[K_Lin]

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!

[mjc123]

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?