This website uses cookies to ensure you have the best experience. Learn more

Experiment 2 Essay

2003 words - 9 pages

Purpose/Introduction
What reaction was conducted in this experiment and with what reagents? Was there a reason for this reaction beyond just synthesis of product(s)? What techniques were used to purify and identify the product(s) of the reaction?
The purpose of this experiment was to investigate the bromination of trans-cinnamic acid and determine what the isolated products tells us about the possible mechanism. The stereochemistry of the product results from either a syn or anti addition of Br2 to the alkene. Recrystallization using ethanol and water solvent mixture was used to purify the crude product and melting point was implemented in order to see which products were synthesized. The ...view middle of the document...

The Br–Br bond is cleaved heterolytically, forming the Br– ion. The nucleophilic attack of Br– opens the bromide ion ring via backside attack resulting in a new C–Br bond on the opposite side. Finally, the mechanism of the both syn and anti addition consists of the electrophilic addition a bromine atom (after the heterolytic cleavage of the Br–Br, forming Br–) by using the pair of electrons in the pi bond of the C=C. Its initial addition occurs from either side of the planar double bond. This results in a carbocation intermediate that is trigonal planar. The addition of the Br– ion can occur from either side of the carbocation face, forming two products of syn and anti addition. (The drawn mechanisms are displayed on the following page.)

Results
What product was obtained? What yield and percent yield were obtained? What percent recovery was obtained from recrystallization? What melting point data were obtained?
The product obtained for the most part was for the anti addition; (2S, 3R- and 2R, 3S) 2,3-dibromo-3-phenylpropanoic acid. The percent yield was calculated by the following:
(0.103g trans-cinnamic acid)/×(1 mol trans-cinnamic acid)/(148.2 g trans-cinnamic acid)×(1 mol 2,3-dibromo-3-phenylpropanoic acid)/(1 mol trans-cinnamic acid)×(307.97 g)/(1 mol 2,3-dibromo-3-phenylpropanoic acid)= 0.214 g 2,3-dibromo-3-phenylpropanoic acid

The theoretical yield was 0.214 g of 2,3-dibromo-3-phenylpropanoic acid. Our actual yield for our recrystallized product was 0.040 g. To calculate percent yield the actual mass is divided by the theoretical mass and multiplied by 100%. So the percent yield was 0.040g/0.214×100%=18.7%.
The percent recovery obtained by the recrystallization was the mass of the pure product divided by the mass of the crude product (0.077g). So the percent recovery was 0.040g/0.077g×100%=51.9%.
The melting point data obtained was:
Compound Melting Point Range ᵒC
(2S, 3R- and 2R, 3S) 2,3-dibromo-3-phenylpropanoic acid (anti) 202-204 ᵒC
(2S, 3S- and 2R, 3R) 2,3-dibromo-3-phenylpropanoic acid (syn) 93.5-95 ᵒC
Experimental Pure Product 177-183 ᵒC

According to the data, it can be seen that there was anti product. The reason is due to the fact that the melting point of the acquired recrystallized product is lower than that of the pure anti product (202-204 ᵒC), but much higher than that of the pure syn product (93.5-95 ᵒC). Since the observed melting range is near the reported melting range from the given, it suggests that the product is of that enantiomer set. For this particular experiment the (2R,3S) and (2S, 3R) enantiomers of 2,3-dibromo-3-phenylproanoic acid are expected; indicating that the bromine addition occurred via an anti addition method. If bromine were to have added via syn addition, the melting point would have been 93.5-95 °C if pure and below that range if impure. The difference of several degrees between the theoretical and the experimental values may be the result of impurities and the possible...

Find Another Essay On EXPERIMENT 2

How Concentration and Temperature Affects the Rate of Reaction

804 words - 3 pages . GRAPH X we have waited for 20 minuets for something to happen. I think this result will take a long time for something to happen so I dint wait any more. Evaluation I feel that experiment was very successful. I think this because we all worked well as a team. However my experiment could have been improved by being more accurate with the timing. Instead of timing it to 2 decimal places I could have timed

Critique of Milgram Essay

897 words - 4 pages while they obeyed.Finally, he mentions about duty without conflict. According to Mailgram ?They are proud of doing a good job, obeying the experimenter under difficult circumstances?. In the end, Milgram used his experiment to explain why the war crimes of the Nazi Party in Germany during World War 2 have to take responsibility. Milgram doesn?t completely the experiment. But he concludes the people the human sometime has to fully obey with tough

The Stanford Prison Experiment: Taking a Deeper Look

1023 words - 5 pages Prison Experiment). Prisoners from day one, of the 2-week experiment, were treated poorly by the guards. They had to face humiliation and embarrassment by being stripped naked and sprayed with water, on account of the explanation of, germs. The prisoners were kept in cells with three total roommates, only leaving enough room for the cots they laid upon. Another difficulty that the prisoners had to face was unfair treatment by the guards

A Shocking Surprise: Dr. Stanley Milgram

1258 words - 6 pages study was sponsored by Yale (a trusted and authoritative academic institution) led many participants to believe that the experiment must be safe. The selection of teacher and learner status seemed random. Participants assumed that the experimenter was a competent expert. The shocks were said to be painful, not dangerous. (Cherry 2) Although many people admire Milgram’s experiment as an outstanding scientific experiment, some criticize his lack

