Chemistry 125 Lecture 21 October 22 2010 Berzelius

Chemistry 125: Lecture 21 October 22, 2010 Berzelius, Gay-Lussac, & Davy (1805 -1830) Wöhler’s Isomerism (1828) Liebig’s Analysis (1831) Berzelius improved Dalton’s atomic weights as well as combustion analysis for organic compounds. Together with Davy in London and Gay-Lussac in Paris, he discovered new elements by electrolysis, which also led to theory of dualism, wherein atoms were united by electrostatic attraction. Wöhler’s report on the synthesis of urea reveals a persistent naiveté about treating quantitative data. His discovery of isomerism made it clear that there was more to chemical substances than which atoms they contained and in what ratios. The progress of structural chemistry throughout the 19 th Century depended heavily on C & H analysis using Liebig’s profoundly simple “Kaliapparat”. Work by Wöhler and Liebig on benzaldehyde inspired a general theory of organic chemistry focusing on so-called “radicals” collections of atoms that appeared to behave as elements and to persist unchanged through organic reactions. For copyright notice see final page of this file

Jöns-Jakob Berzelius BERZELIUS (1779 -1848) Organic & Mineral Analysis 2000 compounds in 6 years! Good Atomic Weights Textbook (1808) for 50 elements! Electrolysis Dualism (double decomposition) Teaching & Writing Notation for Composition

Berzelius’s Table of atomic & molecular weights (1831) Weights

Scaled to modern O = 15. 9994 [15. 999] 0. 998 (-1. 0%) Bars denote doubled atoms 14. 162 (-1. 0) 32. 185 (0. 4) 30. 974 (1. 3) discrepancy from modern value 10 -fold increase in accuracy from Dalton! Based on O = 100 or H 2 = 1

Combustion Analysis

Improved Method of Combustion Analysis Berzelius Analysis (1) Tube 1/2” diameter (Fig 1) charged with 2 dried powder containing: (4) Assembled (Fig 6) so that gases (O 2, CO ) that exit drying tube ~0. 5 Joined (Fig 4) to water-collecting bulb (Fig 3) will of organic bell-jar containing Hg analyzed, (3) gbubble into substance to be(Fig 2) (2) Neck of tube heated and drawn out with floating. Na. Cl. O 3 5) holding KOHsource), CO 2) 3 g bulb drying tube with 2 (to absorb and Ca. Cl 2 (Fig (Gay-Lussac’s Orubber tubing and closed with permeable glove leather dilution). out Hg). 50 g Na. Cl (to moderate reaction by (to keep

Improved Method of Combustion Analysis Berzelius Analysis O 2 KOH CO 2 (5)(6) To be certain the KOH absorbs all of the CO 2 from near end to Build fire in brick enclosure to heat tube slowly through the far. Tubeleather, wait 12 metal sheet to keep it from popping when it glove wrapped with hours after the mercury stops rising in the softensjar before disassembling and weighing. to bubble through Hg. bell at red heat under the pressure necessary

Electricity

N 2 O at the Royal Institution London, 1802 Humphry Davy New York Public Library http: //seeing. nypl. org/152 t. html

1807 -8 Humphry Davy Big Science at London’s Royal Institution Electrolysis Cu Zn “couple” 1. 1 v 26 v 301 v 12× 12” Pile 6× 6” 110 v 1799 4× 4” Volta 165 v Battery of Berzelius

Davy (1808) I acted upon aqueous solutions of potash and soda, saturated at common temperatures, by the highest electrical power I could command, and which was produced by a combination of Voltaic batteries belonging to the Royal Institution, containing 24 plates of copper and zinc of 12 inches square, 100 plates of 6 inches, and 150 of 4 inches square… …though there was a high intensity of action, the water of the solutions alone was affected, and hydrogen and oxygen disengaged with the production of much heat and violent effervescence.

Davy (1808) The presence of water appearing thus to prevent any decomposition, I used potash in igneous fusion. By means of a stream of oxygen gas from a gasometer applied to the flame of a spirit lamp, which was thrown on a platina spoon containing potash, this alkali was kept for some minutes in a strong red heat, and in a state of perfect fluidity. The spoon was preserved in communication with the positive side of the battery of the power of 100 of 6 inches, highly charged; and the connection from the negative side was made by a platina wire. By this arrangement some brilliant phenomena were produced. The potash appeared a conductor in a high degree, and as long as the communication was preserved, a most intense light was exhibited at the negative wire, and a column of flame, which seemed to be owing to the development of combustible matter, arose from the point of contact.

