Question

2KCIO3 → 2KCI + 3O2

For the reaction above, use the balanced equation to determine how many moles of Oxygen would be needed to produce 8 moles of potassium chlorate.

Answer 1

The answer is zero. No amount of oxygen will produce KClO3. What you meant to ask, I'm sure, is "how many moles of KClO3 will be needed to produce 8 moles O2. That answer is
8 moles O2 x (2 moles KClO3/3 mols O2) = 8*2/3 = 16/3 mols

Answer 2

2KCIO3 → 2KCI + 3O2