# How many moles of oxygen are produced by the decomposition of six moles of potassium chlorate in the reaction 2KClO_3 -> 2KCl + 3O_2?

$K C l {O}_{3} \left(g\right) + \Delta \rightarrow K C l \left(s\right) + \frac{3}{2} {O}_{2} \left(g\right)$
From the equation, $\frac{3}{2}$ equiv dixoygen gas evolve from $1$ equiv chlorate.
You started with $6$ equiv chlorate, and thus $9$ equiv dioxygen gas are evolved. This is a common undergrad experiment. I think you need to add some sort of manganese oxide catalyst.