Physical Chemistry Laboratory Research Articles

Working toward a Paperless Undergraduate Physical Chemistry Teaching Laboratory

The use of electronic formats for obtaining, recording, analyzing, and disseminating data is becoming ubiquitous in classrooms, teaching laboratories, research laboratories, and industry. The undergraduate physical chemistry teaching laboratory provides an excellent opportunity to ensure that upper-division chemistry students gain experience in using electronic means of recording and presenting the results of their experiments. To facilitate this action, computers are used in as many aspects of the course as possible: obtaining introductory material, preparing pre-lab reports, recording data in a simulated electronic lab notebook, and submitting final lab reports. Since the physical chemistry laboratory is an advanced undergraduate course, the students are also given increased responsibility for the experiment, creating their own procedure from papers, textbooks, and other additional information.

Measuring Heterogeneous Reaction Rates with ATR-FTIR Spectroscopy To Evaluate Chemical Fates in an Atmospheric Environment: A Physical Chemistry and Environmental Chemistry Laboratory Experiment

This paper reports an undergraduate laboratory experiment to measure heterogeneous liquid/gas reaction kinetics (ozone-oleic acid and ozone-phenothrin) using a flow reactor coupled to an attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrometer. The experiment is specially designed for an upper-level undergraduate Physical Chemistry laboratory course and may be incorporated in environmental chemistry and toxicology laboratory courses as well. From the experiment, students can measure heterogeneous reaction rates, calculate reactive uptake coefficients, and evaluate the lifetime of chemicals in an atmospheric environment, which is conducive to their understanding of several important concepts related to physical chemistry and environmental chemistry.

Evaluating the effectiveness of POGIL-PCL workshops

The POGIL-PCL (Process-Oriented Guided Inquiry Learning in the Physical Chemistry Laboratory) project has developed a series of workshops to introduce faculty to POGIL-PCL and to facilitate the development of new experiments. More than 60 faculty members from various institutions have attended these workshops. Workshop participants were surveyed in order to evaluate the effectiveness of the workshop and better understand why faculty choose to adopt POGIL-PCL. Of the participants who completed the survey, 77% had used POGIL-PCL experiments. The results of the survey show that personal influence is a major factor in all stages of the adoption process.

RANCANG BANGUN PENYARING AIR OTOMATIS

This research aims to design and design an automatic water filter and test the quality of the filtered water using an automatic filter that has been designed. The quality of the filtered water is viewed from physical and chemical parameters, both parameters are measured and observed directly at the Modern Physics Laboratory of the Faculty of Science and Technology and the Physical Chemistry Laboratory of the Faculty of Science and Technology. Based on the results of the study, it was found that the results of water quality in an automatic water filter with proof of two different samples showed that the water produced was not maximal because it had a high conductivity value and a pH value that was in the acid category. Because the water pressure that enters the filter media is too large it can stir / destroy the top layer of the filter so that the top filter cannot filter out impurities optimally.

Exploiting single photon vacuum ultraviolet photoionization to unravel the synthesis of complex organic molecules in interstellar ices

Complex organic molecules (COM) such as aldehydes, ketones, carboxylic acids, esters, and amides are ubiquitous in the interstellar medium, but traditional gas phase astrochemical models cannot explain their formation routes. By systematically exploiting on line and in situ vacuum ultraviolet photoionization coupled with reflectron time of flight mass spectrometry (PI-ReTOF-MS) and combining these data with infrared spectroscopy (FTIR), we reveal that complex organic molecules can be synthesized within interstellar ices that are condensed on interstellar grains via non-equilibrium reactions involving suprathermal hydrogen atoms at temperatures as low as 5K. By probing for the first time specific structural isomers without their degradation (fragment-free), the incorporation of tunable vacuum ultraviolet photoionization allows for a much greater understanding of reaction mechanisms that exist in interstellar ices compared to traditional methods, thus eliminating the significant gap between observational and laboratory data that existed for the last decades. With the commission of the Atacama Large Millimeter/Submillimeter Array (ALMA), the number of detections of more complex organic molecules in space will continue to grow ⿿ including biorelevant molecules connected to the Origins of Life theme ⿿ and an understanding of these data will rely on future advances in sophisticated physical chemistry laboratory experiments.

Citrus Quality Control: An NMR/MRI Problem-Based Experiment

An experiment seated in an industrial context can provide an engaging framework and unique learning opportunity for an upper-division physical chemistry laboratory. An experiment that teaches NMR/MRI through a problem-based quality control of citrus products was developed. In this experiment, using a problem-based learning (PBL) approach, students construct knowledge about the physical properties that make NMR and MRI possible, apply them to make decisions about experimental conditions, and write a final report in the form of a technical report for a fictional company. Implementation in a laboratory course demonstrated that the majority of students met the desired learning outcomes.

