Mixture is gently swirled and drained out into an Erlenmeyer flask. Anhydrous magnesium sulfate is added to dehydrate the washed mixture. The solution is then filter into a weighed, dry, 100mL Erlenmeyer flask. Dichloromethane in the mixture is vaporized with a rotary evaporator. The Caffeine, white powder residue, (0.0486g) should be obtained.
The second tube had beads added to make the total volume of dry seeds and beads equal to the volume of sprouting seeds. The third tube contained enough beads to equal the volume of sprouting seeds. The apparatus consists of respirometers and water baths. Each respirometer is a test tube with a one-hole stopper with a capillary tube inserted. The bottom of the test tube contains sodium hydroxide pellets to absorb any carbon dioxide emitted by the seeds.
Prepare the smear and heat fix it. 2. Add crystal violet (primary stain) - 1minute. 3. Wash and add Gram’s iodine (mordant) - 1 min.
Separation of Metal Ions by paper Chromatography Purpose: Chromatography (from Greek chroma, for colour, and praghein, to write) is a technique often used by chemists to separate components of a mixture. The first trial of chromatography was performed by Russian botanist, Mikhail Tsvet in 1906. He separated colour pigments from plant leaves by allowing a solution of these pigments to react with alumina (Al2O3), starch, and silica (SiO2) insoluble in water. Different colours of the bands have appeared during the reaction. That is how chromatography has taken its name.
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.
Separate the sand by boiling water and pouring the water off, then move on to separating the Benzoic acid using filter paper. Lastly separate the salt out by allowing the water to evaporate from the solution. Data Tables: Data Table 1: Experiment Data | | Grams | Percent of mixture | Iron filings | 1.5g | 24.6% | Sand | 1.6g | 26.2% | Table salt | 1.8g | 29.5% | Benzoic acid | 1.2g | 19.7% | Total | 6.1g | 100% | Questions: A. I proposed the magnet would remove the iron from the mixture. I thought the sand might be removed by filtration. I thought distillation would remove the salt.
The pipette was then filled with 25.0mL’s of acetic acid and then drained into a conical flask, to speed up the process both of the conical flasks were filled with 25.0mL of the acetic acid. 8. Three drops of phenolphthalein was then added to the flask with the acetic acid. 9. The conical flask was then positioned to just under the burettes dropper which had its stopcock opened to allow a medium drip rate and had the sheet of filter paper slipped under it so that the colour could be seen more earily.
These impurities include vanadium, arsenic, zirconium, iron, silicon, and magnesium. Therefore, impure titanium tetrachloride is then cleaned of all these impurities for the purpose of gaining a pure titanium tetrachloride. The cleaning process is initiated by allowing the former mixture to settle, where the undissolved particles are removed as dirt or mud. Afterwards, the liquid that contains several chlorides is passed through a distillation column and is chemically treated with hydrogen sulfide or mineral oil to eliminate vanadium oxychloride, which is a chloride that boils at the same temperature as titanium tetrachloride. Finally, it is redistilled again to further purify the titanium tetrachloride produced.
At this point the volume of base used to neutralized the acid can be determined. Phenolphthalein is the indicator which is colorless in an acid but changes to a faint and permanent pink color in base. The purpose of this experiment is to prepare a sample for titration with a base, become familiar with a buret while using proper titration technique in reaching an end point. Hypothesis : If I titrate a base of known concentration with an acid of unknown concentration then I can determine the concentration can be calculated because of the titration calculation. Materials : • Vinegar • Two small beakers (150mL) • 250-mL Erlenmeyer flask • 10-mL graduated cylinder • 50-mL buret • Buret clamp • Small funnel • M NaOH Hazards : • Chemical spill • Broken glass
The watch glass was removed with the beaker tongs. Using a rubber bulb and a stirring rod to stir the solution continuously, 15.00mL of .25M BaCl2 solution was added to the solution in the beaker. The watch glass is replaced and the solution is keep hot but not boiling for 15 minutes. The precipitate was allowed to settle. When the liquid above the precipitate was clear, the solution was tested for completeness of precipitation when a few drops of BaCl2 solution were added from a pipette.