Question

What is the limiting reactant when 4.5 moles of aluminum react with 6.7 moles of oxygen gas? (4 points) Unbalanced equation: Al + O2 → Al2O3

Answer 1

Answer: -

The limiting reactant is Al.

Explanation: -

Number of moles of O₂ = 6.7 moles

The balanced chemical equation for this process is

4 Al + 3 O₂ → 2Al₂O₃

From the balanced reaction we see

3 mol of O₂ would react with 4 mol of Al

6.7 mol of O₂ would react with $\frac{4 mol Al x 6.7 mol O2}{3 mol O2}$

= 8.933 mol of Al

But the number of moles of Al present is only 4.5 mol.

Hence the limiting reagent is Al.