If you had excess aluminum how many moles of aluminum chloride could be produced from 31.0 g of chlorine gas Cl2?

To calculate the moles of aluminum chloride produced, you would first need to determine the limiting reactant. Compare the moles of each reactant (Aluminum and Cl2) using their molar masses. Whichever reactant produces fewer moles of aluminum chloride would be the limiting reactant. Once you have that, you can use the stoichiometry of the balanced chemical equation to calculate the moles of aluminum chloride produced.