Principles of Chemistry Lab

1577 WordsMay 29, 20127 Pages
CHEM 1211 L Principles of Chemistry Lab 16 February 2004 Lab Report 1 Introduction The purpose of this project is to identify an unknown organic acid (X) by conducting various experiments to determine the acid’s unique properties. By determining selected constant properties of the unknown and then comparing these properties to the constant properties of known substances, it is possible to identify an unknown substance. The properties used to identify the unknown must be intensive, or independent of amount. Both chemical properties and physical properties are intensive properties used in determining the identity of an unknown (Maserton, p. 15). Because even small amounts of impurities systematically affect observed chemical…show more content…
The initial volume of HCl was recorded at 13.01 ml. The final volume was recorded at 20.62 ml and the initial volume was subtracted from the final volume to determine the exact volume of HCl at 7.61 ml. Exactly two drops of phenolphthalein indicator solution was added to the HCl. The initial volume of NaOH was recorded at 24.11 ml and titrated. As the solution neared the end point, the titration of NaOH was slowed to one drop at a time. The flask was shaken vigorously for as long as two minutes or until the solution became colorless. When the solution remained light pink for two minutes, the final volume NaOH was recorded at 32.61 ml. The initial volume NaOH was subtracted from the final volume NaOH to determine the exact volume NaOH at 8.50 ml. The exact volume HCl (7.61 ml) was divided by the exact volume NaOH (8.50 ml) and the quotient was multiplied by 100 to get the HCl/NaOH ratio of 0.8953. _7.61 ml HCl_ = 0.8953 HCl/NaOH ratio 8.50 ml NaOH The table below shows three of the best of the trial titrations and their respective ratios. Trial X Trial X Trial X Volume HCl 7.61 ml 8.99 ml 7.20ml Volume NaOH 8.50 ml 10.10 ml 8.09 ml Ratio HCl/NaOH 0.8953 0.8901 0.8900 The percent error was found by subtracting the lowest HCl/NaOH ratio from the highest ratio. The answer was then divided
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