Using another 125-mL flask, 60-mL of 0.3622 M potassium hydroxide in ethanol was deposited. Both flasks were clamped in a temperature-controlled bath regulated at 50.0˚C. The solutions were then set in the temperature bath for ten minutes to equilibrate. An empty 250-mL Erlenmeyer flask was also clamped in the same water bath. In another flask 50-mL of ice water was deposited with three-drop phenolphthalein.
Heats of Solution and Reaction Name: Cindy Hernandez Purpose: The purpose of this experiment is to decided if the chemical reactions are exothermic and endothermic. By finding the differences between each temperature. Overview: For this lab, we had three different chemicals involved NH4Cl, H2SO4, and NaOH. What we did with these chemicals was that we added water, except NaOH we added HCl, was that we combined both mixtures to determine if there was a temperature change. The reason why we're determining if their was a chemical reaction is to identify if it is exothermic or endothermic.
After heating, the mixture was cooled to room temperature and filtered by vacuum filtration into a fritted funnel to yield a purple product. The product was washed 3 times with (5mL) portions of chilled 6M HCL, then Ethanol, and lastly with acetone. The resulting product was placed into a vial and left to dry in a vacuum desiccator for 1 week and weighed the next week. The yield was 6.029g. The second experiment, procedure 1, combined [Co(NH3)5 (H2O)]Cl2 (0.0060M, 1.52g) and (25mL) of distilled water to an 125mL Erlenmeyer flask.
Record this amount in your data table. 4. Dissolve the NaHCO3 in about 15 milliliters of distilled water in the 500 mL flask. Stir until it is mostly dissolved. (It is okay if some remains undissolved.)
The third test will utilize thin layer chromatography to evaluate the purity of the aspirin as well as testing for the presence of leftover salicylic acid or other by products of the reactions. Experimental: Week 1: For the synthesis of the aspirin, 250 mL of water was boiled. 1.5 g. of salicylic acid were poured on a test tube. Then, 3.5 mL of acetic anhydride and four drops of 85% phosphoric acid were added. A cotton ball was placed to prevent vapor escape.
Add 0.5 ml concentrated HCl and 1.0 ml 15% KI solution. Mixed exactly 1 minute and leave for 5 minutes in a dark place. Add 0.5 ml starch solution, 20 ml distilled water. Mix and titrate with sodium thiosufate solution. Calculate the exact normality of Na2S2O3 knowing that in this chemical reaction 1 gram-equivalent of K2Cr2O7 react with 1 gram-equivalent of Na2S2O3 (1 mole K2Cr2O7 react with 6 moles Na2S2O3).
Compare the MPs of the once recrystallized and the twice recrystallized trimyristin. After the hydrolysis has proceeded for 45 minutes, allow the flask to cool to RT and pour the contents into a 50 mL beaker containing 8 mL of water. Carefully, in the hood, add dropwise with stirring, 2 mL of concentrated HCl (caution: corrosive liquid/noxious vapors). Myristic acid should precipitate. Cool the beaker in ice water for 10 min, with stirring, and collect the solid by vacuum filtration on a small Hirsch funnel.
For a single extraction, use a 50mL graduated cylinder and measure out 50mL of the benzoic acid solution into a 125mL separatory funnel. Add 10mL of methylene chloride (dichloromethane or CH2Cl2 for abbreviation which is the organic layer), the extracting solvent, to the funnel. Shake the funnel for thirty seconds pointing it away from the student and self. Release gas buildup by opening the stopcock of the separatory funnel. This is called the shaking and venting procedure.
In this experiment, you will study temperature changes caused by the evaporation of several liquids and relate the temperature changes to the strength of intermolecular forces of attraction. You will use the results to predict, and then measure, the temperature change for several other liquids. You will encounter two types of organic compounds in this experiment—alkanes and alcohols. The two alkanes are pentane, C5H12, and hexane, C6H14. In addition to carbon and hydrogen atoms, alcohols also contain the -OH functional group.
The purpose of this experiment was to investigate the relationship of dispersion forces as well as the hydrogen bonding forces in intermolecular attractions. In order to determine this, there were temperature probes that were covered in filter paper and placed in several liquids. When removed showed evaporation ; evaporation is the process when a solution in liquid state becomes a gaseous. It is also an endothermic process which results in the decrease of temperature. Evaporating molecules carry away the thermal energy when they leave the liquid.