290
Electrochemistry I Batteries and Free Energy
14 Describe each of the cells in Problem 13 in simplified shorthand notation
15 Calculate the cell voltage for each of the cells constructed in Problem 13,
assuming (;) all components at unit activity, or (a) the negative half-cell ionic
concentrations to be 10~' molar and the positive half-cell ionic concentrations
to be 10~
5 molar
16 Calculate the equilibrium constant for each of the reactions listed in Problem
13
17 Calculate the change in standard free energy that accompanies each of the
reactions listed in Problem 13
18 One-hundredth mole each of Ag 2 SO 4 and FeSO 4 are mixed in one liter of
water at 25 0°C and permitted to reach equilibrium according to the reaction
Ag
+ + Fe
z+ ^ Ag + Fe
3+
The silver that is formed is filtered off, washed, dried, and weighed, and
found to weigh 0 0645 g From these data, calculate AG° for the reaction
19 Equilibrium constants for the following reactions may be found in the tables
cited Calculate AG° for each of the reactions at 25 0°C
(a) HCN ** H
+ + CM"
(Table 23-1)
(b) (CH 3 ) 3 N + H 2 O <=i (CH 3 ) 3 NH
+ + OH
(Table 23-1)
(c) T1 2 S <=t 2T1
+ + S
2 -
(Table 24 1)
(d) Hg(CN) 4
2 +± Hg
2+ + 4CN~
(Table 25-1)
(e) Br 2((1 + C1 2(91 ?± 2BrCl« fl)
(K v = 42 5)
20 Calculate AG° and K e at 25 0°C for each of the following reactions Tell which
ones are spontaneous
(a) Cl 2(ffl + 2HBr (fl) -^ 2HCl< fll + Br 2(()
(b) 2C 6 H 6((1 + 7O 2(0) -> 12CO 2(fll + 6H 2 O,i>
(c) NH 4
+
(M > + N0 3 - (M) -^ N 2 0 (fll + 2H 2 0 (0
(d) I 2(s) + C1 2(9) -> 2IC1< 9)
21 Calculate AS
0 for each of the reactions in Problem 20
22 Calculate A//° for each of the reactions in Problem 20, but do not use data
given in Table 14-1
23 Calculate values of K e at 25 0°C for the following equilibria, using data from
Table 17-1 exclusively
(a) Hg 2 Cl 2 +± Hg 2
2+ + 2C1
(b) 3HN0 2 ?± H
+ + NO 3 - + 2NO + H 2 O
(c) C1 2 + H 2 O ?± H
+ + Cl- + HC1O
24 Use the value of A//° obtained in Problem 9(c), p 224, for the reaction Pb,
2
f +) +
21(09) ** PbI 2(s) along with information given in Table 24-1 to calculate the
value of AS ° for this reaction
Electrochemistry I Batteries and Free Energy
14 Describe each of the cells in Problem 13 in simplified shorthand notation
15 Calculate the cell voltage for each of the cells constructed in Problem 13,
assuming (;) all components at unit activity, or (a) the negative half-cell ionic
concentrations to be 10~' molar and the positive half-cell ionic concentrations
to be 10~
5 molar
16 Calculate the equilibrium constant for each of the reactions listed in Problem
13
17 Calculate the change in standard free energy that accompanies each of the
reactions listed in Problem 13
18 One-hundredth mole each of Ag 2 SO 4 and FeSO 4 are mixed in one liter of
water at 25 0°C and permitted to reach equilibrium according to the reaction
Ag
+ + Fe
z+ ^ Ag + Fe
3+
The silver that is formed is filtered off, washed, dried, and weighed, and
found to weigh 0 0645 g From these data, calculate AG° for the reaction
19 Equilibrium constants for the following reactions may be found in the tables
cited Calculate AG° for each of the reactions at 25 0°C
(a) HCN ** H
+ + CM"
(Table 23-1)
(b) (CH 3 ) 3 N + H 2 O <=i (CH 3 ) 3 NH
+ + OH
(Table 23-1)
(c) T1 2 S <=t 2T1
+ + S
2 -
(Table 24 1)
(d) Hg(CN) 4
2 +± Hg
2+ + 4CN~
(Table 25-1)
(e) Br 2((1 + C1 2(91 ?± 2BrCl« fl)
(K v = 42 5)
20 Calculate AG° and K e at 25 0°C for each of the following reactions Tell which
ones are spontaneous
(a) Cl 2(ffl + 2HBr (fl) -^ 2HCl< fll + Br 2(()
(b) 2C 6 H 6((1 + 7O 2(0) -> 12CO 2(fll + 6H 2 O,i>
(c) NH 4
+
(M > + N0 3 - (M) -^ N 2 0 (fll + 2H 2 0 (0
(d) I 2(s) + C1 2(9) -> 2IC1< 9)
21 Calculate AS
0 for each of the reactions in Problem 20
22 Calculate A//° for each of the reactions in Problem 20, but do not use data
given in Table 14-1
23 Calculate values of K e at 25 0°C for the following equilibria, using data from
Table 17-1 exclusively
(a) Hg 2 Cl 2 +± Hg 2
2+ + 2C1
(b) 3HN0 2 ?± H
+ + NO 3 - + 2NO + H 2 O
(c) C1 2 + H 2 O ?± H
+ + Cl- + HC1O
24 Use the value of A//° obtained in Problem 9(c), p 224, for the reaction Pb,
2
f +) +
21(09) ** PbI 2(s) along with information given in Table 24-1 to calculate the
value of AS ° for this reaction