Carbon monoxide (II) (carbon monoxide, carbon monoxide, carbon monoxide) is a colorless poisonous gas (when normal conditions) is tasteless and odorless. Chemical formula- CO. Lower and upper concentration limits of flame propagation: from 12.5 to 74% (by volume).
The structure of the molecule
The CO molecule has a triple bond, like the nitrogen molecule N 2 . Since these molecules are similar in structure (isoelectronic, diatomic, have close molar mass), then their properties are also similar - very low melting and boiling points, close values of standard entropies, etc.
Due to the presence of a triple bond, the CO molecule is very strong (the dissociation energy is 1069 kJ / mol, or 256 kcal / mol, which is more than that of any other diatomic molecules) and has a small internuclear distance (d C≡O = 0.1128 nm or 1, 13Å).
The molecule is weakly polarized, the electric moment of its dipole is μ = 0.04·10 −29 C·m. Numerous studies have shown that the negative charge in the CO molecule is concentrated on the carbon atom C − ←O + (the direction of the dipole moment in the molecule is opposite to that previously assumed). Ionization potential 14.0 V, force coupling constant k = 18.6.
Properties
Carbon monoxide (II) is a colorless, odorless and tasteless gas. combustible The so-called "carbon monoxide smell" is actually the smell of organic impurities.
Main types chemical reactions in which carbon monoxide (II) is involved are addition reactions and redox reactions, in which it exhibits reducing properties.
At room temperatures, CO is inactive, its chemical activity increases significantly when heated and in solutions (for example, in solutions it reduces salts,, and others to metals already at room temperature. When heated, it also reduces other metals, for example CO + CuO → Cu + CO 2. This is widely used in pyrometallurgy... The method for the qualitative detection of CO is based on the reaction of CO in solution with palladium chloride, see below).
Oxidation of CO in solution often proceeds at a noticeable rate only in the presence of a catalyst. When choosing the latter, the nature of the oxidizing agent plays the main role. So, KMnO 4 most rapidly oxidizes CO in the presence of finely divided silver, K 2 Cr 2 O 7 - in the presence of salts, KClO 3 - in the presence of OsO 4. In general, CO is similar in its reducing properties to molecular hydrogen.
Below 830 °C, CO is a stronger reducing agent, and higher, hydrogen. So the equilibrium of the reaction is:
up to 830 °C shifted to the right, above 830 °C to the left.
Interestingly, there are bacteria capable of obtaining the energy they need for life due to the oxidation of CO.
Carbon monoxide (II) burns with a blue flame (reaction start temperature 700 ° C) in air:
ΔG° 298 = -257 kJ, ΔS° 298 = -86 J/KThe combustion temperature of CO can reach 2100 °C, it is a chain, and the initiators are small amounts of hydrogen-containing compounds (water, ammonia, hydrogen sulfide, etc.)
Due to such a good calorific value, CO is a component of various technical gas mixtures (see, for example, generator gas) used, among other things, for heating.
halogens. Greatest practical use received a reaction with chlorine:
The reaction is exothermic, its thermal effect is 113 kJ, in the presence of a catalyst (activated carbon) it proceeds already at room temperature. As a result of the reaction, phosgene is formed - a substance that has become widespread in various branches of chemistry (and also as a chemical warfare agent). By analogous reactions, COF 2 (carbonyl fluoride) and COBr 2 (carbonyl bromide) can be obtained. Carbonyl iodide was not received. The exothermicity of reactions rapidly decreases from F to I (for reactions with F 2, the thermal effect is 481 kJ, with Br 2 - 4 kJ). It is also possible to obtain mixed derivatives, such as COFCl (for more details, see halogen derivatives carbonic acid).
By the reaction of CO with F 2 , in addition to carbonyl fluoride, a peroxide compound (FCO) 2 O 2 can be obtained. Its characteristics: melting point -42 °C, boiling point +16 °C, has a characteristic odor (similar to the smell of ozone), decomposes with an explosion when heated above 200 °C (reaction products CO 2 , O 2 and COF 2), in acidic medium reacts with potassium iodide according to the equation:
Carbon monoxide(II) reacts with chalcogens. With sulfur it forms carbon sulfide COS, the reaction proceeds when heated, according to the equation:
ΔG° 298 = −229 kJ, ΔS° 298 = −134 J/KSimilar carbon selenoxide COSe and carbon telluroxide COTe have also been obtained.
Restores SO 2:
With transition metals, it forms very volatile, combustible and toxic compounds - Carbonyls, such as Cr (CO) 6, Ni (CO) 4, Mn 2 CO 10, Co 2 (CO) 9, etc.
Carbon monoxide (II) is slightly soluble in water, but does not react with it. Also, it does not react with solutions of alkalis and acids. However, it reacts with alkali melts to form the corresponding formates:
An interesting reaction of carbon monoxide (II) with metallic potassium in ammonia solution. In this case, the explosive compound potassium dioxodicarbonate is formed:
The toxic effect of carbon monoxide (II) is due to the formation of carboxyhemoglobin - a much stronger carbonyl complex with hemoglobin, in comparison with the complex of hemoglobin with oxygen (oxyhemoglobin), thus blocking the processes of oxygen transport and cellular respiration. Air concentrations greater than 0.1% result in death within one hour.
