Energy and entropy > rates of reaction

Cornflour is sprayed into the flame of a candle burning inside a large tin can with the lid on. The resulting small explosion caused by rapid combustion of the cornflour blows the lid off the tin. The reaction dramatically illustrates the conversion of the chemical energy stored in foodsuffs into heat and other forms of energy. It can also be used to show the effect of surface area on the rate of chemical reaction

This is the hydrogen peroxide/ potassium iodide ‘clock’ reaction. A solution of hydrogen peroxide is mixed with one containing potassium iodide, starch and sodium thiosulfate. After a few seconds the colourless mixture suddenly turns dark blue. This is one of a number of reactions loosely called the iodine clock. It can be used as an introduction to experiments on

Magnesium reacts with dilute hydrochloric acid in a conical flask which is connected to an inverted measuring cylinder in a trough of water. The volume of hydrogen gas produced is measured over a few minutes, and the results are used to plot a graph.
 

In this experiment, rhubarb sticks, which contain oxalic acid, are used to reduce and decolourise potassium manganate(VII) solution. The experiment can be used to show how the rate of reaction is affected by surface area or concentration