What is a Chemical Reaction – [ Definition, Equations, Examples ]

At the end of the article, you will able to describe – What is a Chemical Reaction, Definition, chemical reaction equations and examples. Let’s start discussing one by one.

What is a Chemical Reaction – Definition

Chemical reactions are the processes in which a new substance with the new properties is formed. It involves chemical changes.

Must Read: Physical and Chemical Changes.

It is not necessary that chemical reactions can be carried only in the science laboratory. A large number of Chemical reactions keep occurring in our daily life. Soaring of milk, a formation of curd, cooking of food, digestion of food, a process of respiration, fermentation of grapes, rusting of iron, burning of a candle, ripening of fruits all is chemical change. In all this case is the identity and nature of substance changes because the chemical reaction takes place in it.

Chemical Reaction Equations

  • Reactant: The substance which takes part in the chemical reaction.
  • Product: The new substances produced as a result of chemical reactions.

Reactant → Product

In reactions, the substances to react, we call substances as a reactant and convert into new substance called product. During the reaction rearrangement of atoms takes place. As a result, a new substance from after the reaction has entirely different properties. A change involves breaking of old Bond and making of the new chemical bond of a new substance.

During process atoms of one element do not change into another element. The only rearrangement of atoms takes place in a reaction. In a given diagram methane reacts with oxygen to form carbon dioxide and water. A change is taking place which involves the rearrangement of elements.

What is Chemical Reaction

Chemical Reaction Examples

In a chemical reaction, reactant reacts to change into the product.

During the process, Important characteristics may occur

  • Evolution of gas.
  • Formation of precipitation.
  • Change in color.
  • Change in temperature and
  • Change in the state.

Anyone of these general characteristics tells us whether a reaction took place or not. For example: On mixing two substance, if a gas evolves. Then we can say a chemical change has taken place. Similarly for others characteristics.

Example:

The Following reaction showing the combustion of methane (CH4) in oxygen (O2). In this process when methane is burned it releases out the Carbon dioxide (CO2) and Water(H2O).

CH(g)+2O(g)CO2(g)+2H2O(l                   ΔH=890.4kJ

Here the ΔH is the heat evolved. This causes the change in Temperature.

  • ΔH = +ve (Heat absorbed)
  • ΔH = -ve (Heat Release)

This is all about the basics of – What is a Chemical Reaction, Definition, chemical reaction equations and examples.