# Formula Ideal Gas Internal energy    Degrees of freedom    Temperature    Stoffmenge

## Internal energy

Unit
Internal energy is the total energy of molecules or atoms of an ideal gas that is in thermodynamic equilibrium.

## Degrees of freedom

Unit
Number of degrees of freedom of a particle of the gas. In the three-dimensional case and without particles being able to rotate and vibrate, $$f = 3$$. The more degrees of freedom the gas has, the greater the internal energy of the system.

## Temperature

Unit
Absolute temperature of the system, that is the temperature of a gas. The greater the temperature, the greater the internal energy.

## Stoffmenge

Unit
The amount of substance $$n$$ is the ratio between the number of particles $$N$$ and the Avogardo constant $$N_{\text A} = 6 \cdot 10^{23}$$:$$n = \frac{N}{N_{\text A}}$$

So in one mole of gas there are $$6 \cdot 10^{23}$$ gas particles.

## Gas constant

Unit
Gas constant is a physical constant appearing in thermodynamics. It has the following value: $$R ~=~ 8.314 \, \frac{ \mathrm{J} }{ \mathrm{K} \, \mathrm{mol} }$$