Cu will likely have a +2 oxidation state. It is higher in the activity series than Ag, so it is a stronger reducing agent and will reduce Ag in a displacement reaction. Then you need to balance the coefficients knowing than NO3 is -1 and Ag is +1.
Then to calculate the theoretical yield you need to compare moles of the reactants:
m(Cu)=5g
M(Cu)=63.55
n(Cu)=5/63.55=0.0787
By comparing coefficients you require twice as much silver: 0.157mol
n(Ag)=0.157
M(Ag)=107.86
m(Ag)=0.157x107.86=16.9g
Hence, the theoretical yield of this reaction would be 16.9g
