In chemistry, a mole is a unit used to measure the amount of a substance. It is defined as the amount of substance that contains the same number of particles (atoms, molecules, ions, etc.) as there are carbon atoms in exactly 12 grams of pure carbon-12. This number is approximately 6.022 x 10^23, known as Avogadro's constant. The mole allows chemists to conveniently express the amounts of different substances in a consistent and measurable way.