Discovery history
Carbon monoxide (II) was first obtained by the French chemist Jacques de Lasson in the heating of zinc oxide with coal, but was initially mistaken for hydrogen, as it burned with a blue flame.
The fact that this gas contains carbon and oxygen was discovered by the English chemist William Cruikshank. carbon monoxide (II) outside the Earth's atmosphere was first discovered by the Belgian scientist M. Mizhot (M. Migeotte) in 1949 by the presence of the main vibrational-rotational band in the IR spectrum of the Sun.
Receipt
industrial way
- It is formed during the combustion of carbon or compounds based on it (for example, gasoline) in conditions of lack of oxygen:
- or when reducing carbon dioxide with hot coal:
This reaction occurs during the furnace furnace, when the furnace damper is closed too early (until the coals have completely burned out). The resulting carbon monoxide (II), due to its toxicity, causes physiological disorders ("waste") and even death (see below), hence one of the trivial names - "carbon monoxide".
The carbon dioxide reduction reaction is reversible, the effect of temperature on the equilibrium state of this reaction is shown in the graph. The flow of the reaction to the right provides the entropy factor, and to the left - the enthalpy factor. At temperatures below 400 °C, the equilibrium is almost completely shifted to the left, and at temperatures above 1000 °C to the right (in the direction of CO formation). At low temperatures, the rate of this reaction is very low, so carbon monoxide (II) is quite stable under normal conditions. This equilibrium has a special name boudoir balance.
- Mixtures of carbon monoxide (II) with other substances are obtained by passing air, water vapor, etc. through a layer of hot coke, coal or brown coal, etc. (see generator gas, water gas, mixed gas, synthesis gas ).
laboratory method
- Decomposition of liquid formic acid under the action of hot concentrated sulfuric acid, or by passing formic acid over phosphorus oxide P 2 O 5 . Reaction scheme:
- Heating a mixture of oxalic and concentrated sulfuric acids. The reaction goes according to the equation:
- Heating a mixture of potassium hexacyanoferrate (II) with concentrated sulfuric acid. The reaction goes according to the equation:
Determination of carbon monoxide (II)
Qualitatively, the presence of CO can be determined by the darkening of palladium chloride solutions (or paper impregnated with this solution). Darkening is associated with the release of finely dispersed metallic palladium according to the scheme:
This reaction is very sensitive. Standard solution: 1 gram of palladium chloride per liter of water.
The quantitative determination of carbon monoxide (II) is based on the iodometric reaction:
Application
- Carbon monoxide (II) is an intermediate reagent used in reactions with hydrogen in the most important industrial processes for the production of organic alcohols and straight hydrocarbons.
- Carbon monoxide (II) is used to treat animal meat and fish, giving them a bright red color and a fresh look without changing the taste (en:Clear smoke or en:Tasteless smoke technology). The permissible concentration of CO is 200 mg/kg of meat.
- Carbon monoxide from engine exhaust was used by the Nazis during World War II to massacre people by poisoning.
Carbon monoxide (II) in the Earth's atmosphere
Distinguish between natural and anthropogenic sources of
Carbon forms two extremely stable oxides (CO and CO 2), three much less stable oxides (C 3 O 2 , C 5 O 2 and C 12 O 9), a number of unstable or poorly studied oxides (C 2 O, C 2 O 3 etc.) and non-stoichiometric graphite oxide. Among the listed oxides, CO and CO 2 play a special role.
DEFINITION
carbon monoxide at normal conditions combustible gas, colorless and odorless.
It is quite toxic due to its ability to form a complex with hemoglobin, which is about 300 times more stable than the oxygen-hemoglobin complex.
DEFINITION
Carbon dioxide under normal conditions, it is a colorless gas, about 1.5 times heavier than air, due to which it can be poured, like a liquid, from one vessel to another.
The mass of 1 liter of CO 2 under normal conditions is 1.98 g. The solubility of carbon dioxide in water is low: 1 volume of water at 20 o C dissolves 0.88 volumes of CO 2 , and at 0 o C - 1.7 volumes.
Direct oxidation of carbon with a lack of oxygen or air leads to the formation of CO, with a sufficient amount of them, CO 2 is formed. Some properties of these oxides are presented in table. 1.
Table 1. Physical properties oxides of carbon.
Obtaining carbon monoxide
Pure CO can be obtained in the laboratory by dehydrating formic acid (HCOOH) with concentrated sulfuric acid at ~140°C:
HCOOH \u003d CO + H 2 O.
In small quantities, carbon dioxide can be easily obtained by the action of acids on carbonates:
CaCO 3 + 2HCl \u003d CaCl 2 + H 2 O + CO 2.
On an industrial scale, CO 2 is produced mainly as a by-product in the ammonia synthesis process:
CH 4 + 2H 2 O \u003d CO 2 + 4H 2;
CO + H 2 O \u003d CO 2 + H 2.
Large quantities carbon dioxide is produced by burning limestone:
CaCO 3 \u003d CaO + CO 2.
Chemical properties of carbon monoxide
Carbon monoxide is reactive at high temperatures. It manifests itself as a strong reducing agent. Reacts with oxygen, chlorine, sulfur, ammonia, alkalis, metals.
