Undergraduate Physical Chemistry Experiment Research Articles

Adsorção e propriedades de volume de misturas binárias água álcool: um experimento didático com base em medidas de tensão superficial

An undergraduate physical chemistry experiment based on the drop counting method for surface tension measurements is proposed to demonstrate adsorption isotherms of binary aqueous solutions of ethanol, n-propanol, and n-butanol. Excess surface is obtained by the derivative of surface tension taken with respect to alcohol activity, after this activity calculation using van Laar equation. Laboratory class contents are surface tension, excess surface, percolation of hydrogen bonds, micelle, activity, and ideal solution.

An Undergraduate Physical Chemistry Experiment on Surfactants: Electrochemical Study of a Commercial Soap

A general and physical chemistry laboratory on the electrochemistry of soap solutions is proposed. It involves safe, nontoxic, nonpolluting materials, common laboratory apparatuses, and a combination of theoretical and practical concepts. The critical micelle concentration is measured in weight percent and the mean hydrocarbon chain length and soap mixture molar weight are determined. Conductivity data are also used to determine the micelle ionization degree, the micelle and monomer molar conductivity, and the micellar electrophoretic mobility. The existence of a critical micelle concentration range is also visualized. The hydrolysis degree, the fatty acid ionization constant and water solubility, the formation of acid soap, and the concentration at which the first submicellar aggregates form are determined by pH measurements. These results lead to a discussion of several characteristics of surfactant solutions.

Molecular Photophysics of Acridine Yellow Studied by Phosphorescence and Delayed Fluorescence: An Undergraduate Physical Chemistry Experiment

An undergraduate physical chemistry experiment investigating temperature dependent photophysics of acridine yellow is described. The dye molecule exhibits triplet state lifetimes exceeding 150 ms when dissolved in a glassy saccharide host composed of trehalose and glucose. Emission lifetimes are recorded as a function of temperature using camera flash excitation,photomultiplier detection, and a digital scope or analog-to-digital converter requiring only 5 ms resolution. Yellow-green delayed fluorescence is the primary decay route of the triplet state at room temperature, whereas, an orange phosphorescence predominates at lower temperatures. The temperature dependence of the color and duration of delayed emission provide dramatic, tangible evidence of the underlying photophysics. A linear least-squares analysis of the temperature dependence of the excited triplet state lifetime allows both the rate of reverse intersystem crossing to the singlet state and the energy gap between the excited singlet and tripl...

An Undergraduate Physical Chemistry Experiment on the Analysis of First-Order Kinetic Data

The first order kinetic data obtained for the reaction: S2O82- + 2I- --> 2SO42- + I2under pseudo first order conditions is analyzed using the conventional method (Method I), Guggenheim method (Method II) and a similar method proposed by Kezdy et al, Mangelsdorf and Swinborne (Method III). The latter methods are known as time lag methods and they do not require a knowledge of initial and infinite time measurements for the determination of rate constants. These methods are also useful for the prediction of infinite time readings. All the three methods provide results of similar accuracy, if accurate initial and final readins are available. Our present work clearly brings out the approximation involved in assuming a measurement made at finite time as "infinite time reading" in Method I. Between the two time lag methods that we have investigated, Method III is easier to implement.

Kinetic Solvent Isotope Effect: A Simple, Multipurpose Physical Chemistry Experiment

The spontaneous hydrolysis of acetic anhydride in H2O and D2O is a convenient undergraduate physical chemistry experiment that is used to teach practical kinetics, and to demonstrate the kinetic solvent isotope effect. The reaction is monitored by UV-Vis spectroscopy (disappearance of acetic anhydride) by employing a new approach, namely, by measuring the absorbance difference between cuvettes containing the reaction in H2O (reference beam) and D2O (sample beam) in a double-beam spectrophotometer. This technique allows determination of rate constants in both solvents, kH2O and kD2O, respectively, from a single kinetic run by using commercial curve fitting programs. Advantages of the differential absorbance method are instrument time saving, and introduction of the students to the application of curve fitting. To test the quality of the calculated rate constants, the students determine kH2O by conductance measurement, and compare results of both methods. The use of two experiments to study the reaction illustrates the variety of experimental techniques that can be employed for rate measurements.

