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G ° and E ° can be said to measure the same thing, and are convertible by the eq

ID: 954718 • Letter: G

Question

G° and E° can be said to measure the same thing, and are convertible by the equation

G° = nF

Ecell

where n is the total number of moles of electrons being transferred, and F is the Faraday constant 9.64853415104 C/mol. The free energy (G°) of a spontaneous reaction is always negative.

For each of the electrochemical cells below, calculate the free energy of the system and state whether the reaction is spontaneous or non-spontaneous as written based on the cathode and anode assignment given.

The cathode is Ti(III) and the anode is Al.

The cell potential is 0.292 V.

The only reason I don't understand this is because how do I determine the number of moles, n in the equation when there is no balanced equation?

Explanation / Answer

n = number of electrons transferred in balanced equation

Here Ti+3    + 3 e- > Ti at cathode reduction takes place

         Al   >   Al - 3 e-   at anode oxidation takes place

here :

G° = nF

Ecell

   = -3* 9.64853415 *.292   = 8.452 J

Faraday constant 9.64853415104 C/mol.

since delta G is -ve so reaction is spontaneous