Chem. 444,
Fall 2006
Name: ____________________________
Instructor:
Nancy Makri
SECOND HOUR EXAM
November 3, 2006
1.
State whether the temperature
T
of the system, the entropy
sys
S
of the system and the entropy
tot
S
of the universe (i.e., that of the system and its surroundings) increase, decrease or remain constant
during each of the processes described below.
In each case justify your answer in a single sentence.
(a) Reversible isothermal expansion of an ideal gas.
(b) Free expansion of an ideal gas.
(c) Reversible adiabatic compression of an ideal gas.
(20 points)
2.
A fluid (not necessarily an ideal gas) is expanded and heated, such that its temperature is changed
from
1
T
to
2
T
and its volume is changed from
1
V
to
2
V
.
Express an infinitesimal change of the
entropy in terms of infinitesimal changes in the temperature and volume.
You can evaluate the
change in entropy by integrating this differential form.
However, derivatives of the entropy are not
measurable directly.
Therefore, you should first transform this relation to bring it in a form that
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 Fall '08
 Gruebele,M
 Thermodynamics

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