Substitution reactions in inorganic chemistry. Classification of chemical reactions in organic and inorganic chemistry. carboxylic acids. Ionic reactions take place between ions already present or formed during the reaction

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Chemical reactions - chemical processes, as a result of which some substances form others that differ from them in composition and (or) structure. In chemical reactions, a change in substances necessarily occurs, in which old bonds are broken and new bonds are formed between atoms. Signs of chemical reactions: A gas is released A precipitate will fall 3) A change in the color of substances occurs Heat, light is released or absorbed

Chemical reactions in not organic chemistry

Chemical reactions in inorganic chemistry

Chemical reactions in inorganic chemistry 1. By changing oxidation states chemical elements: Redox reactions: Redox reactions are reactions that occur with a change in the oxidation states of elements. Intermolecular - this is a reaction that goes with a change in the oxidation state of atoms in different molecules. -2 +4 0 2H 2 S + H 2 SO 3 → 3S + 3H 2 O +2 -1 +2.5 -2 2Na 2 S 2 O 3 + H 2 O 2 → Na 2 S 4 O 6 + 2NaOH

Chemical reactions in inorganic chemistry 1. By changing the oxidation states of chemical elements that form substances: Redox reactions: 2. Intramolecular - this is a reaction that occurs with a change in the oxidation state of different atoms in one molecule. -3 +5 t 0 +3 (NH4) 2 Cr 2 O 7 → N 2 + Cr 2 O 3 + 4H 2 O Disproportionation is a reaction that occurs with a simultaneous increase and decrease in the oxidation state of atoms of the same element. +1 +5 -1 3NaClO → NaClO 3 + 2NaCl

2.1. Reactions that take place without changing the composition of substances In inorganic chemistry, such reactions include the processes of obtaining allotropic modifications of one chemical element, for example: C (graphite) C (diamond) 3O 2 (oxygen) 2O 3 (ozone) Sn (white tin) Sn ( gray tin) S (rhombic) S (plastic) P (red) P (white) Chemical reactions in inorganic chemistry 2. According to the number and composition of reactants:

Chemical reactions in inorganic chemistry 2. According to the number and composition of reactants: 2.2. Reactions that occur with a change in the composition of a substance Combination reactions are reactions in which one complex substance is formed from two or more substances. In inorganic chemistry, the whole variety of compound reactions can be considered using the example of the reaction for obtaining sulfuric acid from sulfur: a) obtaining sulfur oxide (IV): S + O 2  SO 2 - one complex substance is formed from two simple substances, b) obtaining sulfur oxide (VI ): 2 SO 2 + O 2 2SO 3 - one complex substance is formed from a simple and complex substance, c) obtaining sulfuric acid: SO 3 + H 2 O \u003d H 2 SO 4 - one complex substance is formed from two complex substances.

Chemical reactions in inorganic chemistry 2. According to the number and composition of the reacting substances: 2. Decomposition reactions are those reactions in which several new substances are formed from one complex substance. In inorganic chemistry, the whole variety of such reactions can be considered in the block of reactions for obtaining oxygen by laboratory methods: a) decomposition of mercury (II) oxide: 2HgO  t 2Hg + O 2  - two simple ones are formed from one complex substance. b) decomposition of potassium nitrate: 2KNO 3  t 2KNO 2 + O 2  - one simple and one complex substance are formed from one complex substance. c) decomposition of potassium permanganate: 2 KMnO 4 → t K 2 MnO 4 + MnO 2 + O 2 - two complex and one simple are formed from one complex substance.

Chemical reactions in inorganic chemistry 2. According to the number and composition of reacting substances: 3. Substitution reactions are such reactions as a result of which atoms a simple substance replace the atoms of an element in a complex substance. In inorganic chemistry, an example of such processes is a block of reactions that characterize the properties of metals: a) the interaction of alkali or alkaline earth metals with water: 2 Na + 2H 2 O = 2NaOH + H 2  Ca + 2H 2 O = Ca (OH) 2 + H 2  b) interaction of metals with acids in solution: Zn + 2HCl = ZnCl 2 + H 2  c) interaction of metals with salts in solution: Fe + Cu SO 4 = FeSO 4 + Cu d) metallothermy: 2Al + Cr 2 O 3  t Al 2 O 3 + 2Cr

4. Exchange reactions are those reactions in which two complex substances exchange their constituents. These reactions characterize the properties of electrolytes and proceed in solutions according to the Berthollet rule, that is, only if a precipitate, gas, or a low-dissociating substance (for example, H 2 O) is formed as a result. In inorganic, this can be a block of reactions that characterize the properties of alkalis: a) a neutralization reaction that proceeds with the formation of salt and water: NaOH + HNO 3 \u003d NaNO 3 + H 2 O or in ionic form: OH - + H + \u003d H 2 O b ) the reaction between alkali and salt, which goes with the formation of gas: 2NH 4 Cl + Ca (OH) 2 \u003d CaCl 2 + 2NH 3  + 2 H 2 O c) the reaction between alkali and salt, which goes with the formation of a precipitate: Cu SO 4 + 2KOH \u003d Cu (OH) 2  + K 2 SO 4 Chemical reactions in inorganic chemistry 2. According to the number and composition of the reactants:

Chemical reactions in inorganic chemistry 3. According to the thermal effect: 3.1. Exothermic Reactions: Exothermic reactions are reactions that release energy into the environment. These include almost all compound reactions. Exothermic reactions that proceed with the release of light are referred to as combustion reactions, for example: 4P + 5O 2 \u003d 2P 2 O 5 + Q 3.2. Endothermic Reactions: Endothermic reactions are reactions that absorb energy into the environment. These include almost all decomposition reactions, for example: Calcining limestone: CaCO 3  t CaO + CO 2  - Q