Davy (1808) A small piece of pure potash, which had been exposed for a few seconds to the atmosphere, so as to give conducting power to the surface, was placed upon an insulated disc of platina, connected with the negative side of the battery of the power of 250 of 6 and 4, in a state of intense activity; and a platina wire, communicating with the positive side, was brought in contact with the upper surface of the alkali. …small globules having a high metallic lustre, and being precisely similar in visible characters to quick-silver, appeared, some of which burnt with explosion and bright flame, as soon as they were formed, and others remained, and were merely tarnished, and finally covered by a white film which formed on their surfaces.

1807 -8 Humphry Davy Big Science at London’s Royal Institution Li Be B Na Mg Al K Ca Ga Rb Sr In ~650 v Cs Ba Te Napoleon’s Response (via Gay-Lussac) “. . . on his alluding to the taste produced by the contact of two metals, with that rapidity which characterised all his motions, and before the attendants could interpose any precaution, he thrust the extreme wires of the battery under his tongue, and received a shock which nearly deprived him of sensation. After recovering from its effects, he quitted the laboratory without making any 600 1 kg Cu plates remark, and was never afterwards heard to refer to the 600 2, 200 plates 3 kg Zn v subject. ” from: “The Life of Sir Humphry Davy, Bart. ” 2. 6 tons of metal

Electricity supplied more than new elements. . . It also supplied the organizing principle for Dualism

1774 Symbols Chemical Symbols of 1774 (Sweden) Mix with Caustic Soda

"Double Decomposition" Dualism Explained by Electricity + - AB + + - CD 2 Na. OH + Cu. SO 4 + - AD + + - CB Na 2 SO 4 + Cu (OH)2 precipitate

“Electronegativity” First use in English (according to O. E. D. ) 1837 J. D. Dana Syst. Mineral. 82 When chemistry has so far advanced, that the relative electro-negativity, (if I may so call it, ) or electro-positivity, of the several elements, is fully known, . . we shall probably be able to construct a natural arrangement of minerals on chemical principles. J. D. Dana 1813 -1895 son-in-law of Benjamin Silliman Dana House 1849

Genealogy Top

Wöhler/Liebig

to J. J. Berzelius Heidelberg, 17 July, 1823 “Having developed the greatest respect for you through studying your writings, I have always thought it would be my greatest good fortune to be able to practice this science under the direction of such a man, which has always been my fondest desire. Although I earlier had planned to become a physician…”

With the greatest respect F. Wöhler from Frankfurt am Main

Letter to Berzelius (1837) “To see this old friend [Palmstedt] again, especially here [in Göttingen], was a real delight. He was just the same old guy, with the sole exception that he no longer wears the little toupee swept up over his forehead as he used to do. ” Friedrich Wöhler (1800 -1882)

1828 Urea & Isomerism (problems for Monday, Oct. 25 - see web readings)

Wöhler to Berzelius (1828) "Perhaps you still remember the experiment I carried out in that fortunate time when I was working with you, in which I found that whenever one tries to react cyanic acid with ammonia, a crystalline substance appears which is inert, behaving neither like cyanate nor like ammonia. "

"Ammonium Cyanate" from Double Decomposition NH 3 Not like an ammonium salt! Na. OH + - NH 4 Cl + Ag OCN HNO 3 - + (Just like those from Urea + HNO 3) - NH 4 OCN + Ag Cl H+ OCNH Brilliant Crystal Flakes + Pb++ Pb(OCN)2 Not like a cyanate salt!

Berzelius to Wöhler: "It is a unique situation that the salt nature so entirely disappears when the acid and ammonia combine, one that will certainly be most enlightening for future theory…" Might Ammonium Cyanate Be Urea? Wöhler to Berzelius: "I recently performed a small experiment, appropriate to the limited time I have available, which I quickly completed and which, thank God, did not require a single analysis. "

Urea had already been Analyzed Prout’sof accuracywashonesty than Berzelius’s experiments! Paragon theory and better Approx. Recalc. NH 4 OCN Dr. Prout Atom (calculated by Wöhler (from Berzelius Ratios Modern (1817) Berzelius) atomic weights) N C H O 1 46. 650 46. 65 46. 781 1 19. 975 20. 00 20. 198 2 6. 670 6. 71 //6. 59 06. 595 Discrepancies <2% 1 26. 650 26. 64 26. 24 26. 425 identical Total 99. 875 100. 00 99. 80? 100. 000 99. 945 truncated Error Dyslectic Prout didwrong) bybetter than Berzelius’s Theory dry-lab making an approximate analysis Experimental Candor? (added Prout’s Experiment instead of (& he theory! and reporting results “corrected” by his didn't notice!) Prout N 2 by gas volume: "6. 3 T, P within 0. 02%? Lucky? V, cubic inches" up rounding Just Moral: Don’t dry-lab! (like Lavoisier) Prout’s Atomic Weight Theory: H = 1 ("protyle" ulh rwth) C = 6 ; O = 8 ; N = 14

