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!

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.