How is co2 formed? Formula of carbon dioxide structural chemical

Carbon dioxide

Carbon monoxide(IV) (carbon dioxide, carbon dioxide, carbon dioxide, carbonic anhydride, carbonic acid ) — CO2, colorless gas, odorless, with a slightly sour taste.
The concentration of carbon dioxide in the Earth's atmosphere is on average 0.038%.
It is not suitable for life support. However, plants “feed” on it, turning it into organic matter. In addition, it is a kind of "blanket" of the Earth. If this gas suddenly disappears from the atmosphere, the Earth will become much cooler, and the rains will practically disappear.

"Blanket of the Earth"

Carbon dioxide (carbon dioxide, carbon dioxide, CO 2 ) is formed by combining two elements: carbon and oxygen. It is formed during the combustion of coal or hydrocarbon compounds, during the fermentation of liquids, and also as a product of the respiration of people and animals. In small quantities, it is also found in the atmosphere, from where it is assimilated by plants, which, in turn, produce oxygen.
Carbon dioxide is colorless and heavier than air. Freezes at −78.5°C to form snow composed of carbon dioxide. In the form of an aqueous solution, it forms carbonic acid, but it does not have sufficient stability to be easily isolated.
Carbon dioxide is the earth's "blanket". It easily transmits ultraviolet rays that heat our planet, and reflects infrared rays emitted from its surface into outer space. And if suddenly carbon dioxide disappears from the atmosphere, it will primarily affect the climate. It will become much cooler on Earth, it will rain very rarely. What this will eventually lead to is not difficult to guess.
True, such a catastrophe does not yet threaten us. Rather, on the contrary. Burning organic matter: oil, coal, natural gas, wood - gradually increases the carbon dioxide content in the atmosphere. This means that over time it is necessary to wait for a significant warming and moistening of the earth's climate. By the way, the old-timers believe that it is already noticeably warmer than it was during their youth...
Carbon dioxide is released liquid low temperature, liquid high pressure and gaseous. It is obtained from waste gases from the production of ammonia, alcohols, as well as on the basis of special fuel combustion and other industries. Gaseous carbon dioxide- colorless and odorless gas at a temperature of 20 ° C and a pressure of 101.3 kPa (760 mm Hg), density - 1.839 kg / m 3. Liquid carbon dioxide It is just a colorless, odorless liquid.
Carbon dioxide non-toxic and non-explosive. At concentrations above 5% (92 g/m 3 ), carbon dioxide has a harmful effect on human health - it is heavier than air and can accumulate in poorly ventilated rooms near the floor. This reduces the volume fraction of oxygen in the air, which can cause the phenomenon of oxygen deficiency and suffocation.

Getting carbon dioxide

In industry, carbon dioxide is obtained from furnace gases, from the decomposition products of natural carbonates (limestone, dolomite). The mixture of gases is washed with a solution of potassium carbonate, which absorbs carbon dioxide, turning into hydrogen carbonate. Hydrocarbonate solution decomposes when heated, releasing carbon dioxide. In industrial production, gas is pumped into cylinders.
Under laboratory conditions, small amounts are obtained by reacting carbonates and bicarbonates with acids, such as marble with hydrochloric acid.

Application

In the food industry carbon dioxide is used as a preservative and is indicated on the packaging under the code E290
liquid carbonic acid(liquid food carbon dioxide) - liquefied carbon dioxide stored under high pressure (~ 65-70 atm). Colorless liquid. When liquid carbon dioxide is released from the cylinder into the atmosphere, part of it evaporates, and the other part forms dry ice flakes.
Cylinders with liquid carbon dioxide are widely used as fire extinguishers and for the production of sparkling water and lemonade.
Carbon dioxide It is used as a protective medium in wire welding, but at high temperatures it dissociates with the release of oxygen. The released oxygen oxidizes the metal. In this regard, it is necessary to introduce deoxidizers, such as manganese and silicon, into the welding wire. Another consequence of the influence of oxygen, also associated with oxidation, is a sharp decrease in surface tension, which leads, among other things, to more intense metal spatter than when welding in argon or helium.
Carbon dioxide in cans used in pneumatic weapons and as a power source for engines in aircraft modeling.
Solid carbon dioxide - dry ice- used in glaciers. Liquid carbon dioxide is used as a refrigerant and working fluid in thermal power plants (refrigerators, freezers, solar power generators, etc.).

