Is the chemical reaction exothermic or endothermic and is the chemical reaction endothermic or exoth

There are two types of chemical reactions: one is a natural reaction, which does not require any external conditions, and such a reaction is generally exothermic; The other reaction can only be produced by heating, and it is possible for such a reaction to be exothermic and endothermic.

Most chemical reactions are exothermic reactions, such as combustion, neutralization, metal oxidation, thermite reactions, more active metal and acid reactions, and reactions from unstable substances to stable substancesMost chemical reactions are exothermic. Most decomposition reactions are endothermic.

According to the relationship between the total energy possessed by the reactant and the total energy possessed by the product:

The total energy of the reactant is higher than the total energy of the product, and the reaction is exothermic.

The total energy of the reactant is lower than the total energy of the product, and the reaction is endothermic.

Hydrogen and chlorine gas synthesis reaction:Chlorine gas is prepared in a fume hood, and the mouth of the empty small plastic bag is tied to the trachea pipe of the chlorine generator with a thin wire Rotate the piston of the separating funnel to make concentrated hydrochloric acid enter the round-bottom flask containing manganese dioxide and heat it slowly.

When it is observed that the small plastic bag is gradually rising and the yellow-green gas in the bag is about half of the volume of the small plastic bag, stop the heating, pinch the mouth of the bag, tie the plastic bag tightly on the outside of the catheter with a thin wire, untie the thin wire tied to the catheter, and remove the gas collection plastic bag.

Most of the chemical reactions are exothermic reactions.

However, there are also chemical reactions, such as carbon dioxide and carbon element, which form carbon monoxide at high temperatures, and this reaction is an endothermic reaction.

A chemical reaction is a reaction in which two or more reactants form another substance. It is one of the four basic types of reactions. The four basic types of reactions include chemical reactions, decomposition reactions, displacement reactions, and metathesis reactions.

Not necessarily. A chemical reaction is a reaction in which two or more substances react to form a new substance, some of which are redox reactions and some are non-redox reactions. In addition, chemical reactions generally release energy.

Chemical reaction: One of the reactants is O2

Magnesium burns in the air [2mg+o2==ignition==2mgo].

Iron burns in oxygen [3Fe + 2O2 = = Ignition = = Fe3O4].

Aluminum burns in the air (or slowly oxidizes on the surface) [4Al+3O2==Ignite==2Al2O3].

Precautions for chemical reactions.

If the concept is not clear, the principle is not clear, and the law of change of matter is not very clear, the question will be wrong. For example, if the relative molecular weight of H2O is only the relative molecular weight of one chemical formula, such as H2O with a relative molecular weight of 18, the relative molecular weight of water in 5H2O is still 18 instead of 90. Another example is that the relative molecular mass ratio of C and D in A+2B=C+2D is known to be 22:

9。If 4 grams of C are generated, how many grams of D are generated at the same time?where the mass ratio of c and d must be 22:2 9=22:

18, and then proceed with the relevant calculations. It would be a mistake to calculate the mass ratio of c and d at 22:9, reflecting that you do not know the difference between relative molecular weight and mass.

Is the chemical reaction endothermic or exothermic: The chemical reaction can be either endothermic or exothermic.

Hydrothermic or exothermic reactions: Chemical reactions can be either endothermic or exothermic, depending on the specific chemical reaction. In a chemical reaction, the bonds of a substance are rearranged to form a new chemical substance.

When the formation of a bond requires the absorption of energy, the reaction is endothermic; When the formation of bonds releases energy, the reaction is exothermic.

Endothermic reaction refers to a chemical reaction in which the reactants absorb the heat of the surrounding environment, so the temperature rises during the reaction. These reactions require energy to be supplied from the outside, such as heating or absorbing light. Some common endothermic reactions include dissolved ammonia, evaporation of water, and many acid-base reactions, among others.

An exothermic reaction is a chemical reaction in which the reactants release energy into the surrounding environment, resulting in a decrease in temperature during the reaction. The energy released by these reactions can be transferred in the form of heat, making the surroundings warmer. Common exothermic reactions include combustion reactions, sulfuric acid and water reactions to form copper sulfate, etc.

It is important to note that not all chemical reactions are obsessively or exothermic, and some reactions may have very weak or difficult to observe in terms of energy changes. Therefore, depending on the specific type and conditions of the chemical reaction, it is necessary to determine whether it is an endothermic or exothermic reaction.

Some common application areas for chemical reactions

1. Synthesis of new materials: The chemical reaction can be used to synthesize new materials, such as polymers, metal alloys, etc. By controlling the reaction conditions and formulations, materials with specific properties and functions can be prepared to meet the needs of different fields.

2. Pharmaceutical industry: chemical reaction plays an important role in the pharmaceutical industry. Synthesis of pharmaceutical raw materials, intermediates or final drugs through chemical reaction to achieve disease prevention and prevention.

3. Energy production: Some energy-related reactions are also chemical reactions, such as combustion reactions, nuclear energy reactions, etc. These reactions release energy that is used in areas such as power generation, heat supply, and transportation power.

