Belair High School Caribbean Advanced Proficiency Examination
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50286539-Guidelines-for-Module-One-Essay-Cape-Communication-Studies
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Subject: CAPE Chemistry Unit 1 All You Need to Know! Name: ______Abbyhay Gayle__________________ Lab Write-up Sheet Date: ___/___/___ Lab No. 15 Module: 2 Implementation Skills tested: ORR, All You Need to Know! A&Problem Statement: Krisann and her friend, Aneika having lunch when they Krisann decided to offer Aneika some of her favourite soda. Aneika insisted that Krisann’s brand was more acidic, however she was not convinced. As a CAPE student, on passing Krisann and Aneika's lunch table, overheard their dispute and now you are required to plan and design an experiment to determine which brand of soda is more acidic Theory: All soda has carbon dioxide in it, which forms carbonice acid in aqueous liquids.Soda contains citric acid and carbonic acid this contributes to its acidic charecteristics.The technique titration can be used to determine the concentration of acid presented in soda using a solution with known concentration. Phenophthlein is a good indicator for the reaction because it responds to PH change by the formation of carbonic acid.It is pink in basic solutions and turns colorless as soon as the solution becomes acidic Hypothesis: : Sprite will be more acidic than Ting when the NaOH and phenolphthlein is added reaching its endpoint Aim: To determine if spite soda is more acidic than ting. Apparatus: : Burette, pipette pump, pipette, retort stand, volumetric flask, conical flask, Phenolphthlein purple indicator, dropper, 0.1mol dm3 HCl, NaOH solution. Procedure: The equipment was rinsed with the appropriate solutions. 0.5M of sprite was marked and was measured with a pipette and placed in a conical flask. The burettete was filled to the zero mark with the standard 0.1mol dm-3 NaOH ensuring that no air bubbles were in the tip. Two (2) drops of phenolpthlein indicator was added to the conical flask and swirled. The conical flask was titrated with constant swirling against the acid until one drop of acid turns the mixture purle with a tinge of pink. Steps 2 and 3 were repeated until three concordant values were obtained. Results were placed into a suitable table showing the readings of the burettete and the number of titrations. Steps 1-5 was repeated using ting.
Sprite Average Volume of NaOH used: (____38.4___+____38._5_+_38.6_______)/3 = ______38.5___cm3
Ting Average Volume of NaOH used: (___40.8____+__40.6____+__40.2______)/3 = 40. 5cm Disscusion: Soda is a carbonated water originally made with sodium carbonate that is consumed as a beverage. Titration was used to determine the concentration of sodium carbonate using a solution with a known concentration of NaOH. Sprite and Ting was used because of their colorless characteristics because this is essential to be able to see this color change to determine desired moles. Phenolphthalein is often used as an indicator in acid base titrations.It turns colorless in acidic solutions and pink in basic solutions. When the Sodium hydroxide(NaOH),which is a base, is mixed with phenolphthalein,it turned pink. When the base is neutralized by the acid,citric acid which is presented in the soda,the purple colour will turn colourless.This happens because the base is nuetralized in acid solution,which causes the indicator to become colorless.The average calculated acid concentration is less than it is suppose to be because adding more base than what it was at the equivalence point would push it pass it.The sample remained colorless it it was completely nuetraliszed .Near the endpoint, a pale pink colour appeared in the sample flask then disappeared immediately when it was shook. Limitations: Test tubes may have contained impurities, thus contaminating the samples a and resulting in inaccurate results. Possible source of error: If the titration is not stop when the pink coloration is seen , this could lead to inaccurate results. Precautions: It was ensured that all utensils was wash thoroughly when repeating titration. Make sure the burette is zeroed before titration. Conclusion: The purpose of this lab was to determine which soda was more acidic and this was obtained by the number of moles that was neutralized by NaOH Download 187.37 Kb. Share with your friends:
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