X-ray Diffraction Investigation of Alloys

This manuscript describes an undergraduate physical chemistry experiment which was recently implemented at the University of Pittsburgh. This experimental exercise uses X-ray powder diffraction patterns to study solid materials. The aim of the experiment is to quantify the lattice parameters of copper, nickel and their alloys. In addition, the students study a physical mixture of these two metals and compare the diffraction pattern with their alloy studies. In this laboratory, students gain experience with X-ray techniques and develop a better appreciation of the distinction between mixtures and solutions.

Mass Ratio of the Deuteron and Proton from the Balmer Spectrum of Hydrogen: Variation on an Undergraduate Physical Chemistry Experiment

A common experiment in some Physical Chemistry Laboratory courses involves the analysis of the Balmer series of the hydrogen atom to derive the Rydberg constant. We describe a simple modification of this experiment, which involves a comparison of the Balmer spectrum of hydrogen and deuteron atoms to determine their nuclear mass ratio. The accuracy of the experiment relies on a sufficient amount of 1H2 being present along with 2H2 in the deuterium lamp for its use as an internal standard. In our implementation, we use a gear-driven 0.25 m scanning monochromator with a 1200 lines/mm grating. The typical precision of our measured mass ratio is better than 10 %.

Estimation of pKa* in the first excited singlet state. A physical chemistry experiment that explores acid-base properties in the excited state

The acid-base reactions in excited states are some of the most elementary processes both in photochemistry and biochemistry and are, therefore, well-suited to form the basis for an undergraduate physical chemistry experiment.

Deuterium exchange kinetics by NMR: An undergraduate physical chemistry experiment

A physical chemistry laboratory that deals with chemical kinetics, catalysis, NMR coupling constants, isotope shifts, and the use of NMR for quantitative measurements.

Kinetic study of adsorption processes in solution: An undergraduate physical chemistry experiment

Kinetic study of adsorption processes in solution: An undergraduate physical chemistry experiment

Thermodynamic data from the thermochromic effect. An undergraduate physical chemistry experiment

This experiment is good for basic physical chemistry undergraduate courses because it can be completed in three hours and it requires a minimum of calculation since the reaction is a simple unimolecular rearrangement.

Molecular multiple photon absorption: An undergraduate physical chemistry experiment in laser isotope separation

Requires a CO2 laser, IR spectrophotometer, and a vacuum manifold for the preparation of gas samples.

Kinetics of nitrogen atom recombination. An undergraduate physical chemistry experiment

A study of the kinetics of recombination of nitrogen (N4S) atoms in which the concentration-time relations are determined directly by utilizing visual observations of emissions to make gas phase ti...

The kinetics of an exchange reaction using a radiochemical tracer. An undergraduate physical chemistry experiment

The authors profile an experiment that has been used successfully in the teaching laboratory to demonstrate the kinetics of an exchange reaction using a radiochemical tracer.

Determination of catalytic coefficient for a first-order reaction. An undergraduate physical chemistry experiment

Determining the catalytic coefficient of the hydronium ion in the acid catalyzed hydrolysis of sucrose.

Variation of azeotropic composition and temperature with pressure: An undergraduate physical chemistry experiment

Reviews the theory of azeotropes, examines the results of the theory for binary liquid-vapor equilibrium, and develops equations for the variation of composition and temperature with pressure for binary systems of nonelectrolytes.

Potential curves for the I2 Molecule: An undergraduate physical chemistry experiment

For this experiment the method of analysis makes use of Granck-Condon principle and it is assumed that the potential energy curve of the excited state is well represented by a Morse function at small internuclear distances.

Polymer molecular weight distribution. An undergraduate physical chemistry experiment

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolymer molecular weight distribution. An undergraduate physical chemistry experimentDavid R. Smith and John W. Raymonda Cite this: J. Chem. Educ. 1972, 49, 8, 577Publication Date (Print):August 1, 1972Publication History Received3 August 2009Published online1 August 1972Published inissue 1 August 1972https://doi.org/10.1021/ed049p577RIGHTS & PERMISSIONSArticle Views497Altmetric-Citations5LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (2 MB) Get e-Alerts Get e-Alerts