Lab Report

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These notes contain procedure hints. They also describe some of the "behind the scenes" chemistry that occurs during the experiment. [1] Stacking and clamping equipment in this way is standard procedure. A lab jack is nearly always used to support stirring and heating equipment so that you can safely separate the heater from the flask without having to grab the heater or flask (hot!). The lowest piece of glassware in any apparatus (usually a round bottom flask) must always be clamped to monkey bars; it should never dangle from other glassware. Remember: support apparatus from the bottom, don’t hang it from the top. See Padias p. 23 for description of Thermowell heater, and p. 31 & 33 for drawings (left side Fig. 1-12 shows our setup minus the lab jack; top Fig. 1-13 shows flasks immersed in ceramic heaters). BACK TO PROCEDURE [2] Liquid reagents are most conveniently measured by volume. You must calculate the desired volume of reagent before making any measurements (see Calculations for help). You must also record the actual volume used in your lab notebook. It is not necessary to hit the desired amounts precisely, but you should record your measurements precisely. BACK TO PROCEDURE [3] Aqueous NaOH reacts with the compounds that make up glass, etching and dissolving the glass. Two pieces of glassware can even "freeze" into a single unit if aqueous NaOH is present on the surface where the two pieces touch. Therefore, you should always remove this reagent from ground glass surfaces before assembling apparatus. BACK TO PROCEDURE [4] Methyl salicylate reacts instantly with NaOH to make a white gummy material, but this does not hinder the eventual formation of salicylic acid. The white gummy material may be the product of an acid-base

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