The Law of Conservation of Mass says that in a chemical reaction, matter (or mass) can’t be created or destroyed. This rule is super important when we balance chemical equations.

1. Balancing Chemical Equations:

   • A chemical equation needs to have the same number of each atom on both sides.
   • For example, when hydrogen and oxygen react to make water: $2H_2 + O_2 \rightarrow 2H_2O$
   • In this equation, there are 4 hydrogen atoms and 2 oxygen atoms on each side.

2. Balancing Techniques:

   • Counting Atoms: Check how many of each atom there are on both sides.
   • Adjusting Coefficients: Change the numbers (called coefficients) in front of the compounds to balance the atoms. Remember, you should only change those numbers and not the small numbers attached to the elements.
   • Trial and Error: Sometimes you will need to try different numbers to see what works best to balance the equation.

3. Statistics:

   • In tricky reactions, balancing might take several steps, and sometimes you might use fractions. But in the end, the total mass stays the same during the whole process.

By keeping the mass equal on both sides of the equation, we follow the Law of Conservation of Mass.