Acid Contents of Pepsi Products

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Exploring the acid content of Pepsi products
Lab performed: February 27, 2012,
March 12, 2012, and
March 19, 2012

Purpose:
The purpose of this experiment was to discover the unknown concentration of acid in six different Pepsi products; Pepsi, Diet Pepsi, Dr. Pepper, Diet Dr. Pepper, Pepsi Wild Cherry, and Pepsi Max. Titrations find the point at which equal moles of a known concentration react with equal moles of an unknown concentration giving the equivalence point. Also, the pKa was observed which conveys the equivalence point by graphing the results and determining where each equivalence point happened. Introduction:

Phosphoric acid is contains the high levels of sugar in all sodas. What people don’t know is that phosphoric acid is extremely harmful for one’s body. Not only is it used for sugar in soda’s but also in rust removal chemicals. Phosphoric acid lowers the bone density by not allowing enough calcium to be produced in the body. Once there isn’t enough calcium, the body will naturally start taking calcium from other parts of the body from bones to teeth. This will cause both teeth and bones to become weaker and possibly cause bone fractures, diseases in the body, and also can cause arthritis. Hypothesis of this experiment is, soda’s containing no or little sugars such as Pepsi Max has a higher acid content than those in which contain sugars such as regular Pepsi. Experimental Details:

Materials/Equipment needed:
* Dr. Pepper, Diet Dr. Pepper, Diet Pepsi, Pepsi,
Pepsi Wild Cherry, Pepsi Max
* Vernier pH tester
* Burette
* 6-250 mL beakers
* 1-600 mL Beaker (waste)
* 50 mL graduated cylinder
* 10 mL graduated cylinder
* Rind Stand
* Utility clamp
* Stirring bar
* Hot Plate
* 1 L Volumetric Flask
Chemicals needed:
* .0500 M KOH
Week 1: Prepare the solution of .0500M KOH using a volumetric flask. Determine exactly how much KOH will be needed for all titration. Once the KOH solution has been prepared, start decarbonating the soda’s with a hot plate until all carbonation is gone. Week 2: Determination of pH of sugarless sodas

1. Using graduated cylinder, measure out 50 mL of the decarbonated soda and 70 mL of distilled water into a 250 mL beaker. 2. Do this step of the three sodas containing no sugar (Diet Pepsi, Pepsi Max and Diet Dr. Pepper). 3. Place the beaker on a magnetic stirrer and add a stir bar (Stirring rod can be used during the titration) 4. Use a utility clamp to suspend the pH sensor on a ring stand so that the tip is in the solution but not in contact with the stirring rod. Begin the program using the Vernier. This will be set up in order to collect the pH data. Before titrating make sure to calibrate the Vernier pH tester. 5. Rinse the burette with a few mL of KOH solution. Dispose of the remaining rinse as instructed. Drain a slight amount of the KOH through the burette and make sure there is a small amount in the tip of the burette. This will ensure that the KOH is at the 0.00 mL level. Record the exact concentration of KOH. 6. The titration begins after this point.

7. Begin adding KOH in very small increments (about .5 mL) until the Vernier reaches 10.0. 8. By examining the data displayed on the graph, the equivalence point will be able to be determined. This will be the volume increment that resulted in the largest increase. Record the pH numbers directly before the jump and directly after the jump. 9. Make graphs on excel before leaving lab and draw conclusions. Don’t forget to calculate the Ka’s found. Week 3: Determination of pH of sodas containing sugar

1. Repeat the experiment from week two only using Pepsi, Dr. Pepper and Pepsi Wild Cherry. Preparation of KOH:
.0500 mol X 1 L X 56.1 g KOH X 1 L = 2.81 g KOH 1L 1000 mL 1 mol This is the equation that was figured out, week one, to determine exactly how...
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