Question

What is meant by unified atomic mass.​

Answer 1

The Unified Atomic Mass Unit or Dalton is a standard unit of mass that quantities mass on an atomic or molecular scale.

One unified atomic mass unit is approximately equivalent to 1g/mol.

It is denoted by a symbol: 1u or Da.

Answer 2

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The unified atomic mass unit (u), or dalton (Da), is a unit of atomic and molecular mass. By definition it is one twelfth of the mass of an unbound carbon-12 (12C) atom, at rest and in its ground state. In the literature one still finds the obsolete unit amu (atomic mass unit).