Mole is a unit used to measure the amount of a substance. One mole of any substance contains about 602,214,085,700,000,000,000,000 (602.214 billion trillion) of the elementary entities that make up the substance. These entities can be molecules, atoms, ions, electrons or other subatomic particles, or groups of particles. The large number is called the Avogadro constant, in honor of Italian physicist Amedeo Avogadro.
The mole is a base unit in the metric system of measurement. The symbol for the 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. One amu is 1/12 the mass of one atom of carbon-12. Carbon-12 is the isotope (form) of carbon whose atomic nucleus contains 6 protons and 6 neutrons . Thus, one atom–the elementary entity–of carbon-12 has a mass of 12 amu’s, and 1 mole of carbon-12 has a mass of 12 grams.
