Uploaded August 2025 | Updated September 2026, 2 weeks ago
Balancing Chemical Equations
Dr. DeBacco
Balancing Chemical Equations
Balancing chemical equations is like solving a molecular puzzle
The goal is to make sure the number of atoms on both sides of the equation is equal
Due to the Law of Conservation of Mass
Key Terms
Subscript- indicate the number of atoms of that element present in a molecule or compound.
If no subscript is written, it's understood to be one
Small numbers written to the lower right of an element's symbol in a chemical formula
Coefficient- indicates the relative number of molecules or moles of a substance involved in a chemical reaction.
A number placed in front of a chemical formula in a chemical equation.
Formula- represent the composition of a chemical compound or molecule using symbols of elements and numerical subscripts to indicate the number of atoms of each element
Use Coefficients (whole numbers) to balance never change subscripts
Use coefficients (whole numbers) to balance
*Never change subscripts.
➤ Subscripts change the actual compound, so this is not allowed.
1. Write Correct Chemical Formulas
Write the correct chemical formulas for all reactants and products.
➤ Make sure the formulas are accurate before attempting to balance.
Hopefully you remember your naming rules…
2. Count Atoms of Each Element
Count atoms of each element on both sides.
➤ Use a tally to see which elements need adjusting.
3. Start with Atoms that appear in only one compound on each side.
Start with atoms that appear in only one compound on each side.
➤ Often easiest to begin with metals or complex molecules.
4. Count and Balance Polyatomic Ions Together
Balance polyatomic ions as units if they appear unchanged on both sides.
➤ Example: If “SO₄” appears on both sides, treat it as one item.
5. Leave Hydrogen and Oxygen for Last
Leave hydrogen and oxygen for last, unless present in a single compound.
➤ They often appear in multiple places and can complicate things early on.
6. Check Your Work!
Check your work!
➤ Recount every atom to confirm the equation is balanced.
Link to Lecture Slides: drive.google.com/file/d/1fLjwYtht6YnWjJ2kOMbjShKgczjKTU3A/view?usp=drive_link
*Due to the description character limit the full work cited for "Balancing Chemical Equations" can be viewed at... docs.google.com/document/d/18dhZwSvx0ksE2mRTrLReOiAKDtmwv_Sk/edit?usp=drive_link&ouid=104237452697237972847&rtpof=true&sd=true
Balancing Chemical Equations
Dr. DeBacco
Balancing Chemical Equations
Balancing chemical equations is like solving a molecular puzzle
The goal is to make sure the number of atoms on both sides of the equation is equal
Due to the Law of Conservation of Mass
Key Terms
Subscript- indicate the number of atoms of that element present in a molecule or compound.
If no subscript is written, it's understood to be one
Small numbers written to the lower right of an element's symbol in a chemical formula
Coefficient- indicates the relative number of molecules or moles of a substance involved in a chemical reaction.
A number placed in front of a chemical formula in a chemical equation.
Formula- represent the composition of a chemical compound or molecule using symbols of elements and numerical subscripts to indicate the number of atoms of each element
Use Coefficients (whole numbers) to balance never change subscripts
Use coefficients (whole numbers) to balance
*Never change subscripts.
➤ Subscripts change the actual compound, so this is not allowed.
1. Write Correct Chemical Formulas
Write the correct chemical formulas for all reactants and products.
➤ Make sure the formulas are accurate before attempting to balance.
Hopefully you remember your naming rules…
2. Count Atoms of Each Element
Count atoms of each element on both sides.
➤ Use a tally to see which elements need adjusting.
3. Start with Atoms that appear in only one compound on each side.
Start with atoms that appear in only one compound on each side.
➤ Often easiest to begin with metals or complex molecules.
4. Count and Balance Polyatomic Ions Together
Balance polyatomic ions as units if they appear unchanged on both sides.
➤ Example: If “SO₄” appears on both sides, treat it as one item.
5. Leave Hydrogen and Oxygen for Last
Leave hydrogen and oxygen for last, unless present in a single compound.
➤ They often appear in multiple places and can complicate things early on.
6. Check Your Work!
Check your work!
➤ Recount every atom to confirm the equation is balanced.
Link to Lecture Slides: drive.google.com/file/d/1fLjwYtht6YnWjJ2kOMbjShKgczjKTU3A/view?usp=drive_link
*Due to the description character limit the full work cited for "Balancing Chemical Equations" can be viewed at... docs.google.com/document/d/18dhZwSvx0ksE2mRTrLReOiAKDtmwv_Sk/edit?usp=drive_link&ouid=104237452697237972847&rtpof=true&sd=true
