With the Iodine Clock Reaction: Effect of Concentration, Temperature and a Catalyst—ChemTopic™ Lab Activity, mix a series of two colorless solutions, and measure the time until they change from colorless to deep blue in quick succession to examine the effects of concentration, temperature and a catalyst on the rate of a reaction. Available as part of the Kinetics—ChemTopic™ Labs digital collection. Click the Price link for digital collection pricing.