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Topic: Yield (chemistry)


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In the News (Tue 25 Jun 19)

  
  Chemistry - MSN Encarta
Modern chemistry was established in the late 18th century, as scientists began identifying and verifying through scientific experimentation the elemental processes and interactions that create the gases, liquids, and solids that compose our physical world.
Resources such as coal, petroleum, ores, plants, the sea, and the air yield raw materials that are turned into metal alloys; detergents and dyes; paints, plastics, and polymers; medicines and artificial implants; perfumes and flavors; fertilizers, herbicides, and insecticides.
Chemistry is often called the central science, because its interests lie between those of physics (which focuses on single substances) and biology (which focuses on complicated life processes).
encarta.msn.com /encyclopedia_762504460/Chemistry.html   (1442 words)

  
 Yield (chemistry)
The ideal or theoretical yield of a chemical reaction would be 100%, a value that is rarely reached.
Yields above about 90% are called ''very good'', yields above about 75% are called ''good'', yields below about 60% are called ''modest'', yields below about 30% are called ''poor''.
Yields can also be above 100% when an extraneous chemical from outside of the reaction has found its way into the yield.
www.seattleluxury.com /encyclopedia/entry/yield_(chemistry)   (353 words)

  
 Yield (chemistry) - Wikipedia, the free encyclopedia
Yield in chemistry, also known as chemical yield and reaction yield, is the amount of product obtained in a chemical reaction.
The yield is usually also given as a relative yield, which is the actual yield divided by the theoretical yield (the ideal or mathematically calculated yield).
The % yield is calculated from the actual molar yield and the theoretical molar yield (1.5 mol ÷ 2.0 mol × 100% = 75%).
en.wikipedia.org /wiki/Yield_(chemistry)   (400 words)

  
 Theoretical Yield
The theoretical yield of a reaction is the amount of product that would be formed if the reaction went to completion.
Theoretical yield calculations are carried out in the same way as they were in general chemistry: the moles of limiting reactant determines the moles of product.
A low percentage yield means that the conditions were not optimal and could be improved.
orgchem.colorado.edu /hndbksupport/labnb/theoryield.html   (646 words)

  
 High Yield for Chemistry from Grotes' Gift   (Site not responding. Last check: 2007-10-10)
UTC is the number one producer of chemistry undergraduates in the state of Tennessee.
Today, 23 years after the death of the longtime head of the UTC chemistry department, the fruits of Dr. Irvine Grote's boyhood curiosity continue to nurture the campus he served for 38 years.
Among schools that don't have graduate programs in chemistry, UTC was second.
pr.utk.edu /alumnus/spring96/yield.html   (447 words)

  
 Chemistry Research   (Site not responding. Last check: 2007-10-10)
The highest percent yield, 97.7%, was obtained with a microwave heating time of ten minutes.
A 91.4% yield of benzil (98.8% purity) was obtained.
This is much greater than the % yield of 61% obtained with heating on the hotplate, and with typical student % yields of 70%.
www.heidelberg.edu /depts/chm/microwave1.html   (1118 words)

  
 Herbs Cultivation & Their Utilization, ISBN: 81-7833-064-4 | NIIR
The compounds isolated from Cassia angustifolia leaves are wax, myricyle alcohol, the flavonoids isorhamnetin and kaemp ferol and the anthraquinone rhien and emodin and phenolic compounds.
In this way, it is possible to raise plantations yielding high quality oil, which is not possible when the plantation is raised from seeds as the seeds give rise to many morphologically indistinguishable different varieties.
To obtain a maximum yield of oil and to facilitate release of oil, the grass is chopped into shorter lengths.
www.niir.org /books/book/zb,,37_a_0_0_a/Herbs+Cultivation+&+Their+Util...   (3896 words)

  
 Erik's Chemistry: Chapter 3: Stoichiometry Notes
Therefore, the limiting one is used to calculate the theoretical yield.
The actual yield is the amount formed when the experiment is actually carried out.
The percent yield is found by taking the actual yield and dividing it by the theoretical yield.
members.tripod.com /~EppE/stoictry.htm   (518 words)

  
 quantitative chemistry:theoretical and percent yield
In this case the mass of products formed (the actual yield) is less than the theoretical yield.
A quantity that describes this less-than-ideal yield is known as the "percent yield":
While the percent yield depends upon the above mentioned factors, it also depends upon the experimenter and their technique.
www.iun.edu /~cpanhd/C101webnotes/quantchem/thtclandpctyld.html   (291 words)

  
 Yield Calculations
Calculate the theoretical yield: The theoretical yield is the yield you would get if the reaction worked perfectly.
Calculate the percentage yield: The percent yield is simply the actual yield divided by theoretical yield multiplied by 100.
Be sure that actual and theoretical yields are both in the same units so that units cancel in the calculation.
www.uwosh.edu /faculty_staff/kedrowsk/yield_calc.htm   (1085 words)

