“Advanced General Chemistry” Chemistry 201 Prof. Gordie Miller

1. “Advanced General Chemistry” Chemistry 201 Prof. Gordie Miller Websites: http://avogadro.chem.iastate.edu/chem201/ WebCT: https://webct.its.iastate.edu/ Teaching Assistants: Daping Jing (Sect. 5 & 6; Chem 201L: Sect. 3 & 5) Philip Carlson (Sect. 4; Chem 201L: Sect. 4 & 6) Wednesdays: Sect. 4 in 1801 Gilman; Sect. 5 & 6 in 1114 Gilman Exam Dates: Final: Resources: E-Resources for Chemistry(Library Website) Handbook of Chemistry & Physics (CRC Handbook) Please show respect to your colleagues: Turn off cell phones, put aside the Daily, do not use iPods, laptops, or other devices for messaging, facebook, internet browsing, etc. during lectures and recitations.

2. Department of Chemistry Fall Convocation Friday, August 27, 2010; 2:10 p.m. 1352 Gilman Hall “Atoms, Molecules and Bonds, a Multidisciplinary Journey, 400 B.C. to 2000 A.D.” Prof. Klaus Ruedenberg Department of Chemistry Iowa State University

3. Chemical Fundamentals: Introduction Importance of Chemistry in Our Society Research at ISU Ames Laboratory (US DOE) Catron Center for Solar Energy Research Center for Catalysis Center for Physical and Computational Mathematics Center for Sustainable Environmental Technologies Materials Preparation Center Microelectronics Research Center Midwest Forensics Resource Center • Health Issues: • Energy Issues: • Environmental Issues: Beyond the Molecular Frontier, National Research Council, 2003

4. Chemical Fundamentals: Matter (1) Taxonomy Pure Substances Mixtures

5. Chemical Fundamentals: Matter (2) Scale and States • Nuclear: protons + neutrons • Atomic: nucleus + electrons • Molecular: aggregates of atoms • Nanoscale: oligomers, macromolecules • Microscopic: polymers, small crystals • Macroscopic: bulk materials, powders

6. Chemical Fundamentals: Matter (2) Scale and States Carbon Dioxide • Solids: • Liquids: • Gases: • Plasmas: • Supercritical Fluids:

7. Chemical Fundamentals: Matter (3) Properties of Matter Physical Properties: “Measured without changing the identity of the substance” Chemical Properties: CaC2(s) + H2O(l)  CaO(s) + C2H2(g) 2 C2H2(g) + 5 O2(g)  4 CO2(g) + 2 H2O(l)

8. Chemical Fundamentals: Measurements (4) Units • SI Units:Seven fundamental quantities • Length (Meter) • Mass (Kilogram) • Time (Second) • Temperature (degree Kelvin) • Amount (Mole) • Electric Current (Ampere) • Luminous Intensity (Candela) Density= Energy=

9. Systematic (Determinate) Error • Random (Indeterminate) Error Curve Fitting (Regression) (Propagation of Error) Gaussian Distribution Mean Value: Standard Deviation:  Source: J. Schreiner, MPI-Kernphysic X. Peng, et al., Nature404, 59-61(2000) Chemical Fundamentals: Measurements (5) Error Source: H. Joyce, Millenium Mathematics Project

10. (1) (2) (3) Chemical Fundamentals: Measurements (6) Precision vs. Accuracy Standard Deviation Mean Value =?= True Value

11. Chemical Fundamentals: Measurements (7) Significant Figures For each scale, report the value using the appropriate number of significant figures.

12. Chemical Fundamentals: Atoms, Molecules, … (1) Important Experiments • Faraday’s Experiments: • Thomson’s Experiment: • Milliken’s Oil-Drop Experiment: Source: Atom – The Incredible World Source: Atom – The Incredible World

13. Chemical Fundamentals: Atoms, Molecules, … (1) Important Experiments • Rutherford’s Experiment: Source: Encyclopedia of Science • Stern-Gerlach Experiment: Source: Atom – The Incredible World

14. Source: Dr. R.F.W. Bader, McMaster University, Canada. Chemical Fundamentals: Atoms, Molecules, … (2) Atomic Structure • ATOM= • NUCLEUS=

15. Chemical Fundamentals: Atoms, Molecules, … (2) Atomic Structure • Some key consequences: • # Protons (Z) – • # Electrons= • Coreelectrons • Valenceelectrons • # Neutrons Stability of Isotopes Source: www.mc.maricopa.edu/~gilletti/CHM152/NUCLEAR.ppt

16. Chemical Fundamentals: Atoms, Molecules, … (2) Atomic Structure Stability of Isotopes: Radioactive Decay Alpha emission ( particle = 4He nucleus) Beta emission ( particle = electron) Gamma radiation ( = high energy photons) Positron emission (mass of electron; positive charge) Electron (core) capture

17. Chemical Fundamentals: Atoms, Molecules, … (2) Atomic Structure Stability of Isotopes EB /A Source: http://www.alaskajohn.com/physics/charts/binding_energy.jpg

18. Chemical Fundamentals: Atoms, Molecules, … (2) Atomic Structure Spin: response to a magnetic field E.g. 1H is a single proton (spin = 1/2) Nuclear Magnetic Resonance (MRI) – organic and biomolecules… (Klaus Schmidt-Rohr) 2H (= D, deuterium) is a proton + neutron (spin = 1) has different spin-derived physical properties than 1H Chemical Properties: not significantly affected by isotopes, but … It takes more energy to break an OD chemical bond than an OH bond. Why? HOH vs. DOD

19. Chemical Fundamentals: Atoms, Molecules, … (3) Atomic Mass Standard: 12C atom Mass of 12C atom (6 protons, 6 neutrons, 6 electrons) 1 amu = 1.661  1024 g Many atomic masses are close to integer values, e.g., N (14.007 amu) Ca (40.078 amu) Some are not close to integers, e.g., Cl (35.453 amu) Why not?

