General Chemistry Laboratory Research Articles

Internet-Based Prelaboratory Tutorials and Computer-Based Probes in General Chemistry

A strong desire to upgrade the general chemistry laboratory program at Georgia Southern University (GSU) through greater use of more modern laboratory techniques led to an NSF-DUE grant (0088586) to purchase computers and interfaced analytical probes. Included in the project was a complete restructuring of many of the traditional laboratory experiments to utilize the new equipment and also the development of Web-based laboratory tutorials to better prepare students for the experiments and to ease the transition into use of the new technology. Immediate improvements could be seen with the addition of computers for data acquisition, spreadsheets for data analysis, and molecular modeling software. Furthermore, the use of the Web-based tutorials served to familiarize the students with the equipment and techniques involved in the experiment, reducing the anxiety associated with using previously unseen equipment and allowing students to begin with a greater degree of confidence. This has been very important for...

A General Chemistry Laboratory Theme: Spectroscopic Analysis of Aspirin

In this paper, we describe the introduction of spectroscopy into the general chemistry laboratory using a series of experiments based on a common substance, aspirin. In the first lab the students synthesize and recrystallize aspirin and take melting points of their product, an aspirin standard, and salicylic acid. The students perform the remaining experiments on a rotating basis where the following four labs run simultaneously: structural characterization of the synthesized aspirin by IR and NMR; analysis of synthesized aspirin and commercial products by UV–vis spectroscopy; analysis of synthesized aspirin and commercial products by HPLC; and analysis of calcium in commercial buffered aspirin tablets by AAS. In each of the analysis experiments, students collect, graph, and analyze their data using a spreadsheet. We have found that this series of labs has been very beneficial to our students. From the course evaluations, students indicate that they are beginning to understand how chemistry is applied outs...

A Photolithography Laboratory Experiment for General Chemistry Students

Photolithography is the primary means of pattern transfer used in the production of a multitude of microfabricated devices, including integrated circuits, microelectromechanical systems, and optoelectronic devices. The underlying photochemical process inherent to lithography is an attractive model system to introduce photochemistry, reaction kinetics, polymer chemistry, and materials science to a broader audience in a general chemistry laboratory setting. We report a second-semester general chemistry experiment in which students design and produce a photomask to pattern a silicon wafer using optical lithography. In addition to substrate patterning, students examine the reaction kinetics of the photobleaching process of the photoresist system using a UV–vis spectrometer operating in the kinetics mode. Both experiments introduce lower-division students to a technologically important industrial chemistry process and aid in understanding the topics of polymer chemistry and photochemistry.

Addressing the Professional Preparation of Future Science Teachers to Teach Hands-on Science: A Pilot Study of a Laboratory Model

Research has shown that even when students complete a chemistry degree program and the pedagogical course requirements necessary for teacher licensure, they may still graduate and begin teaching without a firm grasp of how to teach specific chemistry concepts. Although preservice secondary-level science teachers are required to take courses in pedagogy and learning theory, what is learned in a formal instructional setting does not appear to translate well to a laboratory setting. In response to these concerns, the Department of Chemistry and the Science Education program at the University of Central Florida undertook a collaborative pilot study during the Spring 2001 semester to jointly design and develop a laboratory-training course. The purpose of the course was to provide preservice secondary-level science teachers with the opportunity to explore the pedagogical possibilities of the teaching laboratory while gaining hands-on experience running a general chemistry laboratory. Outcomes of the pilot study...

Identifying a Protein by MALDI-TOF Mass Spectrometry: An Experiment for the Undergraduate Laboratory

Matrix-assisted laser desorption ionization time-of-flight (MALDI–TOF) mass spectrometry has become a valuable tool for performing routine biochemical analyses. A common procedure for protein identification involves using tryptic digestion to obtain masses of individual peptides derived from the protein. The masses are compared against an online database, and probability-based scoring systems are used to determine the closest protein matches. This article describes an experiment we have developed for an undergraduate honors general chemistry laboratory to introduce students to state-of-the-art mass spectrometric methods. Students are given an overview of the theory and instrumentation associated with MALDI–TOF, and gain hands-on experience with Internet tools for protein identification using mass spectral data. The experiment would be suitable for upper-division undergraduate laboratory courses as well; appropriate modifications for this purpose are also described.

