What is the atomic mass unit and is atomic mass unit a practical unit ?

Atomic masses are very small. To express atomic masses a unit called atomic mass unit (amu; symbol, u) is commonly used. The atomic mass unit is defined as follows:

The mass equal to 1/12th of the mass of ¹²₆ C atoms is called one atomic mass unit.

1 atomic mass unit = Mass of a¹²₆ C atom/ 12

Absolute mass of a ¹²₆ C atom is 1.9924× 10^–23 g. Therefore,

1 atomic mass unit = 1.9924×10^–23 g /12

1 atomic mass unit = 1.66 ×10^–24 g = 1.66×10^–27 kg

The atomic mass unit is not a practical unit, because it is equivalent to a very small mass. 1 atomic mass unit is equal to 1.66×10^–27 kg or 1.66 ×10^–24 g. Such small masses cannot be measured only any balance. According to IUPAC, the atomic and molecular masses are defined as follows: