the balanced equation for the above reaction is as follows
Cu + 2AgNO₃ ---> Cu(NO₃)₂ + 2Ag
stoichiometry of Cu to Ag is 1:2
the limiting reactant is the reactant that is fully used up in the reaction. the amount of product formed depends on amount of limiting reactant present
Copper reacts with excess silver nitrate therefore Copper is the limiting reactant
mass of copper reacted - 100 g
number of moles of copper reacted - 100 g / 63.5 g/mol = 1.57 mol
according to stoichiometry number of Ag moles formed - number of copper moles x 2
number of Ag moles formed - 1.57 x 2 = 3.14 mol
1 mol of Ag is made of 6.022 x 10²³ atoms of Ag
therefore 3.14 mol of Ag is made of - 6.022 x 10²³ atoms/mol x 3.14 mol = 1.89 x 10²⁴ atoms
1.89 x 10²⁴ atoms of Ag are formed in the reaction