Carbon dioxide. Physical properties CO2 Carbon dioxide physical properties

Carbon dioxide

An integral part of the atmosphere, the main raw material for the process of photosynthesis of green plants, a product of the vital activity of living organisms.

According to the systematic international nomenclature (IUPAC), the substance with the formula CO2 is called Carbon Monoxide (IV). Trivial (common names) - carbon dioxide or carbon dioxide, carbonic anhydride (salt-forming oxide with acidic properties).

Carbon dioxide formula

The carbon dioxide molecule is formed by two oxygen atoms and a carbon atom. Structural formula – O=C=O. The valence of carbon is 4. The oxidation state is (+4). Bond type: polar covalent.

Producing carbon dioxide

Natural sources of carbon dioxide

Carbon dioxide is formed during slow oxidation during the processes of respiration, fermentation, and decay of organic substances. Released during the decomposition of natural carbonates, fuel combustion, and the formation of flue gases. Contained in the air and mineral springs.

The human body emits 1 kg of CO 2 per day. The air contains 0.03% carbon dioxide.

Laboratory methods of obtaining

In the laboratory, gas can be obtained by reacting hydrochloric acid with chalk, marble, and soda. Gas is collected by air displacement method.

CaCO 3 + 2HCl → CaCl 2 + H 2 O + CO 2,

NaHCO 3 + HCl → NaCl + H 2 O + CO 2.

Industrial methods of production

Limestone roasting: CaCO 3 → CaO + CO 2.
As a by-product of air separation when producing oxygen, nitrogen, argon.

Properties of carbon dioxide

Physical properties

The substance is non-toxic, non-flammable.

A substance in a solid state of aggregation is called “dry ice”.

A high concentration of carbon dioxide can be determined organoleptically - in the mouth, a sour taste appears on the tongue. High levels are dangerous for the body - it causes suffocation.

Chemical properties

Qualitative reaction: When carbon dioxide reacts with lime milk (calcium hydroxide), calcium carbonate is formed - a white precipitate.

CO 2 + Ca(OH) 2 = CaCO 3 ↓ + H 2 O.

CO 2 as an acidic oxide, reacts with water with the formation of carbonic acid. This acid is an unstable compound and easily breaks down into carbon dioxide and water. Reaction type – compound reaction, reversible.

CO 2 + H 2 O ↔ H 2 CO 3 .

When heated, it decomposes into carbon monoxide (II) and water: 2CO2 = 2CO + O2.

Interacts with basic oxides, with the formation of salts:

CaO + CO 2 = CaCO 3; Al 2 O 3 + 3CO 2 = Al 2 (CO 3) 3.

Reaction type– compound reaction.

Interacts with alkalis, with the formation of acidic and medium salts:

CO 2 + NaOH = NaHCO 3;

CO 2 + 2NaOH = Na 2 CO 3 + H 2 O.

Medium salt is formed when there is an excess of alkali. An acid salt is formed when the ratio of the amounts of oxide and alkali substances is 1:1.

At temperature it reacts with active metals:

CO 2 + 2Mg = C + 2MgO

Carbon dioxide mainly exhibits reducing properties, but when interacting with active metals it is an oxidizing agent.

Enters into reactions with simple substances:

CO 2 + 4H 2 = CH 4 + 2H 2 O (reaction conditions - high temperature, catalyst Cu 2 O).

Application of carbon dioxide

IN Food Industry:

used in the production of mineral water and carbonated drinks;
as a food additive (E290), increases the shelf life of products;
as a leavening agent, it gives lightness and fluffiness to confectionery products;
as a refrigerant;
to remove caffeine from coffee.

In aircraft modeling it is used as a source of energy for engines; used in pneumatic weapons; as a refill for carbon dioxide fire extinguishers. Used as a protective medium during welding.

Carbon dioxide is also used in medicine - it is used for cryoablation of tumors and serves as a stimulator of deep breathing.

