The effect of chemical titration on the conversion over time of hydrogen peroxide (H2O2) into water and oxygen gas using an enzyme catalase.
MATERIALS AND METHODS: .
PART A: In the fist part of the lab, the catalase is mixed with substrate (hydrogen peroxide). The enzyme catalyzes the conversion of H2O2 to H2O and O2. Before all of the catalase is converted, sulfuric acid (H2SO4) stops the reaction. After the reaction is stopped the amount of H2O2 remaining is measured by the use of potassium permanganate (KMnO4) added in drops until the solution turns a reddish brown or pink color, the final reading on the titration tube is the amount of H2O2 that remains in the solution.
PART B: In order to determine the amount of H2O2 initially present in a 1.5% solution, 10mL of H2O2 is added to a beaker followed by 1 mL of H2O and 10 mL of H2SO4. after mixing thoroughly, 5mL of the solution is removed and assayed for the amount of H2O2 present (following the above procedure using KMnO4).
PART C: To determine the decomposition rate or H2O2 after using a purified catalase extract, place 10 mL of H2O2 and 1mL of catalase in a beaker and swirl for 10 seconds before adding 10 mL of H2SO4 to stop the reaction. For the 30 experiment, begin the experiment in the same manner bu add the H2SO4 after 30 seconds. For 60, 120, and 180 second intervals add H2SO4 at those intervals respectively. .
CONTROL VARIABLE: Temperature of room, amounts of fluids (DI H20, H2SO4, KMnSO4, 1.5% H202) cleanliness of lab equipment (beakers, syringes, etc).
EXPERIMENTAL VARIABLE: Time.
CONTROL GROUP: Assay of H2O2 without enzyme catalase.
EXPERIMENTAL GROUP: Assay of H2O2 with enzyme catalase reacting for periods of 10,30,60,120, and 180 seconds.
HYPOTHESIS: If enzyme catalase is included in the assay solution the rate at which the H2O2 decomposes to H20 and oxygen will increase.
DATA:.
Catalase Activity.
KMnO4(mL) 10 seconds 30 seconds 60 seconds 120 seconds 180 seconds.
