Question

Which choice identifies the limiting reactant and correct reasoning for the reaction 4Al + 3O2 → 2Al2O3?

a) Al (because it has fewer moles)
b) O2 (because it has more moles)
c) Al (because it has more moles)
d) O2 (because it has fewer moles)

Answer 1

In the reaction 4Al + 3O2 -> 2Al2O3, the limiting reactant is Al because it produces a smaller amount of Al2O3 compared to O2.

Step-by-step explanation:

The key to identifying the limiting reactant is based on a mole-mass or mass-mass calculation. Whichever reactant gives the lesser amount of product is the limiting reagent. In this reaction, we have 4 moles of Al and 3 moles of O2. To determine the limiting reactant, we can use the stoichiometry of the reaction to calculate the amount of Al2O3 that can be formed with each reactant. Comparing the amounts, it is clear that Al produces a smaller amount of Al2O3 compared to O2, so Al is the limiting reactant.