Science Bowl Practice Questions Chemistry - 1
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The Lock-And-Key Analogy in 20Th Century Biochemistry
From: Rebecca Mertens The Construction of Analogy-Based Research Programs The Lock-and-Key Analogy in 20th Century Biochemistry April 2019, 224 p., pb., ill. 34,99 € (DE), 978-3-8376-4442-5 E-Book: PDF: 34,99 € (DE), ISBN 978-3-8394-4442-9 When the German chemist Emil Fischer presented his lock-and-key hypothesis in 1899, his analogy to describe the molecular relationship between enzymes and substrates quickly gained vast influence and provided future generations of scientists with a tool to investigate the relation between chemical structure and biological specificity. Rebecca Mertens explains the appeal of the lock-and-key analogy by its role in model building and in the construction of long-term, cross-generational research programs. She argues that a crucial feature of these research programs, namely ascertaining the continuity of core ideas and concepts, is provided by a certain way of analogy-based modelling. Rebecca Mertens (PhD), born in 1984, is a postdoctoral researcher in the history and philosophy of science at the University of Bielefeld, Germany. She works on the role of analogies, models and forms of comparison in the history of molecular genetics and is a member of the collaborative research program "Practices of ComparisonÚ Ordering and Changing the World". During her graduate and doctoral studies, she was a visiting scholar at the École Normale Supérieure in Paris and a visiting graduate fellow at the Minnesota Center for Philosophy of Science. For further information: www.transcript-verlag.de/en/978-3-8376-4442-5 © 2019 -
Colloidal Goldgold
ColloidalColloidal GoldGold Markus Niederberger Email: [email protected] 22.11.2006 OutlineOutline 1) Definition 2) History 3) Synthesis 4) Chemical and Physical Properties 5) Applications 6) References DefinitionDefinition Colloidal gold: Stable suspension of sub-micrometer- sized particles of gold in a liquid ShortShort HistoryHistory ofof GoldGold 4000 B.C.: A culture in Eastern Europe begins to use gold to fashion decorative objects 2500 B.C.: Gold jewelry was found in the Tomb of Djer, king of the First Egyptian Dynasty 1200 B.C.: The Egyptians master the art of beating gold into leaf as well as alloying it with other metals for hardness and color variations 1091 B.C.: Little squares of gold are used in China as a form of money 300 B.C.: Greeks and Jews of ancient Alexandria start to practice Alchemy, the quest of turning base metals into gold 200 B.C.: The Romans gain access to the gold mining region of Spain 50 B.C.: The Romans begin issuing a gold coin called the Aureus 1284 A.D.: Venice introduces the gold Ducat, which soon becomes the most popular coin in the world Source: National Mining Association, Washington HistoryHistory ofof GoldGold ColloidsColloids andand theirtheir ApplicationApplication History: Gold in Medicine Humankind has linked the lustre of gold with the warm, life-giving light of the sun. In cultures, which deified the sun, gold represented its earthly form. The earliest records of the use of gold for medicinal and healing purposes come from Alexandria, Egypt. Over 5000 years ago the Egyptians ingested gold for mental and bodily purification. -
The Correspondence of Julius Haast and Joseph Dalton Hooker, 1861-1886
The Correspondence of Julius Haast and Joseph Dalton Hooker, 1861-1886 Sascha Nolden, Simon Nathan & Esme Mildenhall Geoscience Society of New Zealand miscellaneous publication 133H November 2013 Published by the Geoscience Society of New Zealand Inc, 2013 Information on the Society and its publications is given at www.gsnz.org.nz © Copyright Simon Nathan & Sascha Nolden, 2013 Geoscience Society of New Zealand miscellaneous publication 133H ISBN 978-1-877480-29-4 ISSN 2230-4495 (Online) ISSN 2230-4487 (Print) We gratefully acknowledge financial assistance from the Brian Mason Scientific and Technical Trust which has provided financial support for this project. This document is available as a PDF file that can be downloaded from the Geoscience Society website at: http://www.gsnz.org.nz/information/misc-series-i-49.html Bibliographic Reference