Embed Size (px)
Citation preview
This is not your father’s (or my mother’s) physical chemistry course….
Michelle Francl
Bryn Mawr College
Bryn Mawr College was founded in 1885 with a mission to provide graduate education to women.
Course Goals
• Use quantitative, mathematical approach to the description and analysis of the structure and behavior of matter
• Apply these methods to other fields• Appreciate the strength and limitations of the
methods• Take and succeed in a next course in physical
chemistry or subfield• Read the literature as a novice• Retain student interest in the field
Oure termes so lerned and queynte
Whan we be ther where we shul exerciseOure elvish craft, we seme wondrous wyse,Oure termes be so lerned and so queynte.
Yet wil I telle them, as they come to mynde,Though I can not them set right in their kind;As sal armoniak, verdegres, boras;
Geoffrey Chaucer
Traditionally, the earliest known production of what Chaucer calls “sal armoniak”, or ammonium chloride, was from the burning of camel dung in the temple of Jupiter Ammon in what is now Libya – hence “sal ammoniac” or salt of Ammon. This term is the root for “amine” and eventually “amino acid”.
Calculus of Hours
“The Curta is a precision calculating machine for all arithmetical operations. Curta adds, subtracts, multiplies, divides, square and cube roots... and every other computation arising in science and commerce... Available on a trial basis. Price $125”
From an advertisement in the back pages of Scientific American in the 1960s. This is about $700 in 2002 dollars – about the same price as Mathematica.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
• There is not as much time as you think– Less than 40 hours/semester in the
classroom– Read 180,000 words– Do 150-200 problems
• 150 to 200 hours total/semester
Authority vs. Activity
Life is good for only two things, discovering mathematics and teaching mathematics.
Siméon Poisson
Lecture
Reading
Active
Lecture
Reading
Active
Strategies should be
Josiah Willard Gibbs was not paid a salary for the first 9 years of his job at Yale. Once he had a job offer fromJohns Hopkins University in Maryland, Yale began to pay him. He gained little recognition for his work during hislifetime mainly because of his inability to communicate his ideas so that others could understand the concepts he wasdiscussing.
Active
Current
Connected
Active
“Let us learn to dream, gentlemen: then perhaps we will find the truth. But let us beware of publishing our dreams until they have been tested by the waking understanding.” – August Kekule von Stradonitz (taken from The Scientific Attitude, 2nd Edn by Frederic Grinnell)
Talk less, they learn moreUsing the pause procedure to enhance lecture recall. [Ruhl, K. L., Hughes, C.
A., & Schloss, P. J. (1987, Winter). Teacher Education and Special Education, 10, 14-18]
The importance of lecture in general-chemistry course
performance [Birk, J.P., Foster, J. (1993) J Chem Ed 70 179]
Departing from Lectures: An Evaluation of a Peer-Led Guided Inquiry Alternative [Lewis, S.E., Lewis, J.E. (2005) J Chem Ed 82 135]
Do less, they learn moreEffects of lecture information density on medical student
achievement [Russell. I.J., Hendricson, W.D., & Herbert, R.J. (November, 1984).. Journal of Medical Education, 59, 881-889]
Active Materials
Science: (n.) The attempt by subroutines in an operating system to deduce the source code, and write the instruction manual.
Dave Logan
Materials they can talk aboutPhysical Chemistry: A Guided Inquiry Atoms, Molecules and
Spectroscopy. R. S. Moog, J. N. Spencer, J. J. Farrell; Houghton Mifflin: Boston, 2004. )POGIL/NSF
Physical Chemistry Online (PCOL) http://pcol.ch.iup.edu/ NSFCulture of Chemistry: Physical Chemistry in Context NSF
Materials they can useSymMath collection at JCE http://jchemed.chem.wisc.edu/JCEDLib/SymMath/index.html
Connected
Katharine Blodgett was the first woman to earn a Ph.D. in physics from Cambridge under Ernest Rutherford after Irving Langmuir intervened on her behalf. She earned her A.B. from Bryn Mawr College early in the last century. She is best known for her work on Langmuir-Blodgett films.
Context rich materials• Who, what, where, when, why? As such, physical chemistry underlies much of modern science and is a
motor driving advances in a very wide range of fields. Building on information and concepts from chemistry, physics, mathematics, physical chemistry contributes to and is stimulated by areas as diverse as medicine, molecular biology, biochemistry, molecular engineering, chemical engineering, materials science and earth sciences.
