal supply routes. Carbon monoxide is formed during the incomplete combustion of fuel in furnaces and internal combustion engines. An important source of carbon monoxide is road transport.

As a result of human activity, 350-600x10 6 tons of carbon monoxide enter the atmosphere annually. About 56-62% of this amount is accounted for by vehicles (the content of carbon monoxide in exhaust gases can reach 12%).

Behavior in environment.

Under normal conditions, carbon monoxide is inert. It does not chemically interact with water. The solubility of CO in water is about 1:40 by volume. In solution, it is able to reduce salts of gold and platinum to free metals already at ordinary temperature. CO also does not react with alkalis and acids. It interacts with caustic alkalis only at elevated temperatures and high pressures.

The loss of carbon monoxide in the environment occurs due to its decomposition by soil fungi. In addition, with an excess of oxygen in soils of heavy mechanical composition, rich in organic matter, there is a transition of CO to CO 2 .

Impact on the human body.

Carbon monoxide is extremely toxic. The permissible content of CO in industrial premises is 20 mg / m 3 during the working day, 50 mg / m 3 for 1 hour, 100 mg / m 3 for 30 minutes, in the atmospheric air of the city the maximum one-time (for 20 minutes) - 5 mg / m 3, the average daily MPC - 3 mg / m 3. The natural level of carbon monoxide in the atmospheric air is 0.01-0.9 mg/m 3 .

CO is breathed in with the air and enters the blood, where it competes with oxygen for hemoglobin molecules. Carbon monoxide, having a double chemical bond, binds to hemoglobin more firmly than an oxygen molecule. The more CO2 in the air, the more hemoglobin molecules bind to it and the less oxygen reaches the cells of the body. The ability of blood to deliver oxygen to tissues is impaired, vasospasm is caused, the immunological activity of a person decreases, accompanied by headache, loss of consciousness and death. For these reasons, CO in elevated concentrations is a deadly poison.

CO disrupts phosphorus metabolism. Violation of nitrogen metabolism causes zotemia, a change in the content of plasma proteins, a decrease in the activity of blood cholinesterase and the level of vitamin B 6 . Carbon monoxide affects carbohydrate metabolism, enhances the breakdown of glycogen in the liver, disrupting the utilization of glucose, and raising blood sugar levels. The flow of CO from the lungs into the blood is due to the concentration of CO in the inhaled air and the duration of inhalation. The release of CO occurs mainly through the respiratory tract.

The central nervous system suffers most from poisoning. When inhaled at low concentrations (up to 1 mg/l), heaviness and a feeling of squeezing the head, severe pain in the forehead and temples, dizziness, trembling, thirst, increased heart rate, nausea, vomiting, fever up to 38-40 ° C. Weakness in the legs indicates the spread of action to the spinal cord.

The extreme toxicity of CO, its lack of color and odor, as well as the very weak absorption of it by activated carbon in a conventional gas mask, make this gas especially dangerous.

Ammonia.

Ammonia- colorless gas with a pungent odor, melting point - 80°C, boiling point - 36°C, soluble in water, alcohol and a number of other organic solvents. Synthesized from nitrogen and hydrogen. In nature, it is formed during the decomposition of nitrogen-containing organic compounds.

Finding in nature.

In nature, it is formed during the decomposition of nitrogen-containing organic compounds.

The pungent smell of ammonia has been known to man since prehistoric times, since this gas is formed in significant quantities during the decay, decomposition and dry distillation of organic compounds containing nitrogen, such as urea or proteins. It is possible that in the early stages of the Earth's evolution there was quite a lot of ammonia in its atmosphere. Even now, however, minute amounts of this gas can always be found in the air and in rainwater, since it is continuously formed during the decomposition of animal and vegetable proteins.

Anthropogenic sources of entry into the environment.

The main sources of ammonia emission are nitrogen-fertilizer plants, enterprises for the production nitric acid and ammonium salts, refrigeration plants, coking plants and livestock farms. In areas of technogenic pollution, ammonia concentrations reach 0.015-0.057 mg/m 3 , in control areas - 0.003-0.005 mg/m 3 .

Impact on the human body.

This gas is toxic. A person is able to smell ammonia in the air already at a negligible concentration - 0.0005 mg / l, when not yet great danger for good health. With a 100-fold increase in concentration (up to 0.05 mg / l), an irritating effect of ammonia on the mucous membrane of the eyes and upper respiratory tract is manifested, even reflex respiratory arrest is possible. The concentration of 0.25 mg / l can hardly withstand for an hour even very healthy man. Even higher concentrations cause chemical burns to the eyes and respiratory tract and become life-threatening. External signs Ammonia poisoning can be quite uncommon. In victims, for example, the hearing threshold drops sharply: even not too loud sounds become unbearable and can cause convulsions. Ammonia poisoning also causes strong excitement, up to violent delirium, and the consequences can be very severe - up to a decrease in intelligence and a change in personality. Obviously, ammonia is capable of affecting the vital centers, so that when working with it, precautions must be carefully observed.

