Ag+CuSO4

You can check out the standard potentials for the half reactions

Cu^{+2} + 2e^-\rightleftharpoons Cu

and

Ag \rightleftharpoons Ag^+ + e-

to see if the reaction has any potential to make it go.

Hummm, I don't about potentials, perhaps you'll tell me Perito.

What I have to say here is that a more reactive metal will 'displace' (or take the place if you understand better that way) another less reactive metal from a solution of that less reactive metal salt. So, if Ag is more reactive than Cu, then, a reaction will occur.

from Applications of Standard Electrode Potentials (http://hyperphysics.phy-astr.gsu.edu/Hbase/Chemical/electrode2.html)

Cu2+(aq) + 2e- --> Cu(s) 0.34 V

from Foundations of Electronics - Standard Potentials (http://library.thinkquest.org/10784/chem5.html)

Ag+(aq) + e- --> Ag(s) +.80 V

Reversing the silver half-reaction (since the reaction is written Ag -> Ag+) gives -0.80v. Adding that to the +.34v gives -.46v. This indicates a lack of driving force (Gibbs free energy) for the reaction to occur as stated (Ag+CuSO4). In fact the reverse reaction, Cu + Ag+ = Cu+2 + Ag, is commonly done in quantitative analysis chemistry laboratories.

In other words, there will probably be little or no reaction.

Oh OK! I got it! Thanks Perito. I forgot that that formed part of electrolysis too! I remember now, though I doubt I was told of the terms 'electrode potential' in the chapter. :)