Nolden, S.; Nathan, S.; Mildenhall, E. 2013: The Correspondence of Julius Haast and Joseph Dalton Hooker, 1861-1886. Geoscience Society of New Zealand miscellaneous publication 133H. 219 pages. The Correspondence of Julius Haast and Joseph Dalton Hooker, 1861-1886 CONTENTS Introduction 3 The Sumner Cave controversy Sources of the Haast-Hooker correspondence Transcription and presentation of the letters Acknowledgements References Calendar of Letters 8 Transcriptions of the Haast-Hooker letters 12 Appendix 1: Undated letter (fragment), ca 1867 208 Appendix 2: Obituary for Sir Julius von Haast 209 Appendix 3: Biographical register of names mentioned in the correspondence 213 Figures Figure 1: Photographs -
A History of Iridium OVERCOMING the DIFFICULTIES of MELTING and FABRICATION by L
A History of Iridium OVERCOMING THE DIFFICULTIES OF MELTING AND FABRICATION By L. B. Hunt The Johnson Matthey Group The use in unmanned space craft of iridium to encapsulate the radio- isotope thermoelectric generators, where temperatures of up to 20OO0C have to be withstood over several years of operation, with possible impact velocities of 90 metres per second, has focused greater attention on the remarkable properties of this member of the platinum group of metals. But these same properties of very high melting point and great mechanical strength have been the cause of difficulties in its melting and fabrication over a long period of years. How these problems were tackled and eventually overcome is described in this article. One of the less well-known members of the For some fifty years after the discovery of platinum group, iridium possesses quite platinum in South America and the early remarkable chemical and physical properties. It investigations of its properties by a number of is not only the most resistant of all metals to English, French, German and Swedish scien- corrosion, insoluble in all mineral acids in- tists, it was not realised that the native platinum cluding aqua regia and unattacked by other they were examining also contained other molten metals or by silicates at high tem- elements. The first to recognise that a small in- peratures, but has a very high melting point soluble residue survived the dissolution of and is the only metal to maintain good native platinum in aqua regia was the French mechanical properties in air at temperatures chemist Joseph Louis Proust, working for a above 1600OC.Its great stability can be gauged time in Madrid under the patronage of King from its physical properties, outlined in the Carlos IV, but he failed to grasp that other Table. -
Material Safety Data Sheet AQUA REGIA, 2-1-5 (NITRIC 20%/HCL 5%)
2290 Avenue A, Bethlehem, PA 18017 Effective Date: 4/16/2010 NON-EMERGENCY TELEPHONE 24-HOUR CHEMTREC EMERGENCY TELEPHONE 610-866-4225 800-424-9300 Material Safety Data Sheet AQUA REGIA, 2-1-5 (NITRIC 20%/HCL 5%) 1. Product Identification: MIXED ACID CONTAINING NITRIC ACID AND HYDROCHLORIC ACID Synonyms: None CAS No: N/A Molecular Weight: N/A Chemical Formula: N/A 2. Composition/Information on Ingredients Ingredient CAS No Percent Hazardous Nitric Acid 7697-37-2 1 - 25% Yes Hydrochloric Acid 7647-01-0 1 – 10% Yes Water 7732-18-5 65 - 98% No 3. Hazards Identification Emergency Overview POISON! DANGER! CORROSIVE! CORROSIVE. LIQUID AND MIST CAUSE SEVERE BURNS TO ALL BODY TISSUE. MAY BE FATAL IF SWALLOWED OR INHALED. INHALATION MAY CAUSE LUNG AND TOOTH DAMAGE. Potential Health Effects Nitric acid is extremely hazardous; it is a corrosive and a poison. In concentrated solutions it is an oxidizer. Hydrochloric acid is a corrosive. Mixtures of nitric acid and hydrochloric acid may form aqua regia releasing toxic nitrosyl chloride (yellow to reddish-brown) gas. Inhalation: Corrosive! Inhalation of vapors can cause breathing difficulties and lead to pneumonia and pulmonary edema, which may be fatal. Other symptoms may include coughing, choking, and irritation of the nose, throat, and respiratory tract. Ingestion: 1 Corrosive! Swallowing nitric acid and hydrochloric acid can cause immediate pain and burns of the mouth, throat, esophagus and gastrointestinal tract. Skin Contact: Corrosive! Can cause redness, pain, and severe skin burns. Concentrated solutions cause deep ulcers and stain skin a yellow or yellow-brown color. Eye Contact: Corrosive! Vapors are irritating and may cause damage to the eyes. -
