Answer: 1.75 moles Cu
Explanation: From the balanced equation we can solve the number of moles by using the stoichiometric factor or mole ratio between Ag and Cu which is 2 : 1.
Cu + 2 AgNO3 => 2 Ag + Cu( NO3)2
3.50 moles Ag x 1 mole Cu / 2 moles Ag
= 1.75 moles Cu