The balanced chemical equation for this lab is:
3CuCl2(aq) + 2Al(s) — 3Cu(s) + 2AlCl3(aq)
If 10.5 g copper chloride react with 12.49
aluminum, what is the limiting reactant?
CuCl2
Cu
AICI,

Explanation:

Given parameters:

Mass of CuCl₂  = 10.5g

Mass of Aluminium = 12.49g

Unknown:

Limiting reactant = ?

Solution:

The limiting reactant is the reactant given in short supply. Such reactant determines and controls the extent of the reaction.

Once they are used up, the reaction ceases to progress.

To find such reactant, we need to have a balanced reaction equation and the number of moles of the reactants:

     3CuCl₂   +    2Al     →   3Cu    +    2AlCl₃

number of moles =

Molar mass of CuCl₂  = 63.5 + 2(35.5) = 134.5g/mol

Molar mass of Al  = 27

Number of moles of CuCl₂   =  = 0.08moles

Number of moles of Al  =  = 0.46moles

 From the balanced reaction equation;

         3 mole of CuCl₂ combined with 2 moles of Al

        0.08 mole of CuCl₂  will combine with   = 0.05moles of Al

But the given amount of Al is 0.46moles which is in excess.

Therefore CuCl₂ is in the limiting reactant.

4

explanation: