CHM144 Lab 5 Report.pdf Revised 2.pdf - Caitlyn Servitto Lab Partners Robert Preston and Will Ryan TA Kate Bradford Professor Yasmin Jessa CHM 144

CHM144 Lab 5 Report.pdf Revised 2.pdf - Caitlyn Servitto...

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Servitto 1 Caitlyn Servitto Lab Partners: Robert Preston and Will Ryan TA: Kate Bradford Professor Yasmin Jessa CHM 144 Section D Citric Acid Concentration in Carbonated Beverages Introduction This laboratory experiment focuses on the quantitative determination of citric acid in sodas. Citric acid is an organic acid that is commonly found in citrus fruits. It is also present in carbonated beverages such as sodas to add a sour taste. The amount of citric acid in sodas varies greatly. However, the amount of citric acid in a soda can be determined through a process called acid base titration. Acid base titration involves determining the concentration of an acid by neutralizing that acid with a known concentration of a base. Based on the results of an acid base titration, the unknown concentration of the acid can then be quantitatively determined. The acid with an unknown concentration used in this lab was citric acid. The base or titrant with a known concentration was Sodium Hydroxide (NaOH). Citric acid is considered a polyprotic acid because it consists of multiple acidic protons that can react with a base. Therefore, citric acid requires exactly three moles of base to completely neutralize one mole of citric acid. The balanced chemical reaction of citric acid with NaOH is written below: C 6 H 8 O 7 (aq) + 3NaOH (aq) Na 3 C 6 H 5 O 6 (aq) + 3H 2 O (l) To determine when the appropriate amount of base has been added, scientists use the equivalence point of a titration. The equivalence point can also be referred to as the end point considering it is estimated. The equivalence point of a titration is the point in the experiment in which the number of moles of the titrant added is stoichiometrically equal to the number of moles of the acid initially present. The equivalence point can be observed using a phenolphthalein indicator dye that changes the color of the solution. This type of acid base titration is known as ‘Traditional Titration’ . This procedure was used in week one with Sprite considering it is colorless and the change in color was easily observable. Another way to find the end point of an acid base titration is a procedure that involves relying on the measurement of the pH value of the solution as the titration occurs. This type of ‘Modern T itration was used in week two with Orange Crush soda. The pH is monitored with an
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