Integrating Chemistry Laboratory Instrumentation into the Industrial Internet: Building, Programming, and Experimenting with an Automatic Titrator

This project is designed to improve physical chemistry and instrumental analysis laboratory courses for undergraduate students by employing as teaching tools novel technologies in electronics and data integration using the industrial Internet. The project carried out by upper-division undergraduates is described. Students are exposed to a complete process of building, calibrating, and programming an automatic titrator using an open-source microcontroller platform and standard pH probes, and integrating the instrument into the Internet. The approach is flexible and can be used to enable integration of various laboratory instruments (e.g., temperature, pressure, salinity probes, etc.) into the industrial Internet. The hardware and software are open-source, which makes further modification and development by the academic community possible.

Resonance Energy of an Arene Hydrocarbon from Heat of Combustion Measurements.

A simple experimental method for determination of the resonance energy by measuring the energies of combustion for two isomeric compounds, aromatic 1-tert-butyl-3,5-dimethylbenzene and nonaromatic trans,trans,cis-1,5,9-cyclododecatriene is proposed. Both compounds not only have the same molecular formula, but also contain the same number of sp2 and sp3 carbon atoms. After converting the obtained values into the gas phase heats of combustion and subtracting one value from another, the resulting mean resonance energy of 184 kJ/mol was obtained. The proposed method can be offered as an experiment for an undergraduate physical chemistry lab curriculum.

Molar Mass and Second Virial Coefficient of Polyethylene Glycol by Vapor Pressure Osmometry

In this laboratory experiment, students determine the number-average molar masses and second virial coefficients of polyethylene glycol (PEG) polymers ranging in molar mass from 200 to 1500 g mol–1 using vapor pressure osmometry (VPO). Students assess VPO in relation to accurate molar mass calculations of PEG polymers. Additionally, students use the second virial coefficients to identify any PEG self-interactions and any dependence of the second virial coefficient on PEG molar mass. This laboratory experiment is suitable for a biophysical or physical chemistry laboratory.

Vibrational Spectroscopy of the CCl4 ν1 Mode: Effect of Thermally Populated Vibrational States

In our previous article on CCl4 in this Journal, we presented an investigation of the fine structure of the symmetric stretch of carbon tetrachloride (CCl4) due to isotopic variations of chlorine in C35Clx37Cl4–x. In this paper, we present an investigation of the contributions from both the v = 0 to v = 1 excitation and the v = 1 to v = 2 excitation. We report the calculation of spectral contributions from excited state vibrational transitions (hot bands). All calculations and discussion are appropriate for the undergraduate physical chemistry laboratory as either an independent dry lab or a supplement to a pre-existing vibrational spectroscopy lab.

Fabrication of Metal Nanoparticle-Modified Screen Printed Carbon Electrodes for the Evaluation of Hydrogen Peroxide Content in Teeth Whitening Strips

A laboratory experiment in which students synthesize Ag, Au, and Pt nanoparticles (NPs) and use them to modify screen printed carbon electrodes for the electroanalysis of the hydrogen peroxide content in commercially available teeth whitening strips is described. This experiment is designed for two 3-h laboratory periods and can be adapted for upper-division undergraduate students in instrumental analysis, materials science, or physical chemistry laboratories. The experiment presented has already been used as a hands-on component in a Functional Nanomaterials Course, which exposed students to the analysis of the electrochemical properties of metal nanoparticles. Moreover, it allows for teaching the basics of nanoparticle synthesis and enables students to learn the fundamentals of electrochemical sensing with nanostructured materials.

Tuning the surface microstructure of titanate coatings on titanium implants for enhancing bioactivity of implants

Biological performance of artificial implant materials is closely related to their surface characteristics, such as microtopography, and composition. Therefore, convenient fabrication of artificial implant materials with a cell-friendly surface structure and suitable composition was of great significance for current tissue engineering. In this work, titanate materials with a nanotubular structure were successfully fabricated through a simple chemical treatment. Immersion test in a simulated body fluid and in vitro cell culture were used to evaluate the biological performance of the treated samples. The results demonstrate that the titanate layer with a nanotubular structure on Ti substrates can promote the apatite-inducing ability remarkably and greatly enhance cellular responses. This highlights the potential of such titanate biomaterials with the special nanoscale structure and effective surface composition for biomedical applications such as bone implants.

Self-Assembled Monolayer Experiments in Undergraduate Laboratories

This talk will describe a junior/senior level undergraduate laboratory for analytical or physical chemistry that can be used to demonstrate how self-assembled monolayers (SAM) form and pack onto a surface. The laboratory experiment will also introduce students to electrochemical techniques, instrumentation and surface analysis techniques. This experiment uses both chronocoulometry to determine the surface area of an electrode as well as using reductive desorption to determine the surface coverage and packing of the SAM. Discussion of how molecules interact with the monolayers will also be discussed.