Antibodies with Some Bite Antibodies Have Yet to Be Determined, It Is Reasonable to Suppose That the Ester Or David E
-~-------------------------------------N8NSANDVIEWS----------------_N_A_TU_R_E_V-O_L_._32_5_22_J_A_N_U_A_RY__ 19~87 Enzyme catalysis kinetics and is subject to competitive inhibition. Although the detailed chemical mechanisms of these catalytic Antibodies with some bite antibodies have yet to be determined, it is reasonable to suppose that the ester or David E. Hansen carbamate is strained towards a tetra hedral geometry on binding, thus facilitat THE spectacular specificities and rate William Jencks', more directly, stated in ing the attack of the hydroxide ion. Fur enhancements of enzymes are without 1969 thermore, the Scripps group has already equal among all known catalysts. It is no If complementarity between active site and found that their antibody can act via both wonder then that the design of new en transition state contributes significantly to nucleophilic and general base catalysis, zymes has long been a goal of biochemists. enzyme catalysis, it should be possible to syn depending on the substrate used. Now two independent groups, one led by thesize an enzyme by constructing a binding The fact that this approach succeeded at Alfonso Tramontano and Richard Lerner site. One way to do this is to prepare an anti all gives great hope to those attempting to of the Scripps Clinic and Research Foun body to a haptenic group which resembles the isolate even more efficient antibody cat dation', and the other by Peter Schultz of transition state of a given reaction. The com alysts by this and by other strategies. In the University of California at Berkeley\ bining sites of such antibodies should be com addition, it may be possible to modify have taken steps towards this goal by plementary to the transition state and should cause an acceleration by forcing bound sub existing catalytic antibodies. -
Early Russian Organic Chemists and Their Legacy
SpringerBriefs in Molecular Science Early Russian Organic Chemists and Their Legacy Bearbeitet von David Lewis 1. Auflage 2012. Taschenbuch. xii, 136 S. Paperback ISBN 978 3 642 28218 8 Format (B x L): 15,5 x 23,5 cm Gewicht: 237 g Weitere Fachgebiete > Chemie, Biowissenschaften, Agrarwissenschaften > Chemie Allgemein > Geschichte der Chemie Zu Inhaltsverzeichnis schnell und portofrei erhältlich bei Die Online-Fachbuchhandlung beck-shop.de ist spezialisiert auf Fachbücher, insbesondere Recht, Steuern und Wirtschaft. Im Sortiment finden Sie alle Medien (Bücher, Zeitschriften, CDs, eBooks, etc.) aller Verlage. Ergänzt wird das Programm durch Services wie Neuerscheinungsdienst oder Zusammenstellungen von Büchern zu Sonderpreisen. Der Shop führt mehr als 8 Millionen Produkte. Chapter 2 Beginnings 2.1 Introduction At the start of the twentieth century, organic chemistry was not yet 75 years old as a separate and legitimate sub-discipline of the science. Considerable progress had been made in these first seven decades, and the stage was set for the dramatic advances in the science to come in the following century. Most practicing organic chemists are familiar with many of the great German, French and English organic chemists whose work helped the fledgling discipline grow, but few are familiar with the role that Russian organic chemists of the nineteenth and early twentieth century played in the development of the science. And this is in spite of the fact that many of the named rules and reactions that one studies in the first course in organic chemistry are, in fact, of Russian origin. It is the intent of this book to help rectify that deficiency. -
CV Sir Arthur Harden