In the chemical industry, gas is used in the synthesis of chemicals, the production of carbonic acid salts, drying and purification processes of polymers, fibers of plant and animal origin. Used for wastewater treatment, increases the conductivity of ultrapure water.

Examples of problem solving

Problem 1

Find the mass fraction of carbon in carbon dioxide.

Solution

M(CO 2) = 12+2x16 = 44 g/mol.
Ar(C) = 12 g/mol.
W(C) = 12/44 = 0.27 or 27%

Answer: the mass fraction of carbon in carbon dioxide is 27%.

Problem 2

Calculate the volume of carbon dioxide released during the interaction of hydrochloric acid with marble weighing 100 g.

Solution

CaCO 3 + 2HCl → CaCl 2 + H 2 O + CO 2

1 mole - 1 mole
100 g/mol - 22.4 l/mol
100 g - 22.4 l

x(CO 2) = 300x22.4/100 = 67.2 (l).

Answer: The volume of carbon dioxide is 67.2 liters.

Encyclopedic YouTube

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Carbon(IV) monoxide does not support combustion. Only some active metals burn in it::

2 M g + C O 2 → 2 M g O + C (\displaystyle (\mathsf (2Mg+CO_(2)\rightarrow 2MgO+C)))

Interaction with active metal oxide:

C a O + C O 2 → C a C O 3 (\displaystyle (\mathsf (CaO+CO_(2)\rightarrow CaCO_(3))))

When dissolved in water, it forms carbonic acid:

C O 2 + H 2 O ⇄ H 2 C O 3 (\displaystyle (\mathsf (CO_(2)+H_(2)O\rightleftarrows H_(2)CO_(3))))

Reacts with alkalis to form carbonates and bicarbonates:

C a (O H) 2 + C O 2 → C a C O 3 ↓ + H 2 O (\displaystyle (\mathsf (Ca(OH)_(2)+CO_(2)\rightarrow CaCO_(3)\downarrow +H_( 2)O)))(qualitative reaction to carbon dioxide) K O H + C O 2 → K H C O 3 (\displaystyle (\mathsf (KOH+CO_(2)\rightarrow KHCO_(3))))

Biological

The human body emits approximately 1 kg of carbon dioxide per day.

This carbon dioxide is transported from the tissues, where it is formed as one of the end products of metabolism, through the venous system and is then excreted in the exhaled air through the lungs. Thus, the content of carbon dioxide in the blood is high in the venous system, and decreases in the capillary network of the lungs, and is low in the arterial blood. The carbon dioxide content of a blood sample is often expressed in terms of partial pressure, that is, the pressure that a given amount of carbon dioxide contained in a blood sample would have if it alone occupied the entire volume of the blood sample.

Carbon dioxide (CO2) is transported in the blood in three different ways (the exact proportion of each of these three transport methods depends on whether the blood is arterial or venous).

Hemoglobin, the main oxygen-transporting protein of red blood cells, is capable of transporting both oxygen and carbon dioxide. However, carbon dioxide binds to hemoglobin at a different site than oxygen. It binds to the N-terminal ends of globin chains, rather than to heme. However, due to allosteric effects, which lead to a change in the configuration of the hemoglobin molecule upon binding, the binding of carbon dioxide reduces the ability of oxygen to bind to it, at a given partial pressure of oxygen, and vice versa - the binding of oxygen to hemoglobin reduces the ability of carbon dioxide to bind to it, at a given partial pressure of carbon dioxide. In addition, the ability of hemoglobin to preferentially bind with oxygen or carbon dioxide also depends on the pH of the environment. These features are very important for the successful uptake and transport of oxygen from the lungs into the tissues and its successful release into the tissues, as well as for the successful uptake and transport of carbon dioxide from the tissues into the lungs and its release there.

