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    From Bold Ideas To Nobel Prizes To The Classroom
    By Enrico Uva | October 15th 2012 01:00 AM | 3 comments | Print | E-mail | Track Comments
    About Enrico

    I majored in chemistry, worked briefly in the food industry and at Fisheries and Oceans. I then obtained a degree in education. Since then I have...

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    We often associate awards with recent accomplishments, which is far from the case with Nobel Prizes. They're more akin to Hall of Fame inductions than batting titles. For some time they have been awarded for discoveries that are between one to five decades old. The committee tries to reward an achievement that has withstood the test of time, one that has created a key concept in the field and has opened up new avenues in research and science-related technologies.

    Among key concepts that have been recognized, which ones have become so embedded in chemistry that they are part what's taught in high school? Which started off as unpopular ideas? Although it's expected that the early Nobel Prizes are more likely to fit the former criteria, a few recent prizes honored research that explain basic processes discussed in a first course.

    1. The Oldies

    In 1901, the first Nobel chemistry prize went to Jacobus Henricus Van't Hoff for his studies of osmosis and chemical equilibrium. Seventeen years earlier, in  Etudes de dynamique chimique, he had written that, contrary to what had been previously believed, two-way ongoing reactions occurring at equal rates
    were the rule and not the exception. One of the examples he used became a classic and is still found in current chemistry textbooks 150 years later:
    2 NO2(g)  ⇌ N2O4(g). 
    Although the Nobel prize does not mention Van't Hoff's contribution to stereochemistry, he had also reasoned that a C-C bond with its three other constituents are part of a tetrahedron.

    The above drawings are not the most accurate representation of an alkane, but he was on the right track at a time when the thought of a 3D arrangement wasn't universally well-received:
    The arrangement of atoms in space", by Messrs. van't Hoff and Herrmann, which teems with fantastic trifles. I would ignore this paper as so many others if it were not for a renowned chemist who protected this nonsense and recommended it warmly as meritorious accomplishment. --- Hermann Kolbe (who made many contributions to organic chemistry)
    Since we have no means of knowing the topographical position of the atoms (while we have many for knowing how they are combined) I consider it a bit dangerous for science. ---Adolf Lieben (Held Chair of Pharmacology at Univ. of Vienna for 39 years )
    A good high school student from today would be able to follow a fair share of the 56 -page Nobel lecture given by the third recipient of the chemistry prize, Svante Arrhenius(1903). He not only proposed that acids and bases break up into ions but used ions to explain neutralization reactions and electrical conductivity of solutions. What was interesting is that he used the observation that a constant amount of energy was liberated(13.6 kcal/mole) in the neutralization of any strong acid with a strong base so that in X+ + OH- + H+ + Z---> H2O +  X+ Z-  
    the reaction involved  OH- + H+  -> H2O,  and not the varying spectator ions. Because Perrin had not yet experimentally confirmed Einstein's mathematical analysis of Brownian Motion, the kinetic atomic theory was still in doubt. Arrhenius thus concluded his lecture with the following:
    Theories of molecules and atoms are sometimes attacked on philosophic grounds. Until a better and more satisfactory theory appears, chemists can continue to use the atomic theory with complete confidence. The position is exactly the same as regards electrolytic dissociation.
    Other Nobel Prize ideas that found their way into basic chemistry courses include:
    • The discovery of noble gases and their places in the periodic system by William Ramsay (1904). Through fractional distillation and spectral analysis of liquid argon from liquid air, he isolated new elements: neon, krypton and xenon.
    • (1907) By electrolysis of hydrogen fluoride, HF, Henri Moissan isolated the prostitute of the periodic table, fluorine, which reacts with anything, including cold silicon, burning it with sparks!
    • (1908) Rutherford's research with alpha particles led him to propose a model of the atom in which most of the atom's mass was concentrated in a small positive nucleus. Even though quantum mechanics has changed our concept of subatomic particles, what still holds is that the atom is mostly empty space.
    • (1924) By using a mass spectograph, which separates particles of different masses through ionization and subsequent deflection in a magnetic field, Aston showed that most elements are a mixture of different isotopes. He also used associated an isotope with a whole number to represent the sum of neutrons and protons.
    2. The Babe Ruth of Nobel Chemistry Winners
      (1954) Out of all the chemistry work honored by Nobel committees, Linus Pauling's study of the nature of the chemical bond had the largest impact on the science. He introduced hybridization of electron orbitals to account for the equivalency among carbon's bonds. He also recognized the presence of hybrid orbitals in the coordination of ions or charged groups in a specific geometric arrangement around a central ion. Pauling revealed the polar character of covalent bonds through the concept of electronegativity, the tendency for an atom to dominate the tug of war for electrons while bonded; and resonance hybrids, which explain electromagnetic absorption and chemical reactivity of molecules having conjugated bonds.  
      In the same way that Ruth had a disappointing end to his career and life, Pauling lost the DNA structure race to Crick and Watson by making the embarassing blunder of proposing a structure that neglected the molecule's acidity. Worse, in his ripe years he started a vitamin C cult based on the most scant evidence imaginable.

      3. More Recent Prizes

      (2007) Reaction mechanisms don't reveal themselves too easily. The Haber process has long been described in basic courses, and although the synthetic production of NH3 from N2 is a lot simpler than its natural analogue, it was still a mystery as to how it occurred at the molecular level.  Gerhard Ertl revealed that the rate controlling step involves the chemisorption of dissociated nitrogen atoms on the iron component of the industrial catalyst. Here are all the steps along with the potential energy diagram, which reveals how catalytic adsorption lowers each energy barrier for each step of the mechanism.


      (1992) In papers published between 1956 and 1965, Rudoph Marcus investigated how surrounding solvent molecules affect the rate of redox reactions--oxidation and reduction reactions in which the reactants exchange electrons. Marcus determined that subtle changes occur in the molecular structure of the reactants and the solvent molecules around them. Such changes influence the ability of electrons to move between molecules. He also figured that the relationship between the driving force of an electron-transfer reaction and the reaction's rate is parabolic. As more driving force is applied to a reaction, its rate at first increases but then begins to decrease. There was expected skepticism in the community, until the relation was confirmed experimentally in the 1980s.

      Sources:

      The Arrangement of Atoms in Space.  Van't Hoff. 1874-1877.

      http://www.nobelprize.org/nobel_prizes/chemistry/ (has pdf's of Nobel lectures)

      Double Helix Reader's Guide http://www.brown.edu/Courses/BI0020_Miller/dh/guide.html

      Nobel Prize Winners in Chemistry. Eduard Farber. Abelard-Schuman. 1962

    Comments

    vongehr
    Pauling lost the DNA structure race to Crick and Watson by making the embarassing blunder of proposing a structure that neglected the molecule's acidity. Worse, in his ripe years he started a vitamin C cult based on the most scant evidence imaginable.
    VC = ascorbic acid. You missed the opportunity for a pun on making up for missed acidity.
    miles
    Interesting article Enrico. I bet my students will appreciate your article as we touch the topic on "Who matters in chemistry". Will ask them to check your article.
    UvaE
    Glad the article will prove useful.