Gram Atomic Mass, Gram Molecular Mass And Gram Formula Mass

Mass Measurement on Atomic

Scale

The mass of atoms (e.g.Gold), molecules (e.g. H2O) and formula units (e.g. one NaCl in salt) can be measured in different units. Usually, they can be measured as atomic mass (Number of protons + number of neutrons), molecular mass (sum of atomic masses of atoms in a molecule) and formula mass (sum of at atomic masses of ions in a formula unit e.g. NaCl). These masses can also be measured in other units e.g. grams.

When masses of atoms, molecules and formula units are measured in grams they are termed as:

1.) Gram Atomic Mass

2.) Gram Molecular Mass &

3.) Gram Formula Mass

respectively or simply Molar Mass.

Gram Atomic Mass

When the mass of an atom is measured in grams, then it (Mass of the atom) is called "Gram Atomic Mass" (symbol: GAM),"Gram Atom" or "Molar Mass". It is equal to and also called as a "Mole" (symbol: mol). (Discussed later).

For example:

1 gram atom of hydrogen = 1.0079 grams of H = 1 mole of Hydrogen

1 gram atom of carbon      = 12 grams of C        = 1 mole of Carbon

Gram Molecular Mass

When the mass of a molecule is measured in grams, then it (Mass of the molecule) is called "Gram Molecular Mass" (symbol: GMM),"Gram Molecule" or "Molar Mass". It is equal to and also called as a "Mole" (symbol: mol).. (Discussed later).

For example:

1 gram atom of H2     = 2.0 grams of H            = 1 mole of Hydrogen

1 gram atom of H2O  = 18 grams of water       = 1 mole of Water

Gram Formula Mass

When the mass of a formula unit is measured in grams, then it (Mass of the formula unit) is called "Gram Formula Mass" (GFM),"Gram Formula" or "Molar Mass". It is equal to and also called as a "Mole" (symbol: mol).. (Discussed later).

For example:

1 gram atom of NaCl        = 58.5 grams of salt      = 1 mole of salt

1 gram atom of CaCO3    = 100 grams of water    = 1 mole of calcium carbonate