Carbon dioxide is one of the most important mediators of autoregulation of blood flow. It is a powerful vasodilator. Accordingly, if the level of carbon dioxide in tissue or blood increases (for example, due to intense metabolism - caused by, say, exercise, inflammation, tissue damage, or due to obstruction of blood flow, tissue ischemia), then the capillaries dilate, which leads to increased blood flow and accordingly, to increase the delivery of oxygen to the tissues and the transport of accumulated carbon dioxide from the tissues. In addition, carbon dioxide in certain concentrations (increased, but not yet reaching toxic values) has a positive inotropic and chronotropic effect on the myocardium and increases its sensitivity to adrenaline, which leads to an increase in the strength and frequency of heart contractions, cardiac output and, as a consequence, , stroke and minute blood volume. This also helps to correct tissue hypoxia and hypercapnia (increased carbon dioxide levels).

Bicarbonate ions are very important for regulating blood pH and maintaining normal acid-base balance. Respiration rate affects the carbon dioxide content in the blood. Weak or slow breathing causes respiratory acidosis, while rapid and excessively deep breathing leads to hyperventilation and the development of respiratory alkalosis.

In addition, carbon dioxide is also important in regulating respiration. Although our body requires oxygen for metabolism, low oxygen levels in the blood or tissues usually do not stimulate breathing (or rather, the stimulating effect of low oxygen on breathing is too weak and “turns on” late, at very low levels of oxygen in the blood, at which a person often is already losing consciousness). Normally, breathing is stimulated by an increase in the level of carbon dioxide in the blood. The respiratory center is much more sensitive to increased levels of carbon dioxide than to a lack of oxygen. As a consequence, breathing very thin air (with a low partial pressure of oxygen) or a gas mixture containing no oxygen at all (for example, 100% nitrogen or 100% nitrous oxide) can quickly lead to loss of consciousness without causing a feeling of lack of air (because the level of carbon dioxide does not increase in the blood, because nothing prevents its exhalation). This is especially dangerous for pilots of military aircraft flying at high altitudes (in the event of an emergency depressurization of the cabin, pilots can quickly lose consciousness). This feature of the breathing regulation system is also the reason why flight attendants on airplanes instruct passengers in the event of depressurization of the aircraft cabin, first of all, to put on an oxygen mask themselves, before trying to help anyone else - by doing this, the helper risks quickly losing consciousness himself, and even without feeling any discomfort or need for oxygen until the last moment.

The human respiratory center tries to maintain the partial pressure of carbon dioxide in arterial blood no higher than 40 mmHg. With conscious hyperventilation, the content of carbon dioxide in arterial blood can decrease to 10-20 mmHg, while the oxygen content in the blood will remain virtually unchanged or increase slightly, and the need to take another breath will decrease as a result of a decrease in the stimulating effect of carbon dioxide on the activity of the respiratory center. This is the reason why, after a period of conscious hyperventilation, it is easier to hold your breath for a long time than without previous hyperventilation. This deliberate hyperventilation followed by breath holding can lead to loss of consciousness before the person feels the need to take a breath. In a safe environment, such a loss of consciousness does not threaten anything special (having lost consciousness, a person will lose control over himself, stop holding his breath and take a breath, breathing, and with it the oxygen supply to the brain will be restored, and then consciousness will be restored). However, in other situations, such as before diving, this can be dangerous (loss of consciousness and the need to take a breath will occur at depth, and without conscious control, water will enter the airways, which can lead to drowning). This is why hyperventilation before diving is dangerous and not recommended.

Receipt

In industrial quantities, carbon dioxide is released from flue gases, or as a by-product of chemical processes, for example, during the decomposition of natural carbonates (limestone, dolomite) or during the production of alcohol (alcoholic fermentation). The mixture of the resulting gases is washed with a solution of potassium carbonate, which absorbs carbon dioxide, turning into bicarbonate. A solution of bicarbonate decomposes when heated or under reduced pressure, releasing carbon dioxide. In modern installations for the production of carbon dioxide, instead of bicarbonate, an aqueous solution of monoethanolamine is more often used, which, under certain conditions, is capable of absorbing CO₂ contained in the flue gas and releasing it when heated; This separates the finished product from other substances.

