I am having trouble with calculating the entropy of a lead storage cell. The standard cell potential is given as $\pu{2 V}$ and the standard enthalpy change is $\pu{-306 kJ}$. I found out the Gibbs energy change to be $\pu{-386 kJ}$, then I calculated the entropy by the Gibbs energy equation and found out the entropy to be $80/T~\pu{kJ K-1}$, where $T$ is temperature.

Now, since the temperature is be positive, the entropy should be positive. Mentioned in the question is that all reactions take place in standard states.

Also mentioned is that the cell can exchange heat with its surroundings. The answer is given that entropy is negative. What am I missing here?

  • $\begingroup$ I have accordingly edited the post. I have also mentioned my attempt in the question. $\endgroup$ – Harsh Dec 31 '18 at 13:02

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