  
 2002 Greener Synthetic Pathways Award | Presidential Green Chemistry Challenge | US EPA
Applying the principles of green chemistry, Pfizer has dramatically improved the commercial manufacturing process of sertraline.
The new process consists of imine formation of monomethylamine with a tetralone, followed by reduction of the imine function and in situ resolution of the diastereomeric salts of mandelic acid to provide chirally pure sertraline in much higher yield and with greater selectivity.
By eliminating waste, reducing solvents, and maximizing the yield of key intermediates, Pfizer has demonstrated significant green chemistry innovation in the manufacture of an important pharmaceutical agent.
www.epa.gov /greenchemistry/pubs/pgcc/winners/gspa02.html   (489 words)

  
 Chemistry : Chapter 4 : Overview   (Site not responding. Last check: 2007-10-10)
The mole is just a specific number of things, in the case of chemistry either molecules or atoms.
The yield predicted from stoichiometric calculation is called the theoretical yield, since it is based on our stoichiometric theory.
Consequently, the actual yield, the amount of product really produced by the reaction, is never more than the theoretical yield.
www.wwnorton.com /chemistry/overview/ch4.htm   (1537 words)

  
 General Chemistry Online: FAQ: The mole concept: How do I compute yield for multistep synthesis (Cr(acac)_3_)?
The urea reacts with water to yield CO, ammonium ion, and hydroxide ion.
Find a yield for each of the starting materials, assuming the others are present in excess.
The percentage yield is just your experimental yield divided by the theoretical yield, times 100%.
antoine.frostburg.edu /chem/senese/101/moles/faq/yield-cracac3.shtml   (187 words)

  
 CU Boulder Organic Chemistry Undergraduate Courses
The Organic Chemistry lab and lecture courses are the 3000-level, pre-professional organic courses that are required for chemistry majors and pre-medical students as well as disciplines in biology, engineering, kinesiology, and psychology.
The lecture courses are taught by the Organic Chemistry faculty on a rotating basis.
The organic chemistry laboratories are managed by Patty Feist, the Laboratory Coordinator.
orgchem.colorado.edu   (335 words)

  
 BSU Chemistry - Robert Morris Research
We are currently involved in the synthesis and study of early transition metal indenyl complexes.
to yield new classes of organometallic species that are likely to lead to new reaction pathways involving the metal-indenyl bond.
We are also interested in the chemistry of indenyl metal complexes that contain imido, oxo, sulfido, alkylidene, and alkylidyne ligands.
www.bsu.edu /chemistry/morris_research.html   (273 words)

  
 Dr. Thomas Wiese
The branch of chemistry involved with the measurement of molecules without any particular regard to what the molecule is.
"The chemistry of life" Study of the structure and properties of molecules in living organisms and how those molecules are made, changed, and broken down.
"The physics of chemistry" A branch of chemistry which is interested in things such as, how much pressure would have to be placed on a solid to convert it to a liquid.
www.fhsu.edu /chemistry/twiese/glossary/chemglossary.htm   (5238 words)

  
 Calculating theoretical and percent yield   (Site not responding. Last check: 2007-10-10)
Since chemistry is a cumulative discipline, we expect students to remember topics from previous chemistry course.
If one of the products is organic and the other is inorganic, in an organic chemistry synthesis the product of interest will be the organic compound (duh...).
This is the theoretical yield, expressed in moles.
classes.colgate.edu /pjue/chem263/yields.htm   (221 words)

  
 Yield - Wikipedia, the free encyclopedia
Crop yield, a measure of the output per unit area of land under cultivation
Yield (finance), the rate of return the holder earns on a financial instrument or security
Terminal yield, in formal language theory is the sequence of leaves encountered in an ordered walk of a tree structure
en.wikipedia.org /wiki/Yield   (263 words)

  
 atom economy
Students are often required, especially in laboratory, to determine the theoretical yield based upon the limiting reagent and then to calculate the percentage yield based upon the ratio of the actual yield/theoretical yield X 100.
Rather than consider the percentage yield and (experimental) atom economy separately, an even better indication of the efficiency of a reaction is to consider a combination of the two.
While many chemists would consider a yield of 81% to be a very acceptable, not many would consider the isolation of only 29% of the mass of the reactant atoms in the desired product to be satisfactory.
academic.uofs.edu /faculty/CANNM1/organicmodule.html   (4937 words)

  
 Hypervalent Iodine Chemistry
The authors use this methodology to synthesize diaryl (4, 52-85% yield) and monoaryl (5, 40-60 % yield) derivatives of uracil and thymine (Helv.
The 2-cyano derivatives of pyrrole (43-97% yield), indole (37-62% yield), and thiophene (42-79% yield) were obtained using this cyanation protocol.
This approach was used to synthesize (±)-glaucine (6) (33% yield) and (±)-neospirodienones (7) (42-70% yield).
www.organic-chemistry.org /Highlights/2005/25May.shtm   (736 words)

