Decompostion of Hydrogen Peroxide

The yeast-catalyzed decomposition of hydrogen peroxide to produce water and oxygen is a popular undergraduate experiment often used to investigate gas laws. In order to determine the percent concentration of hydrogen peroxide, the generated oxygen is trapped in a tightly sealed bottle. The mass of oxygen is then determined directly by subtracting the mass of the bottle and its contents after releasing the gas from the mass of the bottle and the gas. All weight measurements are carried out on an analytical balance. The amount of hydrogen peroxide decomposed is calculated from the balanced equation by using gram-mole-mole-gram conversions. This is followed by calculating the concentration of hydrogen peroxide in solution. Unlike so many undergraduate laboratory experiments, the procedure does not produce any toxic substances. Students gain an understanding of stoichiometry by carrying out a reaction that quantitatively produces oxygen. The procedure also demonstrates the law of conservation of matter.