Chemical reactions in inorganic chemistry 4. Process reversibility: 4.1. irreversible reactions: Irreversible reactions proceed under these conditions in only one direction. Such reactions include all exchange reactions accompanied by the formation of a precipitate, gas or a low-dissociating substance (water) and all combustion reactions: S + O 2  SO 2; 4 P + 5O 2  2P 2 O 5; Cu SO 4 + 2KOH  Cu(OH) 2  + K 2 SO 4 4.2. Reversible reactions: Reversible reactions under given conditions proceed simultaneously in two opposite directions. Most of these reactions are. For example: 2 SO 2 + O 2 2SO 3 N 2 + 3H 2 2NH 3

Catalysts are substances that take part in a chemical reaction and change its speed or direction, but at the end of the reaction remain unchanged qualitatively and quantitatively. 5.1. Non-catalytic reactions: Non-catalytic reactions are reactions that take place without the participation of a catalyst: 2HgO  t 2Hg + O 2  2Al + 6HCl  t 2AlCl 3 + 3H 2  5.2. Catalytic reactions: Catalytic reactions are reactions that take place with the participation of a catalyst: t ,MnO 2 2KClO 3 → 2KCl + 3O 2  P,t CO + NaOH  H-CO-ONa Chemical reactions in inorganic chemistry 5 . Catalyst involvement

Chemical reactions in inorganic chemistry 6 . Presence of an interface between phases 6.1. Heterogeneous reactions: Heterogeneous reactions are reactions in which the reactants and reaction products are in different aggregate states (in different phases): FeO (t) + CO (g)  Fe (t) + CO 2 (g) + Q 2 Al (t) + 3C u C l 2 (solution) \u003d 3C u (t) + 2AlCl 3 (solution) CaC 2 (t) + 2H 2 O (l) \u003d C 2 H 2  + Ca ( OH) 2 (solution) 6.2. Homogeneous Reactions: Homogeneous reactions are reactions in which the reactants and reaction products are in the same state of aggregation(in one phase): 2C 2 H 6 (g) + 7O 2 (g)  4CO 2 (g) + 6H 2 O (g) 2 SO 2 (g) + O 2 (g) \u003d 2SO 3 (g) + Q H 2 (g) + F 2 (g) \u003d 2HF (g)

Classification of chemical reactions in inorganic and organic chemistry

Chemical reactions, or chemical phenomena, are processes as a result of which others are formed from some substances, differing from them in composition and (or) structure.

In chemical reactions, a change in substances necessarily occurs, in which old bonds are broken and new bonds are formed between atoms.

Chemical reactions should be distinguished from nuclear reactions. As a result of a chemical reaction total number atoms of each chemical element and its isotopic composition do not change. Another thing nuclear reactions- transformation processes atomic nuclei as a result of their interaction with other nuclei or elementary particles, for example, the conversion of aluminum to magnesium:

$↙(13)↖(27)(Al)+ ()↙(1)↖(1)(H)=()↙(12)↖(24)(Mg)+()↙(2)↖(4 )(He)$

The classification of chemical reactions is multifaceted, i.e. It can be based on various features. But under any of these signs, reactions both between inorganic and between organic substances can be attributed.

Consider the classification of chemical reactions according to various criteria.

Classification of chemical reactions according to the number and composition of reactants. Reactions that take place without changing the composition of the substance

In inorganic chemistry, such reactions include the processes of obtaining allotropic modifications of one chemical element, for example:

$С_((graphite))⇄С_((diamond))$

$S_((rhombic))⇄S_((monoclinic))$

$P_((white))⇄P_((red))$

$Sn_((white tin))⇄Sn_((grey tin))$

$3O_(2(oxygen))⇄2O_(3(ozone))$.

In organic chemistry, this type of reactions can include isomerization reactions that occur without changing not only the qualitative, but also the quantitative composition of the molecules of substances, for example:

1. Isomerization of alkanes.

The reaction of isomerization of alkanes is of great practical importance, because. isostructure hydrocarbons are less prone to detonation.

2. Alkene isomerization.

3. Alkyne isomerization(reaction of A. E. Favorsky).

4. Isomerization of haloalkanes(A. E. Favorsky).

5. Isomerization of ammonium cyanate on heating.

For the first time, urea was synthesized by F. Wehler in 1882 by isomerization of ammonium cyanate when heated.

Reactions that go with a change in the composition of a substance

There are four types of such reactions: compounds, decompositions, substitutions and exchanges.

1. Connection reactions- These are reactions in which two or more substances form one complex substance.

In inorganic chemistry, the whole variety of compound reactions can be considered using the example of reactions for obtaining sulfuric acid from sulfur:

1) obtaining sulfur oxide (IV):

$S+O_2=SO_2$ — one complex substance is formed from two simple substances;

2) production of sulfur oxide (VI):

$2SO_2+O_2(⇄)↖(t,p,cat.)2SO_3$ - one complex substance is formed from simple and complex substances;

3) obtaining sulfuric acid:

$SO_3+H_2O=H_2SO_4$ — one compound is formed from two complex substances.

An example of a compound reaction in which one complex substance is formed from more than two starting materials is the final stage in the production of nitric acid:

$4NO_2+O_2+2H_2O=4HNO_3$.

