Figure 1. A child's helium balloon has roughly 1 mole of helium atoms.[1]

A mole, abbreviated as mol, is a measurement of amount used by scientists. One mole is equal to 6.022x1023 units.[2] A mole is an important unit because on the periodic table a mole of a substance is equal to its atomic mass in grams. A mole is a huge number because if there is a mole of grains of sand, it is roughly the number of grains of sand on Earth, according to XKCD whatif. Moles usually describe the number of molecules or atoms as it allows for an easy conversion between kilograms and atomic mass units easily.

Example: Carbon (atomic mass = 12.01) - 1 mole of Carbon weighs 12.01 grams.

This means that 6.022x1023 carbon atoms (or molecules) weights 12.01 grams.

1 mol 6.022 x 1023 units

Read more about the mole here or at hyperphysics.

For Further Reading


  1. By AJ (Open clip Art Library image's page) [CC0], via Wikimedia Commons. Accessed July 12th, 2018.
  2. Chemistry LibreTexts. (2018). The Mole and Avogadro's Constant. [online] Available at:'s_Constant [Accessed 11 Jul. 2018].