ANSWERS TO END-OF-CHAPTER QUESTIONS

Answer:
a. These batteries are lighter and less toxic than the lead-acid batteries.
b. The overall reaction is:
Zn(s) + Ag2O(s) ⎯→ ZnO(s) + 2 Ag(s)
The oxidation half-reaction is: Zn(s) + O 2– (aq) ⎯→ ZnO(s) + 2 e –
The reduction half-reaction is: Ag2O(s) + 2 e – ⎯→ 2 Ag(s) + O 2– (aq)
36. The battery of a cell phone discharges when the phone is in use. A manufacturer, while
testing a new “power boost” system, reported these data.
Time, min.sec Voltage, V
0.00 6.56
1.00 6.31
2.00 6.24
3.00 6.18
4.00 6.12
5.00 6.07
6.35 6.03
8.35 6.00
11.05 5.90
13.50 5.80
16.00 5.70
16.50 5.60
a. Prepare a graph of these data.
b. The manufacturer’s goal was to retain 90% of its initial voltage after 15 minutes of
continuous use. Has that goal been achieved? Justify your answer using your graph.
Answer:
a.
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