extraction lab organic chemistry sources of error Evart Michigan

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extraction lab organic chemistry sources of error Evart, Michigan

Therefore, one layer is usually ether.A 5% sodium bicarbonate solution is 95% water; therefore, the other layer is aqueous. The final procedure of collecting the crystals yielded from the re-crystallization for analysis of melting ranges could have resulted unwanted contaminates that affected the melting ranges. They were stapled a few times to ensure that they were secure and do not break open during the process. 5.499g of sodium carbonate were weighed and added to a 125mL Procedure: A note before beginning the procedure: KEEP TRACK OF WHAT IS IN EACH TEST TUBE!

Transfer a small if the dried carboxylic acid crystals into a capillary tube. Sometimes an 'apparent' third layer appears between the top and bottom layers. The extracted liquid was dried using anhydrous sodium sulfate and then decanted into a beaker. The common problem, however, is that the cap has been mistakenly left on the separatory funnel while attempting to drain.

The tea solution was allowed to cool. The melting point readings indicated that benzoic acid ,which re-crystallized, was indeed pure and the melting point matched the known melting range of benzoic acid. The resulting p-nitroaniline was weighed at 0.040 g and its melting point was about 139 ºC. Video should be smaller than 600mb/5 minutes Photo should be smaller than 5mb Video should be smaller than 600mb/5 minutesPhoto should be smaller than 5mb Related Questions Organic Chemistry Extraction Lab?

The tube was capped and shaken to thoroughly mix the two phases. It was hard to extract only the dichloromethane layer, so I am sure some of the aqueous layer was picked up with it. A couple other obvious spots where error occurred were during vacuum filtration and decanting of the dichloromethane. Beerbower, A; Wu, Pl; Martin, A.

Such contamination could have fluctuated melting point ranges from the expected temperature readings. A second portion of dichloromethane was added to the brown layer in the separatory funnel and the process was repeated two more times. The tube was shaken allowed to stand with occasional swirling. also, with such a small amount of each compound to start, you never know how much could have stayed in the solution that coated the side of your glassware and wasn't

Remove and dispose of excess solvent with a pasture pipette. The brown layer was the aqueous layer. The washings were also transferred into the separatory funnel. Extraction is a fundamental technique used to isolate one compound from a mixture.

It does absolutely no good to extract ether with ether. 'I forget which layer is ether and which is H2O.' or 'I can't figure out which layer is aqueous.' Remember that II. View Full Document Sources of error that caused deviations in the yield include inaccurate separation of the liquid layers in the separatory funnel, improper extraction with water and rapid crystallization. Due to human error, no naphthalene product was harvested.

Another possible source of error might be during the general extraction procedure in week 2, the separatory funnel was not swirled twice. The solvent was then removed under a stream of nitrogen in the hood. Conclusions The compounds extracted seem to be slightly impure. The second extraction removed the 4-tert-butylphenol form the solution, which required a pH of higher than 10.17 as this is when the conjugate base of 4-tert-butylphenol is most prevalent.

After completing the above steps, it is necessary to collect the phase that has dissolved the compound targeted for isolation. EXPERIMENTAL MELTING POINTS FOR THE NEUTRAL SUBSTANCE, CARBOXYLIC ACID, AND PHENOL: Table of possible compounds and pka's: Analysis/ Discussion: When executing experimentation of this particular lab, it is crucial to understand The melting points for benzoic acid, p-nitroaniline, and naphthalene that were found are all slightly lower than the melting points I looked up beforehand. This academia was first published 17 Oct 2007 and last revised 13 Feb 2016.Adam Cap is a sometimes raconteur, rare dingus collector, and webmaster probably best known for SixPrizes (serving as

Source: Williamson's Macroscale and Microscale Organic Experiments, 4th edition, Chapter 8, Experiment 1, beginning on pg 138. Before crystallization was preformed, hydrochloric acid (a strong acid) was placed into the reaction tubes. Expanded solubility parameter approach .1. In the third week, the crude caffeine was purified by recrystallization and the caffeine crystals were collected.  In the fourth week the mass of the purified caffeine was measured after air

The p-nitroaniline was allowed to air dry for a week. Identify and record the chemical species now in reaction tube #3. The crude caffeine was dissolved in a minimum amount of the solvent. Remember when performing successive extractions to 'keep your eye on the prize.' If you are trying to move a compound from a water mixture to ether, do the extraction as described

Introduction A. Post Lab Questions: Free pass on the post lab questions this week.....Thanks Carol! :) This report earned the following scores for: format (2/2) style (1.5/2) data (3/3) quality of result (1/1) Organic Chemistry Extraction Lab Help!!!? Once it dissolved, the beaker was cooled to room temperature.

After dissolution, add (roughly) 1.0 mL of a saturated aqueous solution of sodium bicarbonate to the tube. The compounds will be extracted on the basis of the solubility properties of the acids, bases, and their salts. Next, 6 M aqueous sodium hydroxide will be added dropwise to the vial labeled “aqueous acid extracts” until the solution is basic. A strong base was then applied to the mixture to allow the phenol to ionize and precipitate into the aqueous layer.

LIQUID/LIQUID EXTRACTION A liquid/liquid extraction involves two immiscible liquids. It is important to make sure the two layers mix thoroughly. Journal of Pharmaceutical Sciences 1984 73(2) pp.179-188 2. Dissolve the mixture in 2.0 mL of a tert-butyl methyl ether in a microscale reaction tube labeled #1.

The mixture will be mixed by capping the tube and shaking it by hand to thoroughly mix the two phases. When dichloromethane was added to the solution, the separatory funnel was not swirled initially as mentioned in the laboratory manual, and was directly inverted. Experiment and Results A. This was folded and placed on the Hirsch funnel to collect the caffeine crystals.

This technique will be repeated by adding another 1.5 mL of 6 M aqueous hydrochloric acid to the centrifuge tube as before. It was then weighed at 0.074 g and its melting point was about 119 ºC. Lastly, I know it was hard to get all of the naphthalene out of tube to weigh it, so the weight of naphthalene recovered is low. View Full Document Company About Us Scholarships Sitemap Standardized Tests Get Course Hero iOS Android Educators Careers Our Team Jobs Internship Help Contact Us FAQ Feedback Legal Copyright Policy Honor Code

Data A sample comprised of a mixture of unknown proportions of benzoic acid, 4-nitroaniline (p-nitroaniline), and naphthalene weighing 0.292 g was obtained.