Lab 12: Heartburn and "AUNTY ACID".docx - Lab 12...

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Lab 12: Heartburn and “AUNTY ACID”Sharmin SultanaLab Partner: Ariel CebelinskiLab Section: CHEM 105 LY77TA: Prachi AnandDate: 03/02/18Introduction:
The purpose of this lab is to determine which antacid (Tums, Alka-Seltzer, or Alcalack) is the most effective in terms of mass and which antacid is most effective in terms of cost. Gastric acid, a digestive fluid composed of HCl, KCl, and NaCl, is responsible for activating digestive enzymes in our stomachs. It is produced by the cells lining the stomach. When we eat or drink too much, we may experience heartburn or indigestion, so we use antacids to neutralize the excess acid. In this lab, we looked at different antacid brands (Tums, Alka-Seltzer, and Alcalack) and compared their efficiency by performing back titrations. Titrations are usually used to determine the concentration of an unknown analyte by neutralizing it with a titrant of known concentration. However, sometimes it is not possible to use standard titration methods so we have to back titrate. In a back titration, the concentration of an analyte is determined by reacting it with a known amount of excess reagent. The remaining excess reagent is then titrated with another second reagent. After collecting data from the back titrations, we performed a series of calculations to determine the mass effectiveness and the cost effectiveness of each antacid.Materials:Antacids (tums, alka-seltzer, alcalack)0.1 M hydrochloric acid (HCl)0.1 M sodium hydroxide (NaOH)PhenolphthaleinMortar and pestle250-mL Erlenmeyer flasks50-mL graduated cylinderWeighing paper and electronic balanceHot plateBuretteBurette clamp and ring standWaste beakerGogglesLab manualLab notebookWriting utensilObservations and Experimental Data:Brand NameMass of OneTablet (g)Price ($/pack)Price per Tablet(¢)Tums1.32$8.37 (150 tablets)Alka-Seltzer3.24$8.75 (36 tablets)24¢Alcalack0.68$23.06 (500 tablets)
Antacid: TumsTrialMass Used (g)Volume NaOHUsed (mL) MassEffectiveness(mol/g)CostEffectiveness(mol/¢)10.537.30.00810.001820.529.00.00790.001730.509.90.00800.0018Average0.00800.0018Trial 1moles HCladded¿antacid=50mL×1L103mL×0.1M=0.005molmoles NaOH required¿back titrate=7.3mL×1L103mL×0.1M=0.000073molmolesof HCl neutralized=0.005mol0.000073mol=0.00427molmolesof HCl neutralized per tablet=0.00427mol×1.32g0.53g=0.011molmasseffectiveness=0.011mol/1.32g

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