Showing posts with label ELECTROCHEMISTRY. Show all posts
Showing posts with label ELECTROCHEMISTRY. Show all posts

Thursday, November 4, 2010

Voltaic Cell and Daniell Cell in simple way

VOLTAIC CELL

Voltaic cell is a simple cell.  It converts chemical energy to electrical energy. 



 At Anode :
  1.    Zinc atoms donate electrons to produce zinc ions, Zn2+
  2.    Zinc ions go into solution
  3.    Half equation :  Zn(s) -------->  Zn2+ (aq)  +  2 e-
        The electrons travel through the wire in the external circuit to the copper electrode

At Cathode :   
  1.  the  electrons are taken by Cu2+ ions in copper(II)sulphate solution and change to copper metal.
  2.  Copper metal is then deposited on the electrode.
  3.   Half equation :  Cu 2+(aq) +  2 e-   ---------->    Cu(s)                          
                         

    • Anode :  electrode where the process of donation of electrons takes place
    • Cathode  :  electrode where the process of acceptance of electrons takes place

     *     The more electropositive metal acts as the negative terminal while the less electropositive  metal acts as the positive terminal



    DANIELL CELL
       
        
                         
 


 At Anode :
  1.    Zinc atoms donate electrons to produce zinc ions, Zn2+
  2.    Zinc ions go into Zinc sulphate solution
  3.    Half equation :  Zn(s) -------->  Zn2+ (aq)  +  2 e-
        The electrons travel through the wire in the external circuit to the copper electrode

At Cathode :   
  1.  the  electrons are taken by Cu2+ ions in copper(II)sulphate solution and change to copper metal.
  2.  Copper metal is then deposited on the electrode.
  3.   Half equation :  Cu 2+(aq) +  2 e-   ---------->    Cu(s)                          
 
The overall chemical reaction :


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


 
Daniell Cell can represented by the following equation
                         
                               Zn(s) / Zn2+(aq)  -------------->  Cu2+ (aq) /Cu(aq)






* http://www.docbrown.info/page07/addhoc07/cell7.gif