final weight percent yield 2,4-DNP Tollen's test pathway
.42g 67% positive negative oxidation of secondary OH
Good Things
My experiment went well. I began my experiment with .64g of
2-ethyl-1,3-hexanediol. The molecular weight of this compound is 146.2g/mol. It is converted into 2-ethyl-1-hydroxyhexan-3-one. This compounds molecular weight is 144.2g/mol. This gives a theoretical yield of .63 grams. My actual yield was .42 grams. Therefore, my percent yield was 67%. This was one of my highest yields yet. I felt that this was a good yield because part of this experiment is an equilibrium reaction. Hypochlorite must be used in excess to push the reaction to the right. Also, there were better ways to do this experiment where higher yields could have been produced. For example PCC could have been used. However, because of its toxic properties, its use is restricted. The purpose of this experiment was to determine which of the 3 compounds was formed from the starting material. The third compound was the oxidation of both alcohols. This could not have been my product because of the results of my IR. I had a broad large absorption is the range of 3200 to 3500 wavenumbers. This indicates the presence of an alcohol. If my compound had been fully oxidized then there would be no such alcohol present. Also, because of my IR, I know that my compound was one of the other 2 compounds because of the strong sharp absorption at 1705 wavenumbers. This indicates the presence of a carbonyl. Also, my 2,4-DNP test was positive. Therefore I had to prove which of the two compounds my final product was. The first was the oxidation of the primary alcohol, forming an aldehyde and a secondary alcohol. This could not have been my product because the Tollen’s test. My test was negative indicating no such aldehyde. Also, the textbook states that aldehydes show 2 characteristic absorption’s in the range of 2720-2820 wavenumbers. No such absorption’s were present in my sample. Therefore my final product was the oxidation of the secondary alcohol. My final product had a primary alcohol and a secondary ketone
Bad Things
I really don’t have that many bad things to write about. I forgot to shake my sep funnel after my first addition of dichloromethane. I had to redo that step. Also, there is a very slight chance that a little bit of dichloromethane could have been left in my final product. When I was distilling, I thought I had boiled away everything in my flask.
As a final point, the unknown secondary alcohol α-methyl-2-naphthalenemethanol had the R-configuration since it reacted the fastest with S-HBTM and much slower with R-HBTM. TLC was a qualitative method and ImageJ served as a quantitative method for determining which reaction was the faster esterification. Finally, 1H NMR assisted in identifying the unknown from a finite list of possible alcohols by labeling the hydrogens to the corresponding peaks.
The experiment was not a success, there was percent yield of 1,423%. With a percent yield that is relatively high at 1,423% did not conclude a successful experiment, because impurities added to the mass of the actual product. There were many errors in this lab due to the product being transferred on numerous occasions as well, as spillage and splattering of the solution. Overall, learning how to take one product and chemically create something else as well as how working with others effectively turned out to be a
The experiment was successful in terms of receiving alkenes by dehydration in the product and not water as seen from the IR
The question that was proposed for investigation was: Can the theoretical, actual, and percent yields be determined accurately (Lab Guide pg. 83)?
Random and systematic errors are both factors that can affect the reliability and accuracy of the results respectively. As all the graphs contained outliers, and hence, scatter, this indicates that random errors were present. Such errors may result from the inconsistent masses of the Alka Seltzer tablets. As these tablets were cut manually with a knife, it is unlikely that the mass of each half of an Alka Seltzer tablet would be the same. Thus, when using the tablets to react with HCl, the true number of tablets reacting would have not been the same as the number denoted for the trial, and with each repeated trial for the same number of tablets reacting, the reacting mass and ratio would have not been inconsistent. Consequently, the
In this experiment, I was making a sample of aspirin and then testing it in order to see how pure the sample of aspirin was. By doing this experiment, I was leaning how to crystalize products, and then used the theoretical yield, along with the percentage yield in order to calculate the amount of aspirin that I had created in the sample. Aspirin is an anti-inflammatory, and analgesic, meaning this medication can reduce inflammation, fever, and pain by blocking the enzymes that promote these issues, and reducing the production of more of these enzymes all over the body.
Type of Alkali - This is the same as the type of acid but instead the
I have chosen to only change the alcohol. I am changing the alcohols because my aim is to find out how different alcohols combust, so by changing them in the experiment I will fulfil my aim. There is no need to change the other variables as they have no significance. To make sure the test is fair, I will make sure that I have made checks on the apparatus before use. The checks will be.
There was not necessarily an error but rather an inconvenience to why the yield was so low. This inconvenience was adding only one equivalent of alkyne to the reflux condenser. The reason for this that there was not enough 2-methyl-butyn-2-ol for the use of two equivalents as stated in the instructions, and because there was less reactant used there would naturally be less product formed. The other source of error is the spillage of some of the reaction. These results does not correlate with the ease of the reaction occurring as mentioned in the reaction scheme. The low mass and percent yield makes it appear as though the tautomerization portion of the reaction was not favorable. I say this based on my observation where there was 35 mL of distillate, which was expected with the one equivalent, but the keto-tautomer results were so low from the theoretical yield (theorictical yield: 7.65g) that it appeared that the tautomerization was not favorable which is not true because the keto-tautomer happens so rapidly due to it being the most stable
I would change a few things about this lab. Firstly, I would have used a micropipette instead of the ones that we used because they would give more precise measurements. Also, I would have had five people in each group so that everyone could add NaOH to the solutions at the same time, stopping the reactions simultaneously.
The Reaction Between Hydrochloric Acid and Sodium Thiosulphate Introduction = == == == ==
The purpose of the experiment was to use the method of simple distillation to separate hexane, heptane, and a mixture of the two compounds into three different samples. After separation, gas chromatography determined the proportions of the two volatile compounds in a given sample.
1. The labels have fallen off of three bottles thought to contain hydrochloric acid, or sodium chloride solution, or sodium hydroxide solution. Describe a simple experiment which would allow you to determine which bottle contains which solution.
Chemical oxidation method, appear to have the maximum ability for use within the textile wastewater industry [37]. Treatment of spent dye effluent by means of a method using ultraviolet light (UV) and a strong oxidant is an effective alternative for the removal of color. Hydrogen peroxide (H2O2) is the most common oxidant utilized in combination with UV. Chlorine dioxide (ClO2) additionally has oxidative capabilities for color elimination. Further, UV in aggregate with ClO2 is a likely treatment for the reduction of colored effluent from textile dyeing facilities. Ozone is one of the most powerful oxidizers commercially to be had and famous for huge complex organic molecules of dyes, detergents, phenols etc. it may be broken the compounds into easier one. It can also oxidize organics and inorganics compounds, hence the disposal of color and odors. For most commercial applications ozone needs to be produced at situ. In textile effluent it
There is also the potential of human error within this experiment for example finding the meniscus is important to get an accurate amount using the graduated pipettes and burettes. There is a possibility that at one point in the experiment a chemical was measured inaccurately affecting the results. To resolve this, the experiment should have been repeated three times.