The relative atomic mass of an element is the number of times on atom of the element is heavier than 1/12 times of the mass of an atom of carbon C-12. Thus

Relative Atomic Mass:
Relative atomic mass is a concept used in chemistry to express the mass of an atom in relation to a standard reference atom. It is a dimensionless quantity that is calculated by taking the weighted average of the masses of all the naturally occurring isotopes of an element, based on their abundance in nature.

Calculation:
To calculate the relative atomic mass of an element, the mass of each isotope is multiplied by its relative abundance and then added together. The formula for calculating relative atomic mass is:

Relative Atomic Mass = (mass of isotope 1 × abundance of isotope 1) + (mass of isotope 2 × abundance of isotope 2) + ...

Use of Relative Atomic Mass:
Relative atomic mass is a crucial concept in chemistry and is used in various applications:

1. Identification of Elements: Relative atomic mass helps in identifying elements based on their atomic masses. By comparing the relative atomic mass of an unknown element with the values of known elements, scientists can determine the identity of the unknown element.

2. Calculating Molecular Mass: The relative atomic masses of the constituent elements are used to calculate the molecular mass of a compound. Molecular mass is important for determining stoichiometry, reaction yields, and other chemical calculations.

3. Isotope Abundance: The relative atomic mass provides information about the abundance of isotopes in a naturally occurring sample of an element. This data is used to understand isotopic variations, such as in radiocarbon dating and isotope geochemistry.

4. Periodic Table: The relative atomic masses of elements are used to arrange them in the periodic table. The periodic table is organized based on increasing atomic number and atomic mass. The relative atomic mass helps in determining the position of an element in the periodic table.

5. Chemical Reactions: Relative atomic mass is used to calculate the amount of elements or compounds involved in a chemical reaction. It allows for accurate stoichiometric calculations and helps determine the quantities of reactants and products.

In conclusion, relative atomic mass is a fundamental concept in chemistry that provides information about the mass of an atom in relation to a standard reference atom. It is used in various aspects of chemistry, including element identification, molecular mass calculations, isotope analysis, periodic table organization, and stoichiometric calculations in chemical reactions.