The four basic chemical reactions, the four basic reactions of chemistry

Common: Decomposition Reaction Compounding Reaction Metathesis Reaction Displacement Reaction 1 Decomposition reaction is one of the common types of chemical reactions, which is the reverse reaction of chemical reactions. It refers to the decomposition of a compound into two or more simple elements or compounds under specific conditions (such as heating, direct current, catalyst, etc.), which is called decomposition reaction.

It can be expressed as: ab a b

2 A chemical reaction is a reaction in which two or more substances produce a new substance. Chemical reactions are generally accompanied by the phenomenon of luminescence, heat release and other energy release.

3 Metathesis reaction is a reaction in which two compounds exchange components with each other to produce two other compounds, which is called metathesis reaction. It can be expressed as AB cd=AD CB4 displacement reaction is one of the basic types of inorganic chemical reactions, which refers to the reaction of one element and one compound to produce another element and another compound, which can be expressed as: A+BC B+AC has some references.

Chemistry reaction: simply, all-in-one reaction decomposition reaction: simply, one change reaction displacement reaction:

To put it simply, the metathesis reaction of elemental to elemental: two substances that can be dissociated (usually in an aqueous solution) into two parts, reconstituted into a reaction containing at least one refractory substance (slowly realized).

Decomposition reactions, chemical reactions, metathesis reactions, displacement reactions.

The four basic types of reactions are: chemical reaction, decomposition reaction, metathesis reaction, and displacement reaction.

The two substances that undergo metathesis reaction exchange ions with each other in the aqueous solution, and combine into substances that are difficult to ionize--- precipitation, gas, and water, so that the ion concentration in the solution decreases, and the chemical reaction proceeds in the direction of the decrease in ion concentration. It can be abbreviated as ab+cd=ad+cb.

Basic reactions. 1.Chemical reactions.

A variety of reactants produce a single product, referred to as multiple variations.

Characteristics: "multiple change one", that is, after the reaction, a variety of compounds are transformed into one compound.

It can be expressed in letters as: a+b+.c=d

2.Decomposition reactions.

One reactant produces multiple products, referred to as one becomes many.

Characteristics: From one substance to a variety of substances "one to many".

It can be expressed in letters as: a+b+.c=d

3.Displacement reaction.

One element and one compound react to produce another element and another compound.

Features: One for one (i.e., one element replaces another: A+BC=B+AC where A, B are elemental and BC is a compound).

The letters are: a+bc=b+ac

4.Metathesis reaction.

The two compounds exchange components with each other to form the other two compounds (the metathesis can only occur when there is a precipitate in the product or when there is gas or water in the product).

Features: There will be no change in valency before and after the reaction.

Condition (1) Requirements for reactants: salt, acid and alkali are generally OK, and salt salt and salt alkali need to be dissolved; (2) Requirements for products: precipitation precipitation or gas release in the products, or water generation.

The letters can be expressed as: ab+cd=ad+cb

The above are the four basic reaction types common in junior high school chemistry, and there are some reactions that do not belong to any of the above four reaction types.

5.Redox reactions.

A chemical reaction in which the valency of an element changes before and after the reaction. This reaction can be understood as consisting of two halves, namely oxidation and reduction. For example, Zn+H2SO4=H2+ZnSO4

The essence of the reaction: there is a change in valency, that is, there is a transfer and shift of electrons.

Type: The half-reaction of the increased valence of the chemical and valence, that is, the loss of electrons is an oxidation reaction, such as C+O2=CO2; The oxidation number decreases, and the reaction to obtain electrons is a reduction reaction. For example, h2+cuo=cu+h2o

1. Chemical reaction: refers to the formation of a product by a variety of reactants, such as:

4fe+3o2→2fe2o3

2. Decomposition reaction: refers to the generation of a variety of products by one reactant, such as:

caco3→co2+cao

3；Displacement reaction: refers to the reaction of one element and one compound to form another element and another compound, such as:

fe+cuso4→cu+feso4

4. Metathesis reaction: refers to the exchange of components between two compounds to form two other compounds, such as:

caco3+2hcl→cacl2+h2o+co2↑

ChemistryThere are four basic types of reactionsYes:

1. Chemical reaction.

A chemical reaction is a reaction in which two or more substances react to form a new substance. Some of these reactions are redox reactions.

Some are non-redox reactions. In addition, chemical reactions generally release energy. It can be abbreviated as a+b=ab.

2. Decomposition reaction: The reaction of two or more other substances from one substance is called decomposition reaction. The abbreviation is divided into two and is expressed as ab=a+b. Only the chemical compound can undergo a decomposition reaction.

3. Displacement reaction.

One element reacts with a compound to form a chemical reaction with another element and compound.

Including the reaction of metals with metal salts, the reaction of metals with acids, etc. It can be abbreviated as ab+c=a+cb.

4. Metathesis reaction.

The reaction of two compounds is generated by exchanging components with each other, resulting in two other compounds. Its essence is: the two substances that undergo metathesis reaction exchange ions with each other in the aqueous solution, and combine into substances that are difficult to ionize - precipitation, gas, and water (weak electrolyte), so that the ion concentration in the solution is reduced, and the chemical reaction is carried out in the direction of the reduction of ion concentration.

It can be abbreviated as ab+cd=ad+cb.

1. Chemical reaction is a general term for a class of chemical reactions (usually referring to inorganic reactions), which refers to the chemical reaction of two or more reactants to form a product. For example, the combustion of hydrogen and oxygen to produce water is a chemical reaction. Usually the chemical reaction is an exothermic reaction.