Carbon dioxide is also produced in air separation plants as a by-product of producing pure oxygen, nitrogen and argon.

In the laboratory, small quantities are obtained by reacting carbonates and bicarbonates with acids, such as marble, chalk or soda with hydrochloric acid, using, for example, a Kipp apparatus. Using the reaction of sulfuric acid with chalk or marble results in the formation of slightly soluble calcium sulfate, which interferes with the reaction, and which is removed by a significant excess of acid.

To prepare drinks, the reaction of baking soda with citric acid or sour lemon juice can be used. It was in this form that the first carbonated drinks appeared. Pharmacists were engaged in their production and sale.

Application

In the food industry, carbon dioxide is used as a preservative and leavening agent and is indicated on the packaging with the code E290.

The device for supplying carbon dioxide to the aquarium may include a gas reservoir. The simplest and most common method of producing carbon dioxide is based on the design for making the alcoholic drink mash. During fermentation, the carbon dioxide released may well provide nutrition for aquarium plants

Carbon dioxide is used to carbonate lemonade and sparkling water. Carbon dioxide is also used as a protective medium in wire welding, but at high temperatures it decomposes and releases oxygen. The released oxygen oxidizes the metal. In this regard, it is necessary to introduce deoxidizing agents 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 spattering than when welding in an inert environment.

Storing carbon dioxide in a steel cylinder in a liquefied state is more profitable than in the form of gas. Carbon dioxide has a relatively low critical temperature of +31°C. About 30 kg of liquefied carbon dioxide is poured into a standard 40-liter cylinder, and at room temperature there will be a liquid phase in the cylinder, and the pressure will be approximately 6 MPa (60 kgf/cm²). If the temperature is above +31°C, then carbon dioxide will go into a supercritical state with a pressure above 7.36 MPa. The standard operating pressure for a regular 40-liter cylinder is 15 MPa (150 kgf/cm²), but it must safely withstand pressure 1.5 times higher, that is, 22.5 MPa, so working with such cylinders can be considered quite safe.

Solid carbon dioxide - “dry ice” - is used as a refrigerant in laboratory research, in retail trade, during equipment repair (for example: cooling one of the mating parts during a press-fit), etc. Carbon dioxide is used to liquefy carbon dioxide and produce dry ice. installations

Registration Methods

Measuring the partial pressure of carbon dioxide is required in technological processes, in medical applications - analysis of respiratory mixtures during artificial ventilation and in closed life support systems. Analysis of CO 2 concentration in the atmosphere is used for environmental and scientific research, to study the greenhouse effect. Carbon dioxide is recorded using gas analyzers based on the principle of infrared spectroscopy and other gas measuring systems. A medical gas analyzer for recording the carbon dioxide content in exhaled air is called a capnograph. To measure low concentrations of CO 2 (as well as) in process gases or in atmospheric air, a gas chromatographic method with a methanator and registration on a flame ionization detector can be used.

Carbon dioxide in nature

Annual fluctuations in the concentration of atmospheric carbon dioxide on the planet are determined mainly by the vegetation of the middle latitudes (40-70°) of the Northern Hemisphere.

A large amount of carbon dioxide is dissolved in the ocean.

Carbon dioxide makes up a significant part of the atmospheres of some planets in the solar system: Venus, Mars.

Toxicity

Carbon dioxide is non-toxic, but due to the effect of its increased concentrations in the air on air-breathing living organisms, it is classified as an asphyxiating gas (English) Russian. Slight increases in concentration up to 2-4% indoors lead to drowsiness and weakness in people. Dangerous concentrations are considered levels of about 7-10%, at which suffocation develops, manifesting itself in headache, dizziness, hearing loss and loss of consciousness (symptoms similar to those of altitude sickness), depending on the concentration, over a period of several minutes up to one hour. If air with high concentrations of gas is inhaled, death occurs very quickly from suffocation.