"Dry ice" and other beneficial properties of carbon dioxide

Carbon dioxide is widely used in everyday practice. For example, carbonated water with the addition of aromatic essences is a wonderful refreshing drink. In the food industry, carbon dioxide is also used as a preservative - it is indicated on the packaging under the code E290 and also as a baking powder.
Carbon dioxide fire extinguishers are used in case of fires. Biochemists have found that fertilizing ... the air with carbon dioxide is a very effective means of increasing the yield of various crops. Perhaps, such a fertilizer has a single, but significant drawback: it can only be used in greenhouses. At plants that produce carbon dioxide, liquefied gas is packaged in steel cylinders and sent to consumers. If you open the valve, then ... snow bursts out of the hole with a hiss. What a miracle
Everything is explained simply. The work expended on compressing the gas is much less than that required to expand it. And in order to somehow compensate for the resulting deficit, carbon dioxide cools sharply, turning into “dry ice”. It is widely used for food preservation and has significant advantages over ordinary ice: firstly, its “cooling capacity” is twice as high per unit weight; secondly, it evaporates without residue.
Carbon dioxide is used as an active medium in wire welding, since at the temperature of the arc, carbon dioxide decomposes into carbon monoxide CO and oxygen, which, in turn, interacts with the liquid metal, oxidizing it.
Carbon dioxide in canisters is used in pneumatic weapons and as a power source for engines in aircraft modeling.

Quality indicators of carbon dioxide GOST 8050-85

Name of indicator

A substance with the chemical formula CO2 and a molecular weight of 44.011 g / mol, which can exist in four phase states - gaseous, liquid, solid and supercritical.

The gaseous state of CO2 is commonly known as carbon dioxide. At atmospheric pressure, it is a colorless gas without color and odor, at a temperature of +20? With a density of 1.839 kg / m? (1.52 times heavier than air), dissolves well in water (0.88 volume in 1 volume of water), partially interacting in it with the formation of carbonic acid. Included in the atmosphere on average 0.035% by volume. With a sharp cooling due to expansion (expanding), CO2 is able to desublimate - go immediately into a solid state, bypassing the liquid phase.

Gaseous carbon dioxide was previously often stored in stationary gas holders. Currently, this method of storage is not used; carbon dioxide in the required amount is obtained directly on site - by evaporating liquid carbon dioxide in the gasifier. Further, the gas can be easily pumped through any gas pipeline at a pressure of 2-6 atmospheres.

The liquid state of CO2 is technically called "liquid carbon dioxide" or simply "carbonic acid". It is a colorless, odorless liquid with an average density of 771 kg / m3, which exists only under a pressure of 3,482 ... 519 kPa at a temperature of 0 ... -56.5 degrees C (“low-temperature carbon dioxide”), or under a pressure of 3,482 ... at a temperature of 0 ... + 31.0 degrees C ("high-pressure carbon dioxide"). High-pressure carbon dioxide is most often obtained by compressing carbon dioxide to a condensation pressure, while cooling it with water. Low-temperature carbon dioxide, which is the main form of carbon dioxide for industrial consumption, is most often produced in a high-pressure cycle by three-stage cooling and throttling in special plants.

With a small and medium consumption of carbon dioxide (high pressure), tons, a variety of steel cylinders are used for its storage and transportation (from cans for household siphons to containers with a capacity of 55 liters). The most common is a 40 l cylinder with a working pressure of 15,000 kPa, containing 24 kg of carbon dioxide. Steel cylinders do not require additional care, carbon dioxide is stored without loss for a long time. High pressure carbon dioxide cylinders are painted black.