In organic chemistry, compound reactions are commonly referred to as addition reactions. The whole variety of such reactions can be considered on the example of a block of reactions characterizing the properties of unsaturated substances, for example, ethylene:

1) hydrogenation reaction - addition of hydrogen:

$CH_2(=)↙(ethene)CH_2+H_2(→)↖(Ni,t°)CH_3(-)↙(ethane)CH_3;$

2) hydration reaction - addition of water:

$CH_2(=)↙(ethene)CH_2+H_2O(→)↖(H_3PO_4,t°)(C_2H_5OH)↙(ethanol);$

3) polymerization reaction:

$(nCH_2=CH_2)↙(ethylene)(→)↖(p,cat.,t°)((-CH_2-CH_2-)_n)↙(polyethylene)$

2. Decomposition reactions These are reactions in which several new substances are formed from one complex substance.

In inorganic chemistry, the whole variety of such reactions can be considered using the example of a block of reactions for obtaining oxygen by laboratory methods:

1) decomposition of mercury oxide (II):

$2HgO(→)↖(t°)2Hg+O_2$ — two simple substances are formed from one complex substance;

2) decomposition of potassium nitrate:

$2KNO_3(→)↖(t°)2KNO_2+O_2$ — from one complex substance one simple and one complex substance are formed;

3) decomposition of potassium permanganate:

$2KMnO_4(→)↖(t°)K_2MnO_4+MnO_2+O_2$ — from one complex substance two complex and one simple are formed, i.e. three new substances.

In organic chemistry, decomposition reactions can be considered using the example of a block of reactions for the production of ethylene in the laboratory and industry:

1) the reaction of dehydration (water splitting) of ethanol:

$C_2H_5OH(→)↖(H_2SO_4,t°)CH_2=CH_2+H_2O;$

2) the reaction of dehydrogenation (hydrogen elimination) of ethane:

$CH_3—CH_3(→)↖(Cr_2O_3,500°C)CH_2=CH_2+H_2;$

3) propane cracking (splitting) reaction:

$CH_3-CH_2CH_3(→)↖(t°)CH_2=CH_2+CH_4.$

3. Substitution reactions- these are reactions in which the atoms of a simple substance replace the atoms of an element in a complex substance.

In inorganic chemistry, an example of such processes is a block of reactions that characterize the properties of, for example, metals:

1) interaction of alkali and alkaline earth metals with water:

$2Na+2H_2O=2NaOH+H_2$

2) interaction of metals with acids in solution:

$Zn+2HCl=ZnCl_2+H_2$;

3) interaction of metals with salts in solution:

$Fe+CuSO_4=FeSO_4+Cu;$

4) metallothermy:

$2Al+Cr_2O_3(→)↖(t°)Al_2O_3+2Cr$.

The subject of study of organic chemistry is not simple substances, but only compounds. Therefore, as an example of a substitution reaction, we present the most characteristic property limiting compounds, in particular methane, is the ability of its hydrogen atoms to be replaced by halogen atoms:

$CH_4+Cl_2(→)↖(hν)(CH_3Cl)↙(chloromethane)+HCl$,

$CH_3Cl+Cl_2→(CH_2Cl_2)↙(dichloromethane)+HCl$,

$CH_2Cl_2+Cl_2→(CHCl_3)↙(trichloromethane)+HCl$,

$CHCl_3+Cl_2→(CCl_4)↙(tetrachloromethane)+HCl$.

Another example is the bromination of an aromatic compound (benzene, toluene, aniline):

Let us pay attention to the peculiarity of substitution reactions in organic matter: as a result of such reactions, not a simple and complex substance is formed, as in inorganic chemistry, but two complex substances.

In organic chemistry, substitution reactions also include some reactions between two complex substances, for example, the nitration of benzene:

$C_6H_6+(HNO_3)↙(benzene)(→)↖(H_2SO_4(conc.),t°)(C_6H_5NO_2)↙(nitrobenzene)+H_2O$

It is formally an exchange reaction. The fact that this is a substitution reaction becomes clear only when considering its mechanism.

4. Exchange reactions- these are reactions in which two complex substances exchange their constituent parts.

These reactions characterize the properties of electrolytes and proceed in solutions according to the Berthollet rule, i.e. only if the result is a precipitate, a gas, or a low-dissociation substance (for example, $H_2O$).

In inorganic chemistry, this can be a block of reactions characterizing, for example, the properties of alkalis:

1) a neutralization reaction that goes with the formation of salt and water:

$NaOH+HNO_3=NaNO_3+H_2O$

or in ionic form:

$OH^(-)+H^(+)=H_2O$;

2) the reaction between alkali and salt, which goes with the formation of gas:

$2NH_4Cl+Ca(OH)_2=CaCl_2+2NH_3+2H_2O$

or in ionic form:

$NH_4^(+)+OH^(-)=NH_3+H_2O$;

3) the reaction between alkali and salt, which proceeds with the formation of a precipitate:

$CuSO_4+2KOH=Cu(OH)_2↓+K_2SO_4$

or in ionic form:

$Cu^(2+)+2OH^(-)=Cu(OH)_2↓$

In organic chemistry, one can consider a block of reactions characterizing, for example, the properties of acetic acid:

1) a reaction proceeding with the formation of a weak electrolyte - $H_2O$:

$CH_3COOH+NaOH⇄NaCH_3COO+H_2O$

$CH_3COOH+OH^(-)⇄CH_3COO^(-)+H_2O$;

2) the reaction proceeding with the formation of gas:

$2CH_3COOH+CaCO_3=2CH_3COO^(-)+Ca^(2+)+CO_2+H_2O$;

3) reaction proceeding with the formation of a precipitate:

$2CH_3COOH+K_2SiO_3=2KCH_3COO+H_2SiO_3↓$

$2CH_3COOH+SiO_3^(−)=2CH_3COO^(−)+H_2SiO_3↓$.