CO + NaOH = Na(HCOO) (t = 120 - 130 o C, p);
CO + H 2 \u003d CH 4 + H 2 O (t \u003d 150 - 200 o C, kat. Ni);
CO + 2H 2 \u003d CH 3 OH (t \u003d 250 - 300 o C, kat. CuO / Cr 2 O 3);
2CO + O 2 \u003d 2CO 2 (kat. MnO 2 / CuO);
CO + Cl 2 \u003d CCl 2 O (t \u003d 125 - 150 o C, cat. C);
4CO + Ni = (t = 50 - 100 o C);
5CO + Fe = (t = 100 - 200 o C, p).
Carbon dioxide exhibits acidic properties: it reacts with alkalis, ammonia hydrate. It is restored by active metals, hydrogen, carbon.
CO 2 + NaOH dilute = NaHCO 3 ;
CO 2 + 2NaOH conc \u003d Na 2 CO 3 + H 2 O;
CO 2 + Ba(OH) 2 = BaCO 3 + H 2 O;
CO 2 + BaCO 3 + H 2 O \u003d Ba (HCO 3) 2;
CO 2 + NH 3 × H 2 O \u003d NH 4 HCO 3;
CO 2 + 4H 2 \u003d CH 4 + 2H 2 O (t \u003d 200 o C, kat. Cu 2 O);
CO 2 + C \u003d 2CO (t\u003e 1000 o C);
CO 2 + 2Mg \u003d C + 2MgO;
2CO 2 + 5Ca = CaC 2 + 4CaO (t = 500 o C);
2CO 2 + 2Na 2 O 2 \u003d 2Na 2 CO 3 + O 2.
Application of carbon monoxide
Carbon monoxide is widely used as a fuel in the form of producer gas or water gas, and is also formed during the separation of many metals from their oxides by reduction with coal. Generator gas is obtained by passing air through hot coal. It contains about 25% CO, 4% CO2 and 70% N 2 with traces of H 2 and CH 4 62.
The use of carbon dioxide is most often due to its physical properties. It is used as a cooling agent, for carbonating beverages, for producing lightweight (foamed) plastics, and as a gas for creating an inert atmosphere.
Examples of problem solving
EXAMPLE 1
EXAMPLE 2
| Exercise | Determine how many times heavier than air is carbon monoxide (IV)CO 2. |
| Solution | The ratio of the mass of a given gas to the mass of another gas taken in the same volume, at the same temperature and the same pressure, is called the relative density of the first gas over the second. This value shows how many times the first gas is heavier or lighter than the second gas. The relative molecular weight of air is taken equal to 29 (taking into account the content of nitrogen, oxygen and other gases in the air). It should be noted that the concept of "relative molecular weight of air" is used conditionally, since air is a mixture of gases. D air (CO 2) \u003d M r (CO 2) / M r (air); D air (CO 2) \u003d 44 / 29 \u003d 1.517. M r (CO 2) \u003d A r (C) + 2 × A r (O) \u003d 12 + 2 × 16 \u003d 12 + 32 \u003d 44. |
| Answer | Carbon monoxide (IV)CO 2 is 1.517 times heavier than air. |
| CO carbon monoxide | CO 2 carbon dioxide |
| Receipt | |
| CO 2 + C → 2CO (when heated) 2C + O 2 (lack) → 2CO | CaCO 3 → CaO + CO 2 (860 o C) CaCO 3 + 2HCl → CaCl 2 + H 2 O + CO 2 CH 4 + 2O 2 → CO 2 + 2H 2 O C + O 2 (excess) → CO 2 |
| Physical properties | |
| The gas is colorless and odorless, slightly lighter than air, slightly soluble in water. | The gas is colorless and odorless, heavier than air, sparingly soluble in water, capable of sublimation in the solid state ("dry ice"). |
| SO | CO 2 |
| The structure of the molecule | |
| C ≡ O (σ + 2π): the second π-bond is formed by transferring the lone electron pair of oxygen to the free orbital of the carbon atom. Linear polar molecule capable of donor-acceptor interaction: Ni + 5CO → Ni(CO) 5 - nickel pentacarbonyl | O = C = O two double bonds (σ + π), linear non-polar symmetrical molecule |
| Physiological action | |
| Poisonous, as it is a hemoblocker: Hb + CO → Hb. CO is carboxyhemoglobin, 210 times stronger than oxyhemoglobin Hb. O 2 . | Participates in the act of inhalation, as it activates the respiratory center of the brain. |
| Place in the classification of oxides | |
| Non-salting oxide Exception: CO + NaOH → HCOONa sodium formate melt | Acid oxide CO 2 + Ca (OH) 2 → CaCO 3 ↓ + H 2 O CaCO 3 + H 2 O + CO 2 → Ca (HCO 3) 2 - a qualitative reaction to CO 2: a white precipitate forms with lime water, which dissolves in excess gas. CO 2 + H 2 O → H 2 CO 3 CO 2 + Na 2 O → Na 2 CO 3 CO 2 + Na 2 SiO 3 + H 2 O → Na 2 CO 3 + H 2 SiO 3 ↓ |
| Redox activity | |
| Strong reducing agent CuO + CO → Cu + CO 2 CO + Cl 2 → COCl 2 (phosgene) | Weak oxidizer 2Mg + CO 2 → 2MgO + C |
Carbonic acid H 3 CO 3- weak, dibasic, unstable.
