MOLE CONCEPT PART-1
Atomic Mass Unit
One atomic mass unit is defined as a mass exactly equal to one twelfth the mass of one carbon -12 atom. And 1 amu = 1.66056×10–24g.
Today, ‘amu’ has been replaced by ‘u’ which is known as unified mass.
Atomic Mass
Atomic mass of an element is defined as the average relative mass of an atom of an element as compared to the mass of an atom of carbon -12 taken as 12.
Gram Atomic Mass
The quantity of an element whose mass in grams is numerically equal to its atomic mass. In simple terms, atomic mass of an element expressed in grams is the gram atomic mass or gram atom.
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Molecular Mass
Molecular mass of a substance is defined as the average relative mass of its molecule as compared to the mass of an atom of C-12 taken as 12. It expresses as to how many times the molecule of a substance is heavier than 1/12th of the mass of an atom of carbon.
For example, a molecule of carbon dioxide is 44 times heavier than 1/12th of the mass of an atom of carbon. Therefore the molecular mass of CO2 is 44 amu.
It is obtained by adding the atomic masses of all the atoms present in one molecule.
Gram Molecular Mass
A quantity of substance whose mass in grams is numerically equal to its molecular mass is called gram molecular mass. In simple terms, molecular mass of a substance expressed in grams is called gram molecular mass.
e.g., the molecular mass of oxygen = 32 amu Therefore, gram molecular mass of oxygen = 32 g
Formula Mass-
Sum of atomic masses of the elements present in one formula unit of a compound. It is used for the ionic compounds.
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