Classification of chemical reactions according to the change in the oxidation states of chemical elements that form substances

Reactions that occur with a change in the oxidation states of elements, or redox reactions.

These include many reactions, including all substitution reactions, as well as those reactions of combination and decomposition in which at least one simple substance participates, for example:

1.$(Mg)↖(0)+(2H)↖(+1)+SO_4^(-2)=(Mg)↖(+2)SO_4+(H_2)↖(0)$

$((Mg)↖(0)-2(e)↖(-))↙(reducing agent)(→)↖(oxidation)(Mg)↖(+2)$

$((2H)↖(+1)+2(e)↖(-))↙(oxidizer)(→)↖(reduction)(H_2)↖(0)$

2.$(2Mg)↖(0)+(O_2)↖(0)=(2Mg)↖(+2)(O)↖(-2)$

$((Mg)↖(0)-2(e)↖(-))↙(reductant)(→)↖(oxidation)(Mg)↖(+2)|4|2$

$((O_2)↖(0)+4(e)↖(-))↙(oxidizer)(→)↖(reduction)(2O)↖(-2)|2|1$

As you remember, complex redox reactions are compiled using the electron balance method:

$(2Fe)↖(0)+6H_2(S)↖(+6)O_(4(k))=(Fe_2)↖(+3)(SO_4)_3+3(S)↖(+4)O_2+ 6H_2O$

$((Fe)↖(0)-3(e)↖(-))↙(reducing agent)(→)↖(oxidation)(Fe)↖(+3)|2$

$((S)↖(+6)+2(e)↖(-))↙(oxidizer)(→)↖(reduction)(S)↖(+4)|3$

In organic chemistry a prime example properties of aldehydes can serve as redox reactions:

1. Aldehydes are reduced to the corresponding alcohols:

$(CH_3-(C)↖(+1) ()↖(O↖(-2))↙(H↖(+1))+(H_2)↖(0))↙(\text"acetaldehyde") (→)↖(Ni,t°)(CH_3-(C)↖(-1)(H_2)↖(+1)(O)↖(-2)(H)↖(+1))↙(\text "ethyl alcohol")$

$((C)↖(+1)+2(e)↖(-))↙(oxidizer)(→)↖(reduction)(C)↖(-1)|1$

$((H_2)↖(0)-2(e)↖(-))↙(reductant)(→)↖(oxidation)2(H)↖(+1)|1$

2. Aldehydes are oxidized to the corresponding acids:

$(CH_3-(C)↖(+1) ()↖(O↖(-2))↙(H↖(+1))+(Ag_2)↖(+1)(O)↖(-2)) ↙(\text"acetaldehyde")(→)↖(t°)(CH_3-(Ag)↖(0)(C)↖(+3)(O)↖(-2)(OH)↖(-2 +1)+2(Ag)↖(0)↓)↙(\text"ethyl alcohol")$

$((C)↖(+1)-2(e)↖(-))↙(reducing agent)(→)↖(oxidation)(C)↖(+3)|1$

$(2(Ag)↖(+1)+2(e)↖(-))↙(oxidizer)(→)↖(reduction)2(Ag)↖(0)|1$

Reactions that take place without changing the oxidation states of chemical elements.

These include, for example, all ion exchange reactions, as well as:

many compound reactions:

$Li_2O+H_2O=2LiOH;$

many decomposition reactions:

$2Fe(OH)_3(→)↖(t°)Fe_2O_3+3H_2O;$

esterification reactions:

$HCOOH+CH_3OH⇄HCOOCH_3+H_2O$.

Classification of chemical reactions by thermal effect

According to the thermal effect, the reactions are divided into exothermic and endothermic.

exothermic reactions.

These reactions proceed with the release of energy.

These include almost all compound reactions. A rare exception is the endothermic reactions of the synthesis of nitric oxide (II) from nitrogen and oxygen and the reaction of gaseous hydrogen with solid iodine:

$N_2+O_2=2NO - Q$,

$H_(2(t))+I(2(t))=2HI - Q$.

Exothermic reactions that proceed with the release of light are referred to as combustion reactions, for example:

$4P+5O_2=2P_2O_5+Q,$

$CH_4+2O_2=CO_2+2H_2O+Q$.

The hydrogenation of ethylene is an example of an exothermic reaction:

$CH_2=CH_2+H_2(→)↖(Pt)CH_3-CH_3+Q$

It runs at room temperature.

Endothermic reactions

These reactions proceed with the absorption of energy.

Obviously, almost all decomposition reactions belong to them, for example:

a) burning limestone:

$CaCO_3(→)↖(t°)CaO+CO_2-Q;$

b) butane cracking:

The amount of energy released or absorbed in a reaction is called the thermal effect of the reaction, and the equation of a chemical reaction indicating this effect is called thermochemical equation, For example:

$H_(2(g))+Cl_(2(g))=2HCl_((g))+92.3 kJ,$

$N_(2(g))+O_(2(g))=2NO_((g)) - 90.4 kJ$.

Classification of chemical reactions according to the state of aggregation of reacting substances (phase composition)

heterogeneous reactions.

These are reactions in which the reactants and reaction products are in different states of aggregation (in different phases):

$2Al_((m))+3CuCl_(2(r-r))=3Cu_((t))+2AlCl_(3(r-r))$,

$CaC_(2(t))+2H_2O_((l))=C_2H_2+Ca(OH)_(2(solid))$.

homogeneous reactions.

