4. Repeat the titration with a second sampleof H2O2from the same bottle as your original trial. 5. Discard the titration solutions and the excess KMnO4remaining in the buret in the designated waste containers for this experiment. Clean and rinse the buretsand return them to their storage box. Technique Hints to make this Titration more successful: The buret must be scrupulously cleaned. Mount the buret in a completely vertical position. Add the reagent solution with assistance from a funnel but remove the funnel before starting to titrate. Make sure no drops of the solution cling to the buret walls. (If they do, the buret was not clean!) Make sure no bubbles of air are in the buret tip before or after the titration. Read volumes to +/- 0.1 mL; push the precision. Read consistently to the bottom of the meniscus. Avoid parallax in reading the buret. Don’t look up from below or down from above but rather at eye level. Be careful to not go below the calibrated portion of the buret. Get the volume added from the buret by simply taking the difference between the initial and the final buret readings. Do not try to fill the buret to exactly 0.0 mL. Use a piece of white paper under the titration flask to make the end point color more easily detected. Touch off the hanging drop from the buret to the flask walls. Mix by gentle swirling as you add reagent from the buret. The pink color will start to persist longer and longer as you near the end point. This is a good signal to slow down addition of KMnO4. You may squirt down the walls of the flask with distilled water. Good titrators can even split drops. Control the stopcock to allow a droplet to begin to form on the buret tip. Squirt this hanging droplet into the flask with water from your squirt bottle.
40Data and Results Table (Include proper units and significant figures for all measurements.) Trial 1 Trial 2 Mass of the flask Mass of the flask + hydrogen peroxide solution Calculated mass of hydrogen peroxide solution Molarity of KMnO4solution (given on the bottle) Initial buret reading Final buret reading Calculated volume of KMnO4added Calculated moles of KMnO4added