CHEMISTRY 160

PHYSICAL MEASUREMENTS AND ANALYSIS

Links are provided in this WWW page to components of the laboratory manual. The document is normally in Microsoft Word .doc format.

Chemistry 160 is an upper-division laboratory course that is divided into two half-course modules, Chemistry 160a and Chemistry 160b. It is a requirement for the concentration in chemistry. The half-courses may be taken in any order. Normally, Chemistry 160a would be taken first. The course is structured so that Chemistry 160a addresses analytical chemistry and Chemistry 160b, physical chemistry. Each half-course has 6 experiments, a statistics exercise, and a library project. In order to receive a passing grade in each half-course, the student must complete all 6 experiments and submit the statistics exercise, the library report, short reports on all 6 experiments, and two papers. The papers are written in the style of a research article in the primary chemical literature. The format of the paper and other administrative details of the course are described in the course syllabus.  Starting with the 2006-2007 academic year, Chemistry 160a will be combined with Chemistry 183 to form Chemistry 161, a full course.  Similarly, Chemistry 160b will morph into Chemistry 162, also a full course with lecture and lab work.  The present 160b will constitute the lab work.  The lecture portion of 162 will include statistical mechanics, group theory, and crystallography.

Handouts Used in Both Chemistry 160a and 160b

Chemistry 160a

Focus: analytical chemistry and instrumental analysis

Prerequisite: General Chemistry (Chem 1a,b or Chem 51) and Organic Chemistry (Chem 110a,b)

Required Texts:

1) J. S. Dodd, ed., The ACS Style Guide, 2nd. Ed., American Chemical Society, Washington, DC, 1997.

2) J. N. Miller and J. C. Miller, Statistics and Chemometrics for Analytical Chemistry, 4th. ed., Prentice-Hall, Harlow, England, 2000.

Recommended Text:

1) D. Skoog, Principles of Instrumental Analysis, Saunders.

Focus of statistics exercise: testing of hypotheses and ANOVA. The text for the discussion is Miller and Miller. However, EURACHEM has produced the second edition of its guide on the application of statistics to analytical chemistry. A pdf copy of this comprehensive guide, Quantifying Uncertainty in Analytical Measurement, is available from this Chem 160 WWW site.

Experiments for the course:

1) DATA ACQUISITION VIA LABVIEW. As an introduction to data acquisition via computer control, the graphical programming language LabVIEW will be used. The decay constant of an RC circuit is determined with the aid of an IBM PC microcomputer and the decay curve for the discharge of the capacitor is plotted.

2) ATOMIC ABSORPTION SPECTROSCOPY. Determination of iron in copper-base alloys using a Perkin-Elmer AA spectrophotometer.

3) QUANTITATIVE ANALYSIS OF ASCORBIC ACID USING HYDRODYNAMIC MODULATION VOLTAMMETRY. The concentration of vitamin C in a fruit juice sample will be determined using voltammetry at a solid-state electrode.

(ANODIC STRIPPING VOLTAMMETRY, an alternative electrochemistry experiment that employs voltammetry in the analysis of trace levels of metal ions)

4) GC-MS ANALYSIS. The volatile components of a fragrant foodstuff such as Colombard wine will be determined using gas chromatography and mass spectrometry. Sample collection will involve SPME. We recommend the excellent review of SPME written by G. Vas and K. Vekey.

5) HIGH PERFORMANCE LIQUID CHROMATOGRAPHY. (first draft).

Chemistry 160b

Focus: experimental physical chemistry

Prerequisites: first semester of Physical Chemistry (Chem 158a) or permission of the instructor. For example, a combination of General Chemistry and Physics 101 would be an appropriate substitute for Chemistry 158a and its prerequisites.

Required Texts:

1) J. S. Dodd, ed., The ACS Style Guide, 2nd. Ed., American Chemical Society, Washington, DC, 1997.

2) J. N. Miller and J. C. Miller, Statistics and Chemometrics for Analytical Chemistry, 4th. ed., Prentice-Hall, Harlow, England, 2000.

Recommended Text:

1) D. P. Shoemaker, C. W. Garland, and J. W. Nibler, Experiments in Physical Chemistry, 6th. ed., McGraw-Hill, New York, 1996.

Focus of the statistics exercise: method of least squares, regression analysis
For your reference, a previous exercise is available here.

Schedule and list with instructors of the experiments in Chemistry 160b for the spring, 2006 semester:

Present experiments for the course:

1) IODINE ABSORPTION SPECTRUM. The vibrational-electronic spectrum of the X-B transition of gaseous iodine is recorded on a Varian 300 spectrophotometer. From the spectrum, the electronic energy, vibrational constants, and dissociation energies are determined.  The protocol comes with a summary of formulae from statistical mechanics.

2) DETERMINATION OF A BARRIER TO INTERNAL ROTATION. Determination of the rate of internal rotation in N,N-dimethylacetamide as a function of temperature from an analysis of the line shape of the proton NMR spectrum. The NMR line shapes are analyzed via a non-linear regression module of NCSS that requires a special template, NMR.15.

3) POWER X-RAY DIFFRACTION. The powder X-ray diffraction pattern of a binary substance is measured and the structure of the substance is determined from a Fourier analysis of the data acquired on the X-ray diffractometer in the Geology Department. A document describing the USE OF THE X-RAY DIFFRACTOMETER accompanies the protocol for this experiment.

4) GAS-PHASE ADSORPTION. The adsorption of nitrogen and dichloromethane on a molecular sieve is determined. The experiment provides experience with manipulations on a vacuum line.

5) STOPPED-FLOW KINETICS. Study of the kinetics of the reaction between iron(III) and thiocyanate ions by the stopped-flow method. The HiTech Stopped-Flow System and a digital oscilloscope will be used.

6) MAGNETIC RESONANCE IMAGING. Biological specimens that fit in a 5 mm NMR tube will be imaged using a triple-axis gradient probe and ParaVision, Bruker's professional imaging software.

Experiments previously used in the course:

1) VIBRATION-ROTATION SPECTRUM OF HCl. Interpretation of the high-resolution ro-vibrational spectra of gaseous HCl and DCl and the calculation of thermodynamic constants from the spectroscopic data using spectra obtained from a Nicolet FT-IR.  This experiment is now part of Chemistry 158a.

2) SELECTIVE IRRADIATION NMR EXPERIMENTS. Develop proficiency in obtaining (1) a spectrum using homonuclear decoupling to assign J-coupled protons and (2) a 1D-NOE difference spectrum to detect spatially proximal protons.

3) DETERMINATION OF T1 AND T2. The longitudinal and transverse relaxation times of water are determined using pulsed NMR on a Bruker 400 MHz spectrometer. The rotational correlation time is determined from the NMR data and compared with a value estimated from viscosity measurements.

4) THE ENTHALPY AND ENTROPY OF EXCIMER FORMATION.    Fluorimetry will be employed to study the thermodynamics and steady-state kinetics of excimer formation.  The department's Varian Eclipse fluorimeter will be used.

 

 

 

http:\\pages.pomona.edu\~wsteinmetz\chem160\index.htm, 20 December 2006