Six Point Zero Two is a blog maintained by Mike Inkpen. A UK chemist currently working in a US physics department, he conducts research in single-molecule electronics, surface and organometallic chemistry. Outside the lab he watches far too many TV series for his own good, but also makes time to explore additional, related interests in topics such as the history, teaching and communication of science.
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 litres) 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).