Chemical Reaction[part=1]

Chemical reaction

Description

A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another.

                        OR

Chemical reactions are the processes by which chemicals interact to form new chemicals with different compositions. Simply stated, a chemical reaction is the process where reactants are transformed into products. 

NOTE=Chemical reactions are constantly occurring in the world around us; everything from the rusting of an iron fence to the metabolic pathways of a human cell are all examples of chemical reactions. Chemistry is an attempt to classify and better understand these reactions.

A chemical reaction is typically represented by a chemical equation, which represents the change from reactants to products. The left hand side of the equation represents the reactants, while the right hand side represents the products. A typical chemical reaction is written with stoichiometric coefficients, which show the relative amounts of products and reactants involved in the reaction. 

                            A + B=====> C + D

In the above example, 
$A$ and 
$B$, known as the reactants, reacted to form C$C$ and D$D$, the products

To write an accurate chemical equation, two things must occur:

1. Each product and reactant must be written using its chemical formula, e.g., H2$H_2$
2. The number of atoms of each element must be equal on both sides of the equation. Coefficients are used in front of the chemical formulas in order to help balance the number of atoms, e.g.

TYPE OF CHEMICAL REACTION

The chemical reaction are of two types on the basis of giving and recieving heat======

[1]=Exothermic Reaction

[2]=Endothermic Reaction

EXOTHERMIC REACTION

The chemical reaction in which heat is given out  or evolved during reaction is called Exothermic reaction.

EX=  Respiration.

ENDOTHERMIC REACTION

The chemical reaction in which heat is absorbed during reaction is called Endothermic reaction.

EX= Photosynthesis

*The chemical reaction are of two types on the basis of their direction.

[1]=Reversible reaction

[2]=Irreversible reaction

  REVERSIBLE TREACTION

The chemical reaction which occurs in both direction [forward and backword] is called Reversible reaction.

EX  = H₂CO₃  + H₂O  ⇌ HCO₃⁻   +  H₃O⁺.

IRREVERSIBLE REACTION

The chemical reaction which occurs in only one dirtection is called Irreversible reaction.

EX=

                                CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂↑