A student measures Ecell of a concentration cell created by having the saturated solution of AgBr on one side and 0.10 M Ag+(aq) on the other (along with silver electrodes). The experimental value is 0.603 V. The student is told to use the theoretical value of the Nernst plot (−0.0591 V). (The concentration of the halide is also 0.10 M.) (a) In which direction will electrons spontaneously flow? from the 'saturated side' to the '0.10 M side' from the '0.10 M side' to the 'saturated side' the electrons will not flow in this cell (b) What is the value of [Ag+]dilute? M (c) What is the experimental Ksp? (d) Calculate ΔG° in kJ/mol using ΔG° = −RTlnKsp. (R = 8.314 J/K · mol, T = 298 K.) kJ/mol

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Complete Question

The complete question is shown on the first uploaded image  

Answer:

a

  From  the saturated side to the '0.10 M ' side

b

 The diluted [tex]Ag^+[/tex] is  [tex][Ag^+] = 4.45*10^{-12} \ M[/tex]

c

 The experimental values of [tex]k_{sp}[/tex] is  [tex]K_{sp} = 4.45 *10^{-13}[/tex]  

d

    [tex]\Delta G ^o = 70.478 \ K J /mol[/tex]

           

Explanation:

   From the question we are told that

        The concentration of [tex]Ag^+ _{(aq)}[/tex] is  [tex][Ag_{(aq)}] = 0.10 M[/tex]

        The experiment value is [tex]E_e = 0.603 V[/tex]

         The value of the  Nernst plot is [tex]E_n = - 0.0591 \ V[/tex]

         The concentration of the halide is [tex][Br] = 0.10 M[/tex]

From the question we are told that one side has a saturated [tex]AgBr[/tex] and the other side has a ion 0.10M  Ag+(aq) this will cause a difference in potential causing the electron to flow from the the saturated side to the side with Ag+(aq) in other to reduce  it

 The equation for the reaction is given as.

       [tex]AgBr_{aq} + e^- \to Ag_{s} + Br^-_{aq}[/tex]     [tex]E^o = 0.07 V[/tex]

       [tex]AgBr_{aq} + e^- \to Ag_{s} + Br^-_{aq}[/tex]    [tex]E^o = 0.80 V[/tex]

This values are constant potential  data for standard reduction of AgBr

      The overall equation of reaction in the cell is  

       [tex]Ag ^+ + Br^- \to AgBr _{(aq)}[/tex]

[tex]E_{cell} = 0.80 - 0.07[/tex]

      [tex]E_{cell} = 0.73 V[/tex]

This potential for the cell can also be represented as

        [tex]E_{cell} = \frac{0.0591}{n_e} log \frac{1}{k_{sp} }[/tex]

Where  is the number of moles of electron which 1 from the chemical equation

[tex]k_{sp}[/tex] is the solubility product which is mathematically represented as

          [tex]k_{sp} = [Ag^+][Br^-][/tex]

So  

    [tex]0.73 = \frac{0.0591}{n_e} log \frac{1}{k_{sp} }[/tex]

=>  [tex]log \frac{1}{K_{sp}} = \frac{0.73}{0.0591}[/tex]

=>  [tex]K_{sp} = 4.45 *10^{-13}[/tex]  

  Now

      [tex]k_{sp} = [Ag^+][Br^-][/tex]

So

      [tex][Ag^+] = \frac{k_{sp} }{[Br^-]}[/tex]

      [tex][Ag^+] = \frac{4.45*10^{-13} }{0.10}[/tex]

       [tex][Ag^+] = 4.45*10^{-12} \ M[/tex]

The Free energy ΔG° is mathematically represented as

      [tex]\Delta G ^o = RTln k_{sp}[/tex]

Where R is the gas constant with value  [tex]R = 8.314 J/K \cdot mol[/tex]

        So

                [tex]\Delta G ^o = -8.314 * 298 * ln (4.45*10^{-13})[/tex]

                        [tex]\Delta G ^o = 70478.3 J /mol[/tex]

Converting to KJ

                       [tex]\Delta G ^o = 70.478 \ K J /mol[/tex]

         

         

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