Posted: December 30th, 2021
2. Experimental ProcedureIn this experiment you will determine the heat of solution of benzoic acid in water. Ill. Saturate about 600 ml of distilled water with benzoic acid (6 g is sufficient), by stirringfor about ten minutes with water heated to 60 °C. Divide the hot solution betweenfive 250-mL conical flasks and stopper each with a rubber bung. Place one each of theconical flasks in constant temperature water baths at 10, 25, 35, 45 and 55 °C. Theflasks will require about half an hour to attain thermal equilibrium; they should beshaken occasionally during this period. While the flasks are thermally equilibrating, standardise (this means use titrations todetermine the exact concentration of) the 0.1 M NaOH solution provided, using pre-standardised HCI solution (0.1xxx M) Titrate the NaOH from a burette into 25.00 mL(pipetted!) aliquots of the HCI. This must be done accurately! Use the standardised0.1xxx M NaOH solution to prepare 0.04xxx M NaOH (accurately dilute say 200 mL(burette) to 500 mL (volumetric f|ask)). After about half an hour, prepare to take two 25-mL samples from the conical flask inthe 10 °C bath. These samples of solution must be collected without drawing up anycrystalline material from the saturated solution into the pipette. This task can bemade much easier by first filtering the solution through a large filter paper (or labpaper) in a filter funnel into another (dry!) flask, so as to remove all of the solid. %a few cgstals of the solid and return them to the solution so as to keep it saturatedIand return this flask to the bath for five minutes to re-equilibrate before withdrawingthe two 25-mL samples. MEASURE AND RECORD THE EXACT TEMPERATURE OF THESOLUTION IN THE FLASK IN THE BATH AT THE TIME THE SAMPLES ARE WITHDRAWN.Titrate these samples with 0.04m M NaOH using phenolphthalein as the indicator. If
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