Part A For the reaction 2Co3+(aq)+2Cl(aq)2Co2+(aq)+Cl2(g). E = 0.483 V what is t
ID: 962149 • Letter: P
Question
Part A
For the reaction
2Co3+(aq)+2Cl(aq)2Co2+(aq)+Cl2(g). E=0.483 V
what is the cell potential at 25 C if the concentrations are [Co3+]= 0.401 M , [Co2+]= 1.50×102M , and [Cl]= 0.272 M and the pressure of Cl2 is PCl2= 6.20 atm ?
Express your answer with the appropriate units.
The Nernst equation is one of the most important equations in electrochemistry. To calculate the cell potential at non-standard-state conditions, the equation is
E=E2.303RTnFlog10Q
where E is the potential in volts, E is the standard potential in volts, R is the gas constant, T is the temperature in kelvins, n is the number of moles of electrons transferred, F is the Faraday constant, and Q is the reaction quotient. At standard temperature, 25 C or 298 K, the equation has the form
E=E(0.0592n)logQ
The reaction quotient has the usual form
Q=[products]x[reactants]y
A table of standard reduction potentials gives the voltage at standard conditions, 1.00 M for all solutions and 1.00 atm for all gases. The Nernst equation allows for the calculation of the cell potential E at other conditions of concentration and pressure.
E =Explanation / Answer
Part A
2Co3+(aq)+2Cl(aq)2Co2+(aq)+Cl2(g). E=0.483 V
[Co3+]= 0.401 M , [Co2+]= 1.50×102M , and [Cl]= 0.272 M and the pressure of Cl2 is PCl2= 6.20 atm ?
Q = [Co+2]^2 [PCl2]/[Co+3]^2 [Cl-]^2
Q = (1.50 x 10^-2)^2 (6.20 ) / (0.401)^2 (0.272)^2
Q = 0.117
n = 2 = electrons transfered
E=E(0.0592/n) logQ
E = 0.483 - (0.0592 / 2) log (0.117)
E = 0.511 V ------------------> answer