December 13, 2019, 07:39:53 AM
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Topic: Finding delta G, delta S and delta H!  (Read 347 times)

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Offline K_Lin

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Finding delta G, delta S and delta H!
« on: November 21, 2019, 09:04:08 AM »
Hey all! New here. I am completing some exercises and I am having some trouble and I would love some input.
Here is one of the questions:

The standard potential of the cell with a Zn metal electrode in Zn(NO3)2 aqueous solution with a semipermeable membrane and then a solution of AgNO3 (aqueous) and a Ag electrode, is +1.561 V at 298 K and +1.550 V at 308 K. State the formal cell reaction and calculate DG, DS and DH for the reaction at 298 K.

For the first part I have:
Zn(s) + 2Ag(aq)3+ --> 3Zn2+(aq) + Ag(s)

Does this look ok? And for the second part, which Delta do I start from? Do I start with DH, but how to calculate that? Enthalpy of formation? But for all the species that I have in my equation (Zn(s), Ag(aq)3+ etc) or differently?
Also what do I use the potentials for?

Thank you if anyone can spare any *delete me* Regards!

Offline mjc123

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Re: Finding delta G, delta S and delta H!
« Reply #1 on: November 21, 2019, 01:07:26 PM »
Your equation is unbalanced, and Ag does not form Ag3+. What is the valency of Ag in AgNO3?
Do you know an equation relating E° and ΔG°? How does ΔG° vary with temperature?

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