Articles that appear intermittently on Six Point Zero Two are posted by Dr Michael Inkpen. Mike is a scientist working at the interface between chemistry and physics, and is currently based in France. His research interests include molecular-scale electronics, surface and organometallic chemistry.
Email: sixpointzerotwo (at) gmail (dot) com
Notes on Nomenclature
6.02 x 1023 is the number of atoms found in 12 g of carbon-12, otherwise known as the Avogadro constant or 1 ‘mole’. You can have 1 mole of anything, including ants. (1 mole of ants, each weighing 0.003 g, would weigh 0.003 x 6.02 x 1023 g = 2 x 1021 g). It is often useful for chemists to know the number of atoms, or molecules, contained in a certain quantity (typically grams or liters) of a substance. For example, in a simple bimolecular reaction where A + B → C, X moles of substance A (Y grams) will react with X moles of substance B (Z grams) to produce X moles of substance C (Y + Z grams). One such bimolecular reaction occurs between hydrogen chloride and ammonia, producing ammonium chloride (HCl + NH3 → NH4Cl).