Ethanoic Acid And Calorimetry Lab Report

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In this experiment I have compared three different methods of determining the amount (percentage) of ethanol present in an aqueous sample. I tested three different samples containing different percentage amounts of ethanol in them; Listerine, Terra Fresca Wine and the last is a mixture of ethanol and water that was made by me. The three different methods compared are the redox titration method which involves the oxidation of ethanol to ethanoic acid and then titrating the residue with sodium thiosulfate, which would then be used to calculate the number of moles of ethanol present in the original sample. The method of distillation involves heating the samples to the boiling point of ethanol causing it to evaporate from the liquid and then measuring the volume of ethanol evolved and comparing it with the original volume. And the density method involves measuring the mass of a specified volume of the sample and using these
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1mL of the diluted sample was pipetted into the sample holder. The sample holder was then suspended over the dichromate solution and held in place using a rubber stopper. The flask is then left overnight at a temperature of about 30oC. The next morning the flask is left to cool to room temperature and the rubber stopper is carefully removed and the sample holder carefully discarded. The walls of the flask are rinsed with distilled water and 1mL of potassium iodide solution is added. The flask is swirled to mix the solution. Blank solutions are prepared by adding 10mL of acid dichromate solution to a conical flask, 100mL of water and 1mL of potassium iodide solution are added and the flask is swirled to mix. A burette is filled with sodium thiosulfate solution and is used to titrate each flask. After the brown iodine colour starts to fade 1mL of starch solution is added and the titration is continued until the blue disappears. This was repeated seven times for each

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