Although, in fact, even a concentration of 5-7% CO 2 is not lethal, already at a concentration of 0.1% (this level of carbon dioxide is observed in the air of megacities) people begin to feel weak and drowsy. This shows that even at high oxygen levels, a high concentration of CO 2 has a strong effect on well-being.

Inhalation of air with an increased concentration of this gas does not lead to long-term health problems, and after removing the victim from the polluted atmosphere, complete restoration of health quickly occurs.

Carbon dioxide (carbon dioxide), also called carbon dioxide, is the most important component in carbonated drinks. It determines the taste and biological stability of drinks, gives them sparkling and refreshing properties.

Chemical properties. Chemically, carbon dioxide is inert. Formed with the release of a large amount of heat, it, as a product of complete oxidation of carbon, is very stable. Carbon dioxide reduction reactions occur only at high temperatures. So, for example, interacting with potassium at 230° C, carbon dioxide is reduced to oxalic acid:

Entering into a chemical interaction with water, the gas, in an amount of no more than 1% of its content in the solution, forms carbonic acid, which dissociates into H +, HCO 3 -, CO 2 3- ions. In an aqueous solution, carbon dioxide easily enters into chemical reactions, forming various carbon dioxide salts. Therefore, an aqueous solution of carbon dioxide is highly aggressive towards metals and also has a destructive effect on concrete.

Physical properties. To carbonate drinks, carbon dioxide is used, brought to a liquid state by compression to high pressure. Depending on the temperature and pressure, carbon dioxide can also be in a gaseous or solid state. The temperature and pressure corresponding to this state of aggregation are shown in the phase equilibrium diagram (Fig. 13).

At a temperature of minus 56.6 ° C and a pressure of 0.52 Mn/m 2 (5.28 kg/cm 2), corresponding to the triple point, carbon dioxide can simultaneously be in a gaseous, liquid and solid state. At higher temperatures and pressures, carbon dioxide is in liquid and gaseous states; at temperatures and pressures below these values, the gas, directly bypassing the liquid phase, passes into the gaseous state (sublimates). At temperatures above the critical temperature of 31.5° C, no amount of pressure can keep carbon dioxide in liquid form.

In the gaseous state, carbon dioxide is colorless, odorless and has a mild sour taste. At a temperature of 0° C and atmospheric pressure, the density of carbon dioxide is 1.9769 kg/f 3 ; it is 1.529 times heavier than air. At 0°C and atmospheric pressure, 1 kg of gas occupies a volume of 506 liters. The relationship between volume, temperature and pressure of carbon dioxide is expressed by the equation:

where V is the volume of 1 kg of gas in m 3 /kg; T - gas temperature in ° K; P - gas pressure in N/m 2; R - gas constant; A is an additional value that takes into account the deviation from the equation of state of an ideal gas;

Liquefied carbon dioxide- a colorless, transparent, easily mobile liquid, reminiscent in appearance of alcohol or ether. The density of the liquid at 0°C is 0.947. At a temperature of 20°C, the liquefied gas is stored under a pressure of 6.37 Mn/m2 (65 kg/cm2) in steel cylinders. When the liquid flows freely from the cylinder, it evaporates, absorbing a large amount of heat. When the temperature drops to minus 78.5° C, part of the liquid freezes, turning into so-called dry ice. Dry ice is close to chalk in hardness and has a matte white color. Dry ice evaporates slower than liquid, and it immediately turns into a gaseous state.

At a temperature of minus 78.9 ° C and a pressure of 1 kg/cm 2 (9.8 MN/m 2), the heat of sublimation of dry ice is 136.89 kcal/kg (573.57 kJ/kg).

You already know that when you exhale, carbon dioxide comes out of your lungs. But what do you know about this substance? Probably a little. Today I will answer all your questions regarding carbon dioxide.

