The molecular, structural and electronic formulas of methane are compiled on the basis of Butlerovâs theory of the structure of organic substances. Before starting to write such formulas, we start with a brief description of this hydrocarbon.
Methane features
This substance is explosive, it is also called "swamp" gas. The specific smell of this saturated hydrocarbon is known to all. In the combustion process, there are no chemical components left from it that have a negative effect on the human body. Methane is an active participant in the formation of the greenhouse effect.
Physical properties
The first representative of the homologous series of alkanes was discovered by scientists in the atmosphere of Titan and Mars. Given the fact that methane is associated with the existence of living organisms, a hypothesis has appeared about the existence of life on these planets. On Saturn, Jupiter, Neptune, Uranus, methane appeared as a product of chemical processing of inorganic substances. On the surface of our planet, its content is negligible.
general characteristics
Methane has no color, it is almost twice lighter than air, it is poorly soluble in water. In the composition of natural gas, its amount reaches 98 percent. Petroleum associated gas contains between 30 and 90 percent methane. To a greater extent, methane is of biological origin.
Ungulate herbivorous goats and cows emit quite a significant amount of methane during processing in the stomachs of bacteria. Among the important sources of the homologous series of alkanes, we distinguish swamps, termites, natural gas filtration, and plant photosynthesis. If traces of methane are found on the planet, we can talk about the existence of biological life on it.
Production methods
The detailed structural formula of methane confirms that in its molecule there are only saturated single bonds formed by hybrid clouds. Among laboratory options for producing this hydrocarbon, we note the fusion of sodium acetate with solid alkali, as well as the interaction of aluminum carbide with water.
Methane burns with a bluish flame, while emitting about 39 MJ per cubic meter. This substance forms explosive mixtures with air. The most dangerous is methane, which is released during underground mining of mineral deposits in mining mines. There is a high risk of methane explosion both in coal and briquette enrichment plants, as well as in sorting plants.
Physiological effect
If the percentage of methane in the air is from 5 to 16 percent, methane can be ignited if oxygen enters. In the case of a significant increase in the mixture of a given chemical substance, the probability of an explosion increases.
If the concentration of this alkane in the air is 43 percent, it is the cause of suffocation.
In an explosion, the propagation speed is between 500 and 700 meters per second. After methane is in contact with a heat source, the ignition of the alkane occurs with some delay.
It is on this property that the production of explosion-proof electrical equipment and safety explosive components is based.
Since methane is the most thermally stable saturated hydrocarbon, it is widely used in the form of industrial and domestic fuel, and is also used as a valuable raw material for chemical synthesis. The structural formula of tri-ethyl methane characterizes the structural features of representatives of this class of hydrocarbons.
In the process of its chemical interaction with chlorine under the influence of ultraviolet radiation, the formation of several reaction products is possible. Depending on the amount of the starting material, chloromethane, chloroform, carbon tetrachloride can be obtained during the substitution.
In case of incomplete combustion of methane, soot is formed. In the case of catalytic oxidation, formaldehyde is formed. The final product of the interaction with sulfur is carbon disulfide.
Structural Features of Methane
What is its structural formula? Methane refers to saturated hydrocarbons having the general formula C n H 2n + 2 . Consider the features of the formation of the molecule to explain how the structural formula is formed.
Methane consists of one carbon atom and four hydrogen atoms bonded together by a covalent polar chemical bond. Let us explain the structural formulas based on the structure of the carbon atom.
Type of hybridization
The spatial structure of methane is characterized by a tetrahedral structure. Since carbon has four valence electrons at the external level, when an atom is heated, the electron transfers from the second s-orbital to p. As a result, at the last energy level, carbon has four unpaired ("free") electrons. The complete structural formula of methane is based on the formation of four hybrid clouds, which are oriented in space at an angle of 109 degrees 28 minutes, forming the structure of the tetrahedron. Next, the vertices of the hybrid clouds overlap with non-hybrid clouds of hydrogen atoms.
