what is meant by Avogadro atomic mass
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In chemistry and physics, the Avogadro constant (named after scientist Amedeo Avogadro) is the number of constituent particles, usually atoms or molecules, that are contained in the amount of substance given by one mole. Thus, it is the proportionality factor that relates the molar mass of a substance to the mass of a sample. The Avogadro constant, often designated with the symbol NA or L, has the value6.022140857(74)×1023 mol−1[1] in theInternational System of Units (SI).[2][3] (The parentheses there represent the degree of uncertainty.)
A much simpler definition is that Avogadro's constant is the conversion factor for converting grams to atomic mass units.
Previous definitions of chemical quantity involved Avogadro's number, a historical term closely related to the Avogadro constant, but defined differently: Avogadro's number was initially defined by Jean Baptiste Perrin as the number of atoms in one gram-molecule of atomic hydrogen, meaning one gram of hydrogen. This number is also known asLoschmidt constant in German literature. The constant was later redefined as the number of atoms in 12 grams of the isotope carbon-12(12C), and still later generalized to relate amounts of a substance to their molecular weight.[4] For instance, to a first approximation, 1 gram of hydrogen element (H), having the atomic (mass) number 1, has6.022×1023 hydrogen atoms. Similarly, 12 grams of 12C, with the mass number 12 (atomic number 6), has the same number of carbon atoms, 6.022×1023. Avogadro's number is a dimensionless quantity, and has the same numerical value of the Avogadro constant when given in base units. In contrast, the Avogadro constant has thedimension of reciprocal amount of substance. The Avogadro constant can also be expressed as 0.602214... mL⋅mol−1⋅Å−3, which can be used to convert from volume per molecule in cubic ångströms to molar volume in millilitres per mole.
Pending revisions in the base set of SI units necessitated redefinitions of the concepts of chemical quantity. Avogadro's number, and its definition, was deprecated in favor of the Avogadro constant and its definition. Based on measurements made through the middle of 2017 which calculated a value for the Avogadro constant of NA =6.022140758(62)×1023 mol−1, the redefinition of SI units is planned to take effect on 20 May 2019. The value of the constant will be fixed to exactly6.02214076×1023 mol−1.[5][6]
Value of NA in various units6.022140857(74)×1023 mol−1[1]2.73159734(12)×1026 (lb-mol)−11.707248434(77)×1025 (oz-mol)−1
A much simpler definition is that Avogadro's constant is the conversion factor for converting grams to atomic mass units.
Previous definitions of chemical quantity involved Avogadro's number, a historical term closely related to the Avogadro constant, but defined differently: Avogadro's number was initially defined by Jean Baptiste Perrin as the number of atoms in one gram-molecule of atomic hydrogen, meaning one gram of hydrogen. This number is also known asLoschmidt constant in German literature. The constant was later redefined as the number of atoms in 12 grams of the isotope carbon-12(12C), and still later generalized to relate amounts of a substance to their molecular weight.[4] For instance, to a first approximation, 1 gram of hydrogen element (H), having the atomic (mass) number 1, has6.022×1023 hydrogen atoms. Similarly, 12 grams of 12C, with the mass number 12 (atomic number 6), has the same number of carbon atoms, 6.022×1023. Avogadro's number is a dimensionless quantity, and has the same numerical value of the Avogadro constant when given in base units. In contrast, the Avogadro constant has thedimension of reciprocal amount of substance. The Avogadro constant can also be expressed as 0.602214... mL⋅mol−1⋅Å−3, which can be used to convert from volume per molecule in cubic ångströms to molar volume in millilitres per mole.
Pending revisions in the base set of SI units necessitated redefinitions of the concepts of chemical quantity. Avogadro's number, and its definition, was deprecated in favor of the Avogadro constant and its definition. Based on measurements made through the middle of 2017 which calculated a value for the Avogadro constant of NA =6.022140758(62)×1023 mol−1, the redefinition of SI units is planned to take effect on 20 May 2019. The value of the constant will be fixed to exactly6.02214076×1023 mol−1.[5][6]
Value of NA in various units6.022140857(74)×1023 mol−1[1]2.73159734(12)×1026 (lb-mol)−11.707248434(77)×1025 (oz-mol)−1
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6.023 * 10` 23 the value of avogadro
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