1. Determine the chemical formula for carbon dioxide:

* Carbon dioxide is CO₂

2. Understand the mole ratio:

* The formula CO₂ tells us that for every 1 molecule of carbon dioxide, there are 2 atoms of oxygen.

3. Calculate the number of moles of oxygen atoms:

* Since there are 2 moles of oxygen atoms per mole of CO₂, we can use the following ratio:

(2 moles O atoms / 1 mole CO₂) * (100.0 moles CO₂) = 200.0 moles of oxygen atoms

Therefore, there are 200.0 moles of oxygen atoms in 100.0 moles of carbon dioxide.