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.
When iodine (I2) is in solution with iodide ion (I-), the brown triiodide ion forms: I2 (aq) + I- (aq) I3- (aq) Purple colorless brown Thus, reaction of iodide ion with a solution of bleach produces iodine, which then reacts with remaining iodide ion to form the brown triiodide ion.n this experiment, you will use a solution of bleach to supply Cl2 (aq) for reaction with iodide ion. The products of this reaction are molecular iodine and chloride ion. Cl2 + 2 I-I2 + 2 Cl-Iodine (I2) exists as a purple solid and dissolves sparingly in water.