• AdvantagesEngagementPerformanceRetention
Context Rich Problems
Context Free:Find an expression for the half-life of the third-order reaction 3A B.
Contextualized:The gas-phase formation of phosgene, CO + Cl2 COCl2 is 3/2 order with respect to CO. Derive the integrated
rate equation for a 3/2 order reaction. Derive the expression for the half-life.
Context rich:In a paper by Bada, Protsch and Schroeder [Nature 241, 394 (1973)], the rate of isomerization of isoleucine in
fossilized bone is used as an indication of the average temperature of the sample since it was deposited. The reaction
L-isoleucine D-alloisoleucineiso allo
produces a nonbiological amino acid, D-alloisoleucine, that can be measured using an automatic amino acid analyzer. At 200C, this first order reaction has a half-life of 125,000 years and its activation energy is 139.7 kJ mol-1. After a very long time, the ratio allo/iso reaches an equilibrium value of 1.38. You may assume that this equilibrium constant is temperature independent.
For a hippopotamus mandible found near a warm spring in South Africa, the allo/iso ration was found to be 0.42. Assuming that no allo was present initially, calculate the ratio of the concentration of allo now present to the concentration of allo after a very long time (Note: the correct answer is between 0.40 and0.60)….
Radiocarbon dating, which is temperature independent, indicated an age of 38,600 years for the hippo tooth….
The famous Boltzmann equation, S=k ln , is inscribed on Boltzmann’s tombstone in Vienna, Austria. Boltzmann did not write it in this form, however, Planck did. Boltzmann also has two other equations named for him, the first is a diffusion equation used in neutron transport theory and the second describes particles in a gravitational field.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Connected Materials
Develop materials keyed to primary scientific literature
• Proof of concept: NSF CCLI-EMD grant
• Early adopter cadre
• Development of materials
• Assessment
Nano comes from the Greek for dwarf: .
What they are not…
• Not to teach library or literature skills
• Not to replace texts
• Not to add new topics
Does anyone actually use nanowires? Well, Dr. Ock in Spiderman 2 claimed to use “nanowires” to connect his neural circuitry to a machine circuit. In fact, silicon nanowires have recently been used to build sensors for DNA. The sensors are designed to detect the presence of mutations in a cystic fibrosis gene. [Nano Letters 2004, 4, 51 -54]
What they are…
• Flexible
• Stand alone
• Extendable
• Context-richEngineers think that equations approximate the real world.
Scientists think that the real world approximates equations.
Mathematicians are unable to make the connection.
Design of Materials
A Case of Mistaken Identity
Fischer of Fischer projections is not the Fischer of Fischer carbenes, and yet another Fischer lends his name to the Fischer-Tropsch reaction All, however, were German.
PapersShortCurrentReadableCross disciplinary
ProblemsCritical readingBasic conceptsVarietyExtendable
MarginaliaHookFaces of chemistryHistory
First order kinetics and ostrich eggs
• Kinetics• Archeology• Biochemistry
Chaos is a name for any order that produces confusion in our minds.
George Santayana
Background
How many millions of years ago were these sediments deposited? Were the colors in this folio applied when it was printed, or sometime later? Is this a modern hippo bone, or a fossil of some similar, earlier species? Just how old is it? The determination of the age of an artifact or sample is a crucial question in many fields, including geology, paleontology, archaeology, anthropology and history. Context often provides a clue to the age of an object. For example, the style of decoration of a vase or the types of pigments applied to a fresco can be used to narrow the time period in which a particular artifact was produced. How deeply something is buried is yet another source of information about an item’s age. Provenance, or the written record of an object’s history, is another source from which the age of an object can be determined. These approaches obviously cannot be applied to find an age for every object or specimen. Chronometric methods, such as the familiar 14C dating, can be brought to bear when the relative dates derived from contextual information are inadequate, or when forgery is suspected.
Amino acids are nearly always found in the L-form in natural products, such as proteins. Uncatalyzed epimerization at the chiral carbon is, not surprisingly, an exceedingly slow….
Prof. Francisco received his Ph.D. in 1983 from MIT, then spent time as a post-doctoral fellow at Cambridge. Prof. Francisco’s group blends high resolution laser spectroscopy and sophisticated electronic structure theory to tease out the connections between reaction rates and chemical structure in free radical chemistries. His research has been key to showing that some refrigerants, such as HFC’s may not pose the same hazards to the ozone layer as CFCs.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Problems
• In an early paper describing this method [Science, 1970, 170, 730-732], there is a note that at equilibrium a small excess of D-alloisoleucine is present (at 140oC they report the ratio of alloisoleucine to isoleucine is 1.25), but that for most amino acids the equilibrium constant between the L and D forms is 1. Why should that be? Why do you suppose it is different for isoleucine?
