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Chemistry 111
Page
1
out of 8
Exam IV /Fall 2002
Answer Key
Bonus (1 point):
What holiday do we celebrate at the end of this month?
Hint…
Doc likes
sandwiches made with leftover turkey made the following way… Bread,
turkey, turkey, bread, turkey, turkey, bread…
☺
Thanksgiving!
1.
In the derivation of W =  n R T ln (V
2
/V
1
), we went in one particular step from…
W
=
−
P
ext
∫
dV
to…
W
=
−
P
gas
∫
In order to do this, we assumed that…
the process is
reversible
.
(02 pts)
2.
In that same derivation, we went in another step from…
W
=
−
P
gas
∫
to…
W
=
−
n R T
V
∫
In order to do this, we assumed that…
the gas is
ideal
.
(02 pts)
3.
Finally, in that same derivation, we went from…
W
=
−
n R T
V
∫
to…
W
=
−
n R T
dV
V
∫
In order to do this, we assumed that…
the process is
isothermal
.
(02 pts)
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View Full Document Chemistry 111
Page
2
out of 8
Exam IV /Fall 2002
Answer Key
Questions
48
are true false questions.
(02 pts each)
4.
False
The reversible, isothermal work of expansion for a Vander Waals gas
can
be determined with the following equation:
W
=  nRT ln (V
2
/V
1
).
This equation is only valid for ideal gases.
We even derived an
equation on the homework for this particular situation, remember?
5.
True
The entropy content of a given substance can never be negative.
The lowest value for the absolute entropy (entropy content) for a
substance is zero and that is only true at the absolute zero of temperature
(0 K).
6.
False
The standard absolute entropy for liquid carbon tetrachloride is 216 eu,
while that of gaseous carbon dioxide is only 214 eu.
This is because
liquids have a higher entropy content than gases.
False!
We would have expected the entropy of the gas to be higher
than that of the liquid.
However, it is unfair to compare these two
substances, since the molecular weight of CCl
4
is much higher than that of
CO
2
.
7.
False
The total energy of a given system
can never change, according to the first
law of thermodynamics.
False.
That would be true had it stated that the total energy of the
universe can never change…
8.
True
In an isothermal, reversible expansion of an ideal gas, all the heat
absorbed by the gas is converted into work (in theory).
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This note was uploaded on 02/08/2010 for the course CHEM 111 taught by Professor Kenney during the Spring '08 term at Case Western.
 Spring '08
 Kenney
 Chemistry

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