A mole is defined as the amount of substance which contains different number of particles like; atoms, molecules, ions etc., as there are atoms in exactly 12.000 gm of Carbon-12.

One mole of Carbon-12 atom has a mass of exactly 12.000 grams and contains (6.02 * 10^23) atoms.

A mole is just a number like a Dozen. A dozen equals to 12 eggs, a gross of pencil equals to 144 pencil, similarly mole is equal to (6.02 * 10^23) atoms, here is Avogadro Constant. Mole is also known as chemist dozen.

The value of (6.02 * 10^23) is known as Avogadro Constant, after the Italian scientist who first recognized the importance of the mass/number relationship.

clF5Main concepts:

  • 6.02 x 1023 of anything.
  • The formula mass in grams of a substance contains one mole of particles.
  • Na = Avogadro’s Number = 6.02 x 1023 Spreading a “mole” of marbles over the entire surface of the earth would produce a layer about three miles thick.


Mole Examples: (Avogadro’s Revenge)

  1. Astronomers estimate that there is a mole (6.02 x 1023) of stars in the universe.
  2. One mole of high school chemistry textbooks would cover the USA to a depth of about 320 km (200 miles).
  3. Water flows over Niagara Falls at about 650,000 kL (172,500,000 gallons) per minute. At this rate it would take 134,000 years for one mole of water drops (6.02 x 1023 drops) to flow over Niagara Falls.
  4. Avogadro’s number (6.02 x 1023) is the approximate number of milliliters of water in the Pacific Ocean (7 x 108 km3 or 7 x 1023 mL).