Chronic exposure to sublethal doses of ammonia leads to autonomic disorders, increased excitability of the parasympathetic nervous system, complaints of weakness, malaise, runny nose, cough, chest pain.

Substance hazard class - 4.

1 water contains oxygen
2 fish breathe oxygen dissolved in water
3 Vessel filled with oxygen
4 The graphite lead of the pencil represents carbon
5 Air contains nitrogen
6 Nitrogen is a colorless gas, slightly lighter than air.

Colorless gas A, which is the main component of air, at elevated temperatures and pressure in the presence of a catalyst, reacted with

hydrogen. As a result, a colorless gas B with a characteristic pungent odor was obtained, which is highly soluble in water. solution B, which is able to color phenolphthalein crimson, absorbed the gaseous (n.o.) substance C, obtained by the action of concentrated sulfuric acid on common salt. At the same time, a solution of salt D was formed, upon addition of which a white curdled precipitate D precipitated to a solution of silver (I) nitrate.

Colorless liquid A was heated with zinc, and gas B was released, colorless and practically odorless, slightly lighter than air. When oxidized with oxygen

In the presence of palladium and copper chlorides, B turns into C. When the vapors of C are passed along with hydrogen over a heated nickel catalyst, compound D is formed.
Choose these substances A-D:
1) CO
2) CH3-CH2-Br.
3) CH3-CH2-OH
4) CH2=CH2
5) CH2Br-CH2Br
6) CH3-CH=O

1. In two identical vessels at n. y. contains 3.36 liters of two colorless gases A and B, each of which is 3.45% lighter than air. When gas is burned

in oxygen, water is not found in the reaction products, and when gas B is burned, water is found. What mass of a 15% solution of lime water will be required to absorb the products of combustion of gases A and B with the formation acid salt? 2. carbon dioxide, formed during the complete combustion of 0.1 mol of an unknown alkane, was passed through an excess of lime water. At the same time, 40 grams of a white precipitate fell out. Determine the molecular formula of this hydrocarbon 3. A mixture of barium and sodium carbonates weighing 150 grams was dissolved in excess of hydrochloric acid. An excess of sodium sulfate solution was added to the resulting solution. At the same time, 34.95 grams of sediment fell. determine the mass fractions of carbonates in the mixture. 4. Given 10 grams of a mixture of aluminum, magnesium and silicon oxide IV. When it was dissolved in a concentrated solution of sodium hydroxide, 6.72 liters of hydrogen were obtained. When the same mixture was dissolved in hydrochloric acid, 8.96 liters of hydrogen were obtained. Calculate the mass fractions of the components of the mixture. 5. Phosphorus oxide obtained by burning phosphorus was dissolved in a 25% sodium hydroxide solution (p = 1.28 g / ml) to form 24 grams of sodium dihydrogen phosphate. Calculate the mass of oxidized phosphorus and the volume of alkali used 6. Manufacturer refrigeration equipment « Electrolux» in quality refrigerant uses hydrocarbon, cyclical buildings, having density on methane 4 ,375 . Determine molecular formula this hydrocarbon

Poison gas is toxic Chemical substance, which causes intoxication of the body and damage to internal organs and systems. Falls through respiratory system, skin, gastrointestinal tract.

List of poison gases according to their toxicological effects:

1. Nerve-paralytic - carbon monoxide, sarin.
2. Skin-blisters - lewisite, mustard gas.
3. Asphyxiants - phosgene, diphosgene, chlorine.
4. Lacrimal - bromobenzyl cyanide, chloroacetophenone.
5. General impact - hydrocyanic acid, cyanogen chloride.
6. Irritant - adamsite, CR, CS.
7. Psychotomimetic - BZ, LSD-25.

Consider the most dangerous gases, the mechanism of their defeat, signs of poisoning in humans.

Sarin

Sarin is a poisonous liquid substance that at a temperature of 20 °C quickly evaporates and has a nerve-paralytic effect on the human body. As a gas, it is colorless and odorless, most dangerous if inhaled.

Symptoms appear immediately upon inhalation. The first signs of poisoning are shortness of breath, constriction of the pupil.

Clinical manifestations:

• irritation of the nasal mucosa, liquid discharge;
• salivation, vomiting;
• chest tightness;
• shortness of breath, blue skin;
• spasm of the bronchi and increased formation of mucus in them;
• pulmonary edema;
• severe cramps and pain in the abdomen.

In case of ingestion of high concentrations of sarin vapours, severe brain damage occurs after 1-2 minutes. A person cannot control the physiological functions of the body - involuntary defecation and urination. There are convulsions, convulsions. A coma develops followed by cardiac arrest.