The complete and abridged structural formula of methane fully corresponds to Butlerovâs theory. A simple (single) bond is formed between carbon and hydrogens; therefore, the attachment reaction is not typical for this chemical.
The final structural formula is presented below. Methane is the first representative of the class of saturated hydrocarbons, it has the typical properties of a saturated alkane. The structural and electronic formulas of methane confirm the type of hybridization of the carbon atom in a given organic substance.
From a school chemistry course
This class of hydrocarbons, the representative of which is âswamp gasâ, is studied in the course of the 10th grade of high school. For example, the children are offered a task of the following nature: "Write the structural formulas of methane." It must be understood that for this substance, only a detailed structural configuration can be described according to Butlerovâs theory.
Its abbreviated formula will coincide with the molecular one, written in the form of CH4. According to the new federal educational standards, which were introduced in connection with the reorganization of Russian education, in the basic chemistry course all questions relating to the characterization of classes of organic substances are dealt with in an overview.
Industrial synthesis
Based on methane, industrial processes have been developed for such an important chemical component as acetylene. The basis of thermal and electrical cracking was precisely its structural formula. During catalytic oxidation with ammonia, methane forms hydrocyanic acid.
This organic substance is used to produce synthesis gas. When interacting with water vapor, a mixture of carbon monoxide and hydrogen is obtained, which is the raw material for the production of saturated monohydric alcohols and carbonyl compounds.
Of particular importance is the interaction with nitric acid, which results in nitromethane.
Automotive fuel
Due to the lack of natural sources of hydrocarbons, as well as the impoverishment of the raw material base, the issue of finding new (alternative) sources for obtaining fuel is of particular relevance. One of these options is biodiesel, which also contains methane.
Given the difference in density between gasoline fuel and the first representative of the class of alkanes, there are certain features of its use as an energy source for automotive engines. In order to avoid the need to carry a huge amount of methane with it, its density is increased by compression (at a pressure of about 250 atmospheres). They store methane in a liquefied state in cylinders installed in automobiles.
Atmospheric effects
We have already discussed that methane has an effect on the greenhouse effect. If the degree of action of carbon monoxide (4) on the climate is taken conditionally per unit, then the share of âswamp gasâ in it is 23 units. Over the past two centuries, scientists have observed an increase in the quantitative content of methane in the earth's atmosphere.
At the moment, the approximate amount of CH 4 is estimated at 1.8 parts per million. Despite the fact that this indicator is 200 times less than the presence of carbon dioxide, there is a conversation between scientists about the possible risk of retaining the heat radiated by the planet.
Due to the excellent calorific value of âswamp gasâ, it is used not only as a feedstock for chemical synthesis, but also as an energy source.
For example, methane operates a variety of gas boilers, water heaters designed for an individual heating system in private houses and country cottages.
Such an autonomous heating option is very beneficial for homeowners, not associated with accidents systematically occurring in centralized heating systems. Thanks to the gas boiler operating on this type of fuel, 15-20 minutes are enough to completely warm the two-story cottage.
Conclusion
Methane, the structural and molecular formulas of which were given above, is a natural source of energy. Due to the fact that it contains only a carbon atom and hydrogen atoms, ecologists recognize the environmental safety of this saturated hydrocarbon.
Under standard conditions (air temperature 20 degrees Celsius, pressure 101325 Pa) this substance is gaseous, non-toxic, insoluble in water.
If the air temperature drops to -161 degrees, methane is compressed, which is widely used in industry.
Methane has an impact on human health. It is not a toxic substance, but is considered a choking gas. There are even limit standards (MPC) for the content of a given chemical in the atmosphere.
For example, work in mines is permitted only in cases where its quantity does not exceed 300 milligrams per cubic meter. Analyzing the structural features of this organic substance, we can conclude that it is similar in chemical and physical properties to all other representatives of the class of saturated (limiting) hydrocarbons.
We analyzed the structural formulas, the spatial structure of methane. The homologous series, which begins the "swamp gas", has the general molecular formula C n H 2n + 2 .