QUESTION 5 The voltage of an electrochemical cell is also related to the Gibbs f
ID: 1074755 • Letter: Q
Question
QUESTION 5
The voltage of an electrochemical cell is also related to the Gibbs free energy of its chemical reaction through the relationship of G = -nFE, where n is the number of electrons transferred in the balanced equation, E is the cell's voltage, and F is the Faraday constant (96,485 C/mol).
(a) In order for a reaction to occur (be spontaneous), what must be the sign (+/-) for G?
(b) Under spontaneous circumstances, then, what must be the sign (+/-) for E (your voltage)?
(c) Knowing the answers to (a) and (b) above, how can one deduce the direction of spontaneity for a particular voltaic cell reaction by using only a voltmeter without doing any calculations
Explanation / Answer
5.(a) in order for a reaction to be spontaneous G should be -ve because if G is -ve then we must have potential of +ve value .
(b)Under spontaneous condition E is less than zero i.e. negative
(c)If the voltmeter shows positive value then the condition is sponatneous and direction of spontaneity is also remain the as the cathode and anode you have taken .
if G is -ve then reaction is spontaneous
if G is +ve then reaction is nonspontaneous
if G is 0 then the reaction is at equlibrium.