• Using the expression in question 5 and the parameters given in the paper, compute the forward rate constant at 144oC. What is the value of the rate constant for the reverse reaction at this temperature?
Alan Turing is perhaps best known for his work on codes in World War II, particularly with the Enigma machines. He is also often called the father of computer science. Turing also had a long standing interest in chemistry, and was a long distance running of near Olympic caliber.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Marginalia
How old is a whale?
Humans are among the longest-living mammals, with a life-span on the order of 100 years. Human ages can be verified by consulting birth and census records. Whales are also apparently very long-lived, but discovering the age of a whale is a somewhat more daunting task and the life-spans of most whale species have not been established. The ages of some whales, such as blue whales and fin whales can be determined by counting the layers of ear wax in their inner ears. ….. The degree of racemization of aspartic acid in the lens of the eye has been used to find the ages in 20 different species, including humans. Ages were obtained for 48 different whales, one which had an apparent age of 211 years [Can. J. Zool. 1999, 77, 571–580], making the bowheads the longest living mammals known!
What can you do with an M.D./Ph.D.? (Bio)chemical kinetics, of course.
Maude Menten (1879-1960) was an early M.D./Ph.D., and one of the first women to become a physician in Canada. …….
Unnatural Amino Acids
Thirty years ago, it was assumed that all amino acid residues in naturally occurring polypeptides were in the L-form. We now know there are a few exceptions. For example, some polypeptide antibiotics found in fungi incorporate D-amino acids. It is thought that in most cases the peptide is synthesized with all L-amino acids, subsequently individual amino acids undergo enzymatically catalyzed epimerization. Only one such epimerase has been identified to date. The serine epimerase found in the venom of the funnel spider, Agelenopsis aperta…
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Winning the Prize wasn’t half as exciting as doing the work.
Maria Goeppert MayerNobel Prize winner in physics (1963)
Further Reading
• “Reliability of Amino Acid Racemization Dating and Paleotemperature Analysis on Bones”, M. L. Bender, Nature, 1974, 252, 378-379. “Dr. Bada Replies”, J.L. Bada, ibid. 1974, 252, 379-381. An early controversy over the accuracy of the dates obtained from amino acid racemization.
• See the whole Chaucerian litany in either Middle English or Modern English at http://classiclit.about.com/library/bl-etexts/gchaucer/bl-gchau-can-can-m.htm. Want the full medieval experience? Images of the full text of two 15th century versions can be found at http://www.bl.uk/treasures/caxton/homepage.html. You can read the Canon’s Yeoman’s Tale in (almost) its original form thanks to the British Library.
There was a time when the newspapers said that only twelve men understood the theory of relativity. I do not believe that there ever was such a time. There might have been a time when only one man did, because he was the only guy who caught on, before he wrote his paper. But after people read the paper a lot of people understood the theory of relativity in some way or other, certainly more than twelve. On the other hand, I think I can safely say that nobody understands quantum mechanics.
R. Feynman in The Character of Physical Law. 1965
Blogging
Physics is very muddled again at the moment; it is much too hard for me anyway, and I wish I were a movie comedian or something like that and had never heard anything about physics!
Wolfgang Pauli (1900-1958) From a letter to R. Kronig, 25 May 1925.
• Marginalia• Topics• Solicit and post student
contributions
CultureOfChemistry.blogspot.com
Acknowledgements
Joseph AliaSwarna BasuJoseph Brom Jeanne Bundens Franklin Chen Lisa Chirlian Paul Davis Raymond Esquerra
Brian Gilbert Rainer Glaser Sam GlazierAlan Goren Steve Gravelle Barry Hicks David Horner Jerry Jasinski Kristin Krantzman
Patti Lang
NSF DUE
Bryn Mawr College
Anne McCoy Michael Moore Lynn Melton Maria Pacheco Carol Parish Virginia Pett Ray Rataiczak Tracy Schoolcraft Marcy Towns Matt Tuchler Jane Van Doren John Wheeler Stephanie Schaertel Kathleen Howard
Activation Energy: The useful quantity of energy available in one cup ofcoffee.
Assessment
Which picture is of Gibbs?