These are reactions in which the reactants and reaction products are in the same state of aggregation (in the same phase):

Classification of chemical reactions according to the participation of a catalyst

non-catalytic reactions.

Non-catalytic reactions go without the participation of a catalyst:

$2HgO(→)↖(t°)2Hg+O_2$,

$C_2H_4+3O_2(→)↖(t°)2CO_2+2H_2O$.

catalytic reactions.

catalytic reactions going on with a catalyst:

$2KClO_3(→)↖(MnO_2,t°)2KCl+3O_2,$

$(C_2H_5OH)↙(ethanol)(→)↖(H_2SO-4,t°)(CH_2=CH_2)↙(ethene)+H_2O$

Since all biological reactions occurring in the cells of living organisms proceed with the participation of special biological catalysts of a protein nature - enzymes, they all belong to catalytic or, more precisely, enzymatic.

It should be noted that more than $70%$ of chemical industries use catalysts.

Classification of chemical reactions by direction

irreversible reactions.

irreversible reactions flow under these conditions in only one direction.

These include all exchange reactions accompanied by the formation of a precipitate, gas or a low-dissociating substance (water), and all combustion reactions.

reversible reactions.

Reversible reactions under these conditions proceed simultaneously in two opposite directions.

Most of these reactions are.

In organic chemistry, the sign of reversibility is reflected in the names-antonyms of processes:

hydrogenation - dehydrogenation;
hydration - dehydration;
polymerization - depolymerization.

All esterification reactions are reversible (the opposite process, as you know, is called hydrolysis) and protein hydrolysis, esters, carbohydrates, polynucleotides. Reversibility underlies the most important process in a living organism - metabolism.

Every teacher faces the problem of lack of teaching time. More precisely, it doesn’t even collide, but constantly works in conditions of its chronic lack. Moreover, over the years, the latter has been steadily increasing due to compaction. educational material, reducing the number of hours devoted to the study of chemistry, and complicating the tasks of teaching, designed to provide a versatile developmental impact on the personality of the student.

To resolve this ever-increasing contradiction, it is important, on the one hand, to convincingly reveal to the student the significance of education, the need for personal interest in it and the prospects of self-promotion in acquiring it. On the other hand, to intensify the educational process carried out at the school (UEP). The first can be achieved if the training is structured in such a way that the student WANTS and CAN recognize himself as the SUBJECT OF LEARNING, that is, such a participant in the UVP who understands and accepts his goals, owns ways to achieve them and strives to expand the range of these ways. Thus, the leading conditions for the transformation of a student into a subject of learning (within the framework of subject teaching of chemistry) is his competence in the content of the educational issues under consideration and ways of mastering them and orientation towards achieving holistic knowledge of the subject.

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Classification of chemical reactions in inorganic and organic chemistry.

/to help a young teacher/

Purpose: to systematize students' knowledge about approaches to the classification of chemical reactions. Educational tasks: · repeat and summarize information about the classification of chemical reactions on the basis - the number of starting and obtained substances; consider the laws of conservation of mass of matter and energy in chemical reactions as special case manifestation of the universal law of nature.

Educational tasks: · to prove the leading role of theory in the knowledge of practice; Show students the relationship of opposite processes; Prove the materiality of the processes under study;

Developing tasks: development of logical thinking through comparison, generalization, analysis, systematization.

Type of lesson: lesson of complex application of knowledge.

Methods and techniques: conversation, paperwork, frontal survey.

Lesson I. Organizational moment

II. Motivation learning activities students, message topics, goals, objectives of the lesson.

III. Checking students' knowledge of factual material.

Frontal conversation: 1. What types of chemical reactions do you know? (reactions of decomposition, connection, substitution and exchange). 2. Define a decomposition reaction? (Decomposition reactions are reactions in which two or more new simple or less complex substances are formed from one complex substance). 3. Define a compound reaction? (Combination reactions are reactions in which two or more substances form one more complex substance). 4. Define a substitution reaction? (Substitution reactions are reactions in which atoms of a simple substance replace the atoms of one of the elements in a complex substance). 5What is the definition of an exchange reaction? (Exchange reactions are reactions in which two complex substances exchange their constituent parts). 6. What is the basis of this classification? (the basis of the classification is the number of starting and formed substances)

IV. Checking students' knowledge of basic concepts, laws, theories, and the ability to explain their essence.

Explain the nature of chemical reactions. (The essence of chemical reactions is reduced to the breaking of bonds in the initial substances and the emergence of new chemical bonds in the reaction products. In this case, the total number of atoms of each element remains constant, therefore, the mass of substances does not change as a result of chemical reactions.)
By whom and when was this pattern established? (In 1748, the Russian scientist M.V. Lomonosov - the law of conservation of the mass of substances).