A Colorful Investigation of a Diprotic Acid: A General Chemistry Laboratory Exercise

A general chemistry laboratory experiment that can be completed in a single laboratory period is described that familiarizes students with the acid—base chemistry of a diprotic acid and with the use of visible spectroscopy to determine species concentrations. This experiment is a modified version of a previously described laboratory exercise developed for an upper-division quantitative analysis course. Students work in teams and as a class to generate different ionization states of various highly absorbing dyes. Both spectroscopic and potentiometric (pH) data is collected using LabWorks II stations, but other inexpensive pH meters and visible spectrometers (e.g., Spec 20s) are suitable. A spreadsheet template is used to determine the percent composition of various ionization states of a diprotic acid and to determine the pKa values. Besides introducing students to fundamental tools and key chemical concepts, this laboratory is also inexpensive to operate and utilizes nontoxic, colorful solutions.

Building Bridges to Material Properties in General Chemistry Laboratories: A Model for Integration Across Disciplines

AbstractMany engineering students enter and exit general chemistry courses with little appreciation of chemistry's relevance to other fields. At WPI many of these students go on to take introductory materials science and arrive with poor attitudes about chemistry and little retention of key concepts, but then become more engaged as they discover connections to engineering applications. Consequently, instructors in chemistry and mechanical engineering collaborated to augment general chemistry laboratories with explicit “bridges” to material properties and applications. Evaluation results showed that while students' attitudes toward chemistry were unaffected by bridging, particular aspects of the students' lab experience were enhanced to a statistically significant degree. Similar cross‐disciplinary collaborations might be considered elsewhere as a means of helping students find meaning and integrate subject matter, in a manner that is more feasible than large‐scale course or curriculum restructuring.

LIMSport: Optimizing a Windows-Based Computer Data Acquisition and Reduction System for the General Chemistry Laboratory

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLIMSport: Optimizing a Windows-Based Computer Data Acquisition and Reduction System for the General Chemistry LaboratoryEd Vitz and Brenda P. Egolf View Author Information Department of Chemistry, Kutztown University, Kutztown, PA 19530 Center for Social Research, Lehigh University, Bethlehem, PA 18015Cite this: J. Chem. Educ. 2002, 79, 9, 1060Publication Date (Web):September 1, 2002Publication History Received3 August 2009Published online1 September 2002Published inissue 1 September 2002https://doi.org/10.1021/ed079p1060RIGHTS & PERMISSIONSArticle Views71Altmetric-Citations-LEARN 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 (66 KB) Get e-AlertsSUBJECTS:Cross-disciplinary concepts,Redox reactions,Students,Transfer reactions Get e-Alerts

The Making of a Solution: A Simple but Poorly Understood Concept in General Chemistry

A primary goal in many general chemistry laboratories is to teach students to properly perform dilutions and make solutions. This article presents a simple exercise to test if your students have acquired this ability from their introductory laboratory exercises. Our results indicate that approximately 50% of the students cannot perform this task on their first attempt, but with guidance and additional attempts their success rate improves. Approximately 30% of the students still fail at this task after additional attempts, but this exercise does improve the laboratory technique of all students. Students used a variety of dilution strategies to achieve the same final concentration; but the most common strategy used by the students was the one deemed most logical by the professors.

Structure and Nuclear Magnetic Resonance. An Experiment for the General Chemistry Laboratory

We have developed an experiment that introduces freshman chemistry students to NMR. Students are trained to work on the instrument, analyze 1H and 13C spectra, and identify simple organic molecules. They are also introduced to the idea of functional groups and they use concepts learned in class about Lewis structures to distinguish among spectra of isomers of C3H8O. As part of this exercise students submit written reports and complete a survey evaluating the experiment. The lab experiment, survey results, and findings are presented.

