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Nernst Equation

Nernst Equation. G =. G o. + RT ln Q. G = -nF cell. G o = -nF o cell. standard. non-standard. nF.  o cell. - RT. ln Q.  cell =. Nernst Equation.  cell =  o cell - RT ln Q nF. anode. cathode. Cu (s) .

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Nernst Equation

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  1. Nernst Equation G = Go + RT ln Q G = -nFcell Go = -nFocell standard non-standard nF ocell - RT ln Q cell =

  2. Nernst Equation cell = ocell - RT ln Q nF anode cathode Cu(s) Cu2+(aq) (1M ) 4M Ag+(aq) (1M) Ag(s) Cu(s) Cu2+ + 2e- Cu2+ + 2e- Cu 2( ) Ag+ + e- Ag(s) o= 0.34 V o= 0.80 V ored - oox= ocell= - 0.34 = 0.80 0.46 V

  3. [products]minitial [reactants]ninitial Nernst Equation cell = ocell - RT ln Q nF anode cathode Cu(s)Cu2+(aq) (4M) Ag+(aq) (1M) Ag(s) Cu (s)  Cu2+ + 2e- 2Ag+ + 2e- 2Ag (s) Q = = [Cu2+] = 4 = 4 [Ag+] 12 2

  4. Nernst Equation cell = ocell - RT ln Q nF anode cathode Cu(s)Cu2+(aq) (4M) Ag+(aq) (1M) Ag(s) Cu(s)  Cu2+ + 2e- 2Ag+ + 2e- 2Ag (8.314) ln 4 = 0.44 V cell = 0.46V - 2 (298) (96,500)

  5. Non-standard conditions Cu(s)Cu2+(aq) (4M) Ag+(aq) (1M) Ag(s) Cu(s)  Cu2+ + 2e- 2Ag+ + 2e- 2Ag G = -nF (0.46V) Go = -(2 mol e-) (96,500 C/mol e-) = -89 kJ (0.44V) G= -(2 mol e-) (96,500 C/mol e-) = -85 kJ

  6. Concentration cell Cu(s) Cu2+(aq) (0.5M)  Cu2+(aq) (2M) Cu(s)  Cu2+ + 2e- + 2e-  Cu(s) Cu(s) Cu2+ oxidation reduction 0 V ln Q cell = ocell - RT nF ocell= ored-oox = 0.34 - 0.34 = 0

  7. Concentration Cells Cu(s)Cu2+(aq) (0.5M)Cu2+(aq) (2M) Cu(s) Cu(s)  Cu2+ + 2e- Cu2+ + 2e- Cu(s) oxidation reduction = [products]minitial Q = [Cu2+] = 0.5 = 0.25 [reactants]ninitial [Cu2+] 2 -RT 2F cell = ocell -RT ln Q = 0 ln .25 = .02 V nF

  8. + - + Concentration Cells h QA P680 Mn + O2 2H2O 4H+ + 4e- pH = 3.0 cell = ocell - RT ln Q nF pH = 7.0 cell = ocell - 0.059 log Q n cell= Q = 10-7 / 10-3 G < 0 0.24 V G > 0 ADP + Pi ATP

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