Mole (mol) - definition
Mole (mol) - definition
Mole (mol) is the SI base unit for the amount of substance, used to quantify the number of molecules, atoms, ions, or other elementary entities in a given system. One mole corresponds precisely to 6 140 76 × 10²³ elementary units, in accordance with Avogadro’s number—a physical constant that defines the quantitative scale in chemistry and molecular physics. The elementary entities to which the mole refers must be specified according to the nature of the system under study, such as atoms in an element, molecules in a compound, or ions in an electrolyte.
The mole bridges the atomic and macroscopic scales, allowing practical quantities of chemical substances to be handled based on their atomic or molecular masses. In quantitative analysis, it enables conversion between the mass of a substance and the number of particles, calculation of concentrations, stoichiometric ratios in chemical reactions, or gas volumes under standard conditions. The use of the mole standardizes calculations in chemistry, biophysics, pharmacy, and materials engineering, and its definition is substance-independent, giving it universal applicability.
As of 2019, the modern definition of the mole is no longer based on the mass of a carbon-12 sample but rather on the exact numerical value assigned to Avogadro’s constant. This redefinition enhances consistency with other SI units based on physical constants and facilitates high-precision measurements across scientific disciplines. In laboratory practice, the mole is used for solution preparation, determining reaction equations, and balancing chemical processes, making it one of the most frequently applied units in quantitative analysis. As a measure of substance amount, the mole also plays a vital role in the ideal gas law and in thermodynamic models describing chemical equilibrium states.
Transfer Multisort Elektronik (TME) is one of the world’s largest global distributors of electronic components, electrotechnical parts, workshop equipment, and industrial automation. The catalog includes over 1,500,000 products from 1,300 leading manufacturers. TME’s modern logistics centers in Łódź and Rzgów (Poland), with a combined area of over 40,000 m², ship nearly 6,000 packages daily to customers in more than 150 countries.
TME also invests in the development of knowledge and skills of young engineers and electronics enthusiasts through the TME Education project, and supports the tech community by organizing the TechMasterEvent series, promoting innovation and experience exchange.
