Purpose: The purpose of this lab is to prepare and purify a fuel, ethanol C2H5OH. We will learn to do so by the process of fermentation, and distillation. Over the course of 2-3 weeks, we will be collecting and analyzing the data for this lab. Hypothesis: If the alcohol ferments correctly, then 75% alcohol will be produced with a volume on 150 mL out of the initial 200 mL solution. Procedure: Refer to Chemistry Lab Manual pp.
Then measure the final mass of the fuel using a mass scale. Record all the results. Repeat all the steps again, but change fuel (Cheetos, half a cashew nut, wax candle and ethanol) every three trials. Data Collection and Processing: Fuel | Trials | Mass H2O (ml) ±1 | Change in Water Temperature (°C) | Mass Loss of Fuel (g) ±0.02 | Energy Produced (J) | Energy Produced per grams (J/g) | Cashew | T1 | 200 | 5 | 0.31 | 4180 | 13483.87
Bring the contents of the distillation flask to a gentle reflux (i.e., vapors are condensing in the first ¼ to 1/3 of the vertical condenser and dripping constantly back into the flask below). Maintain this reflux for 10 minutes, then increase the heat in order to distill the liquid into the collection flask, then the column, and even the distillation head with aluminum foil (shiny side IN). Continue distillation of the cyclohexene product until the volume in the distillation flask is reduced to about 1 mL. Ask the instructor to assist you in removing the heat source and sand bath for the almost empty flask; use Ove Gloves and/or clamps to avoid burns. |
The familiar volcano experiment that we all know, mixing baking soda and vinegar, is used to create a bubbly reaction. In the lab, two substances are mixed and create sodium acetate, carbon dioxide, and water (CH3COOH). The purpose of the lab was to predict how much product was made from the chemical reaction, using stoichiometry. If there is a certain amount of baking soda, mixed with 50 mL of vinegar, then the percent yield will be able to be predicted. The percent yield gained was calculated from the amount that was recovered from the experiment.
Simple and Fractional Distillation of Cyclohexane and Toluene Purpose: The purpose of this experiment was to become familiar with the processes of simple and fractional distillation. In this experiment a mixture of two volatile compounds, cyclohexane and toluene, were separated with the process of distillation. Distillation relies on each compound having distinct and separate boiling points. The pure products were analyzed with gas chromatography to determine the success of the distillation. Introduction: Distillation is the process of heating a liquid until it boils, then condensing and collecting the resulting hot vapors.
The experimenter used 3 identical plastic cups and filled one with room temperature tap water, one with warm tap water and one with boiling tap water. Each cup was placed into the freezer and was checked every 15 minutes for signs of freezing. The experimenter found that the room temperature water showed the first signs of freezing and in the final outcome froze solid before the water in the other cups. His findings showed that water containing impurities, such as tap water, will freeze faster based on a lower starting temperature. The second case study was covered in an article by Science News.
Experiment: Cyclohexanone from Cyclohexanol aq Abstract: The primary objective of this experiment was to create cyclohexene from the dehydration of cyclohexanol with phosphoric acid. Through the use of simple distillation it was possible to separate the solution. The Agilent 7890A Gas Chromatography System was used to determine the purity of the distillate which verified the success of the separation. Introduction: Alkenes can be prepared by from alcohols by an acid catalyzed dehydration reaction. In the experiment a secondary alcohol (cyclohexanol) is heated with acid (phosphoric acid).
The mechanism for the reduction of a ketone by sodium borohydride: (1) Method (Based on Chemistry Laboratory Manual): 1. 0.4510g of benzophenone was dissolved in 5 cm3 of ethanol in boiling tube containing a magnetic stirrer bar. 2. O.1249g of sodium borohydride was added and left for 30 minutes. 3.
The resulting product was [Co(NH3)5Cl]Cl2 and yield was 4.453g (.017 mol, 84.8%) Distilled water (25mL) was added to concentrated ammonia (5mL) in a 125mL Erlenmeyer flask. The reaction was heated and stirred, then [Co(NH3)5Cl]Cl2 (.0060 mol) was added to the solution. The reaction mixture was vacuum filtered, and the filtrate was cooled in an ice bath. 6M HCl was then added until the solution was neutral to litmus. NaNO2 (.0217 mol) was added to the solution and was allowed to react for five minutes.