Calcium chlorate decomposes according to this reaction:
Ca(ClO₃)₂ -----> CaCl₂ + 3 O₂
We can read this reaction like a recipe. When 1 mol of Ca(ClO₃)₂ decomposes, 1 mol of CaCl₂ and 3 moles of O₂ are produced. So 1 mol of mol of Ca(ClO₃)₂ produces 3 moles of O₂ according to the coefficients of the reaction.
When 3 moles of Ca(ClO₃)₂ decomposes:
number of moles of O₂ produced = 3 moles of Ca(ClO₃)₂ * 3 mol of O₂/(1 mol of Ca(ClO₃)₂ )
number of moles of O₂ produced = 9 moles
When 3 moles of Calcium Chlorate are decomposed 9 moles of O₂ are produced. FALSE