Berthelot's equation of state

The Berthelot equation of state is an approximate equation of state , that is a formula showing the relationship between thermodynamic state variables describing. It was formulated around 1900 by the French chemist Daniel Berthelot (1865–1927), son of Marcelin Berthelot .

description

The properties of a real gas can be described with the Berthelot equation . In contrast to the more common Van der Waals equation , the part of the formula that describes the attractive forces depends on the temperature . The equation is:

${\displaystyle \left(p+{\frac {an^{2}}{TV^{2}}}\right)(V-nb)=nRT}$

The individual symbols stand for the following quantities :

• ${\displaystyle p}$- pressure
• ${\displaystyle T}$- temperature
• ${\displaystyle V}$- volume
• ${\displaystyle R}$- universal gas constant
• ${\displaystyle n}$- Amount of substance
• ${\displaystyle a}$- cohesive pressure
• ${\displaystyle b}$- covolume

Berthelot's equation is also often used instead of Dieterici's equation of state , as it can become complex at certain critical points .

literature

• Jaime Wisniak: Daniel Berthelot. Part I. Contribution to thermodynamics . In: Educación química . Volume 21, Number 2, 2010, pp. 155-162.