Use the table of standard reduction potentials given above to calculate the equilibrium constant at standard temperature (25 âC) for the following reaction:
Fe(s)+Ni2+(aq)âFe2+(aq)+Ni(s)
Express your answer numerically.
K =
Part B
Calculate the standard cell potential (Eâ) for the reaction
Free-energy change, ÎGâ, is related to cell potential, Eâ, by the equation
ÎGâ=ânFEâ
where n is the number of moles of electrons transferred and F=96,500C/(mol eâ) is the Faraday constant. When Eâ is measured in volts and can be determined from half-reaction potentials as given in the table below. ÎGâ must be in joules since 1 J=1 Câ V.
Reduction half-reaction
Eâ (V)
Ag+(aq)+eââAg(s)
0.80
Cu2+(aq)+2eââCu(s)
0.34
Sn4+(aq)+4eââSn(s)
0.15
2H+(aq)+2eââH2(g)
0
Ni2+(aq)+2eââNi(s)
â0.26
Fe2+(aq)+2eââFe(s)
â0.45
Zn2+(aq)+2eââZn(s)
â0.76
Al3+(aq)+3eââAl(s)
â1.66
Mg2+(aq)+2eââMg(s)
â2.37
Part A
Calculate the standard free-energy change at 25 âC for the following reaction using the table in the introduction:
Mg(s)+Fe2+(aq)âMg2+(aq)+Fe(s)
Express your answer numerically in joules.
ÎGâ =
J
Part B
Calculate the standard cell potential at 25 âC for the reaction