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The case of carbonic acid

The case of carbonic acid. This means that carbonic acid is stronger than acetic acid!!. However, the conventionally given p K a1(apparent) value refers to the sum of CO 2 and H 2 CO 3 :. Angew. Chem. Int. Ed. 2000, 39 , 892-894. Synthesis and isolation:. Buffer equation or

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The case of carbonic acid

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  1. The case of carbonic acid This means that carbonic acid is stronger than acetic acid!! However, the conventionally given pKa1(apparent) value refers to the sum of CO2 and H2CO3:

  2. Angew. Chem. Int. Ed. 2000, 39, 892-894 Synthesis and isolation:

  3. Buffer equation or Henderson-Hasselbalch Equation Lawrence JosephHenderson (June 3, 1978, Lynn, Massachusetts, USA – February 10, 1942 Boston, USA) Henderson studied medicine at Harvard and was Professor of Biological Chemistry at Harvard University, Cambridge, Massachusetts, from 1904 to 1942 [i]. Henderson published on the physiological role of buffers [ii-vii] and the relation of medicine to fundamental science. Because he and also Hasselbalch made use of the law of mass action to calculate the pH of solutions containing corresponding acid-base pairs, the buffer equation is frequently (esp. in biological sciences) referred to as Henderson-Hasselbalch equation. Refs.: [i] Salié H (ed) (1973) JC Poggendorff Biographisch-literarisches Handwörterbuch der exakten Naturwissenschaften, vol VIIb. Akademie-Verlag Berlin; [ii] Henderson LJ (1908) Am J Physiol 21:173; [iii] Henderson LJ, Spiro E (1908) Biochem Z 15:105; [iv] Henderson LJ (1908) J Amer Chem Soc 30:954; [v] Henderson LJ, Black OF (1908) Amer J Physiol 21:420; [vi] Henderson LJ (1909) Ergebn Physiol 8:254; [vii] Henderson LJ (1910) Biochem Z 24:40; [vii] Henderson LJ (1909) Ergebn Physiol 8:254 Karl Albert Hasselbalch (November 1, 1874, Aastrup, Denmark – September 19, 1962) Hasselbalch studied medicine and physiology, and received his Dr. med. in 1899 for a work on respiration. In 1903/04 he made a study tour to Berlin and Leipzig [i, ii]. Hasselbalch used the law of mass action for carbonic acid as proposed by Henderson to calculate the pH of blood from the carbon dioxide, bicarbonate status [iii, iv]. Hence it happened that the buffer equation is frequently (esp. in the biological sciences) referred to as Henderson-Hasselbalch equation. Refs.: [i] (1936) Dansk Biografisk Leksikon, vol 9. JH Schultz, København; [ii] (1994) Scandinavian Biographical Index. KG Saur, London; [iii] Hasselbalch KA (1916) Biochem Z 78:112; [iv] Warburg EJ(1922) Biochem J 16153

  4. Metal aqua ions are Brønsted acids [Me(H2O)n]m+ + H2O [Me(H2O)n-1(OH)](m-1)+ + H3O+ First acidity constant:

  5. (i.e., ~ ion potential) The polarization of the O-H bond by the metal ion

  6. K.-H. Tytko: Chemie in unserer Zeit 13 (1979) 187 m-th ionisation potential

  7. Examples: MnO4- CrO42-, Cr2O72- Fe3+, Al3+ Fe2+, Ca2+ K+, Na+ Charge of the metal ion K.-H. Tytko: Chemie in unserer Zeit 13 (1979) 187

  8. [Me(H2O)n]m+ + H2O [Me(H2O)n-1(OH)](m-1)+ + H3O+ [Fe(H2O)6]3+ pKa1 = 2.2 Acetic acid pKa1 = 4.75 [Al(H2O)6]3+ pKa1 = 4.9 [Fe(H2O)6]2+ pKa1 = 9.5 [Zn(H2O)6]2+ pKa1 = 9.8