Definition

This substance under normal conditions is a colorless gas. In many sources it can be called differently: carbon monoxide (IV), and carbon anhydride, and carbon dioxide, and carbon dioxide.

Properties

Carbon dioxide (formula CO 2) is a colorless gas, has an acidic odor and taste, and is soluble in water. If it is cooled properly, it forms a snow-like mass called dry ice (photo below), which sublimates at a temperature of -78 o C.

It is one of the products of decay or combustion of any organic matter. It dissolves in water only at a temperature of 15 o C and only if the water:carbon dioxide ratio is 1:1. The density of carbon dioxide may vary, but under standard conditions it is equal to 1.976 kg/m3. This is if it is in gaseous form, and in other states (liquid/gaseous) the density values will also be different. This substance is an acidic oxide; adding it to water produces carbonic acid. If you combine carbon dioxide with any alkali, the subsequent reaction results in the formation of carbonates and bicarbonates. This oxide cannot support combustion, with some exceptions. These are reactive metals, and in this type of reaction they take oxygen away from it.

Receipt

Carbon dioxide and some other gases are released in large quantities when alcohol is produced or natural carbonates decompose. The resulting gases are then washed with dissolved potassium carbonate. This is followed by their absorption of carbon dioxide, the product of this reaction is bicarbonate, upon heating the solution of which the desired oxide is obtained.

But now it is successfully replaced by ethanolamine dissolved in water, which absorbs carbon monoxide contained in the flue gas and releases it when heated. This gas is also a byproduct of those reactions that produce pure nitrogen, oxygen and argon. In the laboratory, some carbon dioxide is produced when carbonates and bicarbonates react with acids. It is also formed when baking soda and lemon juice or the same sodium bicarbonate and vinegar react (photo).

Application

The food industry cannot do without the use of carbon dioxide, where it is known as a preservative and leavening agent, code E290. Any fire extinguisher contains it in liquid form.

Also, tetravalent carbon oxide, which is released during the fermentation process, serves as a good feed for aquarium plants. It is also found in the well-known soda, which many people often buy at the grocery store. Wire welding occurs in a carbon dioxide environment, but if the temperature of this process is very high, then it is accompanied by the dissociation of carbon dioxide, which releases oxygen, which oxidizes the metal. Then welding cannot be done without deoxidizing agents (manganese or silicon). Carbon dioxide is used to inflate bicycle wheels; it is also present in the cans of air guns (this type is called a gas cylinder). Also, this oxide in a solid state, called dry ice, is needed as a refrigerant in trade, scientific research and when repairing some equipment.

Conclusion

This is how beneficial carbon dioxide is for humans. And not only in industry, it also plays an important biological role: without it, gas exchange, regulation of vascular tone, photosynthesis and many other natural processes cannot occur. But its excess or shortage in the air for some time can negatively affect the physical condition of all living organisms.

DEFINITION

Carbon dioxide(carbon dioxide, carbonic anhydride, carbon dioxide) – carbon monoxide (IV).

Formula – CO 2. Molar mass – 44 g/mol.

Chemical properties of carbon dioxide

Carbon dioxide belongs to the class of acidic oxides, i.e. When interacting with water, it forms an acid called carbonic acid. Carbonic acid is chemically unstable and at the moment of formation it immediately breaks down into its components, i.e. The reaction between carbon dioxide and water is reversible:

CO 2 + H 2 O ↔ CO 2 ×H 2 O(solution) ↔ H 2 CO 3 .

When heated, carbon dioxide breaks down into carbon monoxide and oxygen:

2CO 2 = 2CO + O 2.

Like all acidic oxides, carbon dioxide is characterized by reactions of interaction with basic oxides (formed only by active metals) and bases:

CaO + CO 2 = CaCO 3;

Al 2 O 3 + 3CO 2 = Al 2 (CO 3) 3;

CO 2 + NaOH (dilute) = NaHCO 3;

CO 2 + 2NaOH (conc) = Na 2 CO 3 + H 2 O.

Carbon dioxide does not support combustion; only active metals burn in it:

CO 2 + 2Mg = C + 2MgO (t);

CO 2 + 2Ca = C + 2CaO (t).

Carbon dioxide reacts with simple substances such as hydrogen and carbon:

CO 2 + 4H 2 = CH 4 + 2H 2 O (t, kat = Cu 2 O);

CO 2 + C = 2CO (t).

When carbon dioxide reacts with peroxides of active metals, carbonates are formed and oxygen is released:

2CO 2 + 2Na 2 O 2 = 2Na 2 CO 3 + O 2.

A qualitative reaction to carbon dioxide is the reaction of its interaction with lime water (milk), i.e. with calcium hydroxide, in which a white precipitate is formed - calcium carbonate:

CO 2 + Ca(OH) 2 = CaCO 3 ↓ + H 2 O.

Physical properties of carbon dioxide

Carbon dioxide is a gaseous substance without color or odor. Heavier than air. Thermally stable. When compressed and cooled, it easily transforms into liquid and solid states. Carbon dioxide in a solid aggregate state is called “dry ice” and easily sublimes at room temperature. Carbon dioxide is poorly soluble in water and partially reacts with it. Density – 1.977 g/l.

Production and use of carbon dioxide

There are industrial and laboratory methods for producing carbon dioxide. Thus, in industry it is obtained by burning limestone (1), and in the laboratory by the action of strong acids on carbonic acid salts (2):

CaCO 3 = CaO + CO 2 (t) (1);

CaCO 3 + 2HCl = CaCl 2 + CO 2 + H 2 O (2).

Carbon dioxide is used in the food (carbonating lemonade), chemical (temperature control in the production of synthetic fibers), metallurgical (environmental protection, such as brown gas precipitation) and other industries.

Examples of problem solving

EXAMPLE 1

Exercise

What volume of carbon dioxide will be released by the action of 200 g of a 10% solution of nitric acid per 90 g of calcium carbonate containing 8% impurities insoluble in acid?

Solution

Molar masses of nitric acid and calcium carbonate, calculated using the table of chemical elements by D.I. Mendeleev - 63 and 100 g/mol, respectively.

Let us write the equation for the dissolution of limestone in nitric acid:

CaCO 3 + 2HNO 3 → Ca(NO 3) 2 + CO 2 + H 2 O.

ω(CaCO 3) cl = 100% - ω admixture = 100% - 8% = 92% = 0.92.

Then, the mass of pure calcium carbonate is:

m(CaCO 3) cl = m limestone × ω(CaCO 3) cl / 100%;

m(CaCO 3) cl = 90 × 92 / 100% = 82.8 g.

The amount of calcium carbonate substance is equal to:

n(CaCO 3) = m(CaCO 3) cl / M(CaCO 3);

n(CaCO 3) = 82.8 / 100 = 0.83 mol.

The mass of nitric acid in solution will be equal to:

m(HNO 3) = m(HNO 3) solution × ω(HNO 3) / 100%;

m(HNO 3) = 200 × 10 / 100% = 20 g.

The amount of calcium nitric acid is equal to:

n(HNO 3) = m(HNO 3) / M(HNO 3);

n(HNO 3) = 20 / 63 = 0.32 mol.

By comparing the amounts of substances that reacted, we determine that nitric acid is in short supply, therefore, further calculations are made using nitric acid. According to the reaction equation n(HNO 3): n(CO 2) = 2:1, therefore n(CO 2) = 1/2×n(HNO 3) = 0.16 mol. Then, the volume of carbon dioxide will be equal to:

V(CO 2) = n(CO 2)×V m;

V(CO 2) = 0.16 × 22.4 = 3.58 g.

Answer

The volume of carbon dioxide is 3.58 g.