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____________ A voltaic cell has an E_cell^degree of 0.23 V under standard condit

ID: 527175 • Letter: #

Question

____________ A voltaic cell has an E_cell^degree of 0.23 V under standard conditions. What can you conclude K_eq for the reaction? Keq 1 K_eq = 0 K_eq = 1 K_eq = E_cell^degree ___________ You want to make a voltaic cell with copper (Cu, Cu^2+) and another material. Which material do you choose to maximize E_cell^degree? Is copper the anode or cathode? Ag^+/Ag, copper is anode Ag^+lAg, copper is cathode Zn^2+/Zn, copper is anode Zn^2+/Zn, copper is cathode Not enough information ________ Which conditions provide the highest cell potential (E_cell) in a concentration cell? [anode] = [cathode] uparrow [anode], downarrow[cathode] downarrow[anode], downarrow[cathode] uparrow[anode], downarrow[cathode] downarrow[anode], uparrow[cathode]

Explanation / Answer

4)

since Eocell is positive, the reaction is spontaneous and hence equilibrium constant will be greater than 1

Answer: B) Keq > 1

5)

when we used Zn:

from data table:

Eo(Zn2+/Zn(s)) = -0.762 V

Eo(Cu2+/Cu(s)) = 0.337 V

the electrode with the greater Eo value will be reduced and it will be cathode

here:

cathode is (Cu2+/Cu(s))

anode is (Zn2+/Zn(s))

The chemical reaction taking place is

Cu2+ + Zn(s) --> Cu(s) + Zn2+

Eocell = Eocathode - Eoanode

= (0.337) - (-0.762)

= 1.099 V

when we use Ag:

from data table:

Eo(Cu2+/Cu(s)) = 0.337 V

Eo(Ag+/Ag(s)) = 0.8 V

the electrode with the greater Eo value will be reduced and it will be cathode

here:

cathode is (Ag+/Ag(s))

anode is (Cu2+/Cu(s))

The chemical reaction taking place is

Ag+ + Cu(s) --> Ag(s) + Cu2+

Eocell = Eocathode - Eoanode

= (0.8) - (0.337)

= 0.463 V

Clearly Eo is larger in case of Zn. There copper was used as cathode

Answer: D

6)

E = Eo - (2.303*RT/nF) log Q

Q = [anode] / [cathode]

Greater [Cathode] implies smaller Q and hence larger E

Answer: E