Chemistry 125: Lecture 21 Berzelius to Liebig and Wöhler ( ) The most prominent chemist in the generation following Lavoisier was Sweden’s J. J. Berzelius. Together with Gay-Lussac in Paris and Davy in London, he discovered new elements and improved atomic weights and combustion analysis for organic compounds. Invention of electrolysis led not only to new elements but also to the theory of dualism, in which elements were united by electrostatic attraction. Wöhler’s report on the synthesis of urea revealed not only isomerism but also a persistent naiveté about treating quantitative data. Through their collaborative investigation of oil of bitter almonds Wöhler and Liebig extended dualism to organic chemistry via the radical theory. Synchronize when the speaker finishes saying “…pay our salaries and learn from us.” Synchrony can be adjusted by using the pause(||) and run(>) controls. For copyright notice see final page of this file

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

Atomic Weights and Equivalents

Silicon Chloride SiCl T. Thomson SiCl 2 L. Gmelin SiCl 3 J. J. Berzelius SiCl 4 Wm. Odling ?

Eilhard Mitscherlich ( ) Goniometer measures angles between crystal faces.

Relating Crystal Shape to Chemical Proportions (formula)

Isomorphism of (NH 4 ) 2 HAsO 4 / (NH 4 ) 2 HPO 4 ( ) Difference (1/10 °) (same shape)

Isomorphism provided definitive atomic weights ratios for some atom pairs. Need for relative atomic weights: Is water HO (Dalton) or H 2 O (Gay-Lussac) ? As atoms must play exactly the same role in arsenates that P atoms play in phosphates. 100 g of N,O,H combines with g P, or g As  As atom 2.55 times as heavy as P atom (neither nor 5.10 times as heavy)

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

Based on O = 100 or H 2 = 1 O = [15.999] (-1.0%) (-1.0) (0.4) (1.3) Bars denote doubled atoms Scaled to modern discrepancy from modern value 10-fold increase in accuracy from Dalton!

Combustion Analysis

Berzelius Analysis (1) Tube 1/2” diameter (Fig 1) charged with dried powder containing: ~0.5 g of organic substance to be analyzed, 3 g NaClO 3 (Gay-Lussac’s O 2 source), 50 g NaCl (to moderate reaction by dilution). (2) Neck of tube heated and drawn out (Fig 2) (4) Assembled (Fig 6) so that gases (O 2, CO 2 ) that exit drying tube will bubble into bell-jar containing Hg with floating bulb (Fig 5) holding KOH (to absorb CO 2 ) and closed with permeable glove leather (to keep out Hg). Improved Method of Combustion Analysis (3) Joined (Fig 4) to water-collecting bulb (Fig 3) and CaCl 2 drying tube with rubber tubing

Berzelius Analysis (6) To be certain the KOH absorbs all of the CO 2 through the glove leather, wait 12 hours after the mercury stops rising in the bell jar before disassembling and weighing. (5) Build fire in brick enclosure to heat tube slowly from near end to far. Tube wrapped with metal sheet to keep it from popping when it softens at red heat under the pressure necessary to bubble through Hg. Improved Method of Combustion Analysis O2O2 KOH CO 2

Electricity

New York Public Library N 2 O at the Royal Institution London, 1802 Humphry Davy

Pile 1799 Volta Battery of Berzelius Humphry Davy Big Science at London’s Royal Institution Electrolysis CuZn “couple” 1.1 v 301 v 26 v 110 v 165 v

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.

Napoleon’s Response (via Gay-Lussac) Humphry Davy Big Science at London’s Royal Institution 600  1 kg Cu plates 600  3 kg Zn plates 2.6 tons of metal ~650 v “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 remark, and was never afterwards heard to refer to the subject.” from: “The Life of Sir Humphry Davy, Bart.” 2,200 v LiBeB NaMgAl KCaGa RbSrIn CsBaTe

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

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

"Double Decomposition" A B + C DA D + C B Explained by Electricity Dualism CuSO 4 2 NaOH Na 2 SO 4 Cu (OH) 2 ++ precipitate

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

Friedrich Wöhler ( ) 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.”

1828 Urea & Isomerism (problems for Wednesday - 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 4 Cl + Ag OCNNH 4 OCN + Ag Cl NH 3 NaOH OCNH H+H+ Pb ++ Pb(OCN) 2 HNO 3 Brilliant Crystal Flakes (Just like those from Urea + HNO 3 ) Not like an ammonium salt! Not like a cyanate salt!

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." Berzelius to W ö hler: "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…"

truncated instead of rounding up Urea had already been Analyzed Prout Atoms N C H O Total Dr. Prout (1817) NH 4 OCN (W ö hler calc. from Berzelius at. wts.) Recalc. (from Berzelius) Discrepancies <2%  identical Dislectic Error ( & he didn't notice!) Prout’s Atomic Weight Theory: H = 1 ("protyle"  ) C = 6 ; O = 8 ; N = 14 Prout N 2 by volume: "6.3 cubic inches" ? (added wrong)  Modern Experiment better than theory Moral: Don’t dry-lab! (like Lavoisier) Prout did dry-lab by making an approximate analysis and reporting results corrected by his theory! Just Lucky?Prout’s theory was better than Berzelius’s experiments! Paragon of accuracy and honesty Experimental Candor?

? Ammonium Cyanate to Urea n ** n ** n ** poor overlap  probably intermolecular Can ammonium cyanate exist? Resonance Structures! NH 2 H2NH2N C O HH attack  * attack  * C=O very stable (lore)

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 I have decided to choose it." "By isomeric substances I understand those which possess the same chemical composition and the same atomic [molecular] weight, but different properties." X-Ray showed that these crystals are Calcium Tartrate 4 H 2 O

There is more to chemistry than analytical C OMPOSITION! Now we know the importance of atomic arrangement, or STRUCTURE: C ONSTITUTION C ONFIGURATION C ONFORMATION but we need to be patient.

HNCO Isomer Energies W.D. Allen et al., J. Chem. Phys., 120, (2004) O C N -3.1 O C N O C N Cyanic Acid (Wöhler) Fulminic Acid (Liebig) "we have pushed ab initio quantum chemistry to its current limits for the species NCO, HNCO, HOCN, HCNO, and HONO, all in pursuit of subchemical accuracy (approximately kcal/mole)" (Latin fulmen = lightning) ONC _ (same NCO anion  interconvert easily) (same CNO anion)

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

SCL

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

Kaliapparat Backwards!?

Lab Liebig’s Laboratory in Giessen

Stammbaum Liebig’s Scientific Descendants Red = Nobel Prize

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

1832 Radical Theory

Correspondence of Liebig & Wöhler Winter Wöhler and Liebig first meet in Frankfurt. October They first write using familiar “Du”. 16 May 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 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 15 June Liebig: 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. Come to us, I expect you at the end of this week.

Correspondence of Liebig & Wöhler 12 July Wöhler: The oil of bitter almonds has come with the books from Paris. I've kept half of it and am herewith sending you the rest. I've already started all kind of experiments with it, without being able to obtain any precise results. It seems to be a hard nut. I'm coming soon to you and will be able to report. 30 August Wöhler: Here I am again in my gloomy lonesomeness not knowing how to thank you for all the love with which you took me in and kept me for so long. How happy I was to work with you from moment to moment. Herewith I'm sending the paper on oil of bitter almonds.

End of Lecture 21 Oct. 24, 2008 Copyright © J. M. McBride 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-NonCommercial-ShareAlike 3.0).Creative Commons License (Attribution-NonCommercial-ShareAlike 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. McBride, Chem 125. License: Creative Commons BY-NC-SA 3.0