Curriculum Vitae Prof. Dr. Arthur Harden Name: Sir Arthur Harden Lebensdaten: 12. Oktober 1865 ‐ 17. Juni 1940 Arthur Harden war ein britischer Chemiker. Nach ihm sind die Harden‐Young‐Ester (Zuckerphospha‐ te) benannt. Für seine Forschungen über die Gärung von Zucker und dessen Gärungsenzyme wurde er im Jahr 1929 gemeinsam mit dem deutsch‐schwedischen Chemiker Hans von Euler‐Chelpin mit dem Nobelpreis für Chemie ausgezeichnet. Werdegang Arthur Harden studierte von 1882 bis 1885 Chemie am Owens College der University of Manchester. 1868 ging er mit einem Dalton Scholarship an die Universität Erlangen, um beim Chemiker Otto Fi‐ scher, einem Vetter von Emil Fischer (Nobelpreis für Chemie 1902), zu arbeiten. Dort wurde er 1888 promoviert. Im Anschluss arbeitete er als Dozent am Owens College. Ab 1897 war er am neu gegrün‐ deten British Jenner Institute of Preventive Medicine tätig. 1907 wurde er dort Leiter der Abteilung Biochemie. Außerdem erhielt er 1912 eine Professur für Biochemie an der University of London. Auch nach seiner Emeritierung im Jahr 1930 blieb Harden wissenschaftlich aktiv. So befasste er sich unter anderem mit dem Stoffwechsel von E.coli‐Bakterien sowie mit der Gärung. Gemeinsam mit dem deutsch‐schwedischen Wissenschaftler Hans von Euler‐Chelpin gelang es ihm, diesen Vorgang vollständig aufzuklären. Nobelpreis für Chemie 1929 Die Aufklärung der Gärung als eine der ältesten biologischen Technologien der Menschheit hatte bereits zuvor viele Wissenschaftler zu Forschungsarbeiten angeregt, unter ihnen Louis Pasteur und Justus Freiherr von Liebig. Arthur Harden wurde für seine Forschungen über die Gärung von Zucker und die daran beteiligten Gärungsenzyme im Jahr 1929 gemeinsam mit Hans von Euler‐Chelpin mit dem Nobelpreis für Chemie ausgezeichnet. -
Obituary. Sir Edward Frankland
OBITUARY. SIR EDWARDFRANKLAND. E are again called upon to note the departure of a CO- W worker and master in our chosen field of science. Eulogy is not necessary. The good he has achieved lives after him, and we would merely note that the researches of Sir Edward Frankland. extending over a period of thirty years, relate to work in pure, applied, and physical chemistry. Those in pure chemistry were conducted at first in the laboratories of Playfair, Bunsen, and Liebig. They include subjects related to each other as follows : the conversion of the cyanogen group into the carboxyl group ; the change of the alkyl cyanides to the corresponding organic acids, the saponification of ethyl cyanide was announced by Edward Frankland and Hermann Kolbe when they were fellow assistants in Playfair’s laboratory in 1845. Although this reaction was not then pursued beyond the mono- basic acids, others applied it successfully in other directions. Then followed the action of metallic potassium upon ethyl cyanide and the polymerization of the latter, the isolation of the organic radicals, and the discovery of the organo-metallic com- pounds. Of these, which were investigated by Frankland throughout his scientific career, were zinc methyl and zinc ethyl, in. the study of which the author remarks: “ I had not pro- ceeded far in the investigation of these compounds before the facts brought to light began to impress upon me the existence of a fixity in the maximum combining value or capacity of saturation in the metallic elements which had never before been suspected.” The ready introduction of negative chlorine into bodies for a more electropositive constituent is a fact to which we give little thought. -
A Nobel Synthesis
MILESTONES IN CHEMISTRY Ian Grayson A nobel synthesis IAN GRAYSON Evonik Degussa GmbH, Rodenbacher Chaussee 4, Hanau-Wolfgang, 63457, Germany he first Nobel Prize for chemistry was because it is a scientific challenge, as he awarded in 1901 (to Jacobus van’t Hoff). described in his Nobel lecture: “The synthesis T Up to 2010, the chemistry prize has been of brazilin would have no industrial value; awarded 102 times, to 160 laureates, of whom its biological importance is problematical, only four have been women (1). The most but it is worth while to attempt it for the prominent area for awarding the Nobel Prize sufficient reason that we have no idea how for chemistry has been in organic chemistry, in to accomplish the task” (4). which the Nobel committee includes natural Continuing the list of Nobel Laureates in products, synthesis, catalysis, and polymers. organic synthesis we arrive next at R. B. This amounts to 24 of the prizes. Reading the Woodward. Considered by many the greatest achievements of the earlier organic chemists organic chemist of the 20th century, he who were recipients of the prize, we see that devised syntheses of numerous natural they were drawn to synthesis by the structural Alfred Nobel, 1833-1896 products, including lysergic acid, quinine, analysis and characterisation of natural cortisone and strychnine (Figure 1). 6 compounds. In order to prove the structure conclusively, some In collaboration with Albert Eschenmoser, he achieved the synthesis, even if only a partial synthesis, had to be attempted. It is synthesis of vitamin B12, a mammoth task involving nearly 100 impressive to read of some of the structures which were deduced students and post-docs over many years. -
