How many moles of oxygen are produced when 2 mol of potassium chlorate (kclo3) decompose?
1
2
3
6

The answer is 3. The number in front of an element or compound in a chemical reaction usually indicated the number of moles of that compound or element. Therefore two moles of potassium chlorate is; 2KClO3

This means that there are 6 oxygen atoms ( Note: multiplied by the Avogadro's number 6.022 * 10^23). 6 oxygen atoms will form 3 oxygen molecules since an oxygen molecule is made of two (2) oxygen atoms (O2). The following balanced equation indicates this;

2KClO3 - 2KCl + 3O2