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Investigatory report on chemical kinetics experiment
Topics of research for rate of reaction
Topics of research for rate of reaction
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The objective of part A was to determine the rate of the substitution reaction between 1-Chlorobutane and KOH. This information was obtained by using the titration method to record the concentration of KOH over a given amount of time. To start this procedure, 1-Chlorobutane was added to a round bottom flask, which was connected to a reflux apparatus. Once it was observed that reflux had started the KOH was added with EtOH; this is the start of the reaction. The aliquot was then titrated with 0.100 M HCl and the concentration was noted at each interval. By graphing the data one can determine the order of the reaction and the rate of the leaving group. This data will provide the type of the reaction, whether it is SN1 or SN2. In order for the …show more content…
graphs to be accurate in determining the order, the equations for zero, first, and second order had to be plotted. This means the zero order graph was plotted with the information [KOH], the first order with ln[KOH] and lastly the second order with 1/[KOH]. By analyzing the graph of the zero order reaction, it is seen that neither compound has a constant slope of zero.
This means if the concentration were increased, the rate would be increased also. This statement is not true to a zero order reaction, therefore it can be determined that both are not zero order. By observing the first order graph it is seen that the 1-bromobutane is decreasing in a curve while the 1-chlorobutane is straight with a negative slope. With a first order reaction, generally the rate increases linearly which means the rate is proportional to the concentration. This is not occurring with the 1-bromobutane, however is opposite with the 1-chlorobutane. For the compound to be first order the slope is linear with –k, this is evident. Therefore, it is concluded that 1-chlorobutane shows to be a first order reaction. Finally, the second order graph is examined and it is apparent that the points for 1-bromobutane form an increasing straight line with a positive slope, which is essential considering it is a plot of the inverse concentration. The 1-chlorobutane cannot be second order due to the –k value. However, theoretically both electrophiles should follow an SN2 reaction because they are primary alkyl halides. Therefore the interpretation of the graphs makes sense, however due to very similar results the data may be inaccurate in some areas. Therefore, when the leaving group detaches, and the new bond with the nucleophile forms, it occurs immediately therefore, there is no intermediate and the attack occurs
simultaneously. When comparing the group data plots to the global data it is clear that the data is very close, and that the order of the reactions remain the same. Furthermore, by observing the group data and comparing with the data obtained personally in the lab, the values for 1-chlorobutane are extremely close, varying only with 0.1-0.2 difference. The error in the group data could be attributed to delayed start of time; this would alter the concentration values versus time drastically. This error is directly proportional to the plotting of the data, which would give skewed results. The error is minimal due to how close the data is to the global, however when approaching the results with theory, the order for 1-chlorobutane is proved incorrect. The k values that were obtained from the graph are -0.006168 for 1-chlorobutane and 0.1979 for 1-bromobutane.
The goal of this two week lab was to examine the stereochemistry of the oxidation-reduction interconversion of 4-tert-butylcyclohexanol and 4-tert-butylcyclohexanone. The purpose of first week was to explore the oxidation of an alcohol to a ketone and see how the reduction of the ketone will affect the stereoselectivity. The purpose of first week is to oxidize the alcohol, 4-tert-butylcyclohexanol, to ketone just so that it can be reduced back into the alcohol to see how OH will react. The purpose of second week was to reduce 4-tert-butylcyclohexanol from first week and determine the effect of the product's diastereoselectivity by performing reduction procedures using sodium borohydride The chemicals for this lab are sodium hypochlorite, 4-tert-butylcyclohexanone
In this experiment there were eight different equations used and they were, molecular equation, total ionic equation, net ionic equation, calculating the number of moles, calculating the theoretical yield and limiting reagent, calculating the mass of〖PbCrO〗_4, calculating actual yield, calculating percent yield (Lab Guide pg.83-85).
