Step 1: Balance the equation
To balance the equation it is necessary to have the same number of atoms of each element on both sides of the equation (reactant side and product side). Let's count the number of atoms of each element for the unbalanced equation: KClO3 -> KCl + O2
Reactant side:
K - 1
Cl - 1
O - 3
Product side:
K - 1
Cl - 1
O - 2
To balance the equation, we need to fix the number of atoms of O on the product side, let's add a 3/2 in front of it:
KClO3 -> KCl + 3/2 O2
The equation is balanced but 3/2 is not an integer. So let's multply all the equation by 2:
2 KClO3 -> 2 KCl + 3 O2
Now the equation is balanced.
A) To solve this, we need to use the ratio between O2 and KClO3. It is 3:2.
so:
3 moles of O2 ---- 2 moles of KClO3
x moles of O2 ---- 12 moles of KClO3
x = 18 moles of O2
We found the number of moles, the question asks us the number of molecules.
For this, we need to use the avogadro's constant:
6.022x10^23 molecules ---- 1 mol
x molecules ---- 18 moles
x = 1.1 x 10^25 molecules of O2
B) To solve this we use the ratio between KCl and KCl3. It is 2:2
So it is produced 4 moles of KCl when 4 moles of KClO3 react.