23 October 19

Happy National Chemistry Week! And especially, Happy Mole Day! October 23, 10-23, is always of special interest to chemists because of its association with the exponential part of Avogadro's Number (6.02 x 10²³). That is the number of "things" in one mole of any substance, such as the number of water molecules in 18 grams of water (3-1/2 teaspoons) or the number of iron atoms in 56 grams of nails or paper clips. Moles measure the "combining ratios" of chemicals. This year (2019) has also been designated the International Year of the Periodic Table of the Elements, and it is also the centenary for IUPAC, the International Union of Pure and Applied Chemistry. That is the worldwide organization that sets the rules for chemical nomenclature (how chemical compounds are named) and also maintains the official Periodic Table of the Elements!