Moolar Mass Of Citric Acid

Submitted By cgillis95
Words: 599
Pages: 3

9/24/2014

Experiment 7 Molar Mass of Citric Acid

Purpose:
1) To observe the molar mass of citric acid
2) To familiarize yourself with titration techniques

Procedure:
1) Sanitize the burets with the soap solution provided in lab and rinse with water. After this rinse, also rinse twice with a little bit of deionized water making sure that the water flows freely through the open stopcorks. Fixture the burets upside down so the stopcorks can drain.
2) Sanitize the Erlenmeyer flasks with the soap solution provided in lab and rinse with regular tap water. Also rinse twice with deionized water. Write “NaOH” on one of the flasks. Rinse the labeled flask with a tiny amount of the prepared NaOH reagent with an estimated 5mL of NaOH in each. After this is complete pour an estimated 200mL of NaOH into the flask with the label and put a stopper in the flask.

3) Rinse the other Erlenmeyer flask twice with small portions of citric acid like you rinsed the NaOH flask. Fill this flask with an estimated 100mL of citric acid, place a stopper in this flask and label this flask H3Cit

4) Rinse a different buret with 1 to 2 mL of NaOH solution by swishing the solution in the barrel and draining it though the very tip. Close the stopcork and fill the buret to just over the zero marker using the funnel. Use a small piece of tape near the top to label the buret. Re-open the stopcork and allow the tip to fill making sure there are absolutely no air bubbles in the top but also using the littlest amount of NaOH as possible. Re-follow these steps using citric acid in the second buret.

5) Record the initial volumes to the nearest 0.01mL of both burets. Have your instructor confirm that there are no air bubbles present.

6) Place an estimate of 20mL of citric acid in the third flask. Touch the buret tip to the neck of the flask to top it off. Using a tiny amount of deionized water, rinse the flask. Add 5 drops of phenolphthalein indicator. Note the color of the phenolphthalein in an acid and in a base.

7) Put the flask beneath the NaOH buret tip and add the NaOH solution very quickly while swirling the