#### Chemical Reaction

After completion of this lesson, student must be able to:

• Define physical and chemical changes.
• Define a chemical equation and its components.
• Represent chemical reaction in the form of chemical equations and methods of their balancing.

#### Chemical Equation

The chemical reaction which is expressed by using molecular formulae of reactants and products is called chemical equation. The chemical equation is also called formula equation. This note provides information about chemical equation and its types and irreversible reaction and reversible chemical reactions.

#### Chemical Reaction

Physical change is a temporary or reversible change in which no new substances are formed. A chemical change is a permanent and usually irreversible change in which new substances with different properties are formed. This note gives us the information on physical change, chemical change , and chemical reaction.