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A. Consider a system at fixed volume, V = V., in diathermal contact with a thermal reservoir at
fixed constant temperature, T, = const. Assume that the total system (including both the system
and the thermal reservoir) form an isolated closed system. (Remember that this implies that
U = U+U, = const.) Consider three infinitesimal quasistatic processes that result in
infinitesimal variations in the Helmoltz potential of the system at fixed volume and temperature:
CF Score:
Answered:
Skipped:
1. (dA)T.y > 0
2. (DA)t.y = 0
3. (DA)Ty < 0
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Following analogous analysis demonstrated in class for the Gibbs potential, prove that process
(1) is impossible, that process (2) is reversible, and that process (3) is spontaneous and
irreversible. Demonstrate this by considering the resulting change in the entropy of the total
closed system, ds, for each of the three processes.
VERY BIG HINT: Derive (and understand) the relation
du, = dA +TdS
B. Prove that
(GO), - -.Hint: We did this in class.
C. Consider a chemical reaction. At a temperature Ti 300. K and an external pressure P, the
enthalpy of reaction is A,H(T1,P) = 400.J and the Gibbs potential of reaction is 4, G(T1,P) =
100.J.
1.
Is the reaction endothermic or exothermic? Is the forward or backward reaction
favorable under these conditions?
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Answers
Answer:
d temperature:
CF Score:
Answered:
Skipped:
1. (dA)T.y > 0
2. (DA)t.y = 0
3. (DA)Ty < 0
Stats refresh on
Following analogous analysis demonstrated in class for the Gibbs potential, prove that process
(1) is impossible, that process (2) is reversible, and that process (3) is spontaneous and
irreversible. Demonstrate this by considering the resulting change in the entropy of the total
closed system, ds, for each of the three processes.
VERY BIG HINT: D
Explanation:
d temperature:
CF Score:
Answered:
Skipped:
1. (dA)T.y > 0
2. (DA)t.y = 0
3. (DA)Ty < 0
Stats refresh on
Following analogous analysis demonstrated in class for the Gibbs potential, prove that process
(1) is impossible, that process (2) is reversible, and that process (3) is spontaneous and
irreversible. Demonstrate this by considering the resulting change in the entropy of the total
closed system, ds, for each of the three processes.
VERY BIG HINT: D