The initial impure mixture was tan, with large, long crystals that were white or yellow, but after the recrystallization, the pure mixture was white powder with extremely small crystals. Upon testing for the purity through melting point comparison, the melting points were 113.7°C-116.7°C and 113.85°C-116.95°C.
The average temperature is then 113.85°C-116.95°C when the trials were added and divided by two. The actual melting range of pure acetanelide is 113°C-115°C, which means that the melting point of the recovered acetanelide was less than 2°C more than it was supposed to be, which means that there may have been a few minute impurities, but the acetanelide was reasonably pure.
Experiment and Sources of Error: The experiment was followed
…show more content…
The buildup may have allowed some of the impurities to get past the filter paper. In order to re-dissolve the solution, the solution was poured form the funnel back into the flask, heated, and re-added. In order to get all of the solution to go through, a large quantity of hot solvent was added on the filter paper to clear the blockage, which caused a large excess of solvent to be present. This may have led to less pure acetanelide forming as crystals, as more acetanelide would stay in the discarded solution. In response to this, the solution, now with more water than intended, was boiled down as time would allow from about 120 ml to about 80 ml, and the experiment was continued with more solute than …show more content…
Before the cold filtration, the solution was in the flask containing the stir bar, but there were impurities adhering to the stir bar that would not come off, and the stir bar could not be removed without losing any solution. This may have caused some impurities to be re-entered into the solution after it was hot vacuum filtered. Another source of experimental error occurred after the cold vacuum filtration, as the dried acetanelide crystals would not come cleanly off the filter paper. A glass rod was used to try to scrape it off, but a bit was lost as it clung to the glass rod and filter. After being allowed to dry for a week, another source of error occurred, as when the crystals were being transferred from the filter paper to the weight boat, a fair amount of acetanelide was spilled onto the table and some would not come off of the filter paper. These crystals’ melting point was then determined, concluding the
Solid A was identified to be sodium chloride, solid B was identified to be sucrose, and Solid C was identified to be corn starch. Within the Information Chart – Mystery White Solid Lab there are results that distinguishes itself from the other 4 experimental results within each test. Such as: the high conductivity and high melting point of sodium chloride, and the iodine reaction of corn starch. Solid A is an ionic compound due to its high melting point and high electrical conductivity (7), within the Information Chart – Mystery White Solid Lab there is only one ionic compound which is sodium chloride, with the test results of Solid A, it can be concluded that is a sodium chloride. Solid B was identified as sucrose due to its low electrical
* It was almost impossible to tell when the Alka-Seltzer tablet had dissolved, each time the experiment was done. This was a huge problem for the experiment as this could have totally caused problems to the experiment. A special type of detector apparatus, which bleeped when the correct amount of Alka-Seltzer tablet dissolved, could improve this, each time the experiment was done.
Mixed melting point was used to confirm the identity of the product. The smaller the range, the more pure the substance. When the two substances are mixed; the melting point should be the same melting range as the as the melting range obtained after filtering. If the mixed melting point is lower one taken from the crystals, then the two substances are different.
Melting Point Determination of Alum 1. 0.5 g of dry alum was crushed with the mortar and pestle, and then the crushed alum was packed to the bottom the capillary tube. The alum measured about 0.5 cm from the bottom of the tube. Then the tube was fastened to the thermometer with the rubber band, and the thermometer was fastened to the ring stand with the universal clamp. 2.
As proton pump inhibitors (PPIs) Omeprazole and Lansoprazole are effective therapeutic agents for Peptic ulcers. But which one is more effective as a PPI and highly useful for peptic ulcers disease. The basis of the distinction lies in the pharmacological safety and efficacy of each PPI, which is assessed in this paper in a head to head comparison. After obtaining the relevant literature from Database PubMed and Proquest, it is sufficient to conclude that Lansoprazole proved to be a more effective and safe than Omeprazole.
Overall, the experiment produced a successful percent yield of 78.65% of alum from the pieces of aluminum. However, there was a relatively large percent error of 21.34%. This error could have resulted from multiple steps in the experiment. One notable source of error could have stemmed from not obtaining all of the alum crystals from the beaker before aspirating; some crystals could have remained in the beaker, resulting in a lower yield than expected. Another potential source of error may have been only running the alum crystals through the aspirator once; the aspirator removes liquids from the sample, drying them out, however some of the crystals could have ended up in the filtered liquid. By running this solution through the aspirator a second time, a greater yield could have occurred. Finally, when adding H2SO4, white crystals could have formed, resulting in it being necessary to reheat the solution. By not reheating the solution if the crystals did form, a loss of overall alum crystals would be significant, given that they could have formed in these white crystals, rather than the desired alum. To prevent these errors, it would be necessary to ensure that all of the crystals were removed from the beaker by aspirating, as well as filtering the solution more than once. As for the white crystal formation, a
== Refer to, Chemistry Lab #1 – What’s the substance? I didn’t change most materials when I did this experiment, but I added 4 materials, which are: * 5 test tubes * 2 stoppers * 1 large piece of paper And I deleted 1 material, which is: * Spatula Methods = == ==
There were two times in the experiment where substances had to be transferred from a funnel to a watch glass. Error could have occurred here from substances falling off of the filter paper or watch glass. In part C of the experiment, while trying to evaporate only the water, the double salt could have been overheated. Overheating the contents of the crucible was a concern, it would cause the loss of mass other than water. Finally, at the end of the experiment, when using the spectrometer, if the nickel solution had not been stirred enough it would cause the results to be
The purpose of this experiment was to determine the temperatures of the freezing and the melting points of water.
Then, we observed. The learning target that we were testing was I can distinguish physical and chemical changes. When I observed the dry substances with water mixed I noticed that they all dissolved within the water. Next, when the vinegar was mixed I observed fizzing occurring in all of the substances except for corn starch. Finally, the dry substance mixed with iodine solution all changed colors which indicate that it is a chemical change. A physical change in the experiment we did was the substances dissolving because nothing has been created. Errors that might exist are when we were deciding the amount of substance to put in the tray because the stick didn’t provide a perfect amount of substance we should put in the tray. Another error that might exist is using contaminated sticks. Two new things I have learned in this experiment is that iodine can change the color of the substances and two changes of
1. Describe errors in procedure that may cause an observed capillary melting point of a pure compound
We made Acetylsalicylic Acid by reacting Salicylic Acid and Acetic Anhydride. We conducted a series of tests which included white powder comparison, melting point, Iron (Ⅲ) ion, and spectrophotometer to determine the purity. All these tests indicated that we had some amount of contamination. By combining the results of our tests, and spectrophotometer readings, we concluded that our sample was not very pure. We calculated that we had about 14% Salicylic Acid in our purified sample.
Analysis of Aspirin Tablets Aim --- To discover the percentage of acetylsalicylic acid in a sample of aspirin tablets. ----------------------------------------------------------------- In order to do this, the amount of moles that react with the sodium hydroxide must be known. This is achieved by using the method of back titration.
My table and I also made sure that the plate that carried all of the powders was rinsed clear and was dried all the way. Next time to improve this lab I would make sure that my table would not argue with each other so we can get all of our work done.
In this lab, eight unidentified mineral samples are the subject of observation and experimentation. The purpose of this lab is to identify the samples based on the observations and experimentation. This paper will identify each of the samples and briefly discuss each one.