Final answer:
4.5 mol
Step-by-step explanation:
To determine how many moles of oxygen are produced when 3.0 mol of KClO₃ decompose completely, we need to use the stoichiometry of the balanced equation. In the given equation 2KClO₃ → 2KCl + 3O₂, we can see that for every 2 moles of KClO₃, 3 moles of O₂ are produced. This means that for 1 mole of KClO₃, we will have (3/2) mole of O₂. Therefore, when 3.0 mol of KClO₃ decomposes, we will have (3.0 mol) × (3/2) = 4.5 mol of O₂ produced.