A Mole is merely a number. It's a number, by definition, that contains 6.02 x 10^23 things. So, instead of saying we have a billion of something or ten billion, or a sextillion of something, we say we have a Mole, or 6 followed by 23 zeros.
This is a fantastically large number, but atoms and molecules are fantastically small, so the Mole is a convenient unit of counting particles. By definition, a Mole of a gas will occupy exactly 22.4 liters. Moles are also used in calculating the molecular weight of a given quantity of a substance. By knowing the weight, we can calculate the number of particles.
In chemistry "mole is a unit of measurement of quantity of a substance based on number of elementary entities such as, molecules, atoms, ions, electrons, or other similar sub atomic particles making up the substance. A mole of substance contains about 602,213,670,000,000,000,000,000 (602.214 billion trillion) of such entities. This number corresponding to number of entities corresponding to mole is called Avogadro constant. The symbol for mole is mol. The mass in grams of 1 mole of a substance is the same as the number of atomic mass units (amu's) in one elementary entity of that substance.
In chemistry the mole is a unit of measurement that is used to measure a substance. It is like a pile of things or articles put together. This creates mass and volume.
The number of particles in a mole is relevant to the amount of chemical present. People consider the mole a system used for grouping substances. This allows for calculation of data reflecting the mass and volume of a substance.
Unlike other units of measurement, the mole contains an extremely high number of particles One mole is equivalent to 602,214,199,000,000,000,000,000 or more particles or 6.02214199 × 10 23.
The mole is the SI base unit that is used to measure the amount of a substance; it contains as many particles (atoms, molecules, ions, or formula units) as exactly 12g of the isotope carbon-12. Avagadro's constant is the number of particles in one mole of a substance; a value that is equal to 6.02x10^23 particles.