  9. The first protolysis reaction: [Me(H2O)n]m+ + H2O [Me(H2O)n-1(OH)](m-1)+ + H3O+ The second protolysis reaction: [Me(H2O)n-1(OH)](m-1)+ + H2O [Me(H2O)n-2(OH)2](m-2)+ + H3O+ The third protolysis reaction: [Me(H2O)n-2(OH)2](m-2)+ + H2O [Me(H2O)n-3(OH)3](m-3)+ + H3O+ … and so on …

  10. Protolysis reactions are followed by condensation reactions [Me(H2O)n-1(OH)](m-1)+ + [Me(H2O)n-1(OH)](m-1)+ [Me(H2O)n-1-O-M(H2O)n-1]2(m-1)+ + H2O Dimers, trimers, oligomers, polymers … solid precipitates

  11. K.-H. Tytko: Chemie in unserer Zeit 13 (1979) 187

  12. K.-H. Tytko: Chemie in unserer Zeit 13 (1979) 187

  13. „Hydrolysis of Inorganic Iron(III) Salts“ C. M. Flynn, Jr. Chem. Rev.84 (1984) 31-41

  14. The iron oxide story, or why the soils are brown Atmosphere 4[Fe(H2O)6]2+ + O2 + 4H+ 4[Fe(H2O)6]3+ + 2H2O Corrosion of minerals on the surface Soil [Fe(H2O)6]2+ in groundwater

  15. The iron oxide story, or why the soils are brown Iron oxides [Fe(H2O)6]3+ + H2O Hydroxocomplexes Iron oxide hydrates (Goethite, limonite, …) [Fe(H2O)6]2+ in groundwater

  16. Ruda łąnkowa (darniowa, błotna) nem: Raseneisenerz Bog iron ore (morass ore) : Layers of Goethite (or limonite) around a sandstone core

  17. Small Goethite nodules (buły) formed on the bottom of lake Schwielowsee, near Potsdam, Germany. The diameters range from 1 to 6 mm.

  18. overall O2 start of sediment records 58% in Fe2O3 gram gigantic redox titration of Fe2+, S2-, Mn2+, etc. with O2 83% in SO42- O2 in oceans and atmosphere years before present Oxygen produced by photosynthesis. C = cyanobacteria, E = eobionts, EK = eukaryotes, R = red beds

  19. Banded Iron Formations When the oceans first formed, the waters must have dissolved enormous quantities of reducing iron ions, such as Fe2+. These ferrous ions were the consequences of millions of years of rock weathering in an anaerobic (oxygen-free) environment. The first oxygen produced in the oceans by the early prokaryotic cells would have quickly been taken up in oxidizing reactions with dissolved iron. This oceanic oxidization reaction produces Ferric oxide Fe2O3 that would have deposited in ocean floor sediments. The earliest evidence of this process dates back to the Banded Iron Formations, which reach a peak occurrence in metamorphosed sedimentary rock at least 3.5 billion years old. Most of the major economic deposits of iron ore are from Banded Iron formations. These formations, were created as sediments in ancient oceans and are found in rocks in the range 2 - 3.5 billion years old. Very few banded iron formations have been found with more recent dates, suggesting that the continued production of oxygen had finally exhausted the capability of the dissolved iron ions reservoir. At this point another process started to take up the available oxygen. Red Beds Once the ocean reservoir had been exhausted, the newly created oxygen found another large reservoir - reduced minerals available on the barren land. Oxidization of reduced minerals, such as pyrite FeS2 , exposed on land would transfer oxidized substances to rivers and out to the oceans via river flow. Deposits of Fe2O3 that are found in alternating layers with other sediments of land origin are known as Red Beds, and are found to date from 2.0 billion years ago. The earliest occurrence of red beds is roughly simultaneous with the disappearance of the banded iron formation, further evidence that the oceans were cleared of reduced metals before O2 began to diffuse into the atmosphere.