Ammonium Cyanate to Urea make & break s* n ? * n attack * Can ammonium H cyanate exist? H 2 N s* NH 2 C n poor overlap Resonance OH probably Structures! C=O very stable (lore) intermolecular

Dunitz, Harris, et al. (1998)

Wöhler on Isomerism (1828) "I refrain from all the considerations which so naturally suggest themselves from this fact, especially in respect to the composition ratios of organic substances and in respect to similar elemental and quantitative compositions among compounds with very different properties, as may be supposed, among others, of fulminic acid and cyanic acid and of a liquid hydrocarbon and the olefiant gas, and it must be left to further investigations of many similar cases to decide what general laws can be derived therefrom. "

On the Composition of Tartaric Acid and Racemic Acid (John's Acid from the Vosges Mountains), on the Atomic Weight of Lead Oxide, together with General Remarks on those Substances with have the Same Composition but Different Properties. by J. J. Berzelius (1830) "I have thought it necessary to choose between the words : homosynthetic and isomeric substances. The former is built from homos, equivalent, and synthetos, put together; the latter from isomeres has the same meaning, although it only properly says put together from the same pieces. The latter has the advantage with respect to brevity and euphony, and thus. X-Ray showed that I have decided to these crystals are choose it. " Calcium Tartrate • 4 H O "By isomeric substances I understand those which possess 2 the same chemical composition and the same atomic [molecular] weight, but different properties. "

There is more to chemistry than Berzelius’s analytical COMPOSITION! Now we know the importance of atomic arrangement, or STRUCTURE: CONSTITUTION CONFIGURATION CONFORMATION but we need to be patient.

HNCO Isomer Energies W. D. Allen et al. , J. Chem. Phys. , 120, 11586 -11599 (2004) (same CNO anion) N C C + N O +56. 3 _ O +40. 9 Fulminic Acid (Liebig) (Latin fulmen = lightning) "we have pushed ab initio quantum chemistry to its current limits for the C N O -3. 1 species NCO, HOCN, HCNO, and HONO, all in pursuit of (same NCO anion interconvert easily) subchemical accuracy Cyanic Acid (Wöhler) (approximately 0. 1 -0. 2 C -27. 8 N O kcal/mole)"

Justus Liebig (1803 -1873) 1824 in Paris working on Silver Fulminate with Gay-Lussac, who noticed the analysis was like Wöhler's of Silver Cyanate Liebig 1836

SCL Library

Liebig Analysis (1831) (1837) Combustion H 2 O Collector cushioned tilted CO 2 Collector

Backwards! Big Kaliapparat out in 1852

Lab Liebig’s Laboratory in Giessen

Stammbaum Some Liebig Scientific Descendants you Red = Nobel Prize

Lab Workers ? A master and glittering teacher of chemistry the triumphant discoverer of aniline and aniline dyes

1832 Radical Theory

Correspondence of Liebig & Wöhler Winter 1825 - Wöhler and Liebig first meet in Frankfurt. October 1830 - They first write using familiar “Du”. 16 May 1832 - Wöhler: I long to do some more significant work. Shouldn't we try to shed some light on the confusion about the oil of bitter almonds? But where to get material? 15 June 1832 - Liebig: My poor, dear Wöhler, how empty is every comfort against such a loss…When I think how content and happy you were during your move, what attachment and love you had for one another…The good wife, so young, so full of life, and so irreplaceable for her parents and for you…

Correspondence of Liebig & Wöhler Come to us, dear Wöhler, although we may not be able to give you comfort, we will perhaps be able to help you bear your grief. Staying in Cassel at this time would only be detrimental to your health. We need to be busy with something, I have just been able to get some amygdalin from Paris, and I am ordering 25 pounds of bitter almonds. You must not travel, you must busy yourself, but not in Cassel. I haven't had the courage to tell my wife yet. I can only tell her bit by bit because I know how much it will affect her. Come to us, I expect you at the end of this week.

End of Lecture 21 October 22, 2010 Copyright © J. M. Mc. Bride 2009, 2010. Some rights reserved. Except for cited third-party materials, and those used by visiting speakers, all content is licensed under a Creative Commons License (Attribution-Non. Commercial-Share. Alike 3. 0). Use of this content constitutes your acceptance of the noted license and the terms and conditions of use. Materials from Wikimedia Commons are denoted by the symbol . Third party materials may be subject to additional intellectual property notices, information, or restrictions. The following attribution may be used when reusing material that is not identified as third-party content: J. M. Mc. Bride, Chem 125. License: Creative Commons BY-NC-SA 3. 0