Mustard gas

Mustard gas is mustard gas. This is chemical compound blistering action. In liquid form, the substance has the smell of mustard. It enters the body in two ways - by airborne droplets and by contact of liquid with the skin. Has a tendency to accumulate. Signs of poisoning appear after 2-8 hours.

Symptoms of gas intoxication by inhalation:

• damage to the mucous membrane of the eyes;
• lacrimation, photophobia, feeling of sand in the eyes;
• dryness and burning in the nose, then swelling of the nasopharynx with purulent discharge;
• laryngitis, tracheitis;
• bronchitis.

If liquid enters the eyes, it will cause blindness. In severe poisoning with mustard gas, pneumonia develops, death occurs on the 3-4th day from suffocation.

Symptoms of gas poisoning upon contact with the skin are redness followed by the formation of vesicles containing serous fluid, skin lesions, ulcers, necrosis. Gas destroys cell membranes, disrupts carbohydrate metabolism, partially destroys DNA and RNA.

Lewisite

Lewisite is the strongest toxic substance, the vapors of which are able to penetrate through a chemical protection suit and a gas mask. It is a brown liquid with a pungent odor. The gas is classified as a skin blister agent. Acts on the body instantly and has no latent period.

Symptoms of gas poisoning in case of damage to the skin develop within 5 minutes:

• pain and burning at the point of contact;
• inflammatory changes;
• painful redness;
• the formation of bubbles, they quickly open;
• the appearance of erosion, heal for several weeks;
• in severe cases, when large concentrations of lewisite are ingested, deep ulcers form.

Gas inhalation symptoms:

• damage to the mucous membrane of the nasopharynx, trachea, bronchi;
• nasal fluid;
• sneezing, coughing;
• headache;
• nausea, vomiting;
• loss of voice
• feeling of pressure in the chest, shortness of breath.

The mucous membrane of the eyes is highly sensitive to poisonous gas.. It becomes red, eyelids swell, lacrimation intensifies. The person experiences a burning sensation in the eyes. When liquid lewisite enters the gastrointestinal tract, the victim begins to profuse salivation and vomiting. Sharp pains in an abdominal cavity join. Are amazed internal organs, blood pressure falls sharply.

hydrogen sulfide

Hydrogen sulfide is a colorless gas with a pungent odor of rotten eggs. AT high concentrations substance is highly toxic. Entering the body by inhalation, symptoms of general intoxication develop - headache, dizziness, weakness. Hydrogen sulfide is rapidly absorbed into the blood and affects the central nervous system.

Signs of gas poisoning:

• metallic taste in mouth;
• paralysis of the nerve responsible for smell, so the victim immediately ceases to feel any smells;
• respiratory tract damage, pulmonary edema;
• severe convulsions;
• coma.

Carbon monoxide

Carbon monoxide is a colorless poisonous substance, lighter than air. Entering the body through the respiratory tract, it is rapidly absorbed into the blood and binds to hemoglobin. This blocks the transport of oxygen to all cells, oxygen starvation sets in, and cellular respiration stops.

Symptoms of carbon monoxide poisoning:

• dizziness and headache;
• rapid breathing and heartbeat, shortness of breath;
• noise in ears;
• impaired visual acuity, flickering in the eyes;
• skin redness;
• nausea, vomiting.

In severe poisoning, convulsions are observed. The symptoms preceding the coma are growing - a drop in blood pressure, severe weakness, loss of consciousness. In the absence of medical care, death occurs within 1 hour.

Phosgene

Phosgene is a colorless gas with an odor of rotten hay. The substance is dangerous if inhaled, the first signs of intoxication appear after 4-8 hours. At high concentrations, death occurs within 3 seconds. Gas, getting into the lungs, destroys them, causing instant swelling.

Symptoms at different stages of poisoning:

1. Pulmonary edema begins to develop in the latent period, when the victim is unaware of poisoning. The first signals from the body are a sweet, sugary taste in the mouth, nausea. Sometimes there is vomiting. A person feels a sore throat, itching and burning in the nasopharynx. There is a cough reflex, breathing and pulse are disturbed.
2. After a latent period, the victim's condition deteriorates sharply. There is a strong cough, the person begins to choke. Blue skin and lips.
3. The stage of progressive deterioration - strong pressure in chest, leading to suffocation, the respiratory rate increases by 70 per minute (norm 18). The lungs produce a lot of fluid and mucus due to the decomposition of the alveoli. The person coughs up bloody sputum. Breathing becomes impossible. 50% of the BCC (volume of circulating blood) goes to the lungs and increases them. The mass of one lung can be 2.5 kg (norm 500-600 g).

In severe cases, death in 10-15 minutes. In case of gas poisoning of moderate severity, death occurs in 2-3 days. Recovery can occur 2-3 weeks after poisoning, but this is rare due to infection.

