What are the basic laws of chemical change

Chemically, changes that produce other substances are called chemical changes. Chemical changes are characterized by the formation of other substances, often accompanied by color changes, precipitation, gas production, endothermy, exothermics, luminescence and other phenomena.

The law of change in chemistry mainly refers to the study of chemical changes and hail repentance.

Chemistry is the science of studying the properties, composition, structure, and changes of matter at the molecular and atomic levels.

Of course, the law of the cave here mainly refers to the law of chemical changes in matter.

1. The formation of new substances (products) and the change of quantity.

2. The decrease of reactants, that is, the change of quantity.

3. The release or absorption of energy, generally speaking, is the change of energy!! This one is easy to ignore)

4. Conform to the law of conservation of mass.

5. The law of conservation of energy.

The basis of chemical change is the creation of new substances. Chemical change refers to the process of conversion or transfer of atoms or electrons between molecules in contact with each other to form new molecules accompanied by changes in energy, which is essentially the breaking of old bonds and the formation of new bonds.

Chemical change substanceFrom the microscopic point of view, we can understand the essence of the chemical change: the type and number of atoms before and after the chemical reaction do not change, but the way of bonding between atoms has changed, and the atom is the smallest particle of chemical change.

For example, in the case of a substance composed of molecules, it is a molecule that recombines the atoms into new substances and substances. The chemical properties of a substance can only be expressed through chemical changes in the substance, so the chemical properties of the substance can be studied by the method of making the substance react chemically and a new substance can be prepared.

Oxidized xx oxygen is in the back, and the metal elements are on the left and non-metal on the right. For example, magnesium oxide: MGO.

According to the type of reactants and products, it is divided into four categories: chemical reaction, decomposition reaction, displacement reaction, and metathesis reaction.

1. Chemical reaction:

Abbreviation: A + B = C: Two or more elements or compounds to form a complex product. (i.e., a reaction in which two or more substances produce a new substance.) ）

2. Decomposition reaction:

Abbreviation: A = B + C: The compound is broken down into constituent elements or small molecules. (i.e., the reverse reaction of the chemical reaction.) It refers to the reaction in which a compound is broken down into two or more simpler elements or compounds under specific conditions. ）

3. Displacement reaction (single substitution reaction):

Abbreviation: A+BC=B+AC: Indicates an additional reactive element to replace one of the elements in the compound. (i.e., refers to the reaction of one element and one compound to produce another element and another compound.) ）

4. Metathesis reaction (double substitution reaction).

Ab+cd=AD+CB: In an aqueous solution (also known as ionization), two compounds exchange elements or ions to form different compounds. (i.e., a reaction in which two compounds exchange components with each other to produce two other compounds.) ）

1. According to the second law of thermodynamics, any isothermal isobaric closed system tends to reduce Gibbs free energy.

2. The essence of a chemical reaction is the process of breaking old chemical bonds and forming new chemical bonds.

3. The process of chemical reaction is the process of recombining the atoms of various substances participating in the reaction to form other substances. In a chemical reaction, the type of atoms does not change before and after the reaction, the number does not increase or decrease, and the mass of the atoms does not change.

4. In chemical reactions, 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.