If 4.2 moles of copper metal react with 6.3 moles of silver nitrate, how many moles of silver metal can be formed, and how many moles of the excess reactant will be left over when the reaction is complete?

Unbalanced equation: Cu + AgNO3 → Cu (NO3) 2 + Ag

Be sure to show all of your work.

The balanced reaction for the above reaction is;

Cu + 2AgNO₃ - - - > Cu (NO₃) ₂ + 2Ag

we need to first find the limiting reactant

stoichiometry of Copper to AgNO₃ is 1:2

the number go Copper moles are 4.2 mol

the number of AgNO₃ moles are 6.3 mol

if AgNO₃ is the limiting reactant

if 2 mol of AgNO₃ reacts with 1 mol of Cu

then 6.3 mol of AgNO₃ reacts with - 1/2 x 6.3 mol = 3.15 mol of Cu

and 4.2 mol of Cu is present therefore AgNO₃ is the limiting reactant and Cu is in excess.

stoichiometry of AgNO₃ to Ag is 2:2

therefore number of AgNO₃ moles reacted = number of Ag moles formed

number of Ag moles formed = 6.3 mol

excess reactant is copper

only 3.15 mol were used up but 4.2 mol were present initially

the amount of excess reactant moles used = 4.2 - 3.15 = 1.05 mol of copper is in excess