PDAs and Lab Works?A New Way to Make Chemical Measurements

Computer-controlled data acquisition is rapidly becoming the rule rather than the exception in general chemistry laboratories. The LabWorks learning system is one of many computer-controlled data acquisition interfaces that allow students to quickly obtain and analyze chemistry data. This article explains how communication is established between a personal digital assistant (PDA) and the LabWorks interface. This project continues work previously accomplished using an HP 48 calculator to communicate with the LabWorks interface. The PDA has more computing power, more storage ability, and the Windows CE operating system provides a more user-friendly interface than the handheld graphing calculator. Sample experimental data is provided as an example of how this LabWorks/Palm PC combination can be applied to inexpensively enhance laboratory learning.

Aligning General Chemistry Laboratory With Lecture at a Large University

The laboratory and lecture components of general chemistry are commonly offered as two separate courses, with lecture typically meeting two or three times per week and laboratory scheduled to meet only once per week. The concepts, content, and relationships presented in lecture may be disjointed and asynchronous with respect to those encountered in laboratory experiments. In addition, traditional laboratory experiments tend to be confirmation labs, in which students are aware of the “right” answer before beginning the lab. Students enrolled in a specific lecture section do not necessarily meet for the same laboratory section. As such, learning experiences in laboratory do little to help the students construct an understanding of chemical concepts, content, or relationships. The goal of this project was to develop an inquiry‐based approach to curriculum and instruction in first‐semester general chemistry at the University of North Carolina at Charlotte. A major objective of the project was to develop a laboratory curriculum that meshes intimately with lecture. This objective was accomplished by (a) creating a laboratory course that met for 80‐minutes twice a week immediately following the lecture, (b) involving students in laboratory experiments that related to the material presented during lecture, and (c) using laboratory observations and data in lecture to help students construct an understanding of chemical phenomena.

The Visible Spectrum of Liquid Oxygen in the General Chemistry Laboratory

General chemistry experiments that address one or more aspects of molecular orbital theory are scarce. The measurement and interpretation of the visible spectrum of liquid oxygen fills this gap and extends molecular orbital theory described in the typical course. With some guidance from the instructor, students test three energy-level diagrams (hypotheses) to find the one that fits the measured spectrum.Hazard: Liquid oxygen poses a safety hazard. See J. Chem. Educ. 2003, 80, 486.

Web-Based Data Analysis and Feedback for General Chemistry Laboratory: Improving Analysis with Timely, Distance Feedback

ABSTRACTIn a general chemistry course, while the hands-on experience of the laboratory is important, the goals of the laboratory are not fulfilled until the calculations and analysis are complete. Quite often students are capable of following laboratory instructions and generating excellent data, only to fail in the data analysis, which rarely occurs in the confines of the laboratory or the presence of the instructor. All too often, students are unable to learn important information from the interpretation of experimental results and draw correct conclusions because they make calculational errors, which are most often discovered by the instructor in the grading process. There is an opportunity for distance learning to help bridge the gap between collection of data and its correct analysis. At the United States Naval Academy (USNA), we have developed a Web-based system where the students input their data and calculational results into a web form with immediate feedback. The students are then allowed to correct their errors and resubmit. This system has been in successful use for 5 years. A description of a typical experiment will be discussed along with an assessment of student and faculty satisfaction with the program.

Using the Science Writing Heuristic to Move toward an Inquiry-Based Laboratory Curriculum: An Example from Physical Equilibrium

Despite the importance placed on laboratory work in the undergraduate chemistry curriculum, there have been few research studies showing that laboratory experiments are an effective vehicle for promoting understanding of chemistry. Laboratory activities that are inquiry-based have been reported to have potential for improving the pedagogical value of laboratory work. This study compared the performance of general chemistry laboratory students who used the standard laboratory report format to the performance of students who used the Science Writing Heuristic (SWH) format on a lecture examination problem and on a laboratory practical examination task involving physical equilibrium. The standard laboratory reports had title, purpose, procedure, data and observations, calculations and graphs, and discussion sections. The SWH reports had beginning questions and ideas, tests and procedures, observations, claims, evidence, and reflection sections. Students in the SWH sections exhibited a better understanding of equilibrium when written explanations and equations were analyzed, performed slightly better on the equilibrium practical exam task, and spent less time completing the SWH laboratory reports than students in the standard sections. SWH instructors spent less time scoring reports of their students. The SWH was shown to be a feasible mechanism for gradually modifying the laboratory curriculum to reflect inquiry-based learning.

