What reaction in chemical change is exothermic endothermy? 20

Exothermic, so most of the chemical reactions are exothermic reactions, and most of the decomposition reactions are endothermic reactions.

Exothermic reaction: A reaction in which an active metal displaces hydrogen in water or acid.

Acid-base neutralization reaction The reaction of combustion of carbon-containing fuels.

** reaction of explosive substances. Most of the chemical reactions.

Endothermic reaction: Most of the decomposition reactions of Ba(OH)2 8H2O react with NH4Cl.

C reacts with CO2 C reacts with H2O(g).

The conditions are "high temperature", all of which are endothermic reactions;

The condition is "combustion", the slow oxidation of the substance, is an exothermic reaction;

Basically all combustion reactions are exothermic ......Oxidation reactions are also yes. Basically all decomposition reactions are endothermic. (Hope, thank you).

Endothermic reactions:1 2nh4cl(s)+ba(oh)2·8h2o(s)=bacl2+2nh3↑+10h2o：

Most of the decomposition reactions, such as:

CaCO3 = (high temperature) CaO+CO2

CuSO4·5H2O = CuSO4 + 5H2O Dissolution of some substances, such as ammonium nitrate dissolution, etc.

2) Ionization. 3) Hydrolysis of salts. At this time, it must be an endothermic reaction. For example, ammonium root hydrolysis is endothermy.

4) C, H2 CO as a reducing agent.

Exothermic reactions: (1) All combustion or ** reactions.

2) Acid-base neutralization reaction.

3) Most chemical reactions.

4) The reaction of active metals with water or acids to form H2.

5) Slow oxidation of substances.

6) Spontaneous redox reactions.

7) Thermite reaction.

Exothermic reactions are:

1.All combustion reactions such as hydrogen, charcoal combustion, etc.

2.Acid-base neutralization reaction.

3.Most chemical reactions.

4.Thermite reaction.

5.Metals react with acids, etc.

The endothermic reactions are:

1.Most of the decomposition reactions.

Reaction to NH4Cl crystals. Wait.

Common exothermic and endothermic reactions in junior high school chemical reactions:

Common exothermic reactions: all combustion reactions; Neutralization reaction ; Most chemical reactions. Reactive metals react with water or acid; slow oxidation of substances ;

Common endothermic reactions: most decomposition reactions; c+co2＝2co；h2+cuo＝cu+h2o；c+ h2o＝co+h2；ba(oh)2 · 8h2o+2nh4cl=bacl2+2nh3↑+10h2o。

Endothermic reactions (1) Several common reactions, such as: 2NH4Cl(S)+Ba(OH)2·8H2O(S)=BaCl2+2NH3 +10H2O C+H2O(G)=CO+H2 C(S)+CO2(G)=2CO

Most of the decomposition reactions, such as: CaCO3 = (high temperature) Cao + CO2 CuSO4·5H2O = CuSO4 + 5H2O Dissolution of some substances, such as ammonium nitrate dissolution, etc. (It can also be said to be the hydrolysis of salts, which must be an endothermic reaction at this time.)

For example, ammonium root hydrolysis is endothermy.

2) Special endothermic reactions, such as: C+CO2=2COi2+H2=2HI (this reaction is reversible, because the generated hydrogen iodide is unstable).

3) Ionization reaction.

4) Hydrolysis of salts.

5) Barium hydroxide crystals are mixed with ammonium chloride crystals.

6) C, H2 CO as a reducing agent.

There should be 1 decomposition reaction in junior high school, such as: CaCO3 = (high temperature) CaO+CO2

2 C, H2 Co as a reducing agent reaction.

Common exothermic bench noisy and endothermic reactions in junior high school chemical reactions:

Common exothermic reactions: all combustion reactions; Jujube Hu serves neutralization reaction; Most chemical reactions. Reactive metals react with water or acid; slow oxidation of substances ;

Common endothermic reactions: most decomposition reactions; c+co2＝2co；h2+cuo＝cu+h2o；c+ h2o＝co+h2；ba(oh)2 · 8h2o+2nh4cl=bacl2+2nh3↑+10h2o。

1. Endothermic reaction:

1) Definition: Endothermic reaction refers to a chemical reaction that absorbs heat in the process.

2) General endothermic reaction: the condition is high temperature; Ammonium chloride reacts with barium hydroxide, etc.

3) Common endothermic reaction types:

Most decomposition reactions, salt hydrolysis reactions, ionization, and a few chemical reactions.

2. Exothermic reaction:

1) Definition: In a chemical reaction, a reaction in which the total energy of the reactants is greater than the total energy of the products is called an exothermic reaction. These include combustion, neutralization, metal oxidation, thermite reactions, more reactive metal reactions with acids, and reactions from unstable substances to stable substances.

2) Principle: A chemical reaction in which the total energy before the reaction is greater than the total energy after the reaction is called exothermic reaction

h = reactant bond energy - product bond energy.

3) Common exothermic reactions:

All combustion or ** reactions, acid-base neutralization reactions, and most chemical reactions. , the reaction of active metals with water or acids to produce hydrogen, many redox reactions (but not absolute), NaOH or concentrated sulfuric acid dissolved in water.

Extended Information: Relationship of the Four Basic Reaction Types to Exothermic Reactions:

1. Chemical reaction:

The vast majority of chemical reactions are exothermic reactions.

2. Decomposition reaction:

The decomposition reaction is rarely exothermic reaction.

3. Displacement reaction:

Most of the displacement reactions are exothermic reactions.

4. Metathesis reaction:

The acid-base neutralization reaction is an exothermic reaction.