Use the balanced equation from number four above to determine the limiting reactant if we had a mixture of 2.0 moles of Fe and 6.0 moles of O2.

The answer to your question is limiting reactant = Fe

Explanation:

Data

moles of Fe = 2

moles of O₂ = 6

Process

1.- Write the balanced chemical reaction

                    Fe +  O₂   ⇒    Fe₂O₃

              Reactants    Elements     Products

                     1                  Fe                 2

                    2                  O                   3

                    4Fe +  3O₂   ⇒   2Fe₂O₃

              Reactants    Elements     Products

                    4                  Fe                 4

                    6                  O                   6

2.- Use the balanced chemical reaction to determine the limiting reactant.

Theoretical proportion of reactants   4 moles Fe / 3 moles O₂ = 1.33

Experimental proportion of reactants = 2 moles Fe/6 moles O₂ = 0.333

3.- Conclusion

As the experimental proportion was lower than the theoretical we conclude that the amount of Fe was lower in the experiment which is the limiting reactant.