Mole

The mole is the unit of measurement for amount of substance in the International System of Units (SI) Symbol: mol. 

The unit is defined as the amount or sample of a chemical substance that contains as many constitutive particles, e.g., atoms, molecules, ions, electrons, or photons, as there are atoms in 12 grams of carbon-12 (12C), the isotope of carbon with standard atomic weight 12 by definition. 

This number is expressed by the Avogadro constant, which has a value of approximately 6.02214076×1023 mol−1. The mole is an SI base unit, with the unit symbol mol.

At its next meeting in November 2018 the CGPM is expected to accept the proposed redefinition of the mole, kilogram, ampere and kelvin, which will define the mole to have exactly 6.02214076×1023 elementary entities. 

How it is used

The mole is widely used in chemistry as a convenient way to express amounts of reactants and products of chemical reactions. For example, the chemical equation 2 H2 + O2 → 2H2O implies that 2 mol dihydrogen (H2) and 1 mol dioxygen (O2) react to form 2 mol water (H2O). 

The mole may also be used to represent the number of atoms, ions, or other entities in a given sample of a substance. The concentration of a solution is commonly expressed by its molarity, defined as the amount of dissolved substance per unit volume of solution, for which the unit typically used is moles per litre (mol/l).

The term gram-molecule was formerly used for essentially the same concept. The term gram-atom has been used for a related but distinct concept, namely a quantity of a substance that contains Avogadro's number of atoms, whether isolated or combined in molecules. Thus, for example, 1 mole of MgBr2 is 1 gram-molecule of MgBr2 but 3 gram-atoms of MgBr2


Culture/celebrations

International Mole Day is 23rd of October that corresponds to 10^23 using 10th Month (October) and 23rd as the power


Source adapted from: Wikipedia contributors. (2018, October 22). Mole (unit). In Wikipedia, The Free Encyclopedia. Retrieved 01:49, October 23, 2018, from https://en.wikipedia.org/w/index.php?title=Mole_(unit)&oldid=865216128