  20. Steep coast on Rügen island build up from chalk around 70 million years ago as sea sediment (on a grey December day in 2004)

  21. Pyrite (FeS2) nodule (buła)from the chalk of Rügen island (Germany) and Goethite nodules formed by oxidation of such pyrite nodules

  22. Goethite nodules formed by oxidation and leaching of pyrite nodules. The primary product is a very acidic solution of iron(III) sulfate. This salt dissolves and it is washed away. Only at the outside Goethite is formed by protolysis, condensation and aging.

  23. Acid Mine Drainage Rio Tinto, Spain (Wikipedia)

  24. Biogeochemistry Profile of a hydrothermal ore course with sulfidic ore paragenesis in the oxidation-cementation zone

  25. Acidithiobacillus • Acidithiobacillus ferrooxidans: • oxidizes Fe(II) and sulfur (and S-compounds)) • Acidithiobacillus thiooxidans: oxidizes sulfur (and S-compounds)) • autotrophic, chemolithotrophic: • Oxidation von Fe2+, S0, S2-, S22-, S2O32- zu Fe3+, SO42-; • Electron acceptor: O2 • C-source: CO2 Source: http://www.google.de/imgres?imgurl=http://2009.igem.org/wiki/images/thumb/4/4a/Tokyo_tech_Iron_bacteria.jpg/300px-Tokyo_tech_Iron_bacteria.jpg&imgrefurl=http://2009.igem.org/Team:Tokyo_Tech/Iron-oxidizing_bacteria&usg=__BHHdzC2oXQxZWcanm8TBt0r3Br0=&h=225&w=300&sz=11&hl=de&start=0&zoom=1&tbnid=eKmbSklar8kEcM:&tbnh=147&tbnw=196&ei=nTDCTqf-A4aPswavjv3zCw&prev=/search%3Fq%3Dacidithiobacillus%26um%3D1%26hl%3Dde%26sa%3DN%26biw%3D1280%26bih%3D841%26tbm%3Disch&um=1&itbs=1&iact=hc&vpx=204&vpy=540&dur=406&hovh=180&hovw=240&tx=126&ty=209&sig=102996319110756286540&page=1&ndsp=21&ved=1t:429,r:16,s:0 http://www.google.de/imgres?imgurl=http://www.amrita.ac.in/bioprojects/IndusMicroBio/microb%2520_cultech/images_culturetech/Acidithiobacillus%2520ferrooxidans.jpg&imgrefurl=http://www.amrita.ac.in/bioprojects/IndusMicroBio/microb%2520_cultech/Mbocultech32.php&usg=__m4_TkIJPiopOaXVuIi_xwDdPNKU=&h=223&w=570&sz=37&hl=de&start=0&zoom=1&tbnid=KrfrSLfXIIBXqM:&tbnh=90&tbnw=231&ei=nTDCTqf-A4aPswavjv3zCw&prev=/search%3Fq%3Dacidithiobacillus%26um%3D1%26hl%3Dde%26sa%3DN%26biw%3D1280%26bih%3D841%26tbm%3Disch&um=1&itbs=1&iact=rc&dur=188&sig=102996319110756286540&page=1&ndsp=21&ved=1t:429,r:1,s:0&tx=53&ty=48

  26. Naica cave, Mexico: 50 °C, 90% relative humidity; length of gypsum crystals up to 15 m; formed over about 500 000 years. Produced by Acidithiobacillus ferrooxidans!!

  27. The biochemical relevance of the acidity of metal-aqua ions Rate constant of CO2 + H2O → H2CO3 : 0.039 s−1 Rate constant of H2CO3 → CO2 + H2O : 23 s−1 Rate constants of the carbonic anhydrase-catalyzed reactions: CO2 + H2O → H2CO3: 1.000.000 s−1 H2CO3 → CO2 + H2O : 400.000 s−1

  28. Carbonic anhydrase The significance of the acidity of metal-aqua complexes for biochemistry, i.e., for human life

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