What is a chemical reaction and what is a reaction in chemistry?

A chemical reaction is the process by which molecules open atoms and recombine to produce new molecules (macroscopically manifested as the formation of new substances).

Charging is the application of energy to change certain chemicals into other chemicals with higher energy, so that they can spontaneously react back and release electrical energy, so it is a chemical change (the substance changes).

For example, when a silver-zinc battery is discharged, silver oxide turns into silver, emitting energy (the substance changes), and when it is charged, it changes back to absorb energy.

When you heat hot water, the water molecule is still the water molecule, and the molecule doesn't change, so it's a physical change.

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Because the battery itself is a chemical product, lithium is the anode, graphite is the cathode, and the electrolyte is dissolved by lithium aluminum tetrachloride.

LialCl4) dissolved in thionyl chloride (SOCl2) When charging, aluminum gains electrons, (to obtain energy, converted from electrical energy) The above process obeys the energy conservation theorem.

So it's chemistry.

And solar water heating, just like we will heat up when we bask in the sun, water heaters are just collecting energy and speeding up the heating.

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A chemical change is a change in the substance itself.

Physical change means that the matter itself does not change, for example, water becomes ice, becomes water vapor, but the essence is water molecules, so it is a physical change.

During the charging process of the battery, a chemical reaction occurs inside, and some of the chemicals inside it are changed and electrical energy is released, so it is a chemical change.

In solar water heating, the temperature of the water increases, but the water itself does not change, so it is said to be a physical change, not a chemical change.

Why is charging a digital camera with a battery a chemical change?

Because the battery is charged and discharged, it is a redox reaction (electrochemical reaction), and new substances are formed.

Why is heating hot water with solar energy not considered a chemical change?

It is the physical change that solar energy is converted into, thermal energy, electrical energy.

Chemical Reaction Definition: In a chemical reaction, the process by which molecules break down into atoms, and the atoms rearrange and combine to form new substances, is called a chemical reaction. In the reaction, it is often accompanied by luminescence, heat, discoloration, and the formation of precipitate, etc., and the basis for judging whether a reaction is a chemical reaction is whether the reaction generates new substances.

Chemical change, whereas chemical change is essentially a change in chemical properties and a change in molecular structure.

The battery is composed of some chemical components, and the electrical energy is converted into chemical energy and stored in the battery, and when used, it is converted into electrical energy output, so the battery is effective.

Solar heating of hot water is not a chemical change, it is a physical reaction, because it does not produce new mass.

A reaction in which a new substance is formed is a chemical reaction. So the first one is, the second one isn't.

The reactions in chemistry are as follows:

1. Chemical reaction reaction: Chemical reaction refers to the reaction (combination reaction) in which two or more substances react to form a new substance. Some of these reactions are redox reactions and some are non-redox reactions.

In addition, chemical reactions generally release energy.

2. Decomposition reaction: The reaction of two or more new substances from the reaction of one substance is called decomposition reaction. Some of these reactions are redox reactions and some are non-redox reactions.

Decomposition reactions can be classified into different categories according to different classification criteria. In addition, only the compound can undergo a decomposition reaction.

3. Displacement reaction: Displacement reaction is a chemical reaction in which a single element reacts with a compound to form another element and a compound, which is one of the four basic reaction types in chemistry, including the reaction between metal and metal salt, the reaction between metal and acid, etc. It is a reaction of one element with one compound to produce another element with another compound.

4. Metathesis reaction: Metathesis reaction is one of the four basic reaction types. The metathesis reaction is a reaction in which two compounds exchange components with each other to produce two other compounds.

The essence of the metathesis reaction is that the two substances that undergo the metathesis reaction exchange ions in the aqueous solution, and combine into substances that are difficult to ionize - precipitation, gas or weak electrolyte (most commonly water), so that the ion concentration in the solution decreases, and the chemical reaction proceeds in the direction of the reduction of ion concentration. It can be abbreviated as ab+cd ad+cb.

5. Redox reaction: oxidation-reduction reaction (also known as redox reaction) is a type of reaction in which the oxidation number of elements changes before and after a chemical reaction. The essence of a redox reaction is the gain or loss of electrons or the shift of shared electron pairs.

