Electrochemistry

[member123789]

Hey guys,

I'm trying to straighten everything out and I'm getting a bit confused and was hoping you guys could help clarify some of this for me..


1) Whats the difference between electrochemical vs. electrolytic?
-Is it correct to assume that the deltaEcell will ALWAYS be positive?

2) Is it also correct that the cell potential for a galvanic cell is ALWAYS positive? So does that mean that ALL galvanic cells will always be spontaneous according to the equation: deltaG = -nFE?

3) I'm just super confused by what the book means when they say for an electrochemical cell: negative potential and for a galvanic cell it is a positive cell potential.

Thank you so much in advance for your help!

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[drspacheman]

1) Electrochemical is an umbrella term that encompasses galvanic and electrolytic. The definition of an electrochemical cell is "cells that convert energy produced in a chemical reaction and electric flow (current)".
DeltaEcell will always be positive for a favorable reaction - i.e. when electrons spontaneously flow from anode to cathode. Electrolytic cells are those that are thermodynamically unfavorable, so energy (usually supplied by a battery) is needed to push the electrolytic cell.

2) Yes, since galvanic cells are always thermodynamically favorable, the cell potential will be positive and it will be spontaneous. It will react until the anode runs out, the cathode builds up too much, or the ion concentration becomes unfavorable.

3) I'm not sure what you mean in regards to electrochemical cells always having a negative potential and galvanic cells have a positive potential. Can you explain or provide a page reference?

 

[member123789]

1) Electrochemical is an umbrella term that encompasses galvanic and electrolytic. The definition of an electrochemical cell is "cells that convert energy produced in a chemical reaction and electric flow (current)".
DeltaEcell will always be positive for a favorable reaction - i.e. when electrons spontaneously flow from anode to cathode. Electrolytic cells are those that are thermodynamically unfavorable, so energy (usually supplied by a battery) is needed to push the electrolytic cell.

2) Yes, since galvanic cells are always thermodynamically favorable, the cell potential will be positive and it will be spontaneous. It will react until the anode runs out, the cathode builds up too much, or the ion concentration becomes unfavorable.

3) I'm not sure what you mean in regards to electrochemical cells always having a negative potential and galvanic cells have a positive potential. Can you explain or provide a page reference?

Thank you so much for your help!