I think that the theoretical yield is the max amount of the products that can be formed. But I don't see how to find it.

The problem that is stumping me is this:

Given the equation $\displaystyle Cu_2 + O_2 \to 2Cu + SO_2$, what is the theoretical yield of $\displaystyle SO_2$ if $\displaystyle 8.20 g$ of $\displaystyle 0_2$ are used ?

Will someone simply and clearly explain how to go about solving this?