20. Chemical Fundamentals: Atoms, Molecules, … (3) Atomic Mass GC/LC-MS/MS Mass Spectrometer Source: http://www.epa.gov Source: http://history.nasa.gov

21. Chemical Fundamentals: Atoms, Molecules, … (3) Atomic Mass Let x = abundance of 35Cl y = abundance of 37Cl

22. Electron Microscope Ames Laboratory, US Department of Energy Wilhelm Hall Chemical Fundamentals: Atoms, Molecules, … (4) Microscopy: Can we “see” atoms? To “see” atoms, need light with wavelength ca. 0.1 nm (X-rays) Optical Microscopes: Electron Microscopes: Advantages: Disadvantages:

23. Backscattered e X-rays Cathodaluminescence Secondary e Auger e Elastically Scattered e Inelastically Scattered e Unscattered e Chemical Fundamentals: Atoms, Molecules, … (4) Electron Microscopy: SEM vs. TEM Incident e Beam SAMPLE

24. Incident e Beam Backscattered e X-rays Cathodaluminescence Secondary e Auger e SAMPLE Al-Cu alloy. Chemical Fundamentals: Atoms, Molecules, … (4) Electron Microscopy: SEM Backscattered e: Secondary e: Auger e & X-rays: Factors affecting Image Brightness

25. Incident Electron Beam Secondary e Auger e Backscattered e Range of X-rays Chemical Fundamentals: Atoms, Molecules, … (4) Electron Microscopy: SEM

26. Chemical Fundamentals: Atoms, Molecules, … (4) Electron Microscopy: TEM Incident e Beam SAMPLE Elastically Scattered e Inelastically Scattered e Elastically scattered e: Inelastically scattered e: Unscattered e

27. Chemical Fundamentals: Atoms, Molecules, … (4) Electron Microscopy: Examples Semiconductor Chip (ca. 100  150 m2) Powder Particle (Quasicrystal: Y-Mg-Zn) ca. 30 m radius Source: ISU Dept. of Materials Science and Engineering

28. Chemical Fundamentals: Atoms, Molecules, … (4) Electron Microscopy: Carbon Nanotubes SEM Images TEM Image ca. 60  80 m2 10 nm inner diameter 9 concentric walls Source: http://www.nano-lab.com/imagegallery.html ca. 1.5  2 m2 (1500  2000 nm2)

29. Chemical Fundamentals: Atoms, Molecules, … (4) Electron Microscopy: Material Issues in Nuclear Reactors Pressurized water in a closed coolant loop carries intense heat generated by fission reactions in nuclear fuel rods (in the reactor core) to steam generators. There, heat is transmitted to water in a separate closed loop to form steam, which drives the turbine (to generate electricity), cools, condenses, and returns to the steam generators. To stainless steel specimens exposed to a nuclear reactor environment, an oxygen weight difference of just 0.04% causes the oxygen-richer material (bottom) to become brittle and pocked with micrometer-sized grains. The other sample retains its structural integrity, as seen in these SEM images.

30. Source: A. B. Ellis, ACS, 1993 Chemical Fundamentals: Atoms, Molecules, … (4) Microscopy: Imaging Techniques

31. Chemical Fundamentals: Atoms, Molecules, … (4) Microscopy: Imaging Techniques STM Tip (200 kV incident electrons) Bar length: ca. 20 nm Source: TU-Vienna Source: Purdue Univ.

32. S8 Chemical Fundamentals: Atoms, Molecules, … (4) Microscopy: Imaging Techniques -- STM Source: M.D. Porter, ISU

33. Chemical Fundamentals: Atoms, Molecules, … (4) Microscopy: Imaging Techniques -- Lithography Subsurface H atoms in Pd – PSU arises from Pd atoms rising to make “room” for interstitial H atoms. H atoms find sites by using voltage impulses from an STM tip. Letter height = ca. 0.3 Å; Letter width = ca. 40 Å. Image by: E. H. Sykes, L. Fernandez, B. A. Mantooth, P. Weiss

34. Chemical Fundamentals: Atoms, Molecules, … (4) Microscopy: Improved AFM Capabilities C22H14 Scanning tunneling microscopy (STM) has limited ability to distinguish individual atoms and bonds. In the past, AFM has done no better at resolving atomic-scale features, producing only fuzzy images of individual molecules. CO-tip AFM image (bottom) reveals atoms and bonds of pentacene(top), whereas conventional STM image (center) cannot. Scale bars are 5 Å. Chemical and Engineering News, August 31, 2009, p. 6 Gross, et al. Science 2009,325, 1110

35. Metalloids (Semiconductors) Metals Nonmetals Chemical Fundamentals: Atoms, Molecules, … (5) The Periodic Table

36. Chemical Fundamentals: Atoms, Molecules, … (6) Combining Atoms: Do free atoms exist? • Aggregates: • Diatomic Molecules • Three-dimensional Nets • Rings or Chains • Three-dimensional Sphere Packings • (Everything else…) • Layers

37. Chemical Fundamentals: Atoms, Molecules, … (6) Combining Atoms: Ions Two atoms interact with each other by… (a) (b) “Cations” (net positive charge)… “Anions” (net negative charge)… Polyatomic Ions:

38. Chemical Fundamentals: Atoms, Molecules, … (7) Chemical Formulas (Symbolism) (a) Empirical Formulas – (b) Molecular Formulas – (c) Metallurgical Formulas – (8) Nomenclature: see pages 1-24 to 1-27 in 201 Notes