Isobaric process

The isobaric change of state is a term of thermodynamics. It denotes a state change in which the pressure in the system remains constant. According to the law of Gay- Lussac, or the equation of state of an ideal gas holds:

It also follows that the volumes behave like the corresponding absolute temperatures:

According to the first law of thermodynamics () result for the work the following relationships:

Here, p denote the pressure, n is the amount of substance (in moles ) and R is the universal gas constant.

To heat a gas under isobaric conditions to a certain temperature, one must make a larger amount of heat than a isochoric heating, since part of the heat supplied to the expansion of the gas has to be applied.