CHM 130 LL
Section 22258
Lab 12: Introduction to pH, Household Products and Buffers
12/9/14
Introduction In this experiment the students will be determining the pH of household products along with other solutions using several different indicators as well as a pH meter. The experiment also has the student determining what the buffer solution is in an aqueous solution. The student will also be testing the pH of milk of magnesia and will see how it affects the stomach acid. Lastly the student will be using the carbon dioxide found in their breath to neutralize a base.
Apparatus and experimental setup
Experiment:
A. pH measurement with indicators and pH meter
In this experiment the student will need a Bunsen burner, ring stand, wire gauze, pH meter, red cabbage, about seven small beakers (clean), seven test tubes, universal pH paper, both red and blue litmus paper, methyl red and several solutions provided by the instructor. First the student will prepare the red cabbage by filling a beaker with 50 mL of distilled water and placing about 1 gram of finely chopped red cabbage and boil for 10 minuets. Let the beaker cool and decant the solution from the cabbage. While the cabbage is boiling the student should continue with the rest of the experiment, pour about 2 mL into the beaker and test the pH with the pH meter, litmus papers, and universal pH paper and record. Pour half of the solution into a test tube and set aside. With the sample in the beaker add 2 drops of methyl red and record. With the solution in the test tube add a dropper full of the cabbage indicator and record. The student must do these steps with all of the solution provided for in this experiment.
B. Buffer solutions
For this experiment the student will need four beakers, baking soda and a pH meter. In one beaker put 50 mL of distilled water into it and mix about a tablespoon full of baking soda with it. Take the pH of the solution and record. Divide the