The Implications of the Stanford Prison Experiment

1115 words - 4 pages experiment is too different for the purposes of faire testing but not different enough to discover anything new. Another problem facing the repeat is the accusation that it is being done for the purpose of entertainment rather than science. Connections with other experiments have been made. For example in the Milgrim experiment it was revealed that 2/3 of test subjects would administrate a potentially fatal electric

Milgram and Zimbardo: Overpowering Situations

1128 words - 5 pages voltage would increase. If at any point the subjects insisted on stopping the experiment, the administer would give them four statements to push them forward. 1. Please Continue 2. The experiment requires you to continue 3. It is absolutely essential that you continue 4. You have no other choice you must go on. After the four ultimatums if they still refused, the experiment would be discontinued. In the end more than half of the subjects went to the

The Evolution of Ethics in Psychology

2152 words - 9 pages ​The Milgram experiment is probably one of the most well known experiments in Psychology. The reason being is because its participants were not told what was really occurring in the experiment. After the experiment was over, the participants were mentally and emotionally affected. Later, a cognitive psychologist, George Miller described Milgram’s experiments, together with Zimbardo’s Prison Experiment, as “being ideal for public consumption of

Unethical Experiments

1589 words - 6 pages guide research in these experiments. Concluding, some experiments have the tendency to destroy the lives of the humans that have been experimented on. Works Cited http://www.spring.org.uk/2007/06/monster-study.php Mitscherlich, Meilk Doctor of infamy: the story of the nazi medical crimes. New York: Schuman, 1949; xxii-xxv http://www.theunnecesarean.com/blog/2011/2/16/the-vanderbilt-experiment-pregnant-women-as-radiation-test-s.html#sthash.LQnC2Ajz.5uNR9KUW.dpbs http://www.bbc.co.uk/news/world-us-canada-14564182 http://www.infoplease.com/ipa/A0762136.html Allen, Scott. Boston Globe: Boston: Mass, 1993. Print

Introduction to measurement

1754 words - 7 pages AbstractSuccess in lab depends on how students can make precise observations, measurements and write data. This experiment was aimed to make students get acquainted with mass and volume measurement. Five 150-ml beakers, a volumetric pipette, the graduated cylinder were tested in a different measures design to determine variation in mass and in volume. Also the experiment included the first-hand view of volume additives on example of volumes of

The Social Control Theory

1199 words - 5 pages were: • “Prod 1: Please continue. or Please go on. • Prod 2: The experiment requires that you continue. • Prod 3: It is absolutely essential that you continue. • Prod 4: You have no other choice, you must go on.” (Milgram, 1975) Milgram had confidence that the right to withdraw was available and even though the participants didn’t see it some of them did withdraw from the experiment early by protesting against the authority. A questionnaire was

Investigation: How does channging the concentration of a substance affect the rate of reaction?

3909 words - 16 pages escape, however as the time between the calcium carbonate starting to react with the acid and placing the rubber bung on top of the conical flask will be roughly the same for each experiment, I think that my experiment will be fair.Here is the method for the experiment I will perform.1. I will first set up the equipment as shown in my diagram.2. I will then measure out 5 grams of calcium carbonate and the quantity of hydrochloric

Similar Essays

Experiment #2: Forces Essay

8594 words - 34 pages 1. ObjectiveThe objective of the second experiment of the PH1004 laboratory course is broken down into two parts. In part A, the aim is to determine the acceleration due to gravity of a glider, which runs along a straight line on an air track. A weight will be connected to the glider by a string draped over a pulley to create the necessary acceleration. To understand why objects accelerate, force and mass must be defined. A force can either

Essay #2: Milgram Experiment Vs “The Lottery”

1236 words - 5 pages Milgram Experiment presents us the unconscious human nature of obedience towards what perceives to be an authority. Meanwhile the results also serves as a message to promote humanity living a conscious life instead of blindly conforming with the crowd. The following paragraphs explains how each authoritative source established itself, analysis of both “The Lottery” and Milgram Experiment, and how both pieces of work are relevant to society today

Molarity Calculations Essay

1618 words - 6 pages Student Name: Fausto ZuritaPartner #1 Name: Alice ParkPartner #2 Name: Garret KernPartner #3 Name: Sherry FanDate: March 12, 2014Course Title: Magnet ChemistryCourse Teacher: Mr. LodalBlock: C and Period: 6Lab Experiment #2 ~ Molarity CalculationsPurposeThe purpose of this experiment was to determine the concentration of a solution using analytical chemistry. The purpose of this particular experiment was ultimately to determine the concentration

Relations To Pasteur’s Experiment Essay

656 words - 3 pages all grew microbes. Flask 4 did not grow anything. The broth in each flask turned darker and cloudy over a certain time period. Spallanzani’s experiment relates to Pasteur’s experiment because both tests involved broth, flasks, boiling, and flask seals. The only difference is that Spallanzani used 4 flasks instead of 2. Both sealed and boiled containers did not contain mold after the specific time period. John Needham was an English biologist who