With significant consumption, for storage and transportation of low-temperature liquid carbon dioxide, isothermal tanks of the most diverse capacity, equipped with service refrigeration units, are used. There are accumulative (stationary) vertical and horizontal tanks with a capacity of 3 to 250 tons, transportable tanks with a capacity of 3 to 18 tons. Vertical tanks require the construction of a foundation and are used mainly in conditions of limited space for placement. The use of horizontal tanks makes it possible to reduce the cost of foundations, especially if there is a common frame with a carbon dioxide plant. The tanks consist of an internal welded vessel made of low-temperature steel and having polyurethane foam or vacuum thermal insulation; outer casing made of plastic, galvanized or stainless steel; pipelines, fittings and control devices. The inner and outer surfaces of the welded vessel are subjected to special treatment, due to which the probability of surface corrosion of the metal is reduced to a minimum. In expensive imported models, the outer sealed casing is made of aluminum. The use of tanks provides filling and discharge of liquid carbon dioxide; storage and transportation without loss of the product; visual control of weight and operating pressure during filling, storage and dispensing. All types of tanks are equipped with a multi-level security system. Safety valves allow inspection and repair without stopping and emptying the tank.

With an instantaneous decrease in pressure to atmospheric pressure, which occurs during injection into a special expansion chamber (throttling), liquid carbon dioxide instantly turns into gas and the thinnest snow-like mass, which is pressed and carbon dioxide is obtained in a solid state, which is commonly called "dry ice". At atmospheric pressure, it is a white vitreous mass with a density of 1,562 kg / m?, with a temperature of -78.5 ° C, which sublimates in the open air - gradually evaporates, bypassing the liquid state. Dry ice can also be obtained directly at high-pressure plants used to produce low-temperature carbon dioxide from gas mixtures containing CO2 in an amount of at least 75-80%. The volumetric cooling capacity of dry ice is almost 3 times greater than that of water ice and is 573.6 kJ/kg.

Solid carbon dioxide is usually produced in briquettes with a size of 200 × 100 × 20-70 mm, in granules with a diameter of 3, 6, 10, 12 and 16 mm, rarely in the form of the finest powder (“dry snow”). Briquettes, pellets and snow are stored for no more than 1-2 days in stationary underground mine-type storages, divided into small compartments; transported in special isothermal containers with a safety valve. Containers from different manufacturers with a capacity of 40 to 300 kg or more are used. Sublimation losses are, depending on the ambient temperature, 4-6% or more per day.

At a pressure of over 7.39 kPa and a temperature of more than 31.6 degrees C, carbon dioxide is in the so-called supercritical state, in which its density is like that of a liquid, and its viscosity and surface tension are like that of a gas. This unusual physical substance (fluid) is an excellent non-polar solvent. Supercritical CO2 is able to fully or selectively extract any non-polar constituents with a molecular weight of less than 2,000 daltons: terpene compounds, waxes, pigments, high molecular weight saturated and unsaturated fatty acids, alkaloids, fat-soluble vitamins and phytosterols. Insoluble substances for supercritical CO2 are cellulose, starch, high molecular weight organic and inorganic polymers, sugars, glycosidic substances, proteins, metals and many metal salts. Having similar properties, supercritical carbon dioxide is increasingly used in the processes of extraction, fractionation and impregnation of organic and inorganic substances. It is also a promising working fluid for modern heat engines.

Specific gravity. The specific gravity of carbon dioxide depends on the pressure, temperature and state of aggregation in which it is located.
The critical temperature of carbon dioxide is +31 degrees. The specific gravity of carbon dioxide at 0 degrees and a pressure of 760 mm Hg. is equal to 1.9769 kg/m3.
The molecular weight of carbon dioxide is 44.0. The relative weight of carbon dioxide compared to air is 1.529.
Liquid carbon dioxide at temperatures above 0 deg. much lighter than water and can only be stored under pressure.
The specific gravity of solid carbon dioxide depends on the method of its production. Liquid carbon dioxide, when frozen, turns into dry ice, which is a transparent, glassy solid. In this case, solid carbon dioxide has the highest density (at normal pressure in a vessel cooled to minus 79 degrees, the density is 1.56). Industrial solid carbon dioxide is white, close to chalk in hardness,
its specific gravity varies depending on the method of obtaining within 1.3 - 1.6.

