The Hill system (or Hill notation) is a system of writing empirical chemical formulas, molecular chemical formulas and components of a condensed formula such that the number of carbon atoms in a molecule is indicated first, the number of hydrogen atoms next, and then the number of all other chemical elements subsequently, in alphabetical order of the chemical symbols.
Iodine clock reaction. The iodine clock reaction (STd3) is a classical chemical clock demonstration experiment to display chemical kinetics in action; it was discovered by Hans Heinrich Landolt in 1886. Two colourless solutions are mixed and at first there is no visible reaction.
Iodine: An element in the diet that is essential for the manufacture of hormones by the thyroid gland. The thyroid gland uses iodine to make thyroxine (T4), which has four iodine molecules attached to its structure, and triiodothyronine (T3), which has three iodine molecules attached.Iodine is found in seafood, bread, iodized salt, and seaweed.he thyroid gland uses iodine to make thyroxine (T4), which has four iodine molecules attached to its structure, and triiodothyronine (T3), which has three iodine molecules attached. Iodine is found in seafood, bread, iodized salt, and seaweed.