Concentration Of H2O2 In Yeast

4.3: EXPERIMENTAL PROCEDURE
A standard solution of H2O2 was prepared with a concentration of 0.1000 ± 0.0015 mol dm-3 by diluting a 0.88 mol dm-3 sample of H2O2 in an Erlenmeyer flask. Instantly, the Erlenmeyer flask was secured with a rubber stopper to limit the risk of H2O2 from decomposing quickly. Since the reaction of the decomposition of H2O2 with the catalase found in yeast is very fast, a low concentration of H2O2 was kept constant at 0.1000 ± 0.0015 mol dm-3 in order for the reaction to be observed more easily, hence also minimizing systematic errors.
The water bath was completely filled with tap water and was set to 297.0 ± 0.1 K.
Used a scoopula to take out Fleischmann’s active dry yeast from its container and measured exactly

If the contents in the test tube were not equalised, then the test tube was allowed to rest in the water bath for 5.0 ± 0.6 minutes more.
Attached the test tube to the utility clamp, while having the test tube still submerged in the water bath. Used a 10.0 ± 0.1 cm3 graduated cylinder to measure and transfer 10.0 ± 0.1 cm3 of prepared H2O2 solution into the test tube.
Instantly, covered the test tube with the rubber tubing that had a one-hole rubber stopper attached to it and ensured that the rubber stopper fitted securely to avoid any leakage of oxygen gas. The set-up of the experiment at this point can be seen in Figure 3.
Immediately, started the digital stopwatch (± 0.01) s and recorded the time taken (s) for 10.0 ± 0.5 cm3 of oxygen gas to be evolved.
Repeated steps 5-13 four more times to minimize the impact of random error and allow for the collection of sufficient data. Then, all test tubes were thoroughly cleaned using a test tube brush to remove any leftover solutions. Afterwards, placed the test tubes in the test tube rack to air