Avogadro and his Constant
نویسنده
چکیده
Avogadro’s constant is the number of molecules in a mole, or the ratio of the molar mass to the molecular mass. Its great importance is that it provides a link between the properties of individual atoms or molecules and the properties of bulk matter. For example, it links the energies of individual atoms and molecules, which can be determined from spectroscopy, to the thermodynamic energies of bulk matter which are obtained from calorimetric experiments. Its most recent value is
منابع مشابه
The Avogadro constant : determining the number of atoms in a single - crystal 28 Si sphere
The Avogadro constant, the number of entities in an amount of substance of one mole, links the atomic and the macroscopic properties of matter. Since the molar Planck constant—the product of the Planck constant and the Avogadro constant—is very well known via the measurement of the Rydberg constant, the Avogadro constant is also closely related to the Planck constant. In addition, its accurate ...
متن کاملThe Avogadro constant: determining the number of atoms in a single-crystal ²⁸Si sphere.
The Avogadro constant, the number of entities in an amount of substance of one mole, links the atomic and the macroscopic properties of matter. Since the molar Planck constant--the product of the Planck constant and the Avogadro constant--is very well known via the measurement of the Rydberg constant, the Avogadro constant is also closely related to the Planck constant. In addition, its accurat...
متن کاملAvogadro Constant Determination for a Redefined Kilogram
Today the mass unit kilogram is still defined by the mass of an artefact, the international prototype of the kilogram. The Avogadro constant can be used to define the kilogram in terms of a fundamental constant. The International Avogadro Coordination determined the Avogadro constant in a new approach by ‘counting’ the atoms in 1 kg single-crystal spheres, which are highly enriched with the Si ...
متن کاملHistory and progress in the accurate determination of the Avogadro constant
The Avogadro constant, NA, is a fundamental physical constant that relates any quantity at the atomic scale to its corresponding macroscopic scale. Inspired by the kinetic gas theory Avogadro proposed his hypothesis in 1811, in order to describe chemical reactions as an atomic process between atoms or molecules. Starting from his pioneering findings, the determination of this large number has f...
متن کاملSolution to the Avogadro constant challenge.
The Avogadro constant has long been defined as the number of molecules of a substance in a gram molecular weight [1]. In a modern parlance, it is a fundamental physical constant representing the number of entities comprising 1 mol. It is clear that any modification to the definition of macroscopic (kilogram) or microscopic mass scales (atomic mass) will affect the numerical value of the Avogadr...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2002