State equation. The relationship between the volume, temperature, and pressure of carbon dioxide is expressed by the equation
V= R T/p - A, where
V - volume, m3/kg;
R - gas constant 848/44 = 19.273;
T - temperature, K degrees;
p pressure, kg/m2;
A is an additional term characterizing the deviation from the equation of state for an ideal gas. It is expressed by the dependence A \u003d (0.0825 + (1.225) 10-7 p) / (T / 100) 10 / 3.

Triple point of carbon dioxide. The triple point is characterized by a pressure of 5.28 ata (kg/cm2) and a temperature of minus 56.6 degrees.
Carbon dioxide can exist in all three states (solid, liquid and gaseous) only at the triple point. At pressures below 5.28 ata (kg/cm2) (or at temperatures below minus 56.6 degrees), carbon dioxide can exist only in solid and gaseous states.
In the vapor-liquid region, i.e. above the triple point, the following relations hold
i "x + i" "y \u003d i,
x + y = 1, where,
x and y - the proportion of the substance in liquid and vapor form;
i" is the enthalpy of the liquid;
i"" - steam enthalpy;
i is the enthalpy of the mixture.
From these values it is easy to determine the values of x and y. Accordingly, for the region below the triple point, the following equations will be valid:
i"" y + i"" z \u003d i,
y + z = 1, where,
i"" - enthalpy of solid carbon dioxide;
z is the proportion of the substance in the solid state.
At the triple point for three phases, there are also only two equations
i"x + i""y + i"""z = i,
x + y + z = 1.
Knowing the values of i," i"," i""" for the triple point and using the above equations, you can determine the enthalpy of the mixture for any point.

Heat capacity. The heat capacity of carbon dioxide at a temperature of 20 degrees. and 1 ata is
Ср = 0.202 and Сv = 0.156 kcal/kg*deg. Adiabatic exponent k = 1.30.
The heat capacity of liquid carbon dioxide in the temperature range from -50 to +20 deg. characterized by the following values, kcal / kg * deg. :
Deg.С -50 -40 -30 -20 -10 0 10 20
Wed, 0.47 0.49 0.515 0.514 0.517 0.6 0.64 0.68

Melting point. The melting of solid carbon dioxide occurs at temperatures and pressures corresponding to the triple point (t = -56.6 degrees and p = 5.28 atm) or above it.
Below the triple point, solid carbon dioxide sublimates. The sublimation temperature is a function of pressure: at normal pressure it is -78.5 degrees, in vacuum it can be -100 degrees. and below.

Enthalpy. The enthalpy of carbon dioxide vapor in a wide range of temperatures and pressures is determined by the Planck and Kupriyanov equation.
i = 169.34 + (0.1955 + 0.000115t)t - 8.3724p(1 + 0.007424p)/0.01T(10/3), where
I - kcal / kg, p - kg / cm2, T - deg. K, t - deg. C.
The enthalpy of liquid carbon dioxide at any point can be easily determined by subtracting the latent heat of vaporization from the enthalpy of saturated steam. Similarly, by subtracting the latent heat of sublimation, one can determine the enthalpy of solid carbon dioxide.

Thermal conductivity. Thermal conductivity of carbon dioxide at 0 deg. is 0.012 kcal / m * hour * deg. C, and at a temperature of -78 deg. it drops to 0.008 kcal/m*hour*deg.C.
Data on the thermal conductivity of carbon dioxide in 10 4 tbsp. kcal/m*h*deg.С at above-zero temperatures are given in the table.
Pressure, kg/cm2 10 deg. 20 deg. 30 deg. 40 deg.
gaseous carbon dioxide
1 130 136 142 148
20 - 147 152 157
40 - 173 174 175
60 - - 228 213
80 - - - 325
liquid carbonic acid
50 848 - - -
60 870 753 - -
70 888 776 - -
80 906 795 670
The thermal conductivity of solid carbon dioxide can be calculated by the formula:
236.5 / T1.216 st., kcal / m * hour * deg. C.

Thermal expansion coefficient. The volume expansion coefficient a of solid carbon dioxide is calculated depending on the change in specific gravity and temperature. The linear expansion coefficient is determined by the expression b = a/3. In the temperature range from -56 to -80 degrees. the coefficients have the following values: a * 10 * 5st. \u003d 185.5-117.0, b * 10 * 5 st. = 61.8-39.0.

