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The International Bureau of Weights and Measures defined the mole as "the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilograms of carbon-12." Thus, by that definition, one mole of pure 12 C had a mass of exactly 12 g. [15] [5] The four different definitions were equivalent to within 1%.
The standard SI unit of this quantity is mol/m 3, although more practical units are commonly used, such as mole per liter (mol/L, equivalent to mol/dm 3). For example, the amount concentration of sodium chloride in ocean water is typically about 0.599 mol/L. The denominator is the volume of the solution, not of the solvent. Thus, for example ...
"The mole, symbol mol, is the SI unit of amount of substance. One mole contains exactly 6.022 140 76 × 10 23 elementary entities. This number is the fixed numerical value of the Avogadro constant, N A, when expressed in the unit mol −1 and is called the Avogadro number.
In the International System of Units (SI), the coherent unit for molar concentration is mol/m 3. However, most chemical literature traditionally uses mol / dm 3 , which is the same as mol / L . This traditional unit is often called a molar and denoted by the letter M, for example:
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). Atomic and molecular masses are usually reported in daltons, which is defined in terms of the mass of the isotope 12 C (carbon-12).
Amount of substance per unit volume mol⋅m −3: L −3 N: intensive Molar energy: J/mol: Amount of energy present in a system per unit amount of substance J/mol L 2 M T −2 N −1: intensive Molar entropy: S° Entropy per unit amount of substance J/(K⋅mol) L 2 M T −2 Θ −1 N −1: intensive Molar heat capacity: c: Heat capacity of a ...
Since all gases have the same volume per mole at a given temperature and pressure far from their points of liquefaction and solidification (see Perfect gas), and air is about 1 / 5 oxygen (molecular mass 32) and 4 / 5 nitrogen (molecular mass 28), the density of any near-perfect gas relative to air can be obtained to a good ...
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 ...