
Number of Moles
Given: $\displaystyle 2KClO_{3}(s) + heat \to 2KCl(s) + 3O_{2}$
How many moles of $\displaystyle O_2$ form as 3.0 mol of $\displaystyle KClO_{3}$ are totally consumed?
I see that the ratio between $\displaystyle O_2$ and $\displaystyle KClO_{3}$ is 3 : 2.
So since $\displaystyle KClO_{3}$ is 3.0 mol, then I figured $\displaystyle O_2$ must be $\displaystyle \boxed{4.5\,moles}$
Is this correct?

$\displaystyle \text{3.0 mol } KClO_{3} \times \frac{\text{3 mol } O_{2}}{\text{2 mol } KClO_{3} } = \text{4.5 mol } O_{2}$
(Yes) Looks good to me.