Problem 19.58 A certain reaction has delta H degree = + 35.3kJ and delta S degre
ID: 859080 • Letter: P
Question
Problem 19.58 A certain reaction has delta H degree = + 35.3kJ and delta S degree = 85.9J /K. Part C Calculate delta G degree for the reaction at 298 K. Problem 20.102 A voltaic cell is constructed from an Ni2+ (aq)-Ni(s) half-cell and an Ag(aq)-Ag(s) half-cell. The initial concentration of Ni2+ (aq) in the Ni2+ -Ni half-cell is [Ni2+] = 1.60 x 10^-2M . The initial cell voltage is +1.12V. will increase will decrease Part C What is the initial concentration of Ag (aq) in the Ag+ -Ag half-cell? Express your answer using one significant figure. [Ag+ (aq)]1= 0.9 Part B Calculate the standard cell potential (E degree ) for the reaction X(s) + Y+ (aq) X+ (aq) + Y(s) ?f K = 8.70x10^-3. Express your answer numerically in volts.Explanation / Answer
1)
DG = -RTlnK
DG =- 8.314*298ln(8.7*10^-3)
DG = 11756.79J or 11.756 Kj
DG = -nFE0
E0 = -11756.79/96500
E0 = 0.122V
2)
Ecell = E0cell - 0.059/n log[(Ag+)^2/Ni+2]
E0cell = 0.80 - (-0.23) = 1.03V
1.12 = 1.03 - 0.059/2 log[(Ag+)^2/0.016]
[Ag+] = 3.77*10^-4 M
3)
DG = DH - TDS
DG = 35.3 - (298*85.9)
DG = -25562.9Kj