CO 2 + H 2 O ↔ H 2 CO 3 ↔ H + + HCO 3 - ↔ 2H + + CO 3 2-
Forms 2 series of salts: medium carbonates (Na 2 CO 3) and acid bicarbonates (NaHCO 3)
Qualitative reaction to salts of carbonic acid: Under the influence strong acids emit a colorless and odorless gas:
Na 2 CO 3 + 2HCl → 2NaCl + CO 2 + H 2 O
NaHCO 3 + HCl → NaCl + CO 2 + H 2 O
CaCO 3 + 2HCl → CaCl 2 + CO 2 + H 2 O
Mutual transition of carbonates and hydrocarbonates:
Na 2 CO 3 + CO 2 + H 2 O → 2NаНСО 3
NaHCO 3 + NaOH → Na 2 CO 3 + H 2 O or 2NaHCO 3 (t 0) → Na 2 CO 3 + CO 2 + H 2 O
General salt properties of carbonates:
Na 2 CO 3 + Ca(OH) 2 → 2NaOH + CaCO 3 ↓
Na 2 CO 3 + CaCl 2 → 2NaCl + CaCO 3 ↓
Soluble carbonates are hydrolyzed to the anion:
CO 3 2- + HOH ↔ HCO 3 - + OH -
Na 2 CO 3 + H 2 O ↔ NaHCO 3 + NaOH
The use of carbon and its compounds:
CO 2 is used as "dry ice", found in natural mineral waters. CO and coke (C) are metallurgical reducing agents. Activated carbon is used in gas masks and household water filters, in medicine to remove toxins from the body, as an adsorption catalyst. Coal is used as fuel.
Na2CO3. 10H 2 O - soda ash.
NaHCO 3 - baking soda.
(NH 4) 2 CO 3 - the basis of the dough baking powder.
COCl 2 - phosgene - chemical warfare agent.
K 2 CO 3 - potash - potash fertilizer.
CaCO 3 - chalk, marble, limestone.
Regulations in the EPS: Z = 14, 3rd period, IV group (main).
Electronic formula: 1s 2 2s 2 2p 6 3s 2 Sp 2
Oxidation scale: +4: SiO 2, H 2 SiO 3, Na 2 SiO 3
– 4: Mg 2 Si, SiH 4
Finding in nature: second element after oxygen earth's crust: SiO 2 - quartz, sand, rock crystal; silicates and aluminosilicates (clays, kaolin, mica, feldspar). Diatoms and silicon sponges accumulate silicon.
Receipt: when heated
1) SiO 2 (silica) + 2Mg → 2MgO + Si
2) SiO 2 + C → Si + CO 2
3) 3SiO 2 + 4Al → 2Al 2 O 3 + 3Si
4) SiCl 4 + 2Zn → 2ZnCl 2 + Si
Formed amorphous silicon is a brown powder. During its recrystallization (evaporation by the action of high temperature, followed by condensation), crystal silicon - gray crystals with a metallic luster and semiconductor properties.
Chemical properties:
1) Recovery(predominant):
Si + 2F 2 → SiF 4 (silicon (IV) fluoride) - at room temperature, in the light
Si + O 2 → SiO 2 (silicon oxide (IV)) - 600 o C
3Si + 2N 2 → Si 3 N 4 (silicon (IV) nitride) - 1000 o C
Si + С → SiС (silicon carbide (carborundum)) - fusion 2000 о С
Si + 2S → SiS 2 (silicon sulfide) - 600 o C
Si + 2Cl 2 → SiCl 4 (silicon chloride) - 400 o C
Si + 2H 2 O (steam) → SiO 2 + 2H 2
Si + 2NaOH + H 2 O → Na 2 SiO 3 + 2H 2
3Si + 4HNO 3 + 18HF → 3H 2 SiF 6 + 4NO + 8H 2 O (hexafluorosilicic acid)
WITH nitric And concentrated sulfuric acids and hydrogen silicon does not react .
2) Oxidizing properties silicon shows only in reactions with metals:
2Mg + Si → Mg 2 Si (magnesium silicide)
Silicon compounds
Silane SiH 4- colorless poisonous gas, ignites spontaneously in air; is of a neutral nature.
Mg 2 Si + 4HCl → 2MgCl 2 + SiH 4 (the reaction is difficult with water, since insoluble Mg (OH) 2 is formed)
SiH 4 + 2O 2 → SiO 2 + 2H 2 O
Silicon (IV) oxide SiO 2
Silicic acid H 2 SiO 3: insoluble (glassy precipitate), the weakest of the mineral acids.
Receipt:
Na 2 SiO 3 + 2HCl → 2NaCl + H 2 SiO 3 ↓
SiCl 4 + 3H 2 O → H 2 SiO 3 ↓ + 4HCl
SiS 2 + 3H 2 O → H 2 SiO 3 ↓ + 2H 2 S
Chemical properties:
1) Dissolves in alkalis: H 2 SiO 3 + 2NaOH → Na 2 SiO 3 + 2H 2 O
2) Decomposes when heated: H 2 SiO 3 → H 2 O + SiO 2
silicates: soluble only in alkali metals.
