The work done by a gas is W = P(Vf - Vi)
where W is positive if the gas expands.
The change in internal energy of a system is: Uf - Ui = Q -
W
where Q is positive when heat enters the system.
A cyclic process is one in which Uf = Ui, so that Q = W.
An adiabatic process has no heat transfer into or out of the
system.
An isobaric process occurs at constant pressure.
The first law of thermodynamics is an extension of the law of
conservation
of energy.
The second law of thermodynamics tells us that heat flows from
hot to cold objects and that no heat engine can operate at 100% efficiency.
This law also tells us that all natural processes tend toward states of
disorder, and that the entropy (disorder) of the Universe is always
increasing.
Ponderables: