2008 Final #3C: how voltage changes

[Anusha Sadda Lec4 Dis4F]

In 3C of the 2008 final, can you explain why increasing the amount of a solid (PbS) would change the cell voltage? Thank you!

[Niharika Reddy 1D]

Adding a solid would change the cell voltage if the concentrations of ions are changed. Can you post the whole question?

[Anusha Sadda Lec4 Dis4F]

I attached the question in a separate document.

[Chem_Mod]

The sulfide ion from Na2S combines with Pb2+ to create the PbS. So when the solid forms, [Pb2+] goes down. Since lead is the anode, Pb2+ is a product. So Q goes down and E goes up.

[Anusha Sadda Lec4 Dis4F]

That makes sense. Thank you!