General salt properties:
Na 2 SiO 3 + ВаСl 2 → 2NaCl + BaSiO 3 ↓
Na 2 SiO 3 + Ca (OH) 2 → CaSiO 3 + 2NaOH
silicate solutions have alkaline environment due to hydrolysis:
Na 2 SiO 3 + HOH ↔ NaHSiO 3 + NaOH
The use of silicon and its compounds:
Carborundum is used in dentistry for grinding fillings. SiO 2 (quartz) - in optical and chronometric instruments. Na 2 SiO 3 - the basis of stationery glue and glass. Silicon compounds are the basis of the ceramic and cement industry.
Carbon (C) is a typical non-metal; V periodic system is in the 2nd period of the IV group, the main subgroup. Ordinal number 6, Ar = 12.011 amu, nuclear charge +6.Physical properties: carbon forms many allotropic modifications: diamond- one of the most solids, graphite, coal, soot.
A carbon atom has 6 electrons: 1s 2 2s 2 2p 2 . The last two electrons are located in separate p-orbitals and are unpaired. In principle, this pair could occupy one orbital, but in this case the interelectron repulsion strongly increases. For this reason, one of them takes 2p x, and the other, either 2p y , or 2p z-orbitals.
The difference between the energies of the s- and p-sublevels of the outer layer is small, therefore, the atom quite easily passes into an excited state, in which one of the two electrons from the 2s-orbital passes to a free one. 2r. A valence state arises having the configuration 1s 2 2s 1 2p x 1 2p y 1 2p z 1 . It is this state of the carbon atom that is characteristic of the diamond lattice - the tetrahedral spatial arrangement of hybrid orbitals, the same bond length and energy.
This phenomenon is known to be called sp 3 -hybridization, and the resulting functions are sp 3 -hybrid . The formation of four sp 3 bonds provides the carbon atom with a more stable state than three rr- and one s-s-bond. In addition to sp 3 hybridization, sp 2 and sp hybridization are also observed at the carbon atom . In the first case, there is a mutual overlap s- and two p-orbitals. Three equivalent sp 2 - hybrid orbitals are formed, located in the same plane at an angle of 120 ° to each other. The third orbital p is unchanged and directed perpendicular to the plane sp2.
In sp hybridization, the s and p orbitals overlap. An angle of 180° arises between the two equivalent hybrid orbitals formed, while the two p-orbitals of each of the atoms remain unchanged.
Allotropy of carbon. diamond and graphite
In a graphite crystal, carbon atoms are located in parallel planes, occupying the vertices of regular hexagons in them. Each of the carbon atoms is linked to three adjacent sp 2 hybrid bonds. Between parallel planes, the connection is carried out due to van der Waals forces. Free p-orbitals of each of the atoms are directed perpendicular to the planes of covalent bonds. Their overlap explains the additional π-bond between carbon atoms. So from the valence state in which carbon atoms are in a substance, the properties of this substance depend.
Chemical properties of carbon
The most characteristic oxidation states: +4, +2.
At low temperatures, carbon is inert, but when heated, its activity increases.
Carbon as a reducing agent:
- with oxygen
C 0 + O 2 - t ° \u003d CO 2 carbon dioxide
with a lack of oxygen - incomplete combustion:
2C 0 + O 2 - t° = 2C +2 O carbon monoxide
- with fluorine
C + 2F 2 = CF 4
- with steam
C 0 + H 2 O - 1200 ° \u003d C + 2 O + H 2 water gas
— with metal oxides. In this way metal is smelted from ore.
C 0 + 2CuO - t ° \u003d 2Cu + C +4 O 2
- with acids - oxidizing agents:
C 0 + 2H 2 SO 4 (conc.) \u003d C +4 O 2 + 2SO 2 + 2H 2 O
С 0 + 4HNO 3 (conc.) = С +4 O 2 + 4NO 2 + 2H 2 O
- forms carbon disulfide with sulfur:
C + 2S 2 \u003d CS 2.
Carbon as an oxidizing agent:
- forms carbides with some metals
4Al + 3C 0 \u003d Al 4 C 3
Ca + 2C 0 \u003d CaC 2 -4
- with hydrogen - methane (as well as a huge amount organic compounds)
C 0 + 2H 2 \u003d CH 4
- with silicon, forms carborundum (at 2000 ° C in an electric furnace):
Finding carbon in nature
Free carbon occurs as diamond and graphite. In the form of compounds, carbon is found in minerals: chalk, marble, limestone - CaCO 3, dolomite - MgCO 3 *CaCO 3; bicarbonates - Mg (HCO 3) 2 and Ca (HCO 3) 2, CO 2 is part of the air; carbon is the main component of natural organic compounds - gas, oil, hard coal, peat, is part of organic matter, proteins, fats, carbohydrates, amino acids that are part of living organisms.
Inorganic carbon compounds
Neither C 4+ ions, nor C 4- - under any normal chemical processes are not formed: in carbon compounds there are covalent bonds different polarity.
Carbon monoxide (II) SO
Carbon monoxide; colorless, odorless, sparingly soluble in water, soluble in organic solvents, poisonous, bp = -192°C; t sq. = -205°C.
Receipt
1) In industry (in gas generators):
C + O 2 = CO 2
2) In the laboratory - thermal decomposition of formic or oxalic acid in the presence of H 2 SO 4 (conc.):
HCOOH = H2O + CO
H 2 C 2 O 4 \u003d CO + CO 2 + H 2 O
Chemical properties
Under ordinary conditions, CO is inert; when heated - reducing agent; non-salt-forming oxide.
