When balancing chemical equations:

- our goal is to have the same number of each type of atom on both sides of the equation.

- Only change the coefficients (these are the numbers in front substances).

- Never change the subscripts (the small numbers after elements).

How to Balance Chemical Equations

We balance equations for three primary reasons.

• We want the equation to accurately represent what happens when we observe the chemical reaction in the real world.
• A balanced equation obeys the Law of Conservation of Mass. This is an important guiding principal in science.
• Finally, a balanced equation lets up predict the amount of reactants needed and the amount of products formed. Sort of important if you’re trying to decide how much fuel for a spaceship going to Mars!
Video: How to Balance Chemical Equations



Many people struggle because they aren’t which numbers they can change to balance an equation. When you balance an equation you can only change the coefficients (the numbers in front of molecules or atoms).


Coefficients are the numbers in front of the molecule.





Subscripts are the smaller numbers found after atoms. These cannot be changed when balancing chemical equations!


Subscripts are the smaller numbers found after atoms.