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 of an 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 an 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

Explosive and harmful gases are most often found in tanks and underground structures: 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 vegetable matter without access to air: during the decay of fiber under water (in swamps, stagnant waters, ponds) or the decomposition of plant residues in coal deposits. Methane is an integral part of industrial gas and, in the event 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 the decomposition of 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, affects 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 (at 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.

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

The structural and electronic formulas of ethylene are:

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.

Natural gas is a mineral that lies in the bowels of the Earth in a gaseous state. It can represent either individual accumulations (gas deposits) or a gas cap of oil and gas fields. Natural gas and its components are widely used in the national economy.

Composition of natural gas

Natural gas is 98% methane CH4, the properties of which almost completely determine the properties and characteristics of natural gas. It also contains methane homologues - C3H8 propane, C2H6 ethane and C4H10 butane. Sometimes natural gas can contain hydrogen sulfide, helium and carbon dioxide.

Methane (CH4)- colorless and odorless gas, lighter than air. Methane is combustible, but rather easily stored. Most often used as a fuel in industry and everyday life.

Ethane (C2H6)- a colorless and odorless gas, slightly heavier than air. Flammable no less than methane, but not used as a fuel. It is mainly used to produce ethylene, which is the most demanded organic substance in the world. It is the raw material for the production of polyethylene.

Propane (C3H8)- also a gas that is odorless and colorless, poisonous. Possesses useful property: at low pressure, propane liquefies, which greatly facilitates the process of separation from impurities and its transportation. Lighters are fueled with liquefied propane.

Butane (C4H10)- very similar in properties to propane, but has a higher density. Twice as heavy as air. Propane and butane are widely used today as an alternative fuel for cars.

Carbon Dioxide (CO2)- low-toxic colorless gas, odorless, but with a sour taste. Unlike other components of the natural gas composition (except helium), carbon dioxide is not flammable.

Helium (He)- an inert colorless gas, the second lightest (after hydrogen), odorless. Under normal conditions, it does not react with any of the substances. It is non-flammable and non-toxic, but can cause anesthesia at elevated pressure. The lightness and non-toxicity (unlike hydrogen) of helium have found their application. Helium fill airships, balloons and hot air balloons.

Hydrogen sulfide (H2S)– can sometimes be included in natural gas. It is a heavy colorless gas with a pungent odor of rotten eggs. Extremely poisonous, even a small concentration can cause paralysis of the olfactory nerve. Despite its toxicity, hydrogen sulfide is used in small doses for hydrogen sulfide baths, as it has good antiseptic properties.

Natural gas is the best type of fuel

Natural gas is an important source of energy to reduce pollution and help maintain a healthy environment. Compared to other energy sources, it has several advantages:

• burning, it emits only carbon dioxide and water vapor, this is a mixture that we usually breathe on the street;
• when burned, it does not emit soot and smoke;
• ignites quickly and its combustion process is easy to control;
• almost does not contain solid impurities and other harmful components;
• relative cheapness, due to an easier method of extraction and transportation.

In terms of its energy properties, natural gas is second only to oil, which releases more energy when burned. But unlike oil, which must first be processed, natural gas requires little or no pre-treatment.