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Heat Capacity of Hydrogen Gas
On the heat capacity of hydrogen
Between heaven and earth, everything has its own characteristics. In the field of heat science, the study of the heat capacity of hydrogen is quite delicate.
Hydrogen is the light and simple of all gases. The state of its heat capacity is related to the movement of molecules and the transfer of energy. The heat capacity of a gas is related to the degree of freedom of molecules. Hydrogen molecules, made of diatoms, have the degrees of freedom of translation and rotation. At low temperatures, the molecular energy is still small, and only the degrees of freedom of translation can be excited. At this time, the heat capacity of hydrogen is only related to translation. According to the classical principle, the translational degrees of freedom are three, and according to the energy equipartition theorem, the energy per degree of freedom is $\ frac {1} {2} kT $, so the heat capacity of hydrogen at this time is $C_ {V0} =\ frac {3} {2} R $, $R $is the universal gas constant.
Then the temperature gradually rises, and the rotational degrees of freedom are gradually excited. The rotational degrees of freedom of diatomic molecules are two. When the rotation is also distributed with the translational parameter energy, the heat capacity of hydrogen increases, $C_ {V} =\ frac {5} {2} R $. This is a common state at room temperature, and the heat capacity of hydrogen is based on various reactions and heat transfer.
If the temperature is higher, the degree of freedom of vibration in the molecule also plays a role. Although the excitation of vibration energy has a significant quantum effect, under the classical approximation, the degree of freedom of vibration is two. At this time, the heat capacity of hydrogen is higher, $C_ {V} =\ frac {7} {2} R $.
From the perspective, the heat capacity of hydrogen varies with temperature, reflecting the transition of molecular energy states. It is also an important reference in thermal analysis, chemical applications and other fields. Observing the change of its heat capacity shows that the connection between the microstructure of matter and macroscopic heat properties is of great significance to the progress of science and the rise of technology.
Between heaven and earth, everything has its own characteristics. In the field of heat science, the study of the heat capacity of hydrogen is quite delicate.
Hydrogen is the light and simple of all gases. The state of its heat capacity is related to the movement of molecules and the transfer of energy. The heat capacity of a gas is related to the degree of freedom of molecules. Hydrogen molecules, made of diatoms, have the degrees of freedom of translation and rotation. At low temperatures, the molecular energy is still small, and only the degrees of freedom of translation can be excited. At this time, the heat capacity of hydrogen is only related to translation. According to the classical principle, the translational degrees of freedom are three, and according to the energy equipartition theorem, the energy per degree of freedom is $\ frac {1} {2} kT $, so the heat capacity of hydrogen at this time is $C_ {V0} =\ frac {3} {2} R $, $R $is the universal gas constant.
Then the temperature gradually rises, and the rotational degrees of freedom are gradually excited. The rotational degrees of freedom of diatomic molecules are two. When the rotation is also distributed with the translational parameter energy, the heat capacity of hydrogen increases, $C_ {V} =\ frac {5} {2} R $. This is a common state at room temperature, and the heat capacity of hydrogen is based on various reactions and heat transfer.
If the temperature is higher, the degree of freedom of vibration in the molecule also plays a role. Although the excitation of vibration energy has a significant quantum effect, under the classical approximation, the degree of freedom of vibration is two. At this time, the heat capacity of hydrogen is higher, $C_ {V} =\ frac {7} {2} R $.
From the perspective, the heat capacity of hydrogen varies with temperature, reflecting the transition of molecular energy states. It is also an important reference in thermal analysis, chemical applications and other fields. Observing the change of its heat capacity shows that the connection between the microstructure of matter and macroscopic heat properties is of great significance to the progress of science and the rise of technology.
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