how do I find my ratio of moles of KClO3 decomposed to Moles of O2 produced?

Question

i have the moles of KClO3 decomposed and O2 created but how do I find the ratio? I'm told the ratio has to be one of these 2:1, 1:1, 2:3. I have 0.020 mol KClO3 and 0.019 mol O2.

Answer 1

When KClO3 decomposes the reaction is

2KClO3 ==> 2KCl + 3O2

The mole ratio of KClO3 to O2 is 2:3.

Answer 2

A ratio is basically just a fraction. So make a fraction with 0.020 mol KClO₃ in the numerator and 0.019 mol O₂ in the denominator. When you simplify it you get 1.05 over 1.00, which is basically 1:1.