1) with oxygen
2C +2 O + O 2 \u003d 2C +4 O 2
2) with metal oxides
C +2 O + CuO \u003d Cu + C +4 O 2
3) with chlorine (in the light)
CO + Cl 2 - hn \u003d COCl 2 (phosgene)
4) reacts with alkali melts (under pressure)
CO + NaOH = HCOONa (sodium formate)
5) forms carbonyls with transition metals
Ni + 4CO - t° = Ni(CO) 4
Fe + 5CO - t° = Fe(CO) 5
Carbon monoxide (IV) CO2
Carbon dioxide, colorless, odorless, solubility in water - 0.9V CO 2 dissolves in 1V H 2 O (under normal conditions); heavier than air; t°pl.= -78.5°C (solid CO 2 is called "dry ice"); does not support combustion.
Receipt
- Thermal decomposition of salts of carbonic acid (carbonates). Limestone firing:
CaCO 3 - t ° \u003d CaO + CO 2
- The action of strong acids on carbonates and bicarbonates:
CaCO 3 + 2HCl \u003d CaCl 2 + H 2 O + CO 2
NaHCO 3 + HCl \u003d NaCl + H 2 O + CO 2
ChemicalpropertiesCO2
Acid oxide: reacts with basic oxides and bases to form carbonic acid salts
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
May exhibit oxidizing properties at elevated temperatures
C +4 O 2 + 2Mg - t ° \u003d 2Mg +2 O + C 0
Qualitative reaction
Turbidity of lime water:
Ca (OH) 2 + CO 2 \u003d CaCO 3 ¯ (white precipitate) + H 2 O
It disappears when CO 2 is passed through lime water for a long time, because. insoluble calcium carbonate is converted to soluble bicarbonate:
CaCO 3 + H 2 O + CO 2 \u003d Ca (HCO 3) 2
carbonic acid and itssalt
H2CO3 — Weak acid, exists only in aqueous solution:
CO 2 + H 2 O ↔ H 2 CO 3
Dual base:
H 2 CO 3 ↔ H + + HCO 3 - Acid salts - bicarbonates, bicarbonates
HCO 3 - ↔ H + + CO 3 2- Medium salts - carbonates
All properties of acids are characteristic.
Carbonates and bicarbonates can be converted into each other:
2NaHCO 3 - t ° \u003d Na 2 CO 3 + H 2 O + CO 2
Na 2 CO 3 + H 2 O + CO 2 \u003d 2NaHCO 3
Metal carbonates (except alkali metals) decarboxylate when heated to form an oxide:
CuCO 3 - t ° \u003d CuO + CO 2
Qualitative reaction- "boiling" under the action of a strong acid:
Na 2 CO 3 + 2HCl \u003d 2NaCl + H 2 O + CO 2
CO 3 2- + 2H + = H 2 O + CO 2
Carbides
calcium carbide:
CaO + 3 C = CaC 2 + CO
CaC 2 + 2 H 2 O \u003d Ca (OH) 2 + C 2 H 2.
Acetylene is released when zinc, cadmium, lanthanum and cerium carbides react with water:
2 LaC 2 + 6 H 2 O \u003d 2La (OH) 3 + 2 C 2 H 2 + H 2.
Be 2 C and Al 4 C 3 are decomposed by water to form methane:
Al 4 C 3 + 12 H 2 O \u003d 4 Al (OH) 3 \u003d 3 CH 4.
Titanium carbides TiC, tungsten W 2 C (hard alloys), silicon SiC (carborundum - as an abrasive and material for heaters) are used in technology.
cyanides
obtained by heating soda in an atmosphere of ammonia and carbon monoxide:
Na 2 CO 3 + 2 NH 3 + 3 CO \u003d 2 NaCN + 2 H 2 O + H 2 + 2 CO 2
Hydrocyanic acid HCN is an important chemical industry product widely used in organic synthesis. Its world production reaches 200 thousand tons per year. Electronic structure cyanide anion, similarly to carbon monoxide (II), such particles are called isoelectronic:
C = O:[:C = N:]-
Cyanides (0.1-0.2% water solution) are used in gold mining:
2 Au + 4 KCN + H 2 O + 0.5 O 2 \u003d 2 K + 2 KOH.
When cyanide solutions are boiled with sulfur or when solids are fused, thiocyanates:
KCN + S = KSCN.
When cyanides of low-active metals are heated, cyanide is obtained: Hg (CN) 2 \u003d Hg + (CN) 2. cyanide solutions are oxidized to cyanates:
2KCN + O2 = 2KOCN.
Cyanic acid exists in two forms:
H-N=C=O; H-O-C = N:
In 1828, Friedrich Wöhler (1800-1882) obtained urea from ammonium cyanate: NH 4 OCN \u003d CO (NH 2) 2 by evaporating an aqueous solution.
This event is usually seen as the victory of synthetic chemistry over "vitalistic theory".
There is an isomer of cyanic acid - fulminic acid
H-O-N=C.
Its salts (mercury fulminate Hg(ONC) 2) are used in impact igniters.
