What is the relationship between chemical change and physical change

The fundamental difference between physical change and chemical change is that no new matter is formed during physical change, whereas chemical change does.

1. Physical changes.

Physical change refers to the fact that although the state of matter has changed, generally speaking, the composition of the substance itself has not changed. For example, changes in position, volume, shape, temperature, pressure, and conversion between gaseous, liquid, and solid states.

There are also the interaction between matter and electromagnetic fields, the interaction between light and matter, and the interaction and transformation between microscopic particles (electrons, atomic nuclei, elementary particles, etc.), all of which are physical changes.

2. Chemical changes.

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 changes are always accompanied by physical changes. In the process of chemical change, there are usually luminescence, exothermia, and endothermy. According to the atomic collision theory, the chemical change between molecules is accomplished by collision, and two conditions are required to complete the collision reaction molecule: (1) sufficient energy and (2) correct orientation.

Because the reaction needs to overcome a certain molecular energy barrier, it must have a higher energy to overcome the molecular energy barrier. Two colliding molecules must have the correct orientation for the old bond to break.

3. The difference between physical change and chemical change.

The fundamental difference between physical change and chemical change is that no new substance is formed during physical change, while chemical change is (for example, the process of copper forming patina is chemical change). From a macroscopic point of view, no new matter is formed by physical change, whereas new matter is formed by chemical change. From a microscopic point of view, in physical change, the distance between the atoms that make up the molecule does not change (the length of the chemical bond does not change), the shape and size of the substance changes, the molecule itself does not change, the way the atoms combine does not change, and the chemical change is the opposite.

Difference Between Chemical Change and Physical Change.

Chemical changes lead to the formation of new substances, usually accompanied by phenomena such as luminescence and heat, while physical changes are changes in which no new substances are formed.

1. Connection: chemical changes must contain physical changes, and there must be no chemical changes in physical changes.

2. Differences. (1) The essential difference between the two is whether there is a new substance or not.

2) Physical change is only a change in form, property, etc., while chemical change is the formation of new substances.

Examples of physical changes: water evaporates and solidifies, sugar cubes melt, carbon dioxide condenses into dry ice, wine smells, wet clothes dry out.

Examples of chemical changes: sodium hydroxide deterioration, plant photosynthesis, hydrochloric acid rust removal, thermal decomposition of basic copper carbonate, rusting of iron in humid air, burning of candles.

The chemical change is based on the physical change of the previous brightness.

1) The intrinsic characteristics of chemical change: new substances are formed.

2) The relationship between physical change and chemical change: physical change must occur in the process of chemical change, but chemical change does not necessarily occur in the process of physical change.

The connection between physical change and chemical change: If a material undergoes a hail and a physical change, there must be no chemical change, and if there is a chemical change in the substance, there must be a physical change. Take the state.

The source of physical change refers to the fact that although the state of the substance has changed, the composition of the substance itself has not changed, such as the change of the position, volume, shape, temperature, and pressure of the object, as well as the mutual transformation of the substance between gaseous, liquid, and solid states.

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 chemical bonds and the formation of new chemical bonds.