Relating Qualitative Analysis to Equilibrium Principles

Qualitative analysis in the general chemistry laboratory provides an excellent opportunity to help students make connections between ionic equilibrium topics covered in the lecture course and physical reality. Although laboratory manuals generally provide ample discussion of the equilibrium principles upon which the procedures are based, students' attention tends to be focused mostly on techniques, the reactions involved, and physical observations. A lack of understanding of the underlying principles often results in students being unable to make simple modifications to the procedure. This Mathcad document is intended to be used in a prelab activity for qualitative analysis experiments (based on modules ANAL364-366 of the Modular Laboratory Program in Chemistry, Palmyra, PA 17078), which are done toward the end of the general chemistry laboratory course at Nicholls State University. Mathcad is introduced at the beginning of the course and is routinely used throughout the semester for data analysis; handouts for these activities are available. The students are therefore quite competent in Mathcad by the time this activity is conducted. Students are given an incomplete Mathcad document (Qual6.mcd), which they complete as they explore the subject. An exemplary, completed document is available for instructors (Qual6a.mcd).

Analysis of Zinc Tablets: An Extension to a Stoichiometry Experiment

Using a titration, students can determine the stoichiometry of the reaction between zinc ion and ferrocyanide ion. The technique can then be used to determine the concentration of zinc ion or ferrocyanide in unknown solutions or the amount of zinc ion in commercially available tablets. The experiment teaches many important general chemistry laboratory techniques, such as preparation of standard solutions and quantitative use of pipets and burets. The application of solution stoichiometry calculations provides an important link between lecture and the laboratory.

Metal Complexes of Trifluoropentanedione. An Experiment for the General Chemistry Laboratory

The transition-metal complexes produced by the reactions of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), and Cu(II) with 1,1,1-trifluoro-2,4-pentanedione form the basis of this general chemistry laboratory exercise. The complexes can be prepared quickly in 40-60% yield from 150 mg of the metal nitrates. Mass spectroscopy is used to determine the stoichiometry of the reaction products. GCMS is used to show that two isomers result from the formation of the octahedral complex Cr(tfac)3. The end result is a brief survey of the reactions of these first-row transition metals.

Observations on Lemon Cells

The lemon cell, consisting of pieces of two different metals stuck into a lemon or other fruit, is pictured in many general chemistry textbooks without being discussed. We describe simple experiments, suitable for the general chemistry laboratory, which elucidate how this kind of cell works. They show that (i) the cell is not two metal-metal ion half cells, and (ii) the cell reaction involves dissolution of the more active metal and generation of hydrogen on the less active metal. Why the cell works this way is explained, and the cell's historical importance is discussed.

A Strategy for Incorporating Hands-On GC-MS into the General Chemistry Lecture and Laboratory Courses

Simple laboratory experiments employing mass spectrometry can be used to clarify the differences between the masses of the various isotopes of an element and the atomic mass of the element. As an introductory experiment, students use the GC-MS to obtain spectra of the various halobenzenes. This vividly illustrates the differences in isotopic distributions of the halogens and the complications these differences present in calculating molar masses of compounds. The isotopic distribution of iron is then obtained from the mass spectrum of Fe(CO)5, a volatile liquid, and the students calculate the atomic mass of iron from this data. If the spectrometer is equipped for injection of volatile solids, the mass spectra of other volatile metal carbonyls (chromium, molybdenum, tungsten, etc.) can be obtained and their atomic masses calculated. Alternately, data from the NIST (National Institute for Standards and Technology) mass spectral database can be used.