Synthesis urea(carbamide):
CO 2 + 2 NH 3 \u003d CO (NH 2) 2 + H 2 O. At 130 0 C and 100 atm.
Urea is an amide of carbonic acid, there is also its "nitrogen analogue" - guanidine.
Carbonates
The most important inorganic compounds of carbon are salts of carbonic acid (carbonates). H 2 CO 3 is a weak acid (K 1 \u003d 1.3 10 -4; K 2 \u003d 5 10 -11). Carbonate buffer supports carbon dioxide balance in the atmosphere. The oceans have a huge buffer capacity because they are an open system. The main buffer reaction is the equilibrium during the dissociation of carbonic acid:
H 2 CO 3 ↔ H + + HCO 3 -.
With a decrease in acidity, additional absorption of carbon dioxide from the atmosphere occurs with the formation of acid:
CO 2 + H 2 O ↔ H 2 CO 3.
With an increase in acidity, carbonate rocks (shells, chalk and limestone deposits in the ocean) dissolve; this compensates for the loss of hydrocarbonate ions:
H + + CO 3 2- ↔ HCO 3 -
CaCO 3 (tv.) ↔ Ca 2+ + CO 3 2-
Solid carbonates are converted into soluble hydrocarbons. It is this process of chemical dissolution of excess carbon dioxide that counteracts the "greenhouse effect" - global warming due to the absorption of the Earth's thermal radiation by carbon dioxide. Approximately one third of the world's production of soda (sodium carbonate Na 2 CO 3) is used in the manufacture of glass.
State educational institution
"Presnovskaya high school »
North-Kazakhstan region, Kyzylzhar region
Synopsis of a chemistry lesson in grade 9
Topic: “Carbon oxides ( II And IV )».
Prepared by: chemistry teacher
Belousova Ekaterina Pavlovna
2012-2013 academic year
Grade: 9
Topic: Oxides of carbon (II and IV)
Target : Learning new chemical substances– carbon oxides.
Tasks:
- Educational - learn the structure, physical properties, Chemical properties, the production and use of carbon monoxide and carbon dioxide, a qualitative reaction to carbon dioxide, the physiological effect of carbon monoxide and carbon dioxide on the body, to continue work on the development of skills to compare, draw up reaction equations, work with the text of the textbook, receive information from the Internet.
- Educational - fostering a caring attitude towards one's health, nature, development of a responsible attitude to learning, cognitive interest in chemistry, development of communicative skills and abilities, formation of pair and group work skills.
- Educational – disclosure of causal relationships,development of skills to independently set and formulate new tasks for themselves, determine methods of action and correlate with the planned results.
Lesson type: Lesson learning new material
Methods: verbal, visual, research
Methodological techniques: explanation, conversation, individual and group work, the table "Knew - I want to know - I found out"
Equipment and reagents for the teacher: computer, multimedia projector.
Equipment and reagents for students: laboratory glassware (test tubes, test tube rack, chemical beakers), reagents (acetic acid, sodium bicarbonate (soda), calcium hydroxide).
During the classes:
Stages of the lesson and time
Teacher activity
Forms of organization and
Student activities
Planned result for students
Greeting students. Set the mood for cooperation by creating an atmosphere of cooperation. Game "Tangle of Wishes"
Collective .
Teachers greet each other, say wishes to each other for the lesson, standing in a circle.
Get in the mood for work, educational cooperation
Update basic knowledge
In order to update existing knowledge, to attract attention and concentrate it is organized by DIALOGUE:
With which chemical element did we meet in the last lesson? What is formed when carbon is burned? Do you remember what these oxides are? I propose to solve riddles. The answers will be substances that you have heard about and have repeatedly encountered in everyday life.
1. To appear, I managed,
Calcined white chalk.
I'm in sparkling water
I am in bread, in soda; I am everywhere.
And photosynthesis without me
And not there and not here.
And the flame of a small candle
And you just need to take a breath
So that I can come into the world.
The fire in the furnace gives me
(Carbon dioxide or carbon monoxide (IV))
2. I burn with a blue flame
I threaten with fumes
When I'm on fire,
I'm flying out of the oven.
(Carbon monoxide or carbon monoxide(II))
collective, individual.
They express opinions, guess riddles, call formulas (CO, CO 2).
They will remember, formulate and argue their opinion, take into account different views; express their thoughts
setting a learning task
What will be discussed in today's lesson?
Provides lesson objectives:
What can you learn during the lesson?
In order to develop thinking, increase interest in the topic, he invites each student to fill out the “ZKhU” table on this topic 
Collective. Formulate the topic of the lesson and write it down in a notebook. Express opinions, determine the objectives of the lesson
Individual. Two or three read out what they would like to know
They reason logically, remember, define, transform their knowledge, transform, put forward hypotheses
dividing the class into groups
Do you know what role oxides play in nature? Is this knowledge enough for us? What else do we need to know about these substances? And how are we going to do it?
Knowing the abilities of students, the type of character, temperament,
Invites students to take cards, with the help of which they form 3 groups, different in the way they study the proposed new material
Individual
They determine how they want to study the material (reproductively or creatively), choose the color of the card (blue, green, red), form groups
self-determine “looking inside themselves” with a way to achieve goals
Work on the assimilation of new knowledge
Issues a task and Handout each group (appendices No. 1, 2.3)
Clarifies student tasks
Supervises student work, advises and stimulates learning activities students; asking questions
Group.
