Is it possible that there is a chemical change in the physical change

The standard statement in the book is that there must be a physical change in a chemical change, that is, the physical change and the chemical change occur at the same time, so there may be a chemical change in the physical change.

How is that possible?

If there is, it is called a chemical change.

No. If there is a chemical reaction, it is a chemical reaction.

A physical change is a change in which no new matter is generated, while a chemical change is a change in which a new substance is produced is called a chemical change, and if there is a chemical change in the physical change, this proposition is contradictory. Either the physical change is accompanied by a chemical change or the chemical change is accompanied by a physical change.

Physical changes may be accompanied by chemical changes, such as luminescence and heat generation during combustion.

And chemical changes must be accompanied by physical changes.

If you look at the definition, you should understand that there is no chemical change in physical change. But physical changes can occur at the same time as chemical changes.

There is no chemical change in physical change, but there can be physical change in chemical change.

How can it be? Physical change is a change in the form of matter, mass, size, and so on.

Whereas, a chemical change is a change in the properties of a substance, such as density. Chemical changes are generally accompanied by physical changes, but it cannot be said that there are chemical changes in physical changes, which is impossible.

There is a micro problem, but there is no macro problem, if it is a problem in junior high and high school, there is a problem at the level above the university level.

It's hard to say, you may say no now, and you may say that there is in the future.

It depends on how people define it.

The process of chemical change must be accompanied by physical change.

Chemical change is a change in the formation of new substances, so the shape, state, color, etc. of the substance may change in the process of change, as long as the shape changes in the process of change, it is a physical change, so there must be a physical change in the chemical change.

Physical change is that there is no new substance generated, and the change generated by new substance belongs to chemical change, so there must be no chemical change in physical change, and if there is a chemical change, there will be new substance generation, which becomes a chemical change, and it does not belong to physical change.

Yes, chemical change must be accompanied by physical change, because in the process of chemical change, new substances are produced, so the relevant physical properties will also be reflected, such as color change, state change, and so on.

Not necessarily, because chemical reactions with three changes are accompanied by physical changes.

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 the generation of new substances.

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.

Extended information: Combustion is inevitably accompanied by luminescence and heat release, but there is not necessarily a flame. If it is a flammable gas, a flame will be generated, such as:

the combustion of hydrogen, carbon monoxide, methane, sulfur and candles produce sulfur vapor and paraffin vapor when burned, there are also flames; But charcoal is always solid during the combustion process and cannot produce flammable vapors, so there is no flame.

Among them, ** is more complicated, and there are two situations. One is due to the combustion exothermic can not be dissipated, the volume expansion in a limited space is generated, it is a chemical change, such as: H2 and O2 mixed ignition, firecrackers, etc.; The other is due to air pressure**, for example:

Balloons**, tires**, etc., are physical changes.

Endothermic and exothermic reactions can be judged by reaction conditions. "Ignition" is exothermic; "High temperature" is endothermy. Some reactions require a "catalyst" to proceed, but no matter what the reaction, the law of conservation of mass must be observed.

The basic three-state change of matter, and no new substance is produced, so it belongs to physical change. Deliquescence of inorganic salts and alkalis such as NAOH, melting of ice, crushing of bile alum, etc.

For example, molten iron is cast into an iron pot, which involves the combination of carbon and iron elements and new molecules (generally forming Fe3C), which is not counted as a physical change, but if it is 100% pure iron, casting into an iron pot will not undergo chemical changes and no new phases will be generated.

After searching and browsing the relevant information, we also know that graphite turning into diamond under certain conditions is a chemical change, because it becomes another element. But there are also some allotropes that are transformed by physical changes, such as monoclinic sulfide and orthorhombic sulfur.

Before and after the physical change, the type, composition, and chemical properties of the substance remain the same. The essence of this type of change is a change in the state of aggregation of molecules (separation distance, speed of motion, etc.), resulting in a change in the shape or state of the substance. Physical changes express the physical properties of the substance.

Physical change is fundamentally different from chemical change.

The flame color reaction is a physical change. The flame reaction is a change in the energy level of electrons inside the atoms of a substance, which is commonly known as the change in the energy of electrons in an atom, and does not involve a change in the structure and chemical properties of matter.