Viscosity. Viscosity of carbon dioxide 10 * 6st. depending on pressure and temperature (kg*sec/m2)
Pressure, ata -15 degrees. 0 deg. 20 deg. 40 deg.
5 1,38 1,42 1,49 1,60
30 12,04 1,63 1,61 1,72
75 13,13 12,01 8,32 2,30

Dielectric constant. The dielectric constant of liquid carbon dioxide at 50 - 125 ati is in the range of 1.6016 - 1.6425.
Dielectric constant of carbon dioxide at 15 deg. and pressure 9.4 - 39 atm 1.009 - 1.060.

Moisture content of carbon dioxide. The content of water vapor in moist carbon dioxide is determined using the equation,
X = 18/44 * p'/p - p' = 0.41 p'/p - p' kg/kg, where
p' - partial pressure of water vapor at 100% saturation;
p is the total pressure of the vapor-gas mixture.

Solubility of carbon dioxide in water. The solubility of gases is measured by volumes of gas reduced to normal conditions (0 degrees, C and 760 mm Hg) per volume of solvent.
The solubility of carbon dioxide in water at moderate temperatures and pressures up to 4 - 5 atm obeys Henry's law, which is expressed by the equation
P \u003d H X, where
P is the partial pressure of the gas above the liquid;
X is the amount of gas in moles;
H is Henry's coefficient.

Liquid carbon dioxide as a solvent. The solubility of lubricating oil in liquid carbon dioxide at a temperature of -20 deg. up to +25 deg. is 0.388 g in 100 CO2,
and increases to 0.718 g in 100 g of CO2 at a temperature of +25 degrees. FROM.
The solubility of water in liquid carbon dioxide in the temperature range from -5.8 to +22.9 degrees. is not more than 0.05% by weight.

Safety

According to the degree of impact on the human body, gaseous carbon dioxide belongs to the 4th hazard class according to GOST 12.1.007-76 “Harmful substances. Classification and general safety requirements”. The maximum permissible concentration in the air of the working area has not been established; when assessing this concentration, one should be guided by the standards for coal and ozocerite mines, set within 0.5%.

When using dry ice, when using vessels with liquid low-temperature carbon dioxide, safety measures must be observed to prevent frostbite of the hands and other parts of the worker's body.

We all know from the school bench that carbon dioxide is emitted into the atmosphere as a product of human and animal life, that is, it is what we exhale. In fairly small quantities, it is absorbed by plants and converted to oxygen. One of the causes of global warming is the same carbon dioxide or, in other words, carbon dioxide.

But not everything is as bad as it seems at first glance, because humanity has learned to use it in a vast area of its activities for good purposes. So, for example, carbon dioxide is used in sparkling waters, or in the food industry it can be found on the label under the code E290 as a preservative. Quite often, carbon dioxide acts as a leavening agent in flour products, where it enters during the preparation of dough. Most often, carbon dioxide is stored in a liquid state in special cylinders that are used repeatedly and can be refilled. You can learn more about this on the website https://wice24.ru/product/uglekislota-co2. It can be found both in a gaseous state and in the form of dry ice, but storage in a liquefied state is much more profitable.

Biochemists have proven that fertilizing the air with carbon gas is a very good means of obtaining large yields from various crops. This theory has long found its practical application. So in Holland, flower growers effectively use carbon dioxide to fertilize various flowers (gerberas, tulips, roses) in greenhouse conditions. And if earlier the necessary climate was created by burning natural gas (this technology was recognized as inefficient and harmful to the environment), today carbon gas gets to plants through special tubes with holes and is used in the required amount mainly in winter.

Carbon dioxide has also found widespread use in the fire sector as a fuel for a fire extinguisher. Carbon dioxide in canisters has found its way into pneumatic weapons, and in aircraft modeling, it serves as a source of energy for engines.

In the solid state, CO2 has, as already mentioned, the name of dry ice, and is used in the food industry for food storage. It is worth noting that, compared to ordinary ice, dry ice has a number of advantages, including high cooling capacity (2 times higher than usual), and no by-products remain during its evaporation.

