Question

Find the calculated voltages for each cell. Use equation Eo(cell)= E0(cathode) + Eo(anode)

Cell 1: Cu/Cu2+ Zn/Zn2+

Cell 2: Cu/Cu2+ Fe/Fe3+

Cell 3: Cu/Cu2+ Ni/Ni2+

Cell 4: Zn/Zn2+ Fe/Fe3+

Cell 5: Zn/Zn2+ Ni/Ni2+

Cell 6: Ni/Ni2+ Fe/Fe3+

Find the calculated voltage using the equation Eo(Cell)= -(0.0592/n) log (dilute/concentrated)

Cell A 0.0100M 1.00M

Cell B 0.0100M .100M

Cell C 1.00M 0.100M

I don't understand anything, please help.

Answer 1

cell 1)

anode reaction: oxidation takes place

Zn(s) -------------------------> Zn+2 (aq) + 2e-   ,   E⁰_Zn+2/Zn = - 0.76 V

cathode reaction : reduction takes palce

Cu+2(aq) + 2e- -----------------------------> Cu(s) , E⁰_Cu+2/Cu = + 0.34 V

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net reaction: Zn(s) +Cu+2(aq) -------------------------> Zn+2 (aq) + Cu(s)

E⁰_cell= E⁰_cathode- E⁰_anode

E⁰_cell= E⁰_Cu+2/Cu - E⁰_Zn+2/Zn

          = 0.34 - (-0.76)

          = 1.10 V

E⁰_cell = 1.10 V

cell 2 )

anode reaction: oxidation takes place

Fe (s) -------------------------> +3 (aq) + 3e-   ,   E⁰_Fe+3/Fe = - 0.04V

cathode reaction : reduction takes palce

Cu+2(aq) + 2e- -----------------------------> Cu(s) , E⁰_Cu+2/Cu = + 0.34 V

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net reaction: 2Fe (s) +3Cu+2(aq) -------------------------> 2Fe+3 (aq) + 3Cu(s)

E⁰_cell= E⁰_cathode- E⁰_anode

E⁰_cell= E⁰_Cu+2/Cu - E⁰_Fe+3/Fe

          = 0.34 - (-0.04)

          = 0.38 V

E⁰_cell = 0.38 V

Cell 3:

anode reaction: oxidation takes place

Ni (s) -------------------------> Ni+2 (aq) + 2e-   ,   E⁰_Ni+2/Ni = - 0.26V

cathode reaction : reduction takes palce

Cu+2(aq) + 2e- -----------------------------> Cu(s) , E⁰_Cu+2/Cu = + 0.34 V

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net reaction: Ni (s) +Cu+2(aq) -------------------------> Ni+2 (aq) + Cu(s)

E⁰_cell= E⁰_cathode- E⁰_anode

E⁰_cell= E⁰_Cu+2/Cu - E⁰_Ni+2/Ni

          = 0.34 - (-0.26)

          = 0.60 V

E⁰_cell = 0.60 V

note : to solve these problems . first find reduction potential from stnadard chart. high reduction potential element can act as anode and low reduction potential element can act as cathode . once you find anode cathode follow the method i have shown above in 3 examples . good luck