Help!! Please explain how you get the answer

5 moles

Explanation:

First, write out the balanced equation:

2Al + Fe₂O₃ → Al₂O₃ + 2Fe

Reaction ratio of Al to Fe₂O₃ is:

2 : 1

This means 2 moles of Al will react with 1 mole of Fe₂O₃

Al: 5 mol

Fe₂O₃: 3 mol

Multiply the reaction to get moles of both reactants you have:

2 : 1 (×⁵/₂) = 5 : ⁵/₂

2 : 1 (×3) = 6 : 3

In other words, 5 moles of Al will react with ⁵/₂ moles of Fe₂O₃;

And 3 moles of Fe₂O₃ will react with 6 moles of Al;

But, we do not have 6 moles of Al, therefore only the 5 moles of Al available will react;

5 moles of Al reacts with ⁵/₂ moles of Fe₂O₃, as we can see from the ratios we calculated above, the remaining ¹/₂ mole of Fe₂O₃ will not react;

We say that Al is the limiting reactant because all the Al will react but all the Fe₂O₃ does not (i.e. it is in excess);

Next and last, the reaction ratio of Al to Fe is:

2 : 2 or, more simply 1 : 1

This means the moles of Al that reacts is the equal to the moles of Fe produced from the reaction;

We've established that 5 moles of Al will react with ⁵/₂ moles of Fe₂O₃, so 5 moles of Fe will also be produced (since the ratio is 1 : 1);

You could also work this out using the moles of Fe₂O₃ that react;

The reaction ratio of Fe₂O₃ to Fe:

1 : 2

So the moles of Fe produced is 2× the moles of Fe₂O₃;

If ⁵/₂ moles of Fe₂O₃ reacts, then simply multiply this by 2 which is 5 moles