And these are far from all areas where carbon dioxide is effectively and expediently used.

Keywords: Where carbon dioxide is used, Carbon dioxide use, industry, household, cylinder filling, carbon dioxide storage, E290

The most common processes for the formation of this compound are the decay of animal and plant remains, the combustion of various types of fuel, the respiration of animals and plants. For example, one person per day emits about a kilogram of carbon dioxide into the atmosphere. Carbon monoxide and carbon dioxide can also be formed in inanimate nature. Carbon dioxide is released during volcanic activity, and can also be extracted from mineral water sources. Carbon dioxide is found in small quantities in the Earth's atmosphere.

The features of the chemical structure of this compound allow it to participate in many chemical reactions, the basis for which is carbon dioxide.

Formula

In the compound of this substance, the tetravalent carbon atom forms a linear bond with two oxygen molecules. The appearance of such a molecule can be represented as follows:

The theory of hybridization explains the structure of the carbon dioxide molecule as follows: two existing sigma bonds are formed between the sp orbitals of carbon atoms and two 2p orbitals of oxygen; p-orbitals of carbon, which do not take part in hybridization, are connected in conjunction with similar oxygen orbitals. In chemical reactions, carbon dioxide is written as CO2.

Physical Properties

Under normal conditions, carbon dioxide is a colorless, odorless gas. It is heavier than air, so carbon dioxide can behave like a liquid. For example, it can be poured from one container to another. This substance is slightly soluble in water - about 0.88 l of CO 2 dissolves in one liter of water at 20 ⁰С. A slight decrease in temperature radically changes the situation - in the same liter of water at 17⁰С, 1.7 liters of CO 2 can dissolve. With strong cooling, this substance is deposited in the form of snow flakes - the so-called "dry ice" is formed. This name comes from the fact that at normal pressure, the substance, bypassing the liquid phase, immediately turns into a gas. Liquid carbon dioxide is formed at a pressure just above 0.6 MPa and at room temperature.

Chemical properties

When interacting with strong oxidizing agents, 4-carbon dioxide exhibits oxidizing properties. A typical reaction of this interaction:

C + CO 2 \u003d 2CO.

So, with the help of coal, carbon dioxide is reduced to its divalent modification - carbon monoxide.

Under normal conditions, carbon dioxide is inert. But some active metals can burn in it, extracting oxygen from the compound and releasing carbon gas. A typical reaction is the combustion of magnesium:

2Mg + CO 2 \u003d 2MgO + C.

During the reaction, magnesium oxide and free carbon are formed.

In chemical compounds, CO 2 often exhibits the properties of a typical acidic oxide. For example, it reacts with bases and basic oxides. The result of the reaction are salts of carbonic acid.

For example, the reaction of the combination of sodium oxide with carbon dioxide can be represented as follows:

Na 2 O + CO 2 \u003d Na 2 CO 3;

2NaOH + CO 2 \u003d Na 2 CO 3 + H 2 O;

NaOH + CO 2 \u003d NaHCO 3.

Carbonic acid and CO 2 solution

Carbon dioxide in water forms a solution with a small degree of dissociation. This solution of carbon dioxide is called carbonic acid. It is colorless, weakly expressed and has a sour taste.

Recording a chemical reaction:

CO 2 + H 2 O ↔ H 2 CO 3.

The equilibrium is rather strongly shifted to the left - only about 1% of the initial carbon dioxide is converted into carbonic acid. The higher the temperature, the fewer molecules of carbonic acid in the solution. When the compound boils, it disappears completely, and the solution decomposes into carbon dioxide and water. The structural formula of carbonic acid is shown below.

Properties of carbonic acid

Carbonic acid is very weak. In solutions, it decomposes into hydrogen ions H + and HCO 3 - compounds. In a very small amount, CO 3 - ions are formed.

Carbonic acid is dibasic, so the salts formed by it can be medium and acidic. In the Russian chemical tradition, medium salts are called carbonates, and strong salts are called bicarbonates.

Qualitative reaction

One possible way to detect gaseous carbon dioxide is to change the transparency of the lime mortar.

Ca(OH) 2 + CO 2 = CaCO 3 ↓ + H 2 O.

