A Cu/Cu2 concentration cell has a voltage of 0.22 V at 25 o C. The concentration of Cu2 in one of the half-cells is 1.5 x 10-3 M. What is the concentration of Cu2 in the other half-cell

Respuesta :

Answer:

The concentration is  [tex]   [Cu^{2+}]_a  = 10^{-10.269} [/tex]  

Explanation:

From the question we are told that

    The voltage of the cell is  [tex]E =  0.22 \  V[/tex]

   

   

Generally the reaction at the cathode is  

  [tex]Cu^{2+} _{(aq)} + 2e^{-} \to  Cu_{s}[/tex] the half cell voltage is  V_c =  0.337 V

Generally the reaction at the anode is    

   [tex]Cu _{(s)} \to Cu^{2+} _{(aq)} +  2e^{-}[/tex]  the half cell voltage is  V_a = -0.337 V

Gnerally the reaction of the cell is  

    [tex]Cu_{(s)} + Cu^{2+} _{(aq)} \to Cu^{2+}_{(aq)} +  Cu_{(s)}[/tex]

At initial the voltage is  V  =  0 V

Generally the voltage of the cell at 25°C is  

       [tex]E =  V  - \frac{0.0591}{n} log \frac{[Cu^{2+}] _a}{[Cu^{2+}]_c}[/tex]

Here n is number of  of electron and it is 2

So from the question we are told that one cell has a concentration 1.5 x 10-3 M

Let assume it is  [tex][Cu^{2+}]_c[/tex]

So

      [tex]0.22=  0  - \frac{0.0591}{2} log \frac{[Cu^{2+}] _a}{  1.5 * 10^{-3} }[/tex]

=>    [tex]-7.445 =     log \frac{[Cu^{2+}] _a}{  1.5 * 10^{-3} }[/tex]

=>  [tex]-7.445 =     log [Cu^{2+}_a] - log [1.5*10^{-3}][/tex]

=>    [tex]-7.445  + log [1.5*10^{-3} =     log [Cu^{2+}_a] [/tex]

=>    [tex]-7.445  - 2.824 =     log [Cu^{2+}_a] [/tex]

Taking the antilog

=>    [tex]   [Cu^{2+}]_a  = 10^{-10.269} [/tex]    

=>     [tex]   [Cu^{2+}]_a  = 5.38 *10^{-11} \  M  [/tex]  

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