Following is the shorthand notation for a galvanic cell: Al(s) Al^3+(IM)||Cu^+(I

Question

Following is the shorthand notation for a galvanic cell: Al(s) Al^3+(IM)||Cu^+(IM)Cu(s) Write the overall balanced equation occurring in this cell. (Indicate the physical states of reactants and products, i.e. Al(s). Cu^+ (aq). etc). Identify the anode and cathode of this cell. You make the following voltage measurements at four different temperatures. Temperature (degree Celsius): 10 35 55 74 E degree_cell (V): 2.190 2 176 2.165 2.154 Calculate the Delta G degree_rin at each of these temperatures. Now graph this data using the relationship Delta G = DeltaH - T Delta S, and determine DeltaH degree_rxn (in kJ mol) and DeltaS degree_rxn (in J

Explanation / Answer

The balanced reaction is obtained by balancing first the half reactions:
Al -------> Al3+ + 3e-
(Cu+ + 1e- -----> Cu)*3

Al(s) -------> Al3+(aq) + 3e-   Anode
3Cu+(aq) + 3e- -----> 3Cu(s) Cathode

Final reaction: Al + 3Cu+ --------> Al3+ + 3Cu

To calculate dG = -nFE
dG°1 = -3*96500*2.190 = -634005 J/mol
dG°2 = -3*96500*2.176 = -629952 J/mol
dG°3 = -3*96500*2.165 = -626768 J/mol
dG°4 = -3*96500*2.154 = -623583 J/mol

Now, let's plot dG vs T to get dH and dS:
y = -679991.9 + 162.448x

dH = -679991.9 J/mol
dS = 162.448 J/mol

Hope this helps

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