Balancing Chemical Equation

Word equation:

The chemical reaction which is expressed in terms of the word (name of reactants and products) is called word equation. For example:

Sodium + Chlorine \(\longrightarrow\) Sodium Chloride

Formula equation:

The chemical equation which is written in terms of symbols by writing their molecular formula is called formula equation. It is of two types:

1. Skeletal equation: The formula equation in which the number of ions, radicals, atoms etc. in reactant and product side is not equal then it is called skeletal equation. It is also sometimes called unbalanced equation.
   
   
   The above equation is skeletal equation as the number of one oxygen atom in reactant and product sides are not equal.
2. Balanced equation: The formula equation is which the number of atoms, radicals, ions, etc is made equal in both reactant and product side is called balanced equation. For example:
   
   Above equation is now a balanced equation because the number of oxygen is made equal in both reactant and product by keeping suitable number.

   Balancing a chemical equation

   An unbalanced chemical equation can be converted into a balanced equation by using following steps:

   Step 1: Write the word equation.

   Potassium chlorate \( \overset{Heat}{\longrightarrow}\) Potassium chloride + oxygen

   Step 2: Convert the word equation into formula equation.

   KClO₃\( \overset{\Delta}{\longrightarrow}\)KCl +O₂

   Step 3: Count the number of atoms, ions, etc of the reactant and product and make them equal by using the suitable number in front of them.

   2KClO₃ \( \overset{\Delta}{\longrightarrow}\) 2KCl +3O₂

   Information conveyed by balanced chemical equations

   • It gives symbols, name and the molecular formula of the chemical substances involved as reactants and products.
   • It gives the relative number of atoms and molecules of reactants that take part in the chemical reaction.
   • It gives the relative number of atoms and molecules of products formed in the reaction.
   • It gives the ratio of masses of reactants and products.
   • It shows the type of chemical reaction.

   Limitations of balanced chemical equations

   • The physical states of reactants and products is not known.
   • The concentration of reactants and products in the end, is not known.
   • The rate of chemical reaction and the time taken for its completion is not known.
   • The conditions under which chemical reaction takes place is not known.
   • Whether the heat is released or absorbed during the reaction is not known.
   • Some reactions may be explosive. It is not revealed by the chemical equation.
   • Whether the reaction is reversible or not.