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Historically, the mole was defined as the amount of substance in 12 grams of the carbon-12 isotope.As a consequence, the mass of one mole of a chemical compound, in grams, is numerically equal (for all practical purposes) to the mass of one molecule or formula unit of the compound, in daltons, and the molar mass of an isotope in grams per mole is approximately equal to the mass number ...
The mole was defined in such a way that the molar mass of a compound, in g/mol, is numerically equal to the average mass of one molecule or formula unit, in daltons. It was exactly equal before the redefinition of the mole in 2019 , and is now only approximately equal, but the difference is negligible for all practical purposes.
It is also equal to the molar mass (M) divided by the mass density (ρ): = = The molar volume has the SI unit of cubic metres per mole (m 3 /mol), [ 1 ] although it is more typical to use the units cubic decimetres per mole (dm 3 /mol) for gases , and cubic centimetres per mole (cm 3 /mol) for liquids and solids .
For a substance X with a specific volume of 0.657 cm 3 /g and a substance Y with a specific volume 0.374 cm 3 /g, the density of each substance can be found by taking the inverse of the specific volume; therefore, substance X has a density of 1.522 g/cm 3 and substance Y has a density of 2.673 g/cm 3. With this information, the specific ...
Because a dalton, a unit commonly used to measure atomic mass, is exactly 1/12 of the mass of a carbon-12 atom, this definition of the mole entailed that the mass of one mole of a compound or element in grams was numerically equal to the average mass of one molecule or atom of the substance in daltons, and that the number of daltons in a gram ...
The molecular mass and relative molecular mass are distinct from but related to the molar mass. The molar mass is defined as the mass of a given substance divided by the amount of the substance, and is expressed in grams per mol (g/mol). That makes the molar mass an average of many particles or molecules (potentially containing different ...
The SI unit of kilogram per cubic metre (kg/m 3) and the cgs unit of gram per cubic centimetre (g/cm 3) are probably the most commonly used units for density. One g/cm 3 is equal to 1000 kg/m 3. One cubic centimetre (abbreviation cc) is equal to one millilitre. In industry, other larger or smaller units of mass and or volume are often more ...
In chemistry, the mass concentration ρ i (or γ i) is defined as the mass of a constituent m i divided by the volume of the mixture V. [1]= For a pure chemical the mass concentration equals its density (mass divided by volume); thus the mass concentration of a component in a mixture can be called the density of a component in a mixture.