Work to complete the task; use the textbook and Internet resources; answer the questions of the task; defined with the role of everyone in the group
planning joint work, recognize and highlight information, take into account different opinions, determine the role, formulate their opinion, choose, analyze
protecting your work
In order to correct knowledge, the teacher asks questions to students;
Answers students' questions;
Summarizes and sums up the results of creative groups.
Group.
They take turns reporting on the work done (using a magnetic, interactive whiteboard)
Answer the questions of the teacher, outline what they liked in the work of the other group. Evaluate the work of each group
Develop speech skills, listen to each other, ask questions, think, compare
Primary fastening
To improve and raise the internal satisfaction of students from work, to correct knowledge, Invites students in pairs to answer the questions: (Appendix No. 4), with
discussion of each answer
Steam room.
Read the questions, answer in turn, the teacher asks one of the pair 
Learn, reformulate, prove, produce, speak, listen
Independent work with self-test
according to the standard .
To test the assimilation of knowledge, for evaluation offers verification test :
Choose from the given statements those that are true:
Option I: - for carbon monoxide (CO)
II option: - for carbon dioxide (CO 2)
1. Colorless gas, odorless.
2. Gaseous under normal conditions.
3. Poisonous.
4. Not poisonous.
5. Let's well dissolve in water.
6. Poorly soluble in water.
7. Gas is lighter than air.
8. Gas is heavier than air.
9. Shows acidic properties.
10. The degree of oxidation of carbon +2.
11. The degree of oxidation of carbon +4.
12. In reactions, it can be both an oxidizing agent and a reducing agent.
13. In reactions, it can only be an oxidizing agent.
14. Turbidity is observed when passing through lime water.
Answer options are projected onto the screen:
mark "5" - 10 or more correct answers
"2" - 5 or less
Individual. Students complete the written test
steam room
carry out mutual verification according to the standard (exchange notebooks)
They highlight information, analyze the material heard and seen during the lesson, reason, build a logical chain. self-assessment
Reflection of activity
Guys, what new did you learn at the lesson? Record this information in your ZHU tables at home.
Individual.
Give yourself an assessment, completing the lesson with an analysis of the knowledge gained.
Express their attitude to the lesson (Stickers with their own name are glued to the corresponding picture - a smiley face) 
,
formulate and justify their opinion, express their feelings
Homework
Finish the table "ZHU" (everyone)
Read paragraph 26 (everyone)
** from 93 task 3
*** from 93 task 4
*** think of a syncwine about any of the substances discussed today.
Thank the students for the lesson
Write down home 
exercise.
self-determine with the level of work
Annex No. 4.
Carbon monoxide formula
Formula of carbon dioxide
Character of oxides of carbon
Physical properties of carbon monoxide
How carbon monoxide affects the body
How to recognize carbon dioxide
Where is carbon dioxide used?
Application No. 1.
Fill in the gaps in the text using your knowledge, textbook, Internet resources.
Carbon is a non-metal, when burned, 2 are formed ……., they are …………….. The formula of carbon monoxide () is ….., its second name is …………………….., because …… …………………………………………………………………………………………………… The physical properties of carbon monoxide () are as follows:………… ……………………………….. In order to save a person, it is first necessary to …………………………………………..
Carbon monoxide is obtained as a result of reactions:…………………………………………………. Carbon monoxide is used as…………………….., for example, the following reactions occur:………………………………..
The formula of the second oxide - carbon monoxide () - ......., but more often it is called ...……………. In terms of physical properties, this is……………………………………………………. In nature, it appears as a result of………………………….. And in the laboratory it is obtained as follows:………………………………………………………………… . As a typical acid oxide, carbon dioxide interacts with:……………………………………………………………..
To recognize carbon dioxide, it is necessary ………………………………………., then …………………… Carbon dioxide is widely used for……………………………
Application number 2.
Fill in the comparison table using your knowledge, textbook, Internet resources.
Signs of comparison
CO (carbon monoxide)
CO 2 (carbon dioxide)
The structure of the molecule
Physical properties
Chemical properties
How to get
Application
Conduct a laboratory experiment proving a qualitative reaction to CO 2:
Assemble the apparatus for obtaining gases. Place a little sodium bicarbonate in a test tube, add acetic acid drop by drop (remember the rules of TB!). Insert a gas outlet pipe, the end of which is lowered into a glass of lime water. Explain the observations.
Application No. 3
Task 1: Use the Venn diagram to find the common and features two oxides of carbon.
Task 2. Fill in the table using additional material(provided to students)
Signs of comparison
CO (carbon monoxide)
CO2 (carbon dioxide)
Physiological effect on the body
Combining with the hemoglobin of red blood cells, oxygen carriers from the lungs to the tissues of the body, carbon monoxide causes oxygen starvation, and a person can die. When inhaling air containing up to 0.1% CO, a person can lose consciousness and die.
It has a narcotic effect on a person, irritates the skin and mucous membranes, has a central vasoconstrictor and local vasodilating effect, causes an increase in the content of amino acids in the blood, and inhibits the action of enzymes in tissues. With its concentration in the air up to 3%, a person experiences rapid breathing, more than 10% loss of consciousness, death.
