As seen in table 1, the theoretical yield was .712 g of C_17 H_19 NO_3. The % yield of this experiment was 7.51 % of C_17 H_19 NO_3. . This low yield can be explained from a poor recrystallization technique combined with potential contamination. Throughout the experiment, the mixture changed color from green, orange, to yellowish lime, and eventually clear.
The lab started off by measuring critical materials for the lab: the mass of an an empty 100 mL beaker, mass of beaker and copper chloride together(52.30 g), and the mass of three iron nails(2.73 g). The goal of this experiment is to determine the number of moles of copper and iron that would be produced in the reaction of iron and copper(II) chloride, the ratio of moles of iron to moles of copper, and the percent yield of copper produced. 2.00 grams of copper(II) chloride was added in the beaker to mix with 15 mL of distilled water. Then, three dry nails are placed in the copper(II) chloride solution for approximately 25 minutes. The three nails have to be scraped clean by sandpaper to make the surface of the nail shiny; if the nails are not clean, then some unknown substances might accidentally mix into the reaction and cause variations of the result.
In order to begin this experiment, first one must find the balanced chemical equation for the reaction which occurs between the aluminum and copper (II) chloride. This balanced equation being 2Al(s)+3CuCl2 (aq)3Cu(s)+2AlCl3 (aq). After finding this equation, one must use the process of stoichiometry in order to find how many grams of aluminum are needed in order to produce 0.15 grams of copper. In this experiment, the purpose was to produce between 0.1 and 0.2 grams of copper, so one should attempt to produce 0.15 grams of copper seeing as it is the average of those two numbers. The first step in the stoichiometric process which one has to complete is finding how many grams of copper are in one mole of copper.
This would be an excellent yield if it all indeed consisted of fluorenol, but given that -OH peaks were observed in the IR, and that a good yield for this reaction was around 60%, it is possible that this percent is artificially high, and that some of this yield consisted of impurities like water and methanol that had not evaporated away. Of the product that was lost, some was lost due to bad filtration technique, as some of the product was observed to have passed through the filter paper, and into the flask. Some of the product may have also clung to the vial, as the precipitate was difficult to remove from the vial in its entirety. In order to improve this yield, more care could have been taken while removing product from the vial, and during filtration, ensuring that the filter paper was sufficiently wet and no product passed through. As some error most likely occurred due to impurities, inflating the percent yield, the product could have been allowed to dry
Firstly, because the NaHCO3 compound was not stored in a sealed container, therefore dust particles could have changed the results, and making the product impure. Also, there are uncertainties associated with the instruments used in this experiment. This, if the products were measured slightly more than should be, this could have affected the concentrations of the solutions, and therefore causing a larger
Another error was that since the percent yield was over 100, there was an error in obtaining the mass of the vials because the same balance was not used. Also, the addition of the dichloromethane could have added to the mass and when calculating the percent yield, the mass of the dichloromethane was
However, the results were not precise and accurate enough due to some experimental errors and human errors. First, the identicalness of test tubes. The interior of the test tubes were not the same and thus even though the measurement of the hydrogen peroxide and copper (II) sulphate were made precisely and accurately, the volume may differ. This contributed to countless of minor errors thorough the experiment, affecting the precision and accuracy of the result. The volume added should be weighed on the electronic balance every time after substance being added to obtain the most accurate results.
The location I chose for my inventory lab rotation is the Warm Springs Rehab Hospital in Kyle, TX. Warm springs rehab is a Hospital where patients are getting treated will and will be taken good care of and its also a place to feel comfortable such as a home. Which I spent two hours there. At the beginning, we were introduced to the Caroline Holt which is the dietitian of the Warm Springs Hospital, Caroline showed me and my partner the kitchen and she explained what they do on a daily bases, we also saw the dishwasher area which was very neat, then she showed us the cooking area which was next to the cooler, which is easier for them when they need to cook, which everything was organized and clean. After that we went to the office which was
The average concentration of my unknown Al3+ solution (#41) was 0.02372 0.00016 mol/ L. My %RSD was 0.67%, which I would say is very good. This means my precision relative to my average was very good. When calculating the mass of the precipitate, my Trial #1 and #2 were both 0.271X, with Trial #3 being 0.27XX.
After stirring at room temperature for 8 h additional 0.5 ml of 40 mM PEI were added. The solution mixture was kept with stirring overnight. The solvent was removed under reducing
Higher muscle lactate accumulation and venous plasma lactate concentration is observed in a high ambient temperature compared to a moderate temperature. It was previously shown that muscular glycogen utilization is enhanced in during exercise under high temperature (Febbraio et al., 1994). Therefore it is thought that the increase concentration of lactate in muscle under high temperature is caused by accelerated anaerobic glycolysis. Thus more lactate is released into the blood stream. When the exercise to exhaustion in the high temperature happens, muscle glycolygen are not exhausted.
In conclusion, when the concentration of grape juice increased, the average percentage change in the mass of the potato cylinders decreased. The increased concentration of grape juice means that there are more glucose molecules and, hence, the solution had a lower water concentration. There were more water molecules in the potatoes, thus diffusing into the water, against the concentration gradient in order to reach equilibrium. The water being lost decreased the mass of the potato cylinders. For example, in my raw data, concentration of grape juice solution of 40%, the initial weight of the potato was 6.00g however, after 15mins the weight of the potato decreased to 5.63g henceforth, the potato lost 0.37g.
The actual data is the result on our experiment vs theoretical, which is based on the calculations above. I have also learned to pay more attention to draining out all of the product completely before continuing to test the experiment, as any small drop of contaminant can veer our results into a different
Experiment #7: Column Chromatography of Food Dye Arianne Jan D. Tuozo Mr. Carlos Edward B. Santos October 12, 2015 Abstract Column chromatography is the separation of mixture’s components through a column. Before proceeding with the column chromatography itself, a proper solvent system must be chosen among the different solvents. The green colored food dye is the mixture whose components are separated.
Due to the unaccountability of the inconsistency in droplet size, many of the numbers may be varied because in one trial a huge droplet may count as one, but in another trial, I may have counted a small droplet as one, which causes results to possibly be