This experience is known from the school chemistry course. At the beginning of the reaction, a small amount of white precipitate is formed, which subsequently disappears when carbon dioxide is passed through water. The change in transparency occurs because in the process of interaction, an insoluble compound - calcium carbonate turns into a soluble substance - calcium bicarbonate. The reaction proceeds in the following way:

CaCO 3 + H 2 O + CO 2 \u003d Ca (HCO 3) 2.

Getting carbon dioxide

If you want to get a small amount of CO2, you can start the reaction of hydrochloric acid with calcium carbonate (marble). The chemical record of this interaction looks like this:

CaCO 3 + HCl \u003d CaCl 2 + H 2 O + CO 2.

Also for this purpose, combustion reactions of carbon-containing substances, such as acetylene, are used:

CH 4 + 2O 2 → 2H 2 O + CO 2 -.

The Kipp apparatus is used to collect and store the resulting gaseous substance.

For the needs of industry and agriculture, the scale of carbon dioxide production must be large. A popular method for such a large-scale reaction is the burning of limestone, which produces carbon dioxide. The reaction formula is given below:

CaCO 3 \u003d CaO + CO 2.

Application of carbon dioxide

The food industry, after large-scale production of "dry ice", switched to a fundamentally new method of food storage. It is indispensable in the production of carbonated drinks and mineral water. The content of CO 2 in drinks gives them freshness and significantly increases the shelf life. And the carbidization of mineral waters avoids mustiness and unpleasant taste.

In cooking, the method of extinguishing citric acid with vinegar is often used. The carbon dioxide released at the same time gives splendor and lightness to confectionery.

This compound is often used as a food additive to increase the shelf life of foods. According to international standards for the classification of chemical additives in products, it passes under the code E 290,

Powdered carbon dioxide is one of the most popular substances that make up fire extinguishing mixtures. This substance is also found in the foam of fire extinguishers.

It is best to transport and store carbon dioxide in metal cylinders. At a temperature of more than 31⁰С, the pressure in the cylinder can reach critical and liquid CO 2 will go into a supercritical state with a sharp rise in operating pressure to 7.35 MPa. A metal cylinder can withstand an internal pressure of up to 22 MPa, so the pressure range at temperatures above thirty degrees is recognized as safe.

Carbon dioxide is a colorless gas with a slightly sour smell and taste, registered in the international classification of food additives under the code E290. Used as a preservative, propellant, antioxidant and acidity regulator.

General characteristics of carbon dioxide

Carbon dioxide is a heavy, odorless and colorless gas known as carbon dioxide. A feature of carbon dioxide is its ability at atmospheric pressure to go from a solid state immediately to a gaseous state, bypassing the liquid stage (calorizator). In the liquid state, carbon dioxide is stored at elevated pressure. The solid state of carbon dioxide - white crystals - is known as "dry ice".

The formation of carbon dioxide occurs in the process of combustion and decay of organic substances, it is released during the respiration of plants and animals, in nature it is found in the air and mineral springs.

The benefits and harms of carbon dioxide

Carbon dioxide is not a toxic substance, therefore it is considered harmless to the human body. But, being an accelerator of the process of absorption of substances into the gastric mucosa, it provokes, for example, rapid intoxication when drinking carbonated alcoholic beverages. It is not recommended to get involved in the use of soda for everyone who has any problems with the gastrointestinal tract, because the most harmless negative manifestations of the action of E290 are bloating and belching.

Application of E290

The main use of carbon dioxide is its use as a preservative E290 in the production of carbonated drinks. It is often used in the fermentation process of raw grapes to control fermentation. E290 is a part of preservatives for storage in packages of meat and dairy products, bakery products, vegetables and fruits. "Dry ice" is used as a freezing and cooling agent for the preservation of ice cream, as well as fresh fish and seafood. How baking powder E290 "works" in the process of baking bread and muffins.

On sale you can find E290 Carbon Dioxide in cylinders or in the form of "dry ice" blocks in special sealed packages.

Use of E290 Carbon Dioxide in Russia

On the territory of the Russian Federation, the use of the food additive E290 in the food industry as a preservative and baking powder is allowed.