calculate the volume in ml of 0.250 M silver nitrate solution required to react completely with a 5.00 g piece of copper

Write the equation and balance it.

Colnvet 5.00 g Cu to mols. mols = grams/molar mass
Using the coefficients in the balanced equation, convert mols Cu to mols Ag.
M Ag = mols Ag/L Ag. You know mols and M, solve for L and convert to mL