SCIENCE in LANCASTER in the MID-TWENTIETH CENTURY: the FRANKLAND SOCIETY DF Mowle, Retired Pharmacist, Lancaster
SCIENCE IN LANCASTER IN THE MID-TWENTIETH CENTURY: THE FRANKLAND SOCIETY DF Mowle, Retired Pharmacist, Lancaster The past closes its doors with surprising THE FORMATION OF peed. A chance encounter in the ENT THE FRANKLAND SOCIETY department recently rekindled memories of the Lancaster Frankland Society - a Towards the end of the Great society dedicated to maintaining a Depression of the 1920's Lancaster's group where scientists could hear industries were expanding again. speakers drawn from the forefront of Storey' s and Williamson's were still current research and be provided the largest employers and Nelson's with ample time for discussion. and Lansil had set up factories to utilise the pure water of the River Edward Frankland was born in Lune to produce cellulose acetate Churchtown, two kilometres for textile and plastics southeast of Garstang, on 18th applications. With the influx of January 1825. He attended new chemical graduates Mr EH Lancaster Grammar School when Stansbie of Nelson's shared with it was a small stone building other industrialists the vision of situated just below the west side the need to form a group through of Lancaster Castle. Next, he wa which scientists could maintain apprenticed to Stephen Ross , a contact with the increasing flood of pharmacist practising in Cheapside. scientific research and discoveries The huge mortar and pestle used in an being reported. They did not wish attic room by the apprentices to Lancaster to fall behind m the produce mercurial ointment, can be een expan ion of the cience-based indu tries in Lanca ter Museum. Frankland recorded and their concerns were shared by mixing 14 pounds of hog's lard with six educationalists, too , as the numbers in pounds of mercury for two or three hours each secondary and further education began to rise. -
The Evolution of Formulas and Structure in Organic Chemistry During the 19Th Century Dalton (1803)
The Evolution of Formulas and Structure in Organic Chemistry During the 19th Century Dalton (1803) Dalton’s Symbols (1803) Hydrogen Carbon Oxygen Nitrogen • circles for atoms of elements • occasional use of letters - gold G John Dalton (1766-1844) • must learn the symbol for each element Binary atoms Binary “atoms” water ammonia carbon monoxide OH NH CO Dalton (1803) Ternary atoms Ternary “atoms” carbon dioxide acetic acid olefiant gas OCO H HCH CO Dalton (1803) Berzelius • use first letter of Latin name of element SHCON hydrogencarbonoxygennitrogensulfur • use first two letters when first letter is taken J. J. Berzelius (1779-1848) SeSi siliconselenium Latin roots Latin roots English Latin Symbol antimony stibnum Sb tin stannum Sn sodium natrium Na potassium kalium K Why Latin? Why Latin? “Science, like that nature to which it belongs, is neither limited by time nor space, it belongs to the world, and is of no country and of no age” Sir Humphry Davy Affinity Affinity of the elements Oxygen (most electronegative) … … … … … … … … … (most electropositive) Potassium Dualism Dualism … the electrochemical theory By arranging the atoms in the order of their electrical affinities, one forms an electrochemical system, which is more suitable than any other arrangement to give an idea of chemistry. Berzelius Dualism exemplified Dualism exemplified + - + - K O S 3 O + - KO SO3 KO,SO3 Berzelius sulfate of potash The formula Sulfate of potash KO,SO3 • composed of a base KO and an acid SO3 • formula reflects number and kind of each atom • each atom has a defined mass (weight) Berzelius Dilemma The dilemma in the early 19th century • equivalent weights vs.