  
 Syracuse University Department of Chemistry
Professor Ana de Bettencourt-Dias and her group's recently published paper, "Nitro-functionalization and luminescence quantum yield of Eu(III) and Tb(III) benzoic acid complexes," is among the top ten most accessed from Dalton Transactions online for the month of September.
The award is considered the most prestigious scholarship awarded by the University and is a means of remembrance for the 270 people who were killed in the December 21, 1988 bombing of Pan Am Flight 103, of which 35 SU students were aboard.
Construction has begun on the new Life Sciences Complex which will provide an exciting new environment for chemistry and biology research and teaching, and ample space for collaborative and interdisciplinary research.
www-che.syr.edu   (330 words)

  
 Chemistry
The Department of Chemistry is an active centre for teaching and research, well-regarded both in the UK and internationally.
The department was graded 5 in the 2001 Research Assessment Exercise.
Research in the Department spans a range of fields including the traditional subdivisions of organic, inorganic, physical and theoretical chemistry, as well as interdisciplinary areas such as chemical biology, materials science and analytical chemistry.
www.shef.ac.uk /chemistry   (89 words)

  
 Week of January 14,   (Site not responding. Last check: 2007-10-10)
Probably the most important thing that you will learn in Chemistry 200 and Chemistry 201 is the meaning of a balanced equation.
An experimental yield is what you get when you carry out the reaction (or prepare the recipe).
Determine the theoretical yield given a balanced equation and molar masses.
www.science.siu.edu /chemistry/chem201/030402.htm   (397 words)

  
 Organic Chemistry Materials on Xavier Web Sites
Organic Chemistry Lecture I, CHEM 2210 and CHEM 2210D:
Schedule for Organic Chemistry Tutoring, beginning on Monday Sept. 25 in 37-350 (the glass room).
Procedures marked (new) have been revised since the fourth edition was published, and the one marked (all new) isn't in the published version in any form.
www.xula.edu /chemistry/organic/orgo.html   (514 words)

  
 N-chemistry   (Site not responding. Last check: 2007-10-10)
Yield of 20 consective batches of a chemical process.
First 10 batches were run under a standard process and the second 10 under a modified process aimed at increasing mean yield.
Consecutive yields, batch chemical process (Box-J. Series F).
www-personal.buseco.monash.edu.au /~hyndman/TSDL/chemistry.html   (87 words)

  
 For Muslims, strict rules of Ramadan yield to a sweet feast with family and friends   (Site not responding. Last check: 2007-10-10)
For Muslims, strict rules of Ramadan yield to a sweet feast with family and friends
As the holy month of Ramadan draws to a close each fall, however, and Muslim families such as hers begin to prepare for a joyous three-day festival known as "Eid al-Fitr (eed al fitter)," that all changes for Mrs.
Kucukkal, who was born in Ankara, Turkey, and now lives in Forest Hills with her husband, Mustafa, a Ph.D. candidate in chemistry at the University of Pittsburgh.
www.post-gazette.com /pg/06292/731154-34.stm   (1773 words)

  
 Tubular Steel - Product Highlight > TSI-003 High Yield Special Chemistry
Offshore Oil has always used an A106 C specification with a 50,000 lb minimum yield for its crane drums.
Tubular Steel (TSI) met this requirement in the past for Offshore by searching through its inventory to find A106 C material that exceeded traditional specifications and met Offshore's requirements.
In addition, wherever possible, TSI sought to identify material that could meet industry standard specifications, while reducing weight and thus the cost to fabricate and deploy off-shore equipment.
www.tubularsteel.com /solutions_sol010.asp   (368 words)

  
 Amazon.com: Columbia Review High - Yield Organic Chemistry (Columbia Review): Books: Stephen Bresnick MD DDS   (Site not responding. Last check: 2007-10-10)
Examkrackers 1001 Questions in MCAT Chemistry (Examkrackers) by Scott, Ph.D. Calvin
Concise outline of key facts and concepts in organic chemistry for students preparing for post-graduate exams, such as MCAT.
Success in organic chemistry requires a thorough knowledge and understanding of the basics.
www.amazon.com /Columbia-Review-High-Organic-Chemistry/dp/0683180711   (955 words)

  
 General Chemistry Online: FAQ: The mole concept: How do I calculate the "expected yield" for a reaction?
I need to calculate % yield for my lab experiment.
I know it equals actual yield/expected yield x100, but how do I calculate the expected yield?
The expected or theoretical yield is the amount of product obtained if the limiting reagent reacts completely.
antoine.frostburg.edu /chem/senese/101/moles/faq/percent-yield.shtml   (206 words)

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