Question

How do I know if a chemical equation is balanced? I have been explained this but I’m still quite confused. Here’s an example from my textbook:

e.g. H^2 + O^2 —> H^2O

How would you balance this? Please answer in as much detail as possible. Thanks!

Answer 1

Answer:

H^2 +O =>H^2O

Explanation:

The valence electrons Hydrogen contains is just one, while that of oxygen is 2, so for the equation to be balanced, and since oxygen's valency can not be reduced to 1, we increase that of hydrogen by adding one more atom thereby making it H^2O

Answer 2

Answer:

2H2 + O2 —> 2H2O

Explanation:

H2 + O2 —> H2O

From the equation given above, there are 2 atoms of O on the left side and 1 atom of O on the right side. To balance O, put 2 in front of H2O as shown below

H2 + O2 —> 2H2O

Now we have a total of 4 atoms of H on the right side and 2 atoms of H on the left side. To balance this, put 2 in front of H2 as shown below:

2H2 + O2 —> 2H2O

Now we can see that the equation is balanced.