Observing Tin–Lead Alloys by Scanning Electron Microscopy: A Physical Chemistry Experiment Investigating Macro-Level Behaviors and Micro-Level Structures

Scanning electron microscopy (SEM) was introduced into undergraduate physical chemistry laboratory curriculum to help students observe the phase composition and morphology characteristics of tin–lead alloys and thus further their understanding of binary alloy phase diagrams. The students were captivated by this visual analysis method, which allowed them to more fully consider the relationship between macroscopic behaviors and microscopic structures of materials. During this process, the abilities of critical thinking were inspired, and a spirit of team work came into being.

X-ray Diffraction of Intermetallic Compounds: A Physical Chemistry Laboratory Experiment

Here we describe an experiment for the undergraduate physical chemistry laboratory in which students synthesize the intermetallic compounds AlNi and AlNi3 and study them by X-ray diffractometry. The compounds are synthesized in a simple one-step reaction occurring in the solid state. Powder X-ray diffractograms are recorded for the two compounds as well as for the elements Al and Ni, all of which have cubic crystal structures. The students analyze the measured spectra to determine both the type of cubic lattice present and the unit cell dimension for comparison with the literature. The experiment demonstrates the utility of X-ray diffraction for structure determination.

Vibrational Spectroscopy of the CCl4 v1 Mode: Theoretical Prediction of Isotopic Effects

Raman spectroscopy is a powerful experimental technique, yet it is often missing from the undergraduate physical chemistry laboratory curriculum. Tetrachloromethane (CCl4) is the ideal molecule for an introductory vibrational spectroscopy experiment and the symmetric stretch vibration contains fine structure due to isotopic variations of the molecule according to C35Clx37Cl4–x. We report simple theoretical predictions of the fine structure, calculation of Raman differential scattering cross sections, and discussion of the inherent asymmetry in the v1 mode resulting from the different isotopes of chlorine. All calculations and discussion are appropriate for an undergraduate physical chemistry laboratory as either an independent dry lab or a supplement to a pre-existing vibrational spectroscopy lab.

Measuring the Speed of Sound through Gases Using Nitrocellulose

Measuring the heat capacity ratios, γ, of gases either through adiabatic expansion or sound velocity is a well-established physical chemistry experiment. The most accurate experiments depend on an exact determination of sound origin, which necessitates the use of lasers or a wave generator, where time zero is based on an electrical trigger. Other experiments use loudspeakers as the sound source, which eliminates the ability to accurately measure time zero of sound generation. To date, experimental heat capacity ratio data have been reported for measurements at room temperature. We have designed an apparatus to directly measure the speed of sound generated as a result of nitrocellulose ignition via two microphones. Our experimental design also provides the ability to measure the speed of sound at various temperatures and thus determine the heat capacity ratio as a function of temperature. When implemented in a junior-level physical chemistry laboratory course, students learned to use equipment with which they were unfamiliar, such as home-built ignition circuits, a vacuum pump, thermocouple temperature and vacuum gauges, gas cylinders, and an oscilloscope. Students used the data to determine the speed of sound and heat capacity ratio through nitrogen, carbon dioxide, atmospheric air, and argon gases both at 298 K and approximately 253 K. Error analyses of the experimental speed of sound and heat capacity ratio using percent error and propagation of error were performed to ensure a high level of accuracy and precision.

Electrolysis for Colored Organic Wastewater Treatment——Introduction of a Comprehensive Experiment of the Physical Chemistry Laboratory

Electrolysis for Colored Organic Wastewater Treatment——Introduction of a Comprehensive Experiment of the Physical Chemistry Laboratory

TiO2‐Based Nanomaterials: Design, Synthesis, and Applications

(1) National Engineering Laboratory of Modern Silk, College of Textile and Clothing Engineering, Soochow University, Suzhou, China; (2) School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, China; (3) Kazuo Inamori School of Engineering, Alfred University, Alfred; NY, United States; (4) School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, Singapore; (5) State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China

Studying the Binomial Distribution Using LabVIEW

This undergraduate physical chemistry laboratory exercise introduces students to the study of probability distributions both experimentally and using computer simulations. Students perform the classic coin toss experiment individually and then pool all of their data together to study the effect of experimental sample size on the binomial distribution. Simulations of the coin toss experiment are also performed using the software package LabVIEW. LabVIEW facilitates the creation of complex computer programs in a short period of time, even by beginner programmers. Histograms in LabVIEW are displayed in real time with students adjusting the number of simulated coin tosses on the fly using a virtual knob or a slider, up to 1 million individual trials. This allows the students to see firsthand the evolution of the binomial distribution into the Gaussian distribution with a large sample size.