Discussion and Conclusions: Interpreting these results have concluded that relative reactivity of these three anilines in order of most reactive to least reactive go; Aniline > Anisole > Acetanilide. Aniline, has an NH2 , the most active substituent , and adds to any ortho/para position available on the ring. This data is confirmed with the product obtained, (2,4,6 tribromoaniline, mp of 108-110 C). As for anisole, it has a strongly activating group attached, OMe an alkoxy group, and it added in two of the three available spots, both ortho. The results conclude: (2,4-Dibromoanisol mp 55-58 C ). Acetanilide has a strong activating group attached, acylamino group, but this group is large and the ortho positions are somewhat hindered so the majority of the product obtained added at the para position, results conclude: (p-bromoacetanilide mp 160-165 C). Since all the substituents attached to the aromatic rings were activators the only products able to be obtained were ortho/para products.
This experiment was divided into two main steps. The first step was the addition of bromine to trans-stilbene. Trans-stilbene was weighted out 2.00g, 0.0111mol and mixed with 40ml of glacial acetic acid in 100ml Erlenmeyer flask on a hot bath. Pyridinium hydrobromide perbromide of 4.00g, 0.0125mol was added carefully into the flask.
taken into account. It is also best to make sure you are working in a
Abstract: This week we experimentally determined the rate constant k for the reaction 2HCl (aq) +Na2S2O3 (aq) → S (s) + SO2 (aq) + H2O (l) + 2NaCl (aq). In order to do this the average reaction time was recorded in seconds during two trials. The data from the experiment shows this reaction is in the first order overall: rate=.47s-1 [HCl]0 [Na2S2O3]1. These findings seem to be consistent with the expected results
The rate law determines how the speed of a reaction occurs, thus allowing the study of the overall mechanism formation in reactions. In the general form of the rate law, it is A + B C or r=k[A]x[B]y. The rate of reaction can be affected by the concentrations such as A and B in the previous equation, order of reactions, and the rate constant with each species in an overall chemical reaction. As a result, the rate law must be determined experimentally. In general, in a multi-step reaction, there will be one reaction that is slower than the others.
The equation shows how 1 mol of Na2CO3 reacts with 1 mol of H2SO4, so
Acid-Base Titration I. Abstract The purpose of the laboratory experiment was to determine equivalence. points, pKa, and pKb points for a strong acid, HCl, titrated with a. strong base, NaOH using a drop by drop approach in order to determine. completely accurate data. The data for this laboratory experiment is as follows.
This can be explained by addressing the electronegative affect the chlorine has on the molecule. An increase in electronegativity causes a free radical to be less stable. Therefore the closer a free radical is to the electronegative atom, the less stable it will be and vice versa. Because chlorine is highly electronegative, the relative reactivity for 1,2-dichlorobutane might be higher than 1,4-dichlorobutane, but the 1,4-dichlorobutane is also slightly more stable in the sense the electronegativity of the chlorine on carbon one is not affecting it as much as it is for 1,2-dichlorobutane.
The purpose of experiments was to determine the concentration of sodium hydroxide by titrating with KHP and to determine the concentration of Acetic Acid by titrating with a known concentration of sodium hydroxide solution. The titrant is the solution with a known concentration that is titrated to the another solution with an unknown concentration to determine the molarity of the second solution. The analyte is a substance which is examined by analytical procedure; the properties of that solution are measured. In the first reaction the titrant was KHP and the analyte was NaOH, in the second one the titrant was NaOH and the analyte acetic acid.
The problem of this lab is, “What factors affect the rate of chemical reactions?” The hypothesis is, “Temperature, concentration, surface area, and catalysts affect the rate of chemical
Where A molecules are being converted to B molecules, we can say that the rate of this reaction would be:
Reactions of Acids and Bases in Analytical Chemistry. Hulanicki, A. and Masson, M.R. New York: Halsted Press, 1987.
In this experiment three different equations were used and they are the Stoichiometry of Titration Reaction, Converting mL to L, and Calculating the Molarity of NaOH and HCl (Lab Guide pg. 142 and 143).