V. Checking the depth of understanding of knowledge, the degree of generalization.

Task: determine the type of chemical reaction (compound, decomposition, substitution, exchange). Give explanations for your conclusions. Set the ratios. (ICT)

1 OPTION	OPTION 2	3 OPTION
Mg + O 2 \u003d MgO	Fe + CuCl 2 \u003d Cu + FeCl 2	Cu + O 2 \u003d CuO
K + H 2 O = KOH + H2	P + O 2 \u003d P 2 O 5	Fe 2 O 3 + HCl \u003d FeCl 3 + H 2 O
Fe + H 2 SO 4 \u003d FeSO 4 + H 2	Mg + HCl = MgCl 2 + H 2	Ba + H 2 O \u003d Ba (OH) 2 + H 2
Zn + Cu (NO 3 ) 2 \u003d Cu + Zn (NO 3 ) 2	Al 2 O 3 + HCl = AlCl 3 + H 2 O	SO 2 + H2O ↔ H 2 SO 3
CaO + H 2 O \u003d Ca (OH) 2	P 2 O 5 + H 2 O \u003d H 3 PO 4	CuCl 2 + KOH \u003d Cu (OH) 2 + KCl
CaO + H 3 PO 4 \u003d Ca 3 (PO 4) 2 + H 2 O	Ba(OH) 2 + HNO 3 = Ba(NO 3 ) 2 + H 2 O	Ca (OH) 2 + HNO 3 \u003d Ca (NO 3) 2 + H 2 O
NaOH + H 2 S = Na 2 S + H 2 O	Ca + H 2 O \u003d Ca(OH) 2 + H 2	AgNO 3 + NaBr = AgBr↓ + NaNO 3
BaCl 2 + Na 2 SO 4 \u003d BaSO 4 ↓ + NaCl	AgNO 3 + KCl \u003d AgCl + KNO 3	Cu + Hg(NO 3 ) 2 = Cu(NO 3 ) 2 + Hg
CO 2 + H2O ↔ H 2 CO 3	Fe(OH) 3 = Fe 2 O 3 + H 2 O	Mg + HCl = MgCl 2 + H 2

VI Classification of chemical reactions in organic chemistry.

A: In inorganic chemistry, compound reactions, and in organic chemistry, such reactions are often called addition reactions (Reactions in which two or more molecules of reactants combine into one) They usually involve compounds containing a double or triple bond. Varieties of addition reactions: hydrogenation, hydration, hydrohalogenation, halogenation, polymerization. Examples of these reactions:

1. Hydrogenation - the reaction of adding a hydrogen molecule to a multiple bond:

H 2 C \u003d CH 2 + H 2 → CH 3 - CH 3

ethylene ethane

HC ≡ CH + H 2 → CH 2 = CH 2

acetylene ethylene

2. Hydrohalogenation - the reaction of the addition of a hydrogen halide to a multiple bond

H 2 C \u003d CH 2 + HCl → CH 3 ─CH 2 Cl

ethylene chloroethane

(according to the rule of V.V. Markovnikov)

H 2 C \u003d CH─CH 3 + HCl → CH 3 ─CHCl─CH 3

propylene 2 - chloropropane

HC≡CH + HCl → H 2 C=CHCl

acetylene vinyl chloride

HC≡C─CH 3 + HCl → H 2 C=CCl─CH 3

propyne 2-chloropropene

3. Hydration - the reaction of adding water to a multiple bond

H 2 C \u003d CH 2 + H 2 O → CH 3 ─CH 2 OH (primary alcohol)

ethene ethanol

(during the hydration of propene and other alkenes, secondary alcohols are formed)

HC≡CH + H 2 O → H 3 C─CHO

acetylene aldehyde - ethanal (Kucherov reaction)

4. Halogenation - the reaction of adding a halogen molecule to a multiple bond

H 2 C \u003d CH─CH 3 + Cl 2 → CH 2 Cl─CHCl─CH3

propylene 1,2 - dichloropropane

HC≡C─CH 3 + Cl 2 → HCCl=CCl─CH 3

propyne 1,2-dichloropropene

5.Polymerization - reactions during which molecules of substances with a small molecular weight combine with each other to form molecules of substances with a high molecular weight.

n CH 2 \u003d CH 2 → (-CH 2 -CH 2 -) n

Ethylene polyethylene

B: In organic chemistry, decomposition reactions (cleavage) include: dehydration, dehydrogenation, cracking, dehydrohalogenation.

The corresponding reaction equations are:

1. Dehydration (water splitting)

C 2 H 5 OH → C 2 H 4 + H 2 O (H 2 SO 4)

2. Dehydrogenation (hydrogen elimination)

C 6 H 14 → C 6 H 6 + 4H 2

hexane benzene

3.Cracking

C 8 H 18 → C 4 H 10 + C 4 H 8

octane butane butene

4. Dehydrohalogenation (elimination of hydrogen halide)

C 2 H 5 Br → C 2 H 4 + HBr (NaOH, alcohol)

Bromoethane ethylene

Q: In organic chemistry, substitution reactions are understood more broadly, that is, not one atom, but a group of atoms can replace, or not an atom, but a group of atoms is replaced. Substitution reactions include nitration and halogenation. saturated hydrocarbons, aromatic compounds, alcohols and phenol:

C 2 H 6 + Cl 2 → C 2 H 5 Cl + HCl

ethane chloroethane

C 2 H 6 + HNO 3 → C 2 H 5 NO 2 + H 2 O (Konovalov's reaction)

ethane nitroethane

C 6 H 6 + Br 2 → C 6 H 5 Br + HBr

benzene bromobenzene

C 6 H 6 + HNO 3 → C 6 H 5 NO 2 + H 2 O

benzene nitrobenzene

C 2 H 5 OH + HCl → C 2 H 5 Cl + H 2 O

Ethanol chloroethane

C 6 H 5 OH + 3Br 2 → C 6 H 2 Br 3 + 3HBr

phenol 2,4,6 - tribromophenol

D: Exchange reactions in organic chemistry are characteristic of alcohols and carboxylic acids

HCOOH + NaOH → HCOONa + H 2 O

formic acid sodium formate

(neutralization reaction)

CH 3 COOH + C 2 H 5 OH ↔ CH 3 COOC 2 H 5 + H 2 O

acetic ethanol ethyl acetate

(esterification reaction ↔ hydrolysis)

VII Consolidation of ZUN

When iron hydroxide (3) is heated, the reaction occurs
The interaction of aluminum with sulfuric acid refers to the reaction
The interaction of acetic acid with magnesium refers to the reaction
Determine the type of chemical reactions in the chain of transformations:

(use of ICT)

A) Si→SiO 2 →Na 2 SiO 3 →H 2 SiO 3 →SiO 2 →Si

B) CH 4 → C 2 H 2 → C 2 H 4 → C 2 H 5 OH → C 2 H

1) The first sign of classification is by changing the degree of oxidation of the elements that form the reagents and products.
a) redox

FeS 2 + 18HNO 3 \u003d Fe (NO 3) 3 + 2H 2 SO 4 + 15NO 2 + 7H 2 O
b) without changing the oxidation state

CaO + 2HCl \u003d CaCl 2 + H 2 O
redox called reactions accompanied by a change in the oxidation states of the chemical elements that make up the reagents. Redox reactions in inorganic chemistry include all substitution reactions and those decomposition and compound reactions in which at least one simple substance is involved. Reactions that proceed without changing the oxidation states of the elements that form the reactants and reaction products include all exchange reactions.

2) Chemical reactions are classified according to the nature of the process, i.e., according to the number and composition of reagents and products.
-reactions of connection or accession in organic chemistry.
In order to enter into an addition reaction, organic molecule must have a multiple bond (or cycle), this molecule will be the main one (substrate). A simpler molecule (often inorganic matter, reagent) is attached at the site of the break of a multiple bond or ring opening.

NH 3 + HCl = NH 4 Cl

CaO + CO 2 \u003d CaCO 3

decomposition reactions.
Decomposition reactions can be viewed as processes inverse to compound.

C 2 H 5 Br \u003d C 2 H 4 + HBr

Hg (NO 3) 2 \u003d Hg + 2NO 2 + O 2

- substitution reactions.
Their distinguishing feature is the interaction of a simple substance with a complex one. Such reactions exist in organic chemistry.
However, the concept of "substitution" in organics is broader than in inorganic chemistry. If any atom or functional group in the molecule of the original substance is replaced by another atom or group, these are also substitution reactions, although from the point of view of inorganic chemistry, the process looks like an exchange reaction.

Zn + CuSO 4 \u003d Cu + ZnSO 4

Cu + 4HNO 3 \u003d Cu (NO 3) 2 + 2NO 2 + 2H 2 O
– exchange (including neutralization).

CaO + 2HCl \u003d CaCl 2 + H 2 O

KCl + AgNO 3 = AgCl¯ + KNO 3

3) If possible, flow in the opposite direction - reversible and irreversible.

4) By type of bond breaking - homolytic (equal break, each atom receives 1 electron) and heterolytic (unequal break - one gets a pair of electrons)

5) By thermal effect
exothermic (heat generation) and endothermic (heat absorption). Coupling reactions will generally be exothermic reactions, and decomposition reactions will be endothermic. A rare exception is the reaction of nitrogen with oxygen - endothermic:
N2 + O2 → 2NO - Q

6) By phase
a) Homogeneous (homogeneous substances, in one phase, for example g-d, reactions in solutions)
b) Heterogeneous (Mrs., G-TV, W-TV, reactions between immiscible liquids)

7) On the use of a catalyst. A catalyst is a substance that speeds up a chemical reaction.
a) catalytic (including enzymatic) - they practically do not go without the use of a catalyst.
b) non-catalytic.

The classification of chemical reactions in inorganic and organic chemistry is carried out on the basis of various classifying features, details of which are given in the table below.

irreversible are reactions that proceed only in the forward direction, as a result of which products are formed that do not interact with each other. Irreversible include chemical reactions, as a result of which poorly dissociated compounds are formed, there is a release a large number energy, as well as those in which the final products leave the reaction sphere in gaseous form or in the form of a precipitate, for example:

HCl + NaOH = NaCl + H2O

2Ca + O 2 \u003d 2CaO

BaBr 2 + Na 2 SO 4 = BaSO 4 ↓ + 2NaBr

reversible called chemical reactions occurring at a given temperature simultaneously in two opposite directions with commensurate speeds. When writing the equations of such reactions, the equal sign is replaced by oppositely directed arrows. The simplest example of a reversible reaction is the synthesis of ammonia by the interaction of nitrogen and hydrogen:

N 2 + 3H 2 ↔2NH 3

By type of break chemical bond in the original molecule, homolytic and heterolytic reactions are distinguished.

homolytic called reactions in which, as a result of breaking bonds, particles are formed that have an unpaired electron - free radicals.

Heterolytic called reactions that proceed through the formation of ionic particles - cations and anions.

Radical(chain) chemical reactions involving radicals are called, for example:

CH 4 + Cl 2 hv → CH 3 Cl + HCl

Ionic called chemical reactions that take place with the participation of ions, for example:

KCl + AgNO 3 \u003d KNO 3 + AgCl ↓

Heterolytic reactions are called electrophilic. organic compounds with electrophiles - particles that carry a whole or fractional positive charge. They are divided into reactions of electrophilic substitution and electrophilic addition, for example:

C 6 H 6 + Cl 2 FeCl3 → C 6 H 5 Cl + HCl

H 2 C \u003d CH 2 + Br 2 → BrCH 2 -CH 2 Br

Nucleophilic refers to heterolytic reactions of organic compounds with nucleophiles - particles that carry an integer or fractional negative charge. They are subdivided into nucleophilic substitution and nucleophilic addition reactions, for example:

CH 3 Br + NaOH → CH 3 OH + NaBr

CH 3 C (O) H + C 2 H 5 OH → CH 3 CH (OC 2 H 5) 2 + H 2 O
exothermic are chemical reactions that release heat. The symbol for the change in enthalpy (heat content) is ΔH, and the thermal effect of the reaction is Q. For exothermic reactions, Q > 0, and ΔH< 0.

endothermic called chemical reactions that take place with the absorption of heat. For endothermic reactions Q< 0, а ΔH > 0.

homogeneous Reactions that take place in a homogeneous medium are called.

heterogeneous called reactions occurring in an inhomogeneous medium, on the contact surface of the reacting substances that are in different phases, for example, solid and gaseous, liquid and gaseous, in two immiscible liquids.

