Chapter 17 – Entropy, Free Energy, and Equilibrium
Chapter 17
Entropy, Free Energy, and Equilibrium
1. Which of these species would you expect to have the lowest standard entropy (S)?
2. Which of these species would you expect to have the highest standard entropy (S)?
Chapter 17 – Entropy, Free Energy, and Equilibrium
3. Which of these species would you expect to have the lowest standard entropy (S)?
4. Which of these species has the highest entropy (S) at 25C?
5. Which of these species has the highest entropy (S) at 25C?
Chapter 17 – Entropy, Free Energy, and Equilibrium
6. Arrange these compounds in order of increasing standard molar entropy at 25C:
C3H8(g), C2H4(g), ZnS(s), and H2O(l).
7.
Arrange the following substances in the order of increasing entropy at 25C.
HF(g), NaF(s), SiF4(g), SiH4(g), Al(s)
lowest → highest
Chapter 17 – Entropy, Free Energy, and Equilibrium
8. Which one of the following reactions would you expect to have the lowest S?
Chapter 17 – Entropy, Free Energy, and Equilibrium
10.
Which response includes all the following processes that are accompanied by an increase in entropy?
1) 2SO2(g) + O2(g) → SO3(g)
2) H2O(l) → H2O(s)
3) Br2(l) → Br2(g)
4) H2O2(l) → H2O(l) + 1/2O2(g)
11.
Which response includes all of the following processes that are accompanied by an increase in entropy?
1) I2(s) → I2(g)
2) 2I(g) → I2(g)
3) 2NH3(g) → N2(g) + 3H2(g)
4) Mg2+(aq) + 2OH–(aq) → Mg(OH)2(s)
Chapter 17 – Entropy, Free Energy, and Equilibrium
12.
Which response includes all of the following processes that are accompanied by an increase of entropy?
13.
Without reference to a table, arrange these reactions according to increasing S.
1) CH4(g) + H2O(g) → CO(g) + 3H2(g)
2) C(s) + O2(g) → CO2(g)
3) H2O2(l) → H2O(l) + 1/2O2(g)
Chapter 17 – Entropy, Free Energy, and Equilibrium
14.
Arrange these reactions according to increasing S.
1) H2O(g) → H2O(l)
2) 2NO(g) → N2(g) + O2(g)
3) MgCO3(s) → MgO(s) + CO2(g)
Chapter 17 – Entropy, Free Energy, and Equilibrium
15. Which of the following processes would be accompanied by an increase in entropy?
Chapter 17 – Entropy, Free Energy, and Equilibrium
16. Which of the following processes would be accompanied by a decrease in entropy?
Chapter 17 – Entropy, Free Energy, and Equilibrium
17. Which of the following is expected to have zero entropy?
I. N2(g) at 273 K
II. SiO2(s, amorphous) at 0 K
III. NaCl(s) perfectly ordered crystal at 25 K
IV. Na(s) perfectly ordered crystal at 0 K
18.
Aluminum forms a layer of aluminum oxide when exposed to air which protects the bulk metal from further corrosion.
4Al(s) + 3O2(g) → 2Al2O3(s)
Using the thermodynamic data provided below, calculate S for this reaction.
Chapter 17 – Entropy, Free Energy, and Equilibrium
19.
Sulfur can be separated from lead in the mineral galena, PbS(s), by “roasting” the ore in the presence of oxygen as shown in
the following reaction:
2PbS(s) + 3O2(g) → 2PbO(s) + 2SO2(g)
Calculate S for this reaction using the thermodynamic data provided below.
Chapter 17 – Entropy, Free Energy, and Equilibrium
20.
Determine S for the reaction SO3(g) + H2O(l) → H2SO4(l).
Chapter 17 – Entropy, Free Energy, and Equilibrium
21.
Calculate S for the reaction SO2(s) + NO2(g) → SO3(g) + NO(g).
Chapter 17 – Entropy, Free Energy, and Equilibrium
22.
Calculate S at 25C for the reduction of PbO(s), 2PbO(s) + C(s) → 2Pb(s) + CO2(g) given these absolute entropies:
Chapter 17 – Entropy, Free Energy, and Equilibrium
23. Which of the following is consistent with a spontaneous process in the forward direction?
Chapter 17 – Entropy, Free Energy, and Equilibrium
24. Which of the following is consistent with a nonspontaneous process in the forward
direction?
25.
HI has a normal boiling point of –35.4C, and its Hvap is 21.16 kJ/mol. Calculate the molar entropy of vaporization (Svap).
Chapter 17 – Entropy, Free Energy, and Equilibrium
26.
With respect to the system only, a reaction with H > 0 and S < 0 is predicted to be:
27.
With respect to the system only, a reaction with H < 0 and S > 0 is predicted to be:
Chapter 17 – Entropy, Free Energy, and Equilibrium
28. Which of the following is consistent with a spontaneous endothermic reaction?
Chapter 17 – Entropy, Free Energy, and Equilibrium
29. Which of the following is consistent with an exothermic reaction that is spontaneous at all
temperatures?
Chapter 17 – Entropy, Free Energy, and Equilibrium
30. Which of the following is consistent with an exothermic reaction that is nonspontaneous at
high temperatures?
31.
Aluminum forms a layer of aluminum oxide when exposed to air which protects the bulk metal from further corrosion.
4Al(s) + 3O2(g) → 2Al2O3(s)
Calculate G for this reaction, given that Gf of aluminum oxide is –1576.4 kJ/mol.