Final answer:
Four moles of aluminum reacting with an excess of chlorine gas will produce four moles of aluminum chloride, based on the stoichiometric ratios in the balanced chemical equation.
Step-by-step explanation:
When 4 moles of aluminum react with an excess of chlorine gas (Cl₂), according to the balanced chemical equation 2 Al + 3 Cl₂ → 2 AlCl₃, the reaction produces aluminum chloride (AlCl₃).
The stoichiometry of the reaction shows that 2 moles of aluminum react with 3 moles of chlorine gas to produce 2 moles of aluminum chloride. Since aluminum is given in excess (4 moles), we can directly calculate the amount of aluminum chloride produced. The stoichiometric ratio between aluminum and aluminum chloride is 1:1; therefore, 4 moles of aluminum will produce 4 moles of aluminum chloride.