Catalytic reactions proceed only in the presence of a catalyst. Non-catalytic reactions proceed in the absence of a catalyst.

Classification organic reactions is shown in the table:

The classification of chemical reactions in inorganic and organic chemistry is carried out on the basis of various classifying features, details of which are given in the table below.

By changing the oxidation state of elements

The first sign of classification is by changing the degree of oxidation of the elements that form the reactants and products.
a) redox
b) without changing the oxidation state
redox called reactions accompanied by a change in the oxidation states of the chemical elements that make up the reagents. Redox reactions in inorganic chemistry include all substitution reactions and those decomposition and compound reactions in which at least one simple substance is involved. Reactions that proceed without changing the oxidation states of the elements that form the reactants and reaction products include all exchange reactions.

According to the number and composition of reagents and products

Chemical reactions are classified according to the nature of the process, i.e., according to the number and composition of reactants and products.

Connection reactions called chemical reactions, as a result of which complex molecules are obtained from several simpler ones, for example:
4Li + O 2 = 2Li 2 O

Decomposition reactions called chemical reactions, as a result of which simple molecules are obtained from more complex ones, for example:
CaCO 3 \u003d CaO + CO 2

Decomposition reactions can be viewed as processes inverse to compound.

substitution reactions chemical reactions are called, as a result of which an atom or group of atoms in a molecule of a substance is replaced by another atom or group of atoms, for example:
Fe + 2HCl \u003d FeCl 2 + H 2 ⁭

Their distinguishing feature is the interaction of a simple substance with a complex one. Such reactions exist in organic chemistry.
However, the concept of "substitution" in organics is broader than in inorganic chemistry. If any atom or functional group in the molecule of the original substance is replaced by another atom or group, these are also substitution reactions, although from the point of view of inorganic chemistry, the process looks like an exchange reaction.
- exchange (including neutralization).
Exchange reactions call chemical reactions that occur without changing the oxidation states of the elements and lead to the exchange of the constituent parts of the reagents, for example:
AgNO 3 + KBr = AgBr + KNO 3

Run in the opposite direction if possible.

If possible, proceed in the opposite direction - reversible and irreversible.

N 2 + 3H 2 ↔2NH 3

irreversible are reactions that proceed only in the forward direction, as a result of which products are formed that do not interact with each other. Irreversible include chemical reactions that result in the formation of slightly dissociated compounds, a large amount of energy is released, as well as those in which the final products leave the reaction sphere in gaseous form or in the form of a precipitate, for example:

HCl + NaOH = NaCl + H2O

2Ca + O 2 \u003d 2CaO

BaBr 2 + Na 2 SO 4 = BaSO 4 ↓ + 2NaBr

By thermal effect

exothermic are chemical reactions that release heat. The symbol for the change in enthalpy (heat content) is ΔH, and the thermal effect of the reaction is Q. For exothermic reactions, Q > 0, and ΔH< 0.

endothermic called chemical reactions that take place with the absorption of heat. For endothermic reactions Q< 0, а ΔH > 0.

Coupling reactions will generally be exothermic reactions, and decomposition reactions will be endothermic. A rare exception is the reaction of nitrogen with oxygen - endothermic:
N2 + O2 → 2NO - Q

By phase

homogeneous called reactions occurring in a homogeneous medium (homogeneous substances, in one phase, for example, g-g, reactions in solutions).

By using a catalyst

A catalyst is a substance that speeds up a chemical reaction.

catalytic reactions proceed only in the presence of a catalyst (including enzymatic ones).

Non-catalytic reactions run in the absence of a catalyst.

By type of rupture

According to the type of chemical bond breaking in the initial molecule, homolytic and heterolytic reactions are distinguished.

homolytic called reactions in which, as a result of breaking bonds, particles are formed that have an unpaired electron - free radicals.

Heterolytic called reactions that proceed through the formation of ionic particles - cations and anions.

homolytic (equal gap, each atom receives 1 electron)
heterolytic (unequal gap - one gets a pair of electrons)

Radical(chain) chemical reactions involving radicals are called, for example:

CH 4 + Cl 2 hv → CH 3 Cl + HCl

Ionic called chemical reactions that take place with the participation of ions, for example:

KCl + AgNO 3 \u003d KNO 3 + AgCl ↓

Electrophilic refers to heterolytic reactions of organic compounds with electrophiles - particles that carry a whole or fractional positive charge. They are divided into reactions of electrophilic substitution and electrophilic addition, for example:

C 6 H 6 + Cl 2 FeCl3 → C 6 H 5 Cl + HCl

H 2 C \u003d CH 2 + Br 2 → BrCH 2 -CH 2 Br

CH 3 Br + NaOH → CH 3 OH + NaBr

CH 3 C (O) H + C 2 H 5 OH → CH 3 CH (OC 2 H 5) 2 + H 2 O