so in order to find out how many moles of O2 are produced from 12 moles of KClO3:

Question

2 mols KClO3 form 3 mols O2
4 mols KClO3 form ? mols O2
Do you double the mols of O2
4 mols KClO3 form 6 mols O2?
6 mols KClO3 form 9 mols O2