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General Chemistry Principles, Patterns, and Applications, 2011

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2. What is the relationship between the measured cell potential <strong>and</strong> the total charge that passes through a cell?<br />

Which of these is dependent on concentration? Which is dependent on the identity of the oxidant or the<br />

reductant? Which is dependent on the number of electrons transferred?<br />

3. In the equation w max = −nFE° cell , which quantities are extensive properties <strong>and</strong> which are intensive properties?<br />

4. For any spontaneous redox reaction, E is positive. Use thermodynamic arguments to explain why this is true.<br />

5. State whether you agree or disagree with this statement <strong>and</strong> explain your answer: Electrochemical methods<br />

are especially useful in determining the reversibility or irreversibility of reactions that take place in a cell.<br />

6. Although the sum of two half-reactions gives another half-reaction, the sum of the potentials of the two halfreactions<br />

cannot be used to obtain the potential of the net half-reaction. Why? When does the sum of two<br />

half-reactions correspond to the overall reaction? Why?<br />

7. Occasionally, you will find high-quality electronic equipment that has its electronic components plated in<br />

8.<br />

9.<br />

gold. What is the advantage of this?<br />

Blood analyzers, which measure pH, PCO2,<br />

<strong>and</strong> PO2, are frequently used in<br />

clinical emergencies. For example,<br />

blood PCO2 is measured with a pH electrode covered with a plastic<br />

10. membrane that is permeable to CO 2 . Based on your knowledge of how electrodes function, explain how such<br />

an electrode might work. Hint: CO 2 (g) + H 2 O(l) → HCO 3 − (aq) + H + (aq).<br />

11. Concentration cells contain the same species in solution in two different compartments. Explain what<br />

produces a voltage in a concentration cell. When does V = 0 in such a cell?<br />

12. Describe how an electrochemical cell can be used to measure the solubility of a sparingly soluble salt.<br />

A N S W E R S<br />

1.<br />

2.<br />

3. extensive: w max <strong>and</strong> n; intensive: E° cell<br />

4.<br />

5.<br />

6.<br />

7. Gold is highly resistant to corrosion because of its very positive reduction potential.<br />

8.<br />

Saylor URL: http://www.saylor.org/books<br />

Saylor.org<br />

1773

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