Summary. Analysis] Chemical reactions can be either endothermic or exothermic, depending on the type and conditions of the reaction. Endothermic reaction (exothermic reaction):

When heat is absorbed during a chemical reaction, it is called an endothermic reaction; When heat is released, it is called an exothermic reaction. Endothermic reactions: Endothermic reactions need to absorb heat to take place, so the reaction process absorbs heat energy from the surrounding environment.

This causes the temperature of the reaction system to rise, giving the impression that the surroundings are getting colder. For example, many dissolution reactions, evaporation reactions, and some chemical synthesis reactions are endothermic reactions. Exothermic reactions:

An exothermic reaction releases heat into the surrounding environment. This causes the temperature of the reaction system to decrease, giving the impression that the surrounding environment is getting hotter. For example, combustion reactions and some acid-base neutralization reactions are exothermic reactions.

Analysis] The chemical reaction can be either endothermic pure embedding or exothermic, depending on the type and conditions of the reaction. Endothermic reaction (exothermic reaction): When heat is absorbed during the chemical reaction, it is called endothermic reaction; When heat is released, it is called an exothermic reaction.

Endothermic reactions: Endothermic reactions need to absorb heat to take place, so the reaction process absorbs heat energy from the surrounding environment. This causes the temperature of the reaction system to rise, giving the impression that the surrounding environment is getting colder.

For example, many dissolution reactions, evaporation reactions, and some chemical synthesis reactions are endothermic reactions. Exothermic reactions: Exothermic reactions release heat into the surrounding environment.

This causes the reaction system to become cooler, and the larger side gives the impression that the surrounding environment is getting hotter. For example, combustion reactions and some acid-base neutralization reactions are exothermic reactions.

Expansion] Enthalpy of Reaction: The degree of endothermic or exothermic of a chemical reaction can be described by the enthalpy change (δH) of the reaction. The enthalpy change of the reaction surface indicates the change in energy between the reaction and the product during the chemical reaction.

Positive δH value: indicates that the reaction is endothermic, i.e., the reaction needs to absorb heat from the outside in order to proceed. This reaction is called endothermic reaction.

Negative δH value disturbs slag: indicates that the reaction is exothermic, that is, the reaction will release heat into the surrounding environment. This reaction is called exothermic reaction.

It is important to note that different reactions have different enthalpy changes in reaction, so reactions of the same substance may behave as endothermic or exothermic properties under different conditions.

Most of the chemical reactions are exothermic reactions of crude ash, such as combustion, neutralization, metal oxidation, thermite reaction, more active metal and acid reaction, reaction from unstable substance to stable substance, most chemical reactions are exothermic, and most decomposition reactions are endothermic.

Exothermic reactions:

1. Combustion phenomenon;

2. Most chemical reactions are exothermic reactions;

3. Reaction between metal and acid;

4. The neutralization reaction of all strong acids and strong bases (strictly speaking, weak acids and weak bases are also counted, but because the exothermic phenomenon is not obvious, middle schools generally do not get them).

Endothermic reaction

1. Chemical reactions with ammonium salt - such as BA(OH)2+NH4CI in textbooks. There are other ammonium salts such as NH4NO3 or NH4HCO3 (the main component of chemical fertilizers), such as self-made travel "ice packs" that use sodium carbonate and ammonium nitrate to react to absorb heat, so the ammonium rolling shed salt and alkali or acid salt reaction can absorb heat;

2. Most of the decomposition reactions, such as the laboratory preparation method of O2 in textbooks. Generally, the decomposition reaction that needs to be heated is also an endothermic reaction;

3. Another typical example is the reaction of red-hot carbon C with CO2 or H2O. (The former is a chemical reaction).

Most chemical reactions are exothermic reactions, such as combustion, neutralization, oxidation of known metals, thermite reactions, more active metal and acid reactions, and reactions from unstable substances to stable substancesMost of the chemical reactions are exothermic. Most decomposition reactions are endothermic.

1. The reaction of hydride formation is a ventive thermothermal reaction.

For example, hydrogen and fluorine are exothermic in the dark: the formation of H2+F2=2HF2 oxide is an exothermic reaction.

For example, charcoal is burned in air or oxygen to exothermic: the formation of C+O2=CO23 oxygenated acid.

For example, the dissolution of sulfur trioxide in water to form sulfuric acid is an exothermic reaction: the formation reaction of SO3 + H2O = H2SO44 strong base is an exothermic reaction.

For example, sodium oxide reacts with water to form sodium hydroxide exothermy: Na2O + H2O = 2NaOH

Most chemical reactions are exothermic reactions, such as combustion, neutralization, metal oxidation, thermite reactions, more active metal and acid reactions, and reactions from unstable substances to stable substancesMost chemical reactions are exothermic, and most decomposition reactions are endothermic (but not absolute, such as potassium chlorate decomposition to potassium chloride and oxygen is a common exothermic reaction).