2mg+o2→2mgo

2h2+o2→2h2o

c(s) +o2(g)→co2(g)

2. Decomposition reaction is one of the common types of chemical reactions. It refers to the reaction in which a compound is broken down into two or more elements or compounds under specific conditions.

Electrolysis of water to produce hydrogen and oxygen: 2 H2O(L) 2H2(G) + O2(G).

3. Displacement reaction, also known as single displacement reaction, refers to the reaction between the ionic root of an element or compound and an ionic compound, and the redox reaction in the narrow sense is a kind of displacement reaction, and it must be a redox reaction in the broad sense.

In the reaction, the key lies in the strength of the reducing or oxidizing substance, and the substitution of the reducing or oxidizing substance with the relatively weak substance. Displacement reaction is one of the basic types of inorganic chemical reactions, which refers to the reaction of one element and one compound to produce another element and another compound.

4. Metathesis reaction, also known as double displacement reaction, is a reaction of two compounds by exchanging components with each other and generating two new compounds, with the mode of AB+CD AD+CB. It must occur in aqueous solution, which is one of the basic types of chemical reactions. None of the metathesis is a redox reaction (some reactions are redox reproduction of metathesis products, rather than the result of metathesis).

Chemical reactions, decomposition reactions, displacement reactions, and metathesis reactions.

Chemical reaction: the reaction of two or more substances to produce one substance, which is called a chemical reaction; The alphabetic relation of the chemical reaction can be expressed as: a+b c.

For example: cao+h2o=ca(oh)2

Decomposition reaction: The reaction in which a substance is decomposed into two or more substances is called a decomposition reaction; The alphabetic relation of the decomposition reaction can be expressed as: a b + c.

For example: H2CO3=H2O+CO2

Displacement reaction: One elemental substance and one compound react to produce another elemental substance and another compound, and the letters are denoted as: A+BC B+AC.

For example: Fe+2HCl=FeCl2+H2; Cuo+H2=Cu+H2O (this reaction requires heating conditions, which is omitted because the heating symbol cannot be marked on the horizontal line); The displacement reaction must have an increase and decrease in the valency of the elements, so it must be a redox-reduction reaction.

Metathesis reaction: the type of reaction in which one compound reacts with another compound and exchanges components with each other, and the letters are expressed as: ab+cd=ad+cb;

For example: cuso4+bacl2=cucl2+baso4; na2co3+2hcl=nacl+co2↑+h2o;Certain conditions are required for the metathesis reaction to occur, that is, at least one of the substances participating in the reaction is soluble in water, and the product must have at least a precipitate or gas or water; The acid-base neutralization reaction belongs to the metathesis reaction.

Carbon and oxygen are combined for reaction.

Calcium carbonate is decomposed by heat and decomposition reaction.

Iron and copper sulfate solution displacement reaction.

Barium sulfate and copper chloride metathesis reaction.

Decomposition reaction: 2H2O = 2H2 + O2

Chemical reaction: 2H2 + O2 = 2H2O

Displacement reaction: Zn+2HCl=ZnCl2+H2 metathesis reaction: CaCO3+2HCl=CaCl2+CO2+H2O

The four basic chemical reactions are:

Chemical reaction: A reaction in which two or more substances produce one substance. For example, hydrogen is burned in oxygen to produce water;

Decomposition reaction: A reaction in which a substance produces two or more substances. For example, the reaction of potassium chlorate to oxygen in the laboratory;

Displacement reaction: A reaction in which one element and one compound exchange components with each other to produce another element and another compound. Such as: the reaction of zinc and dilute sulfuric acid to hydrogen.

Metathesis reaction: A reaction in which two compounds exchange components with each other to form two new compounds.

The four basic types of chemical reactions are as follows:The four basic types of reactions are: chemical reactions, decomposition reactions, displacement reactions and metathesis reactions.

1. Chemical reaction: a reaction in which two or more substances produce a new substance.

Features: A+B+....=d

A type of reaction in which at least two substances are reacted to produce a substance. The product must be a compound.

Note: The valency of an element may vary.

2. Decomposition reaction: The common type of chemical reaction is the reverse reaction of chemical reaction.

Features: ab==a+b+....

A type of reaction in which at least two substances are produced by the reaction of one substance. The reactant lithocoma must be a compound.

Note: The valency of an element may vary.

3. Displacement reaction: a chemical reaction in which one element reacts with a compound to produce another element and a compound.

Features: ab+d==db+a

The reaction type of a jujube species compound reacts with one elemental substance to generate another compound and elemental substance.

The reactants are one and one single, and the product is one and one single.

Note: The valency of the element must change.

4. Metathesis reaction: the reaction of two compounds to generate two other compounds by exchanging components with each other.

Features: ab+de===ae+db

The reaction type is made by the reaction of two compounds and the exchange of components with each other to generate two other compounds.

The reactants are two compounds, exchange components; The products are two other compounds.

Note: The valency of the element must not change.

Extended information: To determine whether a reaction is a chemical reaction, it is necessary to focus on the concept and reaction characteristics of chemical reactions. To determine whether a reaction chemical equation is a chemical reaction, it is necessary to assume that the reaction can occur, and then compare it with all the characteristics of the chemical reaction, and only if there are three reaction characteristics at the same time, it can be determined as a chemical reaction.

Otherwise, the chemical reaction cannot be included.

To determine whether a reaction has a metathesis reaction, it is necessary to meet the characteristics of the metathesis reaction and the conditions for the reaction to occur.

It is particularly emphasized that oxidation reaction and reduction reaction do not belong to the four basic reaction types.