How to Balance Chemical Equation
In previous sessions, we learned about chemical reaction, chemical equations, how to write a chemical equation and different symbols used to represent chemical equation.
Learning Sessions:With this session we will learn about balancing of chemical equations. We will focus on steps that need to follow to balance a chemical a equation.
Balancing of chemical equation
Chemical Equation is a symbolic representation of chemical reaction, where the reactants and the products are expressed through formula & symbols.
Balancing of chemical equation is important to understand the number of atoms required in reactant to form a stable & desired product. Balancing of chemical equation is based on ‘Law of Conservation of Mass’.
Law of Conservation of Mass – It means “mass can neither to be created nor be destroyed”.
In balanced chemical equation, the mass of reactant side (total elements taking as per the mass) it should be equal to the mass of elements in the reactant side.
Total Mass of Elements (Reactants) = Total Mass of Elements (Products)
We can also say, the total number of atoms of each element should remain equal in both side, reactant side as well as in product side.
Like, in this example where Zinc (Zn) reacts with Sulfuric Acid (H2SO4) and forms Zinc Sulfide (ZnSO4) and Hydrogen (H2) gas will release.
Zn + H2SO4 → ZnSO4 + H2
In this table, all four elements (Zinc, Hydrogen, Sulfur and Oxygen) are mentioned and their total number of atoms in the reactant and product side.
Each element have equal number of atoms in reactant and product. State of each element is balanced. So, the overall equation is also balanced.Steps for balance chemical equation
Let’s take an chemical equation for a reaction.
Methane (CH4) gets reacted with Chlorine (Cl2) to form Carbon Tetra-Chloride (CCl4) and Hydrogen Chloride (HCl).
Methane + Chlorine → Carbon Tetrachloride + Hydrogen Chloride
CH4 + Cl2 → CCl4 + HCl
Step 1:
We will take all elements which take apart in reaction, their total number of atoms at the reactant side and total number of atoms in the product side. Each elements balance state will be mentioned.
- To Balance – Add coefficients for Hydrogen and Chlorine atoms
Step 2 – Balance Hydrogen Atoms
Add 4 as a coefficient on product.
No. of atoms of Chlorine also become 8 in products.
CH4 + Cl2 → CCl4 + 4HCl
Add 4 as a coefficient on product.
No. of atoms of Chlorine also become 8 in reactants.
CH4 + 4Cl2 → CCl4 + 4HCl
- Equation is completely balanced for both Hydrogen and Chlorine atoms
Other Example
Methane(CH4) gets reacted with Oxygen (O2) to form Carbon-Dioxide (CO2) and Water (H2O).
Methane + Oxygen → Carbon Dioxide + Water
CH4 + O2 → CO2 + H2O
- Initial representation of number of atoms for each element
- Balance Hydrogen and Oxygen Atoms:
CH4 + 2O2 → CO2 + 2H2O
