A “mole” in chemistry is a standard scientific unit for measuring a lot of very small things like atoms, molecules, and other kinds of particles.
“For a given molecule, one mole is a mass (in grams) whose number is equal to the molar mass of the molecule,” explains Mole Day on its website. “For example, the water molecule has an molar mass of 18, therefore one mole of water weighs 18 grams. Similarly, a mole of neon has a molar mass of 20 grams.”
In 1811, the Italian scientist Amedeo Avogadro discovered this concept. Known as Avogadro’s law, the law states that equal volumes of gases under the same conditions of temperature and pressure will have equal numbers of molecules.
“For example, the water molecule has a molar mass of 18, therefore one mole of water weighs 18 grams. Similarly, a mole of neon has a molar mass of 20 grams,” explains Mole Day. “In general, one mole of any substance contains Avogadro’s Number of molecules or atoms of that substance.”
Now one of the fundamental constants of chemistry, Avogadro’s Number is how scientists understand both what is in molecules and their interactions and combinations.
“Avogadro’s number is sort of like a bridge,” explains Rhett Allain in Wired Magazine. “It bridges chemistry and atomic physics. In chemistry we measure things based on their bulk properties. Things like mass (total mass), pressure, volume, temperature. However, when we consider these things from an atomic perspective we look at individual atoms and the momentum, velocity of these particles. Avogadro’s number connects these two ideas and allows us to explore atomic-level things by measuring macroscopic level quantities. It’s a big deal.”
Want to Celebrate Mole Day? Check out the Mole Day website.
