19TQ: Chemical Thermodynamics
Name: _________________________
Text Questions from Brown, et. al.
1. What is the relationship between the activation energy and the rate of a reaction?
2. Reactions involve changes in what two thermodynamic quantities?
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3. What does the first law of thermodynamics state?
4. What does our experience tell us about physical and chemical processes?
5. What is a spontaneous process?
6. Processes that are spontaneous in one direction are…
7. What experimental conditions are often important in determining whether a process is spontaneous?
8. List two things thermodynamics CAN tell us about a reaction. Then list one thing it CAN’T.
9. Most, but not all, spontaneous reactions are…
10. In a reversible process, we can completely restore the system to its original condition…
11. What is an irreversible process?
12. All _____ processes are irreversible, and all _______________ processes are also irreversible.
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13. Although it is a multifaceted concept, entropy is perhaps best associated with the extent of…
14. Write the equation for finding the change in entropy for an isothermal process.
15. What are the units for a change in entropy?
16. Entropy __________ in any spontaneous process, which means that the sum of the entropy changes of
the system and of the surroundings for a spontaneous process is always…
17. Which “profound generalization” expresses the second law of thermodynamics?
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18. As the temperature increases, what happens to the distribution of molecular speeds?
19. List the three kinds of motion particles can undergo.
20. What does statistical thermodynamics do, and what tools does it use?
21. What is a microstate?
22. Each _______________ state has a characteristic number of _____________ associated with it,
symbolized by the letter ___.
23. Write the equation that relates a system’s entropy with its microstates, and define the terms.
24. What is entropy a measure of?
25. Increases in what three things generally increase the number of a system’s microstates?
26. List the three conceptual descriptions of entropy.
27. What happens to the water molecules AND their motion when salts with highly charged ions dissolve?
28. What are three processes for which we expect a system’s entropy to increase?
29. What is the third law of thermodynamics?
30. A crystalline solid at absolute zero has ___ microstate(s). As a result, S = k ln W = k ln ___ = ___.
31. With reference to Fig. 19-14…
A…when does entropy increase without a temperature change?
B…what happens to entropy as temperature increases within a state of matter?
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32. What are standard molar entropies, and how are they denoted?
33. Unlike Hof values, standard molar entropies (i.e., So) of __________ at 298 K are NOT zero. So values
for gases are ________ than those for liquids and solids. So values increase with increasing ________
______ AND with an increasing number of ______ in the chemical formula.
34. Write the equation for finding a reaction’s entropy change.
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35. Spontaneous processes that result in a decrease in the system’s entropy are always…
36. Write an equation to find the change in Gibbs free energy.
37. What are the relationships between the sign of G and the direction of spontaneity?
38. When does the free energy always decrease?
39. When Q __ K, the reaction will proceed spontaneously in the forward direction. When Q __ K, the
reaction will proceed spontaneously in the reverse direction. When Q __ K, the reaction is at
equilibrium.
40. What is the value of the free energy for any element in its standard state?
41. Write the equation to find the standard free energy change for a chemical process.
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42. When will the sign of G depend on the magnitudes of H and –TS?
43. What two terms vary little with temperature?
44. What is the equation for finding the free-energy change under nonstandard conditions?
45. When using the equation in Q44, what must be the unit used for gases in calculating Q?
46. A. Which equation will allow you to calculate the standard
free energy change from the equilibrium constant?
B. Which equation will allow you to calculate the equilibrium
constant from the standard free energy change?
47. In the equations in Q46, K is ___ for gas-phase reactions and ___ for reactions in solution.