1. Write the balanced chemical equation:

4 Al + 3 O₂ → 2 Al₂O₃

2. Determine the mole ratio:

The balanced equation tells us that 4 moles of Al react with 3 moles of O₂.

3. Calculate the moles of O₂:

* We have 2.0 moles of Al.

* Using the mole ratio from step 2, we can set up a proportion:

(4 moles Al / 3 moles O₂) = (2.0 moles Al / x moles O₂)

* Solve for x:

x = (3 moles O₂ * 2.0 moles Al) / 4 moles Al

x = 1.5 moles O₂

Therefore, 1.5 moles of O₂ will react with 2.0 moles of Al.