Hydrocyanic acid

Hydrocyanic acid is a colorless, light and mobile liquid with a pronounced odor. It blocks the chain of oxygen movement through the tissues, causing tissue hypoxia. Gas affects the nervous system, disrupting the innervation of organs.

Symptoms of respiratory poisoning:

• dyspnea;
• at the beginning of the development of the clinical picture, frequent breathing;
• with severe intoxication - respiratory depression and its stop.

Signs from the heart:

• slowing down of heart beats;
• increase in blood pressure;
• vasospasm;
• as symptoms increase - pressure drop, increased heart rate, acute cardiovascular failure, cardiac arrest.

Poison gases are strong, fast-acting substances. Emergency resuscitation measures are needed to save a person. With a favorable outcome, the victim needs long-term rehabilitation treatment.

In tanks and underground structures, explosive and harmful gases: methane, propane, butane, propylene, butylene, carbon monoxide, carbon dioxide, hydrogen sulfide and ammonia.

Methane CH 4(marsh gas) - colorless, odorless, combustible gas, lighter than air. Penetrates into underground structures from the soil. It is formed during the slow decomposition of plant substances without air access: during the decay of fiber under water (in swamps, stagnant waters, ponds) or decomposition of plant residues in deposits hard coal. Methane is integral part industrial gas and, in case of a faulty gas pipeline, can penetrate into underground structures. It is not poisonous, but its presence reduces the amount of oxygen in the air of underground structures, which leads to a violation of normal breathing when working in these structures. When the content of methane in the air is 5-15% by volume, an explosive mixture is formed.

Propane C 3 H 8, butane C 4 H 10, propylene C 3 H 6 and butylene C 4 H 8- colorless combustible gases, heavier than air, odorless, difficult to mix with air. Inhalation of propane and butane in small amounts does not cause poisoning; propylene and butylene have a narcotic effect.

Liquefied gases with air can form explosive mixtures with the following content, % by volume:

Propane 2.1-9.5

Butane 1.6-8.5

Propylene 2.2-9.7

Butylene 1.7-9.0

Means of protection - hose gas masks PSh-1, PSh-2, self-rescuers SPI-20, PDU-3, etc.

Carbon monoxide CO- colorless gas, odorless, flammable and explosive, slightly lighter than air. Carbon monoxide is extremely poisonous. The physiological effect of carbon monoxide on a person depends on its concentration in the air and the duration of inhalation.

Inhalation of air containing carbon monoxide above the maximum permissible concentration can lead to poisoning and even death. When the content in the air is 12.5-75% by volume of carbon monoxide, an explosive mixture is formed.

Means of protection - a filtering gas mask of the SO brand, self-rescuers SPI-20, PDU-3, etc.

Carbon dioxide CO 2(carbon dioxide) - a colorless gas, odorless, with a sour taste, heavier than air. Penetrates into underground structures from the soil. Formed as a result of decomposition organic matter. It is also formed in reservoirs (tanks, bunkers, etc.) in the presence of sulfocoal or coal in them due to its slow oxidation.

Getting into the underground structure, carbon dioxide displaces air, filling the space of the underground structure from the bottom. Carbon dioxide is not poisonous, but it has a narcotic effect and can irritate mucous membranes. At high concentrations, it causes asphyxiation due to a decrease in the oxygen content in the air.

Means of protection - hose gas masks PSh-1, PSh-2, self-rescuers SPI-20, PDU-3, etc.

Hydrogen sulfide H 2 S- a colorless combustible gas, has the smell of rotten eggs, somewhat heavier than air. Poisonous, acts on the nervous system, irritates the respiratory tract and eyes.

Means of protection - filtering gas masks of grades V, KD, self-rescuers SPI-20, PDU-3, etc.

Ammonia NH3- a colorless combustible gas with a pungent characteristic odor, lighter than air, poisonous, irritating to the eyes and respiratory tract, causes suffocation. When the content of ammonia in the air is 15-20% by volume, an explosive mixture is formed.

Means of protection - a filtering gas mask of the KD brand, self-rescuers SPI-20, PDU-3, etc.

Hydrogen H 2 It is a colourless, odorless, flammable gas, much lighter than air. Hydrogen is a physiologically inert gas, but at high concentrations it causes asphyxiation due to a decrease in oxygen content. When acid-containing reagents come into contact with the metal walls of containers that do not have an anti-corrosion coating, hydrogen is formed. When the hydrogen content in the air is 4-75% by volume, an explosive mixture is formed.

Oxygen O 2- colorless gas, odorless and tasteless, heavier than air. It does not have toxic properties, but with prolonged inhalation of pure oxygen (with atmospheric pressure) death occurs due to the development of pleural pulmonary edema.

Oxygen is not combustible, but is the main gas supporting the combustion of substances. Highly active, connects with most elements. Oxygen forms explosive mixtures with combustible gases.