You're asking about the reaction between sulfur dioxide (SO₂) and oxygen (O₂) to produce sulfur trioxide (SO₃):

2 SO₂ (g) + O₂ (g) → 2 SO₃ (g)

This reaction is balanced, meaning for every 2 moles of sulfur dioxide, you need 1 mole of oxygen to produce 2 moles of sulfur trioxide.

To answer your question directly, we need to know how many moles of oxygen are reacting with the sulfur dioxide.

Here's how to solve a problem like this if you know the moles of oxygen:

* If you have 1 mole of oxygen: You'll produce 2 moles of sulfur trioxide.

* If you have 2 moles of oxygen: You'll produce 4 moles of sulfur trioxide.

* And so on...

Let me know if you have the number of moles of oxygen, and I can calculate the moles of sulfur trioxide produced!