Balancing Chemical Equations

 Hints to Balancing Chemical Equations

• Adjust the coefficients not the subscripts.
• Even/Odd – Multiply by 2 to make all even.
• Balance polyatomic ions as a whole.
• Check the balanced equation.

Example:
ZnS + O₂ → ZnO + SO₂ (O is even on the left and odd on the right)
ZnS + O₂ → 2ZnO + SO₂ (multiply by 2 to make O even)
2ZnS + 3O₂ → 2ZnO + 2SO₂ (balance the Zn, S and O)

Example:
Pb(NO₃)₂ + NaCl → NaNO₃ + PbCl₂ (balance NO₃ as a whole)
(NO₃ is even on the left and odd on the right)
Pb(NO₃)₂ + NaCl → 2NaNO₃ + PbCl₂ (multiply by 2 to make NO₃ even)
Pb(NO₃)₂ + 2NaCl → 2NaNO₃ + PbCl₂ (balance the Na)