The temperature of the object itself rises, absorbs the external heat, and the external temperature decreases
Heat absorption means that the temperature of the object itself rises, absorbs the heat from the outside world, and the outside temperature decreases.
In the gravity field of the earth, the matter changes from a liquid solid state to a gas state, and the volume expands. Some matter may have higher potential energy. In this process, it is necessary to obtain energy from the surrounding, and the internal energy increases.
If it is not in the gravity field, the material changes from liquid solid state to gas state, and the internal energy does not increase, so it does not absorb heat.
That is to say, the endothermic phenomenon of material state change can only occur in the gravity field.
Chinese name
endothermic
Foreign name
endothermic
Meaning
Absorb external heat and reduce external temperature
Reaction mode
2KClO3==MnO2
Include
Vaporization, melting and sublimation in state change
Heat absorption in physics includes vaporization, melting and sublimation in the change of state of matter.
Note: The increase of object temperature (increase of internal energy) does not necessarily absorb heat.It can increase the internal energy of objects by doing work, such as:meteorThe temperature rises due to severe friction with the atmosphere, but there is no heat absorption.
Chemical endothermic
Announce
edit
The endothermic reactions in chemistry generally include two types:
(1) Most reaction conditions are "high temperature" reactions, for example: CO2+C==high temperature==2CO;
(2) Most decomposition reactions, for example: 2H2O2==MnO2==2H2O+O2 ↑.
But this is not absolute. For example, a reaction to produce oxygen: 2KClO3==MnO2, △==2KCl+3O2 ↑. Although it is a decomposition reaction, it is a typical one.
