We determined that the mass of zinc necessary to completely react with the copper (II) ions in the solution was 1.308g. We added an excess of 0.050 to make sure the copper completely reacted. 1.358g of zinc was then added to the solution. The solution with the zinc was heated and stirred until it was colorless, showing that the reaction was done. Hydrochloric acid was then added to the solution until the bubbles stopped in order to completely get rid of all of the zinc.
Extraction of Benzoic Acid Experimental 4.08 g of crude benzoic acid mixture was weighed and placed in a 125 mL Erlenmeyer flask. Then 50 mL of diethyl ether was added into the 125 mL Erlenmeyer flask. Some boiling stones were added before heating the mixture on a steam bath. After the ether began to boil, the ether insoluble material was removed from the ether solution using the technique of Buchner funnel vacuum filtration. Then the filtrate was placed in a 500 mL separatory funnel and 30 mL of 1M NaOH was added into the separatory funnel.
A flame test was then conducted and the identity of the cation was determined. To determine the anion, the anion had to be separated first from the cation in the unknown compound. To do this, 0.1 grams of the unknown compound and 0.5 grams of sodium carbonate had to be boiled in 5 mL of distilled water. Once the solution boiled for 10 minutes, the precipitate was centrifuged out and the anion solution was left. 0.1 M silver nitrate was added to the anion solution and a precipitate was formed.
Lab #3/Limiting Reagents Abstract The purpose of this laboratory experiment was to determine whether an unknown compound was sodium carbonate or sodium hydrogen carbonate by reacting a sample of it with hydrochloric acid and comparing the resulting yield of NaCl to the calculated values. The mass of an evaporating dish was taken at the start of the experiment. Then the unknown carbonate A was added in the amount of approximately one gram. The dish was weighed once more to find the definite mass of the unknown carbonate. Then, by means of a dropper bottle and stirring rod, hydrochloric acid was added until all of the unknown carbonate appeared to have reacted.
The color change in the copper sulfate when we heated it indicated that all of the water has evaporated, to be sure, we heated and weighed the crucible and CuSO4 again, and it came out to be .901g again. Finally, before disposing of the CuSO4 we added a little bit of water and observed the changes, the crucible quickly heated up and bonds were formed. Section 2: Results Measurement include: • The initial mass of crucible: 19.071g • The mass of the CuSO4: 1.509 • The mass of CuSO4 after mortar and pestle: 1.424g • The mass of the crucible and the CuSO4: 19.972g Observations: • The color change when the copper sulfate was heated,
Analysis of an Aluminum-Zinc Alloy Objective: The objective of this lab was to analyze the alloys of aluminum and zinc to see how not all compositions correspond with stoichiometric ratios. Procedure: A suction flask, large test tube, stopper assemblies and a sample of Al-Zn alloy was obtained and figure 1 was replicated. Then a gelatin capsule was obtained an weighed in an analytical balance, the alloy sample was placed in the capsule and the weight was measured again. The mass was between .1000 and .2000 grams more than the original weight. The suction beaker was weighed then filled with water and reweighed.
The mixture was decanted again in to the same beaker. Next, we added boiling chips to the liquid and evaporated the solvent over the hot plates under the hood. After the solvent was evaporated and the flask was cooled, we used a spatula to remove a small amount of the crude product and took its melting point. We determined the melting point range of the sample to be 43.0-46.0 degrees Celcius.The crude product was yellow colored when it was warm and orange in color when cooled and sticky. We then recrystallized our sample using 5 ml of warm acetone that was heated on a hot plate under a hood.
Second, methyl benzoate is added to form a new carbon-carbon sigma bond. The intermediate magnesium alkoxide will then be hydrolyzed to form tertiary alcohol product. Experimental Procedure: Part A: Preparing the Grignard reagent • I placed 1.98 grams of magnesium turnings into a cleaned 250mL round-bottom flask and then attached the calcium chloride drying tube into the round-bottom flask • Then, I placed this flask onto a heating mantel and adjust the controller to setting ‘6’. This flask is heated until it was too hot to touch. • After the flask was heated, I removed it from the heating mantel and allowed it to cool to room temperature.
Extraction and Drying: Using a separatory funnel, the cooled filtrate was extracted with 10ml of methylene chloride. After shaking our mixture, we broke and dried our emulsion by slowing passing the lower layer through a cotton ball layered with anhydrous magnesium sulfate. The extraction process was repeated 2 more times for maximum collection of the organic layer. Distillation: The extracts were poured into a 50ml round bottle flask and connected to a simple distillation apparatus. To obtain the caffeine, the methylene chloride was removed from the extract, leaving us with our solid caffeine residue.
The normality of the unknown base is calculated after the solution has reached the end point. The amount of substance being delivered is calculated in units of equivalents per litre using the formula: VaNa = VbNb Experimental In order to titrate the acid with the unknown base, a solution of the acid was prepared. 5.1722 (±10%)g of potassium hydrogen phthalate acid is obtained using a weighing boat and transferred into a volumetric flask containing 250mL of boiled distilled water. Volumetric flask was shaken several times in order to assist the powder to dissolve. Once dissolved, 24.9734 (± 0.0045)mL of acid was pipetted into an Erlenmeyer flask along with 25mL of cool (recently boiled) distilled water.