Question

When the equation below is properly balanced, what coefficient is in front of KCl?

KClO3 —-> KCl + O2

a) 1
b) 2
c) 3
d) 4

Answer 1

The balanced decomposition reaction of Potassium chlorate is 2KClO3 —-> 2KCl + 3O2, where the coefficient in front of KCl is 2. Answer to the question is (b) 2.

Step-by-step explanation:

When balancing the decomposition reaction of Potassium chlorate (KClO3) to form Potassium chloride (KCl) and Oxygen (O2), you will aim to have the same number of atoms of each element on both sides of the equation. The balanced chemical equation for this reaction is:

2KClO3 —-> 2KCl + 3O2

According to the balanced equation, the correct coefficient in front of KCl is 2. Therefore, the answer to the question is (b) 2.

Answer 2

In order to balance a chemical equations, the amount of atoms on the left side must be equ to the amount of atoms on the right side. There are 3 O atoms on the left side and 2 on the right. This means you should write 2 in front of KClO3 and 3 in front of O2.
2KClO3 - > KCl + 3O2
Now there are 6 O atoms on both sides. But now there are 2 K and CL atoms on the left and only one of each on the right. To balance that, you should write 2 in front of KCl, too. At the end, the equation should look like this:
2KClO3 - > 2KCl + 3O2
The answer is b) 2