Chemical Reaction: Limiting Reactant Calculation

What is the limiting reactant when 10.5 g of copper chloride react with 12.4 g of aluminum?

If 10.5 g copper chloride react with 12.4 g aluminum, what is the limiting reactant?

Answer:

CuCI2 is the limiting reactant.

In a chemical reaction, the limiting reactant is the reactant that will be completely consumed first, thereby limiting the amount of product that can be formed. To determine the limiting reactant in a reaction, we need to compare the amount of each reactant to the stoichiometry of the reaction.

In this case, we have 10.5 g of copper chloride (CuCl2) and 12.4 g of aluminum (Al). To find the limiting reactant, we first need to calculate the number of moles of each reactant.

Given:

m(CuCl₂) = 10.5 g

M(CuCl₂) = 134.45 g/mol

n(CuCl₂) = 10.5/134.45 ≈ 0.0781 mol

m(Al) = 12.4 g

M(Al) = 26.98 g/mol

n(Al) = 12.4/26.98 ≈ 0.4596 mol

Using the balanced chemical equation: 3CuCl₂ + 2Al = 3Cu + 2AlCl₃, we can see that the stoichiometric ratio of CuCl₂ to Al is 3:2. By comparing the moles of CuCl₂ to Al, we get:

0.0781 mol CuCl₂ : 0.4596 mol Al ⇒ 3 : 17.7

Based on the calculation, we can see that CuCl₂ is the limiting reactant since it will be completely consumed first in the reaction.