Yeast Beasts In Action: Lab Investigation

During the Yeast Beasts in Action Lab investigation I did not know what to expect. We were trying to figure out the highest pressure change that occurred in the test tubes once the yeast was added. We used diet soda as the acid, skim milk as the neutral and antacid as the base. The combination is 3mL of hydrogen peroxide, 3mL of the mixture and two drops of yeast. There was never a noticeable physical change in the combination after being shaken, but the pressure did rise. My hypothesis was right, but I was surprised. I thought that if the yeast was added to the mixture then the mixtures pressure would rise. I was right, but I thought that the acid’s pressure would have gone way beyond the bases pressure. But it was a real close tie between all of them. I did expect the neutral mixture to lack in pressure. The acid had the highest pressure at 101.71 pKa, while the neutral mixture had the lowest at 99.36 pKa. The bases pressure was at 101.35 pKa. The reason that acid had the highest pressure is became yeasts are microorganisms. They break down the hydrogen peroxide into oxygen gas and water. Acids produce more oxygen gas then neutral and base mixtures. The oxygen gas causes the pressure. I conclude that acid produce more pressure than bases and neutrals. Some problems that may have occurred might have been caused by distraction and miss measurements.