The balanced chemical equation for the reaction of copper (Cu) and silver nitrate (AgNO3) is shown below.

Cu + 2AgNO3 → 2Ag + Cu (NO3) 2

How many moles of copper must react to form 3.50 mol of Ag?

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

1.75 mol.