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For example, the equivalent weight of oxygen is 16.0/2 = 8.0 grams. For acid–base reactions, the equivalent weight of an acid or base is the mass which supplies or reacts with one mole of hydrogen cations (H +). For redox reactions, the equivalent weight of each reactant supplies or reacts with one mole of electrons (e −) in a redox ...
Mass fraction can also be expressed, with a denominator of 100, as percentage by mass (in commercial contexts often called percentage by weight, abbreviated wt.% or % w/w; see mass versus weight). It is one way of expressing the composition of a mixture in a dimensionless size ; mole fraction (percentage by moles , mol%) and volume fraction ...
The gram-atom is a former term for a mole of atoms, and gram-molecule for a mole of molecules. [ 7 ] Molecular weight (M.W.) (for molecular compounds) and formula weight (F.W.) (for non-molecular compounds), are older terms for what is now more correctly called the relative molar mass ( M r ). [ 8 ]
Historically, N 0 approximates the number of nucleons (protons or neutrons) in one gram of ordinary matter. The Avogadro constant (symbol N A = N 0 /mol) has numerical multiplier given by the Avogadro number with the unit reciprocal mole (mol −1). [2] The ratio n = N/N A is a measure of the amount of substance (with the unit mole). [2] [3] [4]
The standard atomic weight takes into account the isotopic distribution of the element in a given sample (usually assumed to be "normal"). For example, water has a molar mass of 18.0153(3) g/mol, but individual water molecules have molecular masses which range between 18.010 564 6863(15) Da (1 H 2 16 O) and 22.027 7364(9) Da (2 H 2 18 O).
The mole and the atomic mass unit (dalton) were originally defined in the International System of Units (SI) in such a way that the constant was exactly 1 g/mol, which made the numerical value of the molar mass of a substance, in grams per mole, equal to the average mass of its constituent particles (atoms, molecules, or formula units) relative ...
That is, the molar mass of a chemical compound expressed in g/mol or kg/kmol is numerically equal to its average molecular mass expressed in Da. For example, the average mass of one molecule of water is about 18.0153 Da, and the mass of one mole of water is about 18.0153 g.
It is a dimensionless quantity with dimension of / and dimensionless unit of moles per mole (mol/mol or mol ⋅ mol-1) or simply 1; metric prefixes may also be used (e.g., nmol/mol for 10-9). [5] When expressed in percent , it is known as the mole percent or molar percentage (unit symbol %, sometimes "mol%", equivalent to cmol/mol for 10 -2 ).