The first law of thermodynamics has been first proposed by MAYER2.8 in
1841 [74]: ``Heat is a kind of energy and can therefore neither be
created nor destroyed.'' Hence, heat has been defined as the transfered thermal
energy between two systems if they are brought into thermal
contact [75]. The infinitesimal change of the internal energy
of a system
can be expressed as
|
(2.28) |
where
is the infinitesimal heat added to the system and
represents the infinitesimal work performed by the system
. This equation follows directly from the total differential of the
entropy
With the equations (2.22)-(2.24), the
total differential of the entropy becomes
|
(2.30) |
where the pressure
can be found as
|
(2.31) |
and the chemical potential
as
|
(2.32) |
By comparison of the coefficients from (2.28) and (2.30)-(2.32),
the net heat flow
and the work
done by the system
can be
found as
Stefan Holzer
2007-11-19