Relationship To SI
The definition of the mole, an SI base unit, was accepted by the CGPM in 1971 as:
- The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon-12; its symbol is "mol".
- When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles.
The definition of the mole also determines the value of the universal constant that relates the number of entities to amount of substance for any sample. This constant is called the Avogadro constant, symbol NA or L, and is equal to 6.02214129(27)×1023 entities per mole.
Given that the unified atomic mass unit is one twelfth the mass of one atom of carbon-12, meaning the mass of such an atom is 12 u, it follows that there are NA atoms of carbon-12 in 0.012 kg of carbon-12. This can be expressed mathematically as
- NA (12 u) = 0.012 kg/mol, or
- NA u = 0.001 kg/mol
Masses of proteins are often expressed in daltons. For example, a protein with a molecular weight of 64000 g mol−1 has a mass of 64000 daltons or 64 kDa in short.
Read more about this topic: Atomic Mass Unit
Famous quotes containing the words relationship to and/or relationship:
“Whatever may be our just grievances in the southern states, it is fitting that we acknowledge that, considering their poverty and past relationship to the Negro race, they have done remarkably well for the cause of education among us. That the whole South should commit itself to the principle that the colored people have a right to be educated is an immense acquisition to the cause of popular education.”
—Fannie Barrier Williams (1855–1944)
“But the relationship of morality and power is a very subtle one. Because ultimately power without morality is no longer power.”
—James Baldwin (1924–1987)