How to balance chemical equations

Atoms can neither be destroyed nor created during a simple chemical reaction. Therefore, in a chemical reaction

The sum of atoms before reaction = the sum of atoms after reaction

General Rules for balancing chemical equations

The following figure gives some hints on how to balance chemical equations. Scroll down the page for more examples and solutions.

Balancing chemical equations may require some trial and error. There are some general rules that could be helpful, but they may not work all the time.

• Rule 1: Balancing chemical equations using the one’s and two’s technique
• Rule 2: Balancing chemical equations using the two’s and three’s technique
• Rule 3: Balancing chemical equations using the CHO technique
• Rule 4: Balancing chemical equations using the even technique
• Rule 5: Balancing chemical equations containing polyatomic ions

In this page, we will look at some examples of applying

Rule 3: Balancing chemical equations using the CHO technique.

If you are balancing equations that have carbon, hydrogen and oxygen atoms then balance the carbon atoms first, the hydrogen atoms second and the oxygen atoms last.

Example:

Balance the chemical equation

C₅H₁₂ + O₂ → CO₂ + H₂O

Solution:

Step 1: Start with C. To balance the C put the coefficient of 5 for CO₂

C₅H₁₂ + O₂ → 5CO₂ + H₂O

Step 2: Then, balance the H by placing the coefficient of 6 for H₂O

C₅H₁₂ + O₂ → 5CO₂ + 6H₂O

Step 3: Lastly, balance the O by placing the coefficient of 8 for O₂

C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O

Step 4: Check that all the atoms balance and make sure that all coefficients are in the lowest-possible ratio.

The following videos show some examples of using the CHO method to balance chemical equations.

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• Show Step-by-step Solutions

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