Concise Physical Chemistry

c14 JWBS043-Rogers September 13, 2010 11:27 Printer Name: Yet to Come

PROBLEMS AND EXAMPLES 233

compartment is 0.0100 m but the concentration of the other Zn^2 +half-cell is unknown.

The whole-cell potential was measured and found to be 32.4 mV.

(a) Without doing a numerical calculation, is the unknown more or less concen-

trated than the 0.0100 m solution?

(b) What is the unknown concentration?

(c) Does your answer to part b agree with your answer to part a?

Problem 14.3

The half-cell (reduction) potential of the Ag:AgBr electrode is 0.071 volts. Use this

information with information in Section 14.3 to determine the solubility product

constantKspof AgBr in water.

Problem 14.4

A very important extension of electrochemical of solubility determination is gener-

alization of the method to determine other kinds of equilibrium constant and fur-

ther generalization to determination of the enthalpy, entropy, and Gibbs free energy

changes for electrochemical reactions. Write or derive the equations for doing this.

Problem 14.5

Is it possible to reduce all of the Fe+^3 ion in an aqueous solution containing Fe^2 +and

Fe^3 +by filtering the solution through finely divided Zn(s)?

Problem 14.6

What is the standard Gibbs free energy change for the preceding reaction, and does

your answer agree with the preceding answer?

Problem 14.7

A hydrogen half-cell combined with a saturated calomel electrode has a measured

cell potential of 57.3 mV. What is the pH of the aqueous solution in the hydrogen

half-cell? If the hydrogen electrode is a standard hydrogen electrode (SHE), what is

the cell potential?

Problem 14.8

From the cell

Pt(s); H 2 (g,1 atm); HCl(aq); AgCl(s); Ag(s)