A measurement of around 0.5 µL, for each compound, was inserted into a gas chromatography in such a way, a syringe holding the compound was pushed down into a column and injection occurred to then start the machine in separating the compound. A computer was right beside it, indicating the graph of multiple peaks and later, after a duration of 4 minutes, a graph was printed out and obtained to then analyze the retention times and percent composition. “The percent composition was found by inserting the following values into the following equation,
Mole % A = (area of Peak / A total area)×100%
acquiring our desired values shown in the table above” (Z. 2016).
Discussion Odor Analyses: Beginning the experiment, a test of determining which
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However, instead of calculating the refractive index, the following values were obtained by inserting each compound into a refractometer and carefully following the procedure to then retrieve the value shown through the lens. The following shows the compound along with its refractive index: 1.4601 for spearmint, 14554 for caraway oil, 1.4638 for S-(+)-Carvone, 1.4661 for R-(-)-Carvone, and 1.4602 for limonene. For the two types of Carvones used while determining their refractive index, comparing R-(-)-Carvone with a value of 1.4661 and S-(+)-Carvone with 1.4638 we do see a difference of 0.0027 among the values, but all in all, being quite similar from a standpoint and a bit more different from the other compounds like spearmint. However, towards their reference values at 20℃, a difference is clearly seen, to where for R-(-)-Carvone, comparing the refractive index we got at 1.4661 to the literature value of 1.497 (R-(−)-Carvone 2017) , with a difference of almost 0.03. The same goes for S-(+)-Carvone, with the refractive index of 1.4638 to the “literature value of the same value, 1.497” (S-(+)-Carvone 2017), with a difference of 0.035; error may have occurred here when looking at the following compounds through the refractometer either through incorrectly aligning the adjuster to the correct color sequence or improperly adjusting the “X” symbol to which no black spots can be
In this Chemistry Lab the main objective is to perform accurate chemical analysis for the quantity of elements and compounds in a sample. There will be a compound made then synthesized. The methods used were acid-base titrations, redox titrations, gravity filtration, and distillation. General conclusions included
The objective of this extraction experiment was to achieve a comprehensive understanding, as well as master the practice, of the technique of separating various individual components of a compound.
Day 1. Michael was coming home for vacation from college. When he got home he found out that
The primary goal of this laboratory is to correctly identify an unknown substance. To achieve this task, one may use various tests that reveal both chemical and physical properties of a substance. By comparing the results of a known substance and the unknown substance, one may eliminate alternative possibilities and more accurately predict the undisclosed compound. Furthermore, by performing these tests, data can be collected and verified regarding chemical and physical properties of the unknown. Understanding the chemical properties of a known substance aids one’s understanding of the unknown based on comparative analysis of the results of the tests.
Experiment 55 consists of devising a separation and purification scheme for a three component mixture. The overall objective is to isolate in pure form two of the three compounds. This was done using extraction, solubility, crystallization and vacuum filtration. The experiment was carried out two times, both of which were successful.
6-3: This process is used by cells to manufacture _biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products__
Abstract: One mixture of two unknown liquid compounds and one mixture of two unknown solid compounds were separated, isolated, purified, and characterized by boiling point. Two liquid unknowns were separated, isolated, and purified via simple distillation. Then, the process of an acid-base extraction and washing were used to separate two unknown compounds into two crude compounds: an organic acid and a neutral organic compound. Each crude compound was purified by recrystallization, resulting in a carboxylic acid (RCO2H) and a pure organic compound (RZ). The resulting mass of the pure carboxylic acid was 1.688g with a percent recovery of 31.80%, the boiling range was 244-245 °C, and its density was 2.0879g/mL. The resulting mass of the pure organic solid was 2.4902g with a percent recovery of 46.91%, the boiling range was 52.0-53.4°C, and its density was 1.5956 g/mL.
The original 1.0 gram of the 50/50 mixture of the benzoic acid and benzil contain 0.5 gram of benzil. Thus, from 0.5 gram of benzil, only 0.266 gram of benzil was collected. The percent recovery of benzil was calculated to be 53.2%. This low percent recovery could be due to filtration errors. Some amount of benzil remained on the filtration paper that contained the MgSO4. In order for determining the purity of the
The Lab One was done on Laboratory Techniques and Measurements. The first experiment with my Lab partner; we got opportunity to experiment how to conduct measurements in length by using metric conversion. We started in cm units and changed into mm by x10, and moving decimal point x1 to right. To find in meter we moved from cm to meter two decimal points to the left or double check our self divided by 100 and all records in data table 1. The second experiment was to measure temperature of how cold and hot tap water can be by using thermometer in Celsius units. From this experiment, gained knowledge that tab water doesn’t boil to 100 Celsius related to containing different
Me and my lab partner, obtained a mixture of a un known proportion from the instructor and then flow the guide line in our lab manual to separate the mixture by applying the separation method motioned in our lab manual pages 33-40 . In this experiment, the separation methods were decantation,
In this experiment 10 cuvettes were filled with the appropriate dilution, an additional cuvette should be filled with distilled water which should be used to calibrate the colorimeter. Record the absorbance and transmittance for each dilution generated from the Webquest. Additionally, two samples of Gatorade contains Blue Dye #1 (Low Calorie and Glacial Frost) were tested and found that the Low Calorie Gatorade had an absorbance of .135 and the absorbance of the Glacial Frost Gatorade was .153. Using linear regression the concentration of the two samples can be found if the value of transmittance is substituted for the Y value. The concentration of sample 1 is 62.8 µM and the concentration of sample 2 is 69.68 µM respectively reporting in four significant
In 1909 S.P.L. Sorensen published a paper in Biochem Z in which he discussed the effect of H1+ ions on the activity of enzymes. In the paper he invented the term pH to describe this effect and defined it as the -log[H1+ ]. In 1924 Sorensen realized that the pH of a solution is a function of the "activity" of the H1+ ion not the concentration and published a second paper on the subject. A better definition would be pH=-log[aH1+ ], where aH1+ denotes the activity of the H1+ ion. The activity of an ion is a function of many variables of which concentration is one. It is unfortunate that chemistry texts use a definition for pH that has been obsolete for over 50 years.
1. What type of macroscopic evidence for chemical change did you observe during this experiment? Give at least three different examples. (15 points) The main evidence of chemical change in this lab is the change in color, production of gas, and the production of precipitate.
Part 2 to determine the empirical formula and percentage yield of the compound synthesized in Part 1. Spectrophotometry is a routine laboratory test that has the added advantage
The experimental refractive index was found to be 1.392, which is slightly different from the literature value of 1.421. This could be due to human error or a misread in the refractive index itself. Although the literature value from Dr. Kwan says 1.421, the literature value on Sigma Aldrich gives a literature value of 1.388, which is much closer to the experimental refractive index, assuring that it is the correct identity of the unknown. The slight difference between the values may be due to an impurity that was left inside of the ester at the time of the reading. Once the refractive index was compared, the melting point of the 3,5-dinitrobenzoic acid compared.