# Help Zone

### Student Question

Secondary IV • 2yr.

Can we add molecules and atoms to chemical equations when we balance them?

Science

## Explanations (1)

• Explanation from Alloprof

Explanation from Alloprof

This Explanation was submitted by a member of the Alloprof team.

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Team Alloprof • 2yr.

No, it is not possible to add new substances to a chemical equation when balancing it.

However, it is possible to multiply the coefficients of the substances that are present in the equation.

For example, if you have to balance the following equation:

C7H14 + O2⟶CO2 + H2OCAN

* DO NOT add C6H12 on the right side like that:

C7H14 + O2⟶CO2 + H2O + C6H12

Adding a substance would change the chemical formula and would give a different result. It would be like if you added an ingredient to a recipe. The final product would not be the same.

However, we CAN multiply the coefficients of the molecules to balance the equation and have the same number of atoms of each kind on each side of the equation:

2C7H14 + 21O2⟶14CO2 + 14H2O

In short, we only need to multiply the coefficients of the molecules of the chemical equation when we balance chemical equations and not add new substances.