6. Non-redox reaction: In contrast to "redox reaction", in a chemical reaction, the reaction in which the valency of the element does not change is called "non-redox reaction".

A chemical reaction is a reaction in which two or more substances produce another substance.

Definition of Chemical Reaction:

A chemical reaction is the process by which a molecule is broken into atoms, and the atoms are rearranged and combined to form a new molecule, and is a reaction in which two or more substances produce another substance. In the reaction, it is often accompanied by luminescence, heating, discoloration, precipitate, etc., and the basis for judging whether a reaction is a chemical reaction is whether the reaction generates new molecules.

The essence of chemical reactions:

The essence of chemical reactions is the process of breaking old chemical bonds and forming new chemical bonds. In the reaction, it is often accompanied by luminescence, heating, discoloration, and the formation of precipitates. The basis for determining whether a reaction is chemical is whether the reaction produces a new substance.

According to the theory of chemical bonds, it can be judged whether a chemical reaction is based on whether there is the breaking of old bonds and the formation of new bonds in a change process.

Basic Types of Chemical Reactions:

1. Chemical reaction.

A chemical reaction is a reaction in which two or more substances react to form a new substance. Among them, the trapped part of the reaction is a redox reaction, and the part is a non-redox reaction. In addition, chemical reactions generally release energy. It can be abbreviated as a+b=ab.

2. Decomposition reaction.

The reaction in which two or more other substances are produced from one substance is called a 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.

The reaction of one element with a compound to form another chemical reaction with another element and compound is one of the four basic reaction types in chemistry, including the reaction between metal and metal salt, the reaction between metal and acid, 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 the metathesis collapse 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 decreases, 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.

The reactions in chemistry are:

1. Chemical reaction. It refers to the reaction of two or more substances to produce a new substance, some of which are redox reactions, and some are non-redox reactions, in addition, chemical reactions generally release energy, which can be abbreviated as a+b=ab.

2. Decomposition reaction. The reaction in which two or more other substances are generated from one substance is called a decomposition reaction Abbreviated as a split into two Expressed as ab=a+b Only compounds can undergo decomposition reactions.

3. Displacement reaction. It is one of the four basic types of reactions in chemistry, including the reaction between metal and metal salt, the reaction between metal and acid, etc., which can be abbreviated as ab+c=a+cb.

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

The reaction is the process of the formation of new substances, which is the breaking of the chemical bonds of the reactants and the formation of the chemical bonds of the products. Chemical reactions involve energy changes, and from an atomic point of view, the chemical reaction process is the rearrangement and combination of atoms (clusters).

There are four basic types of chemical reactions: chemical reaction (reaction of two or more substances to produce a new substance), decomposition reaction (reaction of two or more substances to produce two or more new substances from one substance), metathesis reaction (reaction in which two compounds exchange components with each other to form two new compounds), and displacement reaction (reaction in which one element and one compound are reacted to produce another element and another compound).

According to whether there is electron transfer (rise and fall of valency): non-redox reaction (there is no change in the valency of the element in the reaction, that is, no electron transfer occurs), redox reaction (electron transfer occurs when the valency of the element changes).

According to the participation of ions: ionic reactions (reactions in which ions are generated or participated in in an aqueous solution or in which ions participate in the molten state), molecular reactions (non-ionic reactions).

According to the degree of reaction progression, it is divided into: reversible reaction (under the same conditions, it can be carried out in both the direction of the positive reaction and the direction of the reverse reaction), and the irreversible reaction (under certain conditions, the reaction can only be carried out in one direction).

According to the thermal effect of the reaction, it is divided into: exothermic reaction (chemical reaction that emits heat), endothermic reaction (chemical reaction that absorbs heat).

Reactions that change the chemical results and chemical properties of the original substance. To put it simply, the concentrated hydrogen is separated from the cylinder into the air, and the composition is still hydrogen, which is a physical reaction, but if it encounters fire at **, it will quickly burn into water, and the chemical properties will be completely changed, which is a chemical change.

There are old chemical bonds broken and new chemical bonds are generated. For example, water splits into hydrogen and oxygen. H-O breaks between water molecules to form new H-H and O-O.

The process by which a substance undergoes a chemical change to produce a new substance with a different nature, composition, and structure from the original.