# please explain me mole concept.

swapnil sharma
32 Points
12 years ago

a group of 6.022 * 1023

molecules/atoms/ions is reffered as one mole of substance..it is the basic unit of measurement in chemistry..

shyam sundar
36 Points
12 years ago

Atoms and molecules are extremely small insize and their numbers in even a small amountof any substance is really very large. To handlesuch large numbers, a unit of similarmagnitude is required.Just as we denote one dozen for 12 items,score for 20 items, gross for 144 items, weuse the idea of mole to count entities at themicroscopic level (i.e. atoms/molecules/particles, electrons, ions, etc).In SI system, mole (symbol, mol) wasintroduced as seventh base quantity for theamount of a substance.One mole is the amount of a substancethat contains as many particles or entitiesas there are atoms in exactly 12 g (or 0.012kg) of the 12C isotope. It may be emphasisedthat the mole of a substance always containthe same number of entities, no matter whatthe substance may be. In order to determinethis number precisely, the mass of a carbon?12 atom was determined by a massspectrometer and found to be equal to1.992648 10?23 g. Knowing that one mole ofcarbon weighs 12 g, the number of atoms in itis equal to :1223 1212 g/mol C1.992648×10− g/ Catom= 6.0221367 ×1023 atoms/mol..The mass of one moleof a substance in grams is called itsmolar mass..