Mole Concept

Mole Concept
The mole concept is an essential tool for the study of the fundamentals of chemical calculations.
Mole in Latin means heap or mass or pile. A mole of atoms is a collection of atoms whose total weight is the number of grams equal to the atomic weight. As equal numbers of moles of different elements contain equal numbers of atoms, ti is convenient to express amounts of the elements of the elements in terms of moles. Just as a dozen means twelve objects, a score means twenty objects, chemists have defined a mole as a definite number of particles. This definite number is called the Avogadro constant, equal to 6.022 X 10 to the power 23, in honour of the concept of a mole without knowing the value of the Avogadro constant. Thus, a mole of hydrogen atoms or a mole of hydrogen molecules or a mole of hydrogen ions, or a mole of electrons means the Avogadro constant of hydrogen atoms, hydrogen molecules, hydrogen ions or electrons respectively.
The value of the Avogadro constant depends on the atomic-weight scale. The mole is defined as the amount of a substance containing as many atoms, molecules, ions, electrons or other elementary entities as there are carbon atoms in exactly 12 g of 12C.
In modern practice, a gram-molecule and a gram-atom are termed as a mole of molecules and a mole of atoms respectively,
Significance of Chemical Equations
A chemical equation describes the chemical process both qualitatively and quantitatively. The stoichiometric coefficients in the chemical equation give the quantitative information of the chemical process. These coefficients represent the relative number of molecules or moles of the reactants and products.
Principle of Atom Conservation
The principle of conservation of mass, expressed in the concepts o atomic theory, means the conservation of atoms. And if atoms are conserved, moles of atoms shall also be conserved. This is known as the principle of atom conservation. This principle is in fact the basis of the mole concept.
Advantages of the Mole Method over other Methods
The advantages of the Mole Method are as under:
1. Balancing of chemical equations is not required in the majority of problems as the method of balancing the chemical equation is based on the principle of atom conservation.
2.Number of reactions and their sequence, leading from reactants to